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LA-3449UC-41 , HEALTH ANDSAFETY

LOS ALAMOS SCIENTIFIC LABORATORYof the

University of CaliforniaLOS ALAMOS, NEW MEXICO

Report written: January 1968Report distributed: April 1968

Environmental Effects of the Kiwi-TNT Effluent:

A Review and Evaluation

by

R. V. Fultyn

CONTENTS

I.

II.

III.

N.

v.

VI.

VII.

vm.

IX.

x.

la.

Abstract

Foreword

Tntrcduction

The Experimental Plan

The Weather

The Reactor Eruption

The Recovered Debris

Proximate Nuclear Radiation Measurements

The Cloud Growth and Ascent

The Cloud Wake

The Radiological Composition of the Cloud

The Impact on the Neighborhood

Conclusions

Appendix

Page

iv

1

1

2

4

12

13

22

36

39

58

60

65

67

. ..Ill

The Kiwi Transient Nuclear Test (Kiti-TNT) was a controlled excursionin which reactivity was inserted into a nuclear rocket engine prototype fastenough to vaporize a significant portion of the reactor core. The test studiedthe neutronic behavior of the reactor and the enviromnental effects of theradioactive materials released. This report discusses in detail only the de-termination of environmental effects.

The test was conducted at the Nuclear Rocket Development Station,Jackass Flats, Nevada, on January 12, 1965, at 1058 PST. The Los AlamosScientific Laboratory collected environmental data from the test point to ap-proximately 50 miles downwind. The U.S. Public Health Service monitoredthe neighborhood and collected milk samples in southern Nevada and Californiato beyond 200 miles downwind. The course of the effluent cloud was trackedby aircraft from the U. S. Public Health Service and EG&G.

From 5 to 2Q% of the reactor core was vaporized, with approximately67% of the products from about 3 X 1020 fissions released to the effluentcloud. Radiation effects from the cloud passage were less than predicted in thepretest safety evaluation report. The maximum off-site, integrated, whole-bodyexposure was 5.7 mrad about 15 miles from the test point. No fresh fissionproducts were detected in any of the milk samples.

iv

FOREWORD

me principal concern of this report is to summarize and interpret allavailable data concerning the environmental effects of the Kiwi Transient Nu-clear Test (Kiwi-TNT). In addition to data obtained by the Los AlamosScientific Laboratory (LASL), the report includes summaries of data collectedby other participating agencies, notably the U. S. Public Health Service(USPHS), the U.S. Weather Bureau (USWB), EG&G, Inc., and Pan Americ-an World Airways, Inc. This report collects under a single cover all thesignificant information about the environmental effects. Pertinent data andfigures from referenced works are reproduced in this report to enable thereader to understand the overall interpretation of environmental effects. Someof the original reports received only limited distribution and their availabilitytvill decrease with time; the interested reader is referred to the source reportsfor fuller treatment of sampling, measurement, and analytical techniques andfor details of the neutronics and mechanical aspects of the experiment.

1. INTRODUCTION

The Kiwi Transient Nuclear Test (Kiwi-TNT) was a controlled power excursion in whichreactivity was inserted into a nuclear rocket en-gine prototype at an unusually high rate cal-culated to vaporize a significant portion of thereactor core. The objectives of this simulated re-actor accident were to examine the material andneutronic behavior of the reactor and to studythe effects of the radiation and radioactive ma-terials released.

The reactor, including the core and pressurevessel, was, with few exceptions, a typical, latemodel Kivvi-B4. The nozzle was replaced with amirror apparatus that permitted high-speedphotography of the core top during the test. Cool-ant supply piping to the reactor shell was re-moved because no hydrogen coolant-propellantwas used. A point worthy of emphasis is that toachieve a reactivity insertion rate sufficient tovaporize a significant fraction of the core, thecontrol rod mechanisms were modified to rotateat approximately 100 times the normal rate.

The reactor core is extremely refractory, de-signed for normal operation above 2,000”C. Evenin normal operation, the core materials are in-candescent, and any abnormal operation thatcauses structural damage, so that core materialsare expelled from the reactor by the exhaustedcoolant, produces a shower of sparks. In earlytests, before many structural problems weresolved, some fuel elements broke and were ejectedfrom the nozzle with the exhaust gases. Thisspectacle resembled a Roman candle. Therefore,

in an experiment of the Kiwi-TNT type, it wasapparent that the released vapor would be in-candescent. Except for the pressure vessel normal-ly used with a Kivvi reactor, the core was un-shielded and uncontained; therefore, all vaporizedand pulverized materials would be immediatelyreleased before any appreciable cooling could takeplace.

A few months before the test, the best neu-tronics estimates indicated that the excursionwould produce approximately 9 X 1020 fhsions,with approximate] y 1.8% of the core being vapor-ized, assuming that the carbon vapor was mono-atomic, and would release the products from ap-proximately 4 X 1020 fissions. A few days beforethe tes~ these estimates were revis~d to approxi-mately 36~o of the core vaporized and 75 ~. of thefission products released, or the products fromapproximately 7 X 1020 fissions. There was nofission-product inventory in the reactor at thetime of the test. As discussed later, the excursionproduced 3.1 X 1020 fissions, 5 to 20~o of thecore was vaporized (assuming monoatomic car-bon vapor), and approximately 67% of the fis-sion products were released in the effluent cloud.The total energy release was about 1 X 104 MW-sec; an estimated 1‘~ was kinetic energy. Nor-mal runs of this type of reactor produced a maxi-mum of about 5 X 106 MW-sec of energy.

Details of the neutronics and mechanical as-pects of the experiment are given in References1-4.

I

1

II. THE EXPERIMENTAL PLAN

The test was conducted at the NucIearRocket Development Station (NRDS), JackassFlats, on January 12, 1965, at 1058 PST. Figure1 shows the topography of the test point anddownwind terrain out to approximately 50 tiles.Jackass Flats and the Amargosa Desert form aflat plain, bordered by mountains, which slopesgently down to the southwest for about 30 milesfrom the test point. Death Valley, California, isapproximately 50 miles from the test point. TheLASL sampling array covered this entire area;the more distant stations are also shown in Fig. 1.

The weather requirements for the test werenortheasterly winds in excess of 5 mph blowingtoward 240° * 20°, neutral to slightly unstablevertical temperature profile, nearly clear skies,and a reasonable certainty of persistence of theseconditions to ensure that the effluent cloud wouldtraverse the entire instrumented array.

For cloud sampling, LASL trailer-mountedequipment was located at approximately 10° in-tervals between i 80 and 270° on arcs at 4,000,8,000, and 16,000 ft, and at 6, 12, 25, and 50 milesfrom the test point. A typical sampling trailercontains an engine-driven generator, one or morehigh-volume air samplers with filter paper andcharcoal cartridges as collection media, a cascadeimpactor for particle size measurement, and a setof cycling, high-volume samplers with filter papercollectors for timing cloud passage. The trailersare radio-equipped so that sampling equipmentmay be started and stopped remotely. Resin-coatedtrays for the collection of deposited activity wereplaced on stands near the trailers at each samplinglocation. Stations for collecting cloud depositionactivity and reactor debris extended from 100 to2,000 ft from the test point.

‘Collectors for particles and fragments ofnear-microscopic size consisted of resin-coatedMylar film on special frames, which also heldlarge sheets of x-ray film for autoradiography ofcollected particles. After the event, the MyIarfilm was examined visually and microscopicallyto characterize the collected particles. The auto-radiographs helped to distinguish the radioactiveparticles from desert dust. Specially mountedgroups of microscope slides were placed with theMylar films to provide samples for microscopicexarh.ination and analysis. Approximately half ofthese close-range stations also contained large,4 X 4 ft funnel-shaped hoppers to collect frag-ments large enough to separate by sieving. To

%

correlate data between close- and long-rangeactivity deposition, resin-coated trays identical tothose used at the extended range stations werepIaced at 50 intervals around the reactor at dis-tances of 500, 1,000, and 2,000 ft. The test pointwas on a railroad culvert damming a wash ap-proximately 500 ft wide and 30 ft deep. Thus,many of the short-range stations were at levelsbelow the reactor.

The Southwestern Radiological Health Labo-ratory (SWRHL) of the USPHS provided off-site radiation surveillance by aerial tracking ofthe effluent cloud, monitoring radiation dosageof the off-site population, and collecting environ-mental samples in southern Nevada and Cali-fornia. Twelve ground monitoring teams equippedwith portable instruments tracked the cloud pas-sage. Dose-rate recording instruments were placedat eight downwind locations bracketing the antici-pated path of the effluent cloud. Film badges wereissued to 157 people in Lathrop Wells, &-nargosaDesert, and Death Valley. Forty-five routine airsamplers were operated in Nevada, Utah, Arizona,and California, supplemented by 18 samplers atanticipated downwind locations. All these high-volume air samplers were equipped with filterpapers and charcoal cartridges.

An Air Force U3-A aircraft carrying twoUSPHS monitors tracked the reactor effluent andassisted in positioning ground monitors. Twoother PHS aircraft containing sampling equip-ment were used in cloud tracking, although theirprimary purpose was to determine cloud size andinventory.

Following the test, 74 milk samples were col-lected from two ranches in the Arnargosa Desertand from 14 locations in southern California. Themilk sampling program continued for approxi-mately a week. Vegetation samples were obtainedat most milk sampling locations; attempts weremade to make these representative of the cows’feed but the forage samples were taken primarilyas early indicators of areas of milk contaminationrather than to yield cow intake-excretion data.s

An aircraft of the Nevada Aerial TrackingSystem, manned by EG&G personnel, tracked theeffluent cIoud from Death Valley over the LosAngeles area and terminated contact over thePacific Ocean.8

Neutron and gamma radiation measurements

3

were obtained by LASL by methods used in otherKiwi reactor tests. Neutron integral fluxes anddoses were determined by threshold detectors con-sisting of 23DPu, ‘37Np, and 23SU fission foilscomplemented by gold and sulfur activation de-tectors.? Gamma doses were measured by gamma-sensitive glass dosimeters and by dosimetry films.Combinations of these detectors were positionednear the reactor to measure the prompt radiation.Dosimetry films were placed at all cloud samp-ling stations downwind to indicate gamma dosesfrom the radioactive effluent cloud and subse-quent deposited activity. Gamma dose-rate de-tectors with remote readout equipment wereplaced around the test point, but concentrateddownwind, out to 8,000 ft. Ahhough the dose-rate instruments were inadequate to measure

prompt radiation, they were useful in determiningthe decay of activity deposited around the testsite.

For several days after the test, radiation sur-veys of the area were made by monitors fromLASL and the Radiation Services of Pan AmericanWorld Airways, Inc.; isodose rate contours weremade from these hand-held instrument surveys tofollow the decay of the deposited activity.

During decontamination of the test pointarea, recovered reactor fragments were placedin containers marked to indicate where they werefound. After all locatable fragments had been re-covered, they were sorted by size distribution andlocation. ‘$

Ill. THE WEATHER

The material in this chapter is largely fromWBRS-LA-9, “Analysis of Meteorological Data forthe Kiwi-TNT Reactor Test” by Mueller andWilson.10

The weather at the time of the test fulfilledthe desired conditions in every respect: it wasclear. windy, and mild. The winds were north-easter y at all levels, ranging from 14 to 27 knots.Persistent northeasterly winds were the result ofa surface high-pressure cell centered over easternOregon. South of this high, a“ fairly strong pres-sure gradient over Nevada helped prevent surfacewinds from turning toward the northeast, as fre-quently results fro,m daytime surface solar heat-ing. In addition, a pressure ridge over the PacificNorthwest, combined with a weak low off BajaCalifornia, produced the desired northeasterlywinds over NRDS. Synoptic charts of these con-dit ions are shown in Fig. 2.

Temperature soundings made at the NRDSweather station a few minutes after run time,and in the Amargosa Desert at about the time ofcloud arrival, were similar. The lapse rate wasunstable near the surface, nearly neutral up toapproximately 9,000 ft MSL, and more stableabove that height. These temperature profiles areshown in Fig. 3.

L’pper-air data for Jackass Flats and the Amar-gosa Desert shortly after the test are listed inTable I. Table II gives winds-aloft data from fivestations near the test point for several hours be-fore and after the test. Fallout holographs madefrom these data and plotted from the test pointusing Jackass Flats data for i 100 PST, and from

Lathrop Wells using its 1115 PST data are shownin Fig. 4. Air trajectories plotted from these andother wind data for 5,000. 7,000, and 9,000 ftMSL are shown in Fig. 5. The theoretical tra-jectories of the lower levels correspond well withactual trajectories constructed from aircraft track-ing data, as can be seen by comparing Fig. 5 withFigs. 52 and 53. The smaI1 amount of shear inthe lower winds (approximately 10° up to 2,500ft above the surface) led one to expect a narrowcloud and deposition sector, with a centerlinebearing of 215°. At higher altitudes the shear in-creased. to about 250, and a centerline bearing of220° was suggested. These expectations were con-sistent with the cloud and deposition patterns con-structed from sampling data, as discussed inChapter VIII.

Two constant-level balloons (tetroons), re-leased from the NRDS weather station at i 035and 1133 PST on the day of the run, were trackedfrom the Lathrop Wells radar station and werefirst contacted approximately 6 miles from therelease point. They were inflated to fly at 5,000to 6,000 ft MSL, but considerable fluctuation inheight occurred because of up- and downdrafts.The tracks of the tetroons plotted in Fig. 6 havebeen shifted about 2 miles to the west to simulatea release from the test point. This is considered tobe valid because wind soundings from variousstations in the area were similar at this time. Thetracks were similar for about 15 miles south ofthe test point. Both balloons traveled this distancein about 40 minutes. Beyond this distance thetracks diverge, but both tetroons remained overareas where radioactive material from the effluentcloud was collected by ground-level samplers.

4

1024

1020

102

‘RESSURE VALUIN MILLIBARS

Ja2s2SURFACE ANALYSIS

7000 FOOT MSL STREAMLINES

SECOND STANOARO LEVEL STREAMLINES

9000 FOOT MSL STREAMLINES

Fig. 2. Me&orological conditions atl~PST, Janua~ 12,1965.

5

JACKASS FLATS1118 PST, 1-12-65

I I I I I

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TEMPERATURE (“C)

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AMARGOSA DESERT1200 PST, 1-12-65

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TEMPERATURE(”C)

Fig.3. Temperature soundinga.

7[$1 U&u

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L.?.- W.LL8

NEIGHT IN FEET X 10-3 MSL

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Fig. 4. 1100 PST NRDS and 1115 PST Lathrop Wells holographs, January 12, 1965.

6

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Fig. 5. Air

wcAT~LLO

----~...

13/0700 PST9000 FT. MSL

LEvEL

trajectories, January 12, 1965.

TUT Cu.u

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LATH- Wcus

7000’ M&; /

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—1133 PST\

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UL~\.

Fig. 6. Tetroon tracks.

?

TABLE I. UPPER-AIR DATA

Jackass Flats, 1118 PST, 1/12/65

RelativeHeight Wind Pressure Temperature Dew Point Humidity

(Ft. MSL) (Deg/Kt) (w) (“c) (“c) (%)

SFC 36154QO04800500060007000800086309000

10000100851100012000126501300013780140001!5000160001700018000

9600”28303000400050005030!539060007000800090009200

100001010010150! 100012000122001300014QO0150001600017000

020/1 8020/19030/22030/22020/18020/1 7030/16040/15040/14030/15030,/16030/1 7050/19050/23060/24060/26060/26060/27060/26050/26050/23

893880855850818788759740730704700676648632624606600576553531511

12.711.0

7.47.04.11.5

-1.4-3.2-3.6-5.0-5.1-6.4-7.9-8.8-9.5

-11.0-11.7-14.1-16.6-19.2-21.7

Arnargosa Farm Road, 1200 PST, 1/12/65

330/20330/19330/1934Q/17350/17350/16350/15360/12030/10050/12050/17050/17040/21040/21040/21050/23060/25060/26066/!28

‘060/29060/27060/27060/27

929919916883851850837820789759731725704702700679652646626602578556534

16.014.113.810.5

;::5.64.11.8

-0.7-3.0-3.6-3.8-3.8-3.9-4.9-6.1-6.5-8.3

-10.6-12.7-15.3-17.8

-!.!-3.8-3.5-4.4-5.2-6.6-7.5-8.2

-11.0-11.3-13.7-17.0-18.9-Z1 .2-27.2

MB

2.80.0

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TABLE IT,

Height(fty MSL)

Surface

3000

4000

5000

6000

7000

8000

9000

1000o

i 1000

12000

13000

14000

15000

Surface

Sea Level

1000

2000

3000

4000

5000

6000

7000

8000

9000

10000

11000

12000

13000

144)00

15000

CONTINUED

Death Valley Junction, 1/12/65 (Pibal Measurements)

0800

340/15

350/29

360/27

020/23

030/23

040/22

050/22

050/20

060/19

050/21

040/21

040/18

040/15

030/15

166/03

100/05

350/10

350/14

360/1 7

010/17

030/13

030/12

050/14

050/16

050/18

050/19

050/19

050/20

060/20

050/21

050/23

0900

345/18

360/25

010/27

020/26

040/23

050/20

060/18

050/1 7

050/1 7

0!50/16

050/14

040/14

040/14

044)/13

1000

340/20

360/25

010/25

030/24

050/24

050/21

050/20

050/1 7

04)//16

050/18

050./20

050/20

060/20

060/16

1100

340/20

350/25

010/27

020/27

040/23

050/19

060/16

070/16

060/14

060/12

050/15

050/18

050/23

050/27

1200

345/1 8

360/28

010/29

030/21

050/19

060/14

070/09

090/07

090/07

070/1 o

070/14

060/21

—

—

1300

340/15

350/20

360/20

020/18

020/22

030/24

040/19

060/12

080/09

090/08

070/11

060/2Q

060/28

060/30

Furnace Creek, 1/12/65 (Pibal Measurements)

170/05

360/05

010/06

350/1 1

350/12

360/12

030/13

050/16

050/1 7

04Q/18

030/19

050/20

060/21

060/21

060/20

060/17

060/14

210/10

025/10

035/12

360/15

360/13

360/1 1

360/10

020/12

030/16

040/1 8

04Q/18

050/18

060/1 8

060/1 8

060/19

0$0/19

060/19

114/10

020/10

340/10

340/12

340/10

350/1 1

010/15

020/20

030/17

040/15

050/14

040/14

050/16

060/1 8

060/22

060/25

060/26

Ii

271/04

030/07

350/11

360/12

350/13

360/15

010/1 7

020/1 7

040/15

050/12

050/12

050/14

060/1 8

060/22

060/25

060/24

060/24

218/06

030/08

340/17

343/19

350/19

360/19

020/1 9

030/13

040/09

070/09

070/12

030/15

060/21

070/24

070/24

070/25

070/26

1400

340/18

340/18

350/18

010/19

020/21

030/21

040/1 7

060/14

090/12

090/13

080/1 7

070/24

060/30

060/31

348/20

343/21

330/21

330/19

330/18

350/15

360/12

010/05

020/18

050/19

050/21

060/19

070/18

070/20

070/23

070/26

070/26

1500

—

—

—

—

—

—

—

—

—

—

—

—

—

320/22

330/21

340/20

350/22

350/22

360/18

360/18

010/17

030/16

060/16

080/1 7

080/15

070/1 7

070/24

070/27

070/27

070/27

IV. THE REACTOR ERUPTIONThe matetial in this chapter is largely from

LA-335 1, “Kiwi-TNT Explosion,” by Reider.11

The Kivvi-TNT reactor was “exploded” inthe sense that it was a violent disruption and dis-persion of an originally intact object. It blew upin an unusual fashion resembling neither a typi-cal nuclear detonation nor most types of chemicalexplosions. To give a better understanding of theeruption, its characteristics wdl he compared tothose of more common explosions.

The deflagration accompanying the Kiwi-TNT excursion was the result of rapid vaporiza-tion of part of the carbon-uranium-carbide core.The pressure VS. time relationships in the Kiwi-TNT event were unusual, but not unique. Theyare most nearly approximated by the explosion ofblack powder, one of the few explosive materialsthat acts by exothermic chemical reaction ofphysically mixed reactants rather than by exo-thermic decomposition of a chemical compound.The Kiwi-TNT energy release was physical inorigin rather than chemical, however. The vapor-ization occurred too fast for the resultant gas toescape through the reactor interstices, pressurequickly built up in the core until it exceeded theyield strength of the pressure vessel (a feyvthousand psi), and the vessel burst with explosiveviolence. The time required for this peak pressureto occur is estimated to be about 1 msec. In con-trast, the production of gas required to release anequivalent energy during detonation of high ex-plosives such as trinitrotoluene or nitroglycerinis much more rapid, requiring perhaps a twentiethof the time needed to vaporize a part of the Kiwi-TNT core. On the other hand, deflagrations ofgas-air mixtures at atmospheric pressure and ex-plosions involving organic dusts are much lessviolent than the Kiwi-TNT even~ demonstratingpressure rises of only a few psi/mseco

From the nature of recovered reactor frag-ments, one can conclude that the Kiwi-TNT eventresembled a deflagrating explosive such as blackpowder, rather than a detonating or brisant onk,such as trinitrotoluene, or a slower reaction suchas occurs during explosions of gas-air mixtures.The Kiwi-TNT excursion produced a shower ofincandescent sparks rarely seen in anything buta pyrotechnic display. Fragments of various sizesand weights were thrown as far as 2,000 ft, witha distribution similar to that from chemicaI highexplosives. However, unlike missiles from chemi-cal high explosives, which experience an almostinstantaneous pressure rise from the detonation

wave, these fragments did not show extensiveshredding and stretching. Missiles from dust oratmospheric gas-air mixture explosions would havebeen larger, with less shredding and stretchingthan those of the Kiwi-TNT test, and they wouldnot have traveled so far. Boiler explosions usuallyproduce only a few large missiles from compon-ents, coming apart at their seams. Explosions ofcombustible gas mixed with oxidant at high pres-sures, such as high-pressure oxygen contaminatedwith hydrocarbons, would have missile patternsmore nearly like those of Kiwi-TNT.

The thermal release and the extremely hightemperatures occurring during the excursion areresults associated almost exclusively with nuclearreactions. The charring of wooden poles as faraway as 70 ft and the brilliant mass of hot, burn-ing graphite are phenomena not usually seen inexplosions. Brightness is a function of temperatureand emissivity, and carbon at or above its vapori-zation temperature of 3,900° K is an efficientemitter, in contrast to other explosive products.High explosives detonate rapidly, but they arepoor heat sources and essentially undergo exo-thermic decomposition without producing hightemperatures; they usually go from the solid orliquid to the gaseous phase without much burningand usually without scorching nearby objects.Dust explosions do not have a very high energydensity and are not very bright. Gas explosionsdo not scorch things very much even if the mix-ture is fuel-rich.

Overpressures and blast effects associatedwith the Kiwi-TNT event must be compared tothose of high-explosive detonations, even thoughthe phenomena differ in many respects, becausehigh-expkxive effects are the only ones whichhave been adequately quantitated for comparison.Two blast gauges 100 ft from the Kiwi-TNTevent gave readings of 3 and 5 psi. The lowerreading could have come from a surface burst ofa 125-lb hemisphericzd charge of trinitrotoIuene,and the higher reading from a 300-lb charge ofsimilar shape. Corrugated metal buildings 600 to700 ft away, designed to withstand 100-mphwinds, showed no sign of damage. None wouldbe expected following the explosion of about 100lb of trinitrotoluene, but a 300-lb charge mighthave affected them. The walls of several officetrailers 800 to 1,000 ft from the test point had de-flected, throwing many wall fixtures to the floorbut no permanent deformation was evident. Afew, but not all, of the windows, even in thefacing walls of the closest trailer, were broken,

12

—

I

These effects are consistent with those of an ex-plosion of approximately 100 lb of trinitrotoluene.b examination of the test point after the ex-periment showed evidence not typical of a high-explosives accident. Although it was not com-pletely inconsistent with the explosion of about100 lb of trinitrotoluene, it was certainly incon-sistent with one involving significantly more, say300 to 500 lb. In the latter case, one would ex-pect more sweeping away of the debris beneaththe explosion, and possibly even cratering, whichdid not occur. Therefore, it can be concluded thatthe Kiwi-TNT blast was roughly equivalent tothat from the detonation of 100 to 150 lb oftrinitrotoluene.

From the effects discussed above, an estimateof the possible nonrad.iation hazards to anyone inthe vicinity of the excursion is as follows: every-one within 100 ft of a IGwi-TNT deflagrationwould be seriously or fatally injured by blast,thermal burns, missiles, physical displacement, orany combination thereof. Thermal burns wouldprobably be the most significant cause of injury.

Overpressure from the blast would not be serious-ly injurious to a person beyond 50 ft unless itphysically displaced him. Between 100 and 250 ftthere would be a significant number of bodily in-juries, possibly to 1 in 4 persons, but few injurieswould be serious or fatal. Probably no more thanfirst-degree burns would occur. Blast damagewould be minimal. The most common injurieswould be from missiles and physical displacement.At 250 ft the probability of being struck by asmall core fragment would be about 1 in 8, butthe probability of injury would be less than 1 in100. No harm would result from blast. Thermalburns would be minimal. The peak overpressuremight knock a person over but would not accele-rate him enough to do appreciable harm. Beyond500 ft there would be a chance of no more than1 in 1,000 of being injured by a missile, althoughthe probability of being struck by a small frag-ment would be about 1 in 100. No danger wouldexist from blast or heat. As discussed later, theseeffects are all overshadowed by the radiationhazards.

V. THE RECOVERED DEBRIS

Much of the material in this chapter is fromLA-3337-MS, “Kiwi-TNT Particle Study”, com-piled by Campbell? and LA-3445-MS, “KiwiTransient Nuclear Test Fuel Element and Sup-port Element Fragment Study”, by Fultyn andBoasso.g

One of the secondary objectives of the Kiwi-TNT test was to quantitatively determine thecharacter of the resulting debris. This aspect ofthe test inchided various experiments designed toobtain information concerning the size distribu-tion, nature of the radioactivity, and other physi-cal characteristics of the debris. The developmentof techniques to study the nature of the radio-activity of the smaller debris particles and thefindings of the study are fully describd in theabove reports. This chapter sketches the experi-mental plans, reports the unclassified results, andrelates some conclusions.

In this discussion debris is classified intotwo categories: particles and fragments. Particlesare pieces of the reactor or neighboring materialsmall enough for their trajectories to be influencedby wind and atmospheric eddies. Fragments arelarger pieces, ranging upward from a few milli-meters long, whose trajectories may be approxi-mately described by ballistic equations.

Since numerous techniques of particle tech-nology were to be compared, a variety of appreaches was taken for deployment of partickcollecting devices. Numerous sampling stationswere placed at carefully surveyed locations a-round the test point. These are shown in Fig. 7.

The simplest device was sheets of polyethy-lene, about 6 ft wide, laid on the ground in con-tinuous strips. Five of these strips were laid inthe anticipated upwind and downwind directions.It was hoped that debris falling on the sheetscould be photographed to obtain information aboutits dispersion. These hopes were not realized be-cause strong winds several days before and afterthe test made it difficult to keep the sheets cleanand in place. No debris was seen on the sheetsexcept along the edges where the wind had win-nowed some of it. In additio~ the plastic becametattered out to beyond 200 ft as hot debris fallingon the plastic burned many holes through it. Someuseful samples of larger particles and fragmentswere collected from the vvinnowings and bysearching under the burn holes.

Two types of gummed-tray collectors used toobtain samples for visual and microscopic analy-sis were called the macrocollection tray and micro-collection tray, respectively,

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Fig. 7. Debris collection stations.

14

The macrocollection tray or “macrotray”(Fig, 8a) consisted of two open aluminum frames

between two 14 X 17-in. hardboard covers. Mylarsheets, 0.003 in. thick, were stretched over facingsides of the aluminum frames. When placed ontheir special stands in the field, the macrotray“books” lay open with the Mylar sheets facingup. Under one “page” was a 14 X 17-in. sheetpacket of type M x-ray film covered with a sheetof aluminum foil, under the other was a 4 X 5-in.sheet packet of ASA 3000 Type 57 Polaroid film.The books were clipped to stands to prevent themfrom blowing away. The macrotrays were openedin the field a few hours before the test and theMylar surfaces were sprayed with Dow Corningsilicone antifoam to promote adhesion of particlesfalling on them. When recovered within a fewhours after the test, the x-ray films were removedand the macrotray books were closed and clippedshut for transport back to the laboratory wherethe films were developed. Fresh x-ray films wereplaced in the books to obtain autoradiographs ofthe debris on the Mylar, to collect data concern-ing the activity of the particles, and to assist inlocating them during subsequent visual and micro-scopic analysis.

The microcollection tray or’’microtray” (Fig.8b) consisted of six 1 X 3-in. standard glassmicroscope slides coated with nonhardening alkydresin side by side in a plastic holder. The holderswere opened a few hours before the test and’covered and collected a few; hours after. Auto-radiographs were made of the slides and the slideswere examined microscopically.

Although not originality intended for inclu-sion in this particular, study, the resin-coated traysused to measure radioactivity deposited from theeffluent cloud at great distances from the testpoint were also subjected to some of the tech-niques used on the other sampling devices. Thiswas done after they had served their purposesin the effluent studies.

To collect debris samples large enough forsieve analysis, 100 hopper-type collectors wereplaced around the test point. The hopper collector(Fig. 8c), was a sq~lare, inverted, pyramidal fun-nel of sheet metal. The open top measured 4 X 4ft. A 1-gallon paint can was held in a slide un-der the funnel against spring tension by a pin.Several hours after the tes~ the pin was auto-matically removed by a string attached to thewindup key of an alarm clock. The spring thenpulled the can from under the funnel to a closedsection of the slide until the samples could be re-covered. A few hours before the test, the cans

were placed under the funnel openings and thealarm clocks were wound and set for late after-noon. Two days after the test the cans were re-moved, tightly covered with standard paint canlids, and brought back to the laboratory wherethe contents were completely transferred tosmaller plastic jars. In spite of the closure deviceemployed, the samples contained much materialother than reactor debris, contrary to prior hopes.Also, the explosive shock of the test actuatedsome of the retaining pins at the moment of de-flagration, causing the collecting cans to with-draw from under the funnels before much debrisreached them.

As an afterthough~ eight wet collectors werealso placed in the field. These were 16 X 20-in.photographic developing trays containing a fewliters of distilled water and weighted by plastic-covered lead bricks to prevent their being blownaway. During analysis of the reactor debris, itwas concluded that these devices yielded some ofthe best samples collected.

The collection of material to document thesize distribution and geographic locations of thelarger reactor fragments was undertaken con-currently with efforts to decontaminate the testsite. The test area was divided into sectors boundedby stakes marking the positions of other samplingdevices (Fig. 9). Each sector was systematicallyscanned by radiation detection survey teams hold-ing the probes of survey instruments a few inchesabove the ground. Any area that produced a meterreading above background was carefully searched;if a reactor fragment was found it was picked upwith tongs and placed in a container. The smallestfragments readily found by this method were ap-proximately 1A in. long. The containers for each

w

,mo.

Fig. 9. Fragment coUection sectors<

15

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Fig. 8. Particle mllection devices.

16

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Fig. 10. Particles/1000 mz vs. sise class for a typicaldebris collection station.

area segment were marked by location. Un-fortunately, the samples from some of the firstsegments were accidentally combined, resultingin, loss of detail. The fragments from each sectorwere separated according to size and reactor corn.ponent type: loaded fuel elements containingfissionable material, unloaded core support ele-ments, and other reactor com~nents. Only fxag-ments in the first two of these categories werefurther classified by size using remote handlingequipment in the hot cells* of the Reactor As-sembly and Disassembly building at the NevadaTest Site, and at the Chemical and MetallurgicalLaboratory at Los Alamos.

Figure 10 shows the number of particles/1000m2 vs. size class for a typical station representinga composite of data obtained from all samplingmethods employed. The graph shows deviationsfrom a linear relationship between number ofparticles vs. particle size on a log-log presentation.The data for approximately half of the samplingstations would have plotted as nearly straightlines in such graphs, while the data from the re-maining stations exhibited deviations typified byFig. 10. Figure 11 is a histogram of the totalnumber of particles in each size classification de-posited over the total area covered by the debrissampling array as determined by all particlesampling methods. For the construction of tl&graph, the test area was divided into sectors, witha sampling station located at the center of eachsector. It was assumed that the number of particksper unit area in each size class remained con-stant over the sampling sector. Figure 12 presenta

—

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puma sm {OIAMEIER IN MImcus)

Fig. 11. Number. of particles in each size class asdebrmimxi by all sampling methods overentiie sampling area

the same data as those in Fig. 11, but shows thepercent -of total number of particles less than agwen size deposited over the sampling array.Figure 13 is another presentation of these samedata as percent of mass of total debris less thana ~ven size deposited over the sampling array,the conversion using representative size and densi-ty data. The data in Figs. 10 to 13 represen~ i.mofar as possible, only particles definitely identifiedas reactor debris. However, for some size classi-fications it was impossible to separate reactorparticles from desert dust that had adsorbed radio-activity. Such particles were included as reactordebris: -

1 1 I 1 [ 1 # 1 1 1 1 1 1 1 I I 1

I f 1 1 ! 1 1 1 ! ! 1 ! , i 1 t 1

01 12510 ZU40S080 SS939S9 IA

Fig. 12. Percent of total number of particles lessthan Stated ai2e.

17

I 1 1 I 1 1 I I I 1 I 1 I 1 I 1 I

Lll,lllllllll,0.115 2040a08J 9599999

Fig. 13. Percent of maSS Of Particles kss than statedsize.

Figures 14 to 17 illustrate’ the distribution ofuranium in the particles in one sampling sector.These data are confined to graphitic particles lessthan 5 mm in diameter. The difficulty of per-forming this type of analysis precluded its use forall samples. The concentration of uranium inparticles approximately 100 p in diameter can beattributed to a detail of reactor design d~cussedIater.

Figure 18 shows the ganuna activity perparticle vs. particle diameter for a typical samp-ling sector. Particle activity is directly propor-tional to the square of the particle diameter, orto the surface area. This strongly suggests thatthe activity was deposited on the surface of theparticles rather than being distributed throughoutthe particle vohune. This behavior was found inall samples so analyzed, and was assumed to ap-ply to all those collected.

The size distribution of the fragments cd-Iected during ground pickup is shown in Fig. 19which gives the fraction less than a given size bycount for loaded fuel element fragments, un-loaded support element fragments, and the sumof all core elements, respectively. Figure 20 pre-sents the geographic distribution of fragmentdensity (fragments/ft2) around the test point and

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LOG MEAN PARTICLE OIAMETER, MICRONS

Fig. 14. Curies of uranium per particle vs. particlesize.

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Fig. 15. Weight of uranium per particle vs. particlesize.

shows that the center of fragment distributionwas translated doivmvind.

To interpret these data, one should under-stand some details of construction of the reactorcore. In the simplest terms, the core is composedof bundles of graphite elements loaded with fis-sionable material and support elments containingno fissionable material. The fissionable material isnot mixed homogeneously with the graphite of the

18

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LOG MEA~PARTtCLE DIAM~TER, MICRONSFig. 16. Curies of uranium per gram of material VS.

particle size.

1 1 1 1 1 1 1 1 1 I 1 1 1 ! I 1 r ! I 1 r

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I I I I 1 I I I I I I I I 1 I I I I I I I 1alos125ww30E070 go 2s 293 239 99,92

PERcENT OF URANIUM IN PARTICLES LESS THAN STATEO SIZE

Fig. 17. Weight fraction of rwovered uranium con-tained in particles leas than stated size.

fuel elements, but is contained in small, evenlydispersed beads. Thus, fission energy is not pro-duced uniformly throughout the core, but occursat numerous small discontinuous points and isabsent from the support elements.

During normal reactor operation, fission oc-curs slowly enough to allow the resulting ther-mal energy to be transferred from the uraniumbeads through the surrounding graphite to thecoolant flowing through the core, so that tempera-tures high enough to cause mechanical failure ofthe core materials do not occur.

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PARTICLE SIZE

DIAMETER OF LOGMEAN SIEVE SIZE (MIcROhJS)

F~g. 18. C+amma activity per particle vs. particle size.

During the Kiwi-TNT excursio~ however,the fission rate was deliberately increased so thatthe resulting heat could not be transferred fastenough to avoid vaporizing significant amountsof the beads and their surrounding graphite. Thepressures resulting from this vaporization causeddestruction of the reactor. fl.her experiments haveshown that there is a critical fission density ratebelow which vaporization does not occur, sinceheat transfer is adequate to prevent it. It is alsoknown that fission density rate is not uniformthroughout the reactor core, but is highest at thecenter and diminishes towards the ends. Further-more, neutronics calculations showed that someregions of the Kiwi-TNT core experienced fissiondensity rates above, and others below, the criticalvahzes.

Thus, it may be hypothesized that, as re-activity was rapidly inserted into the reactor, thefission density rate at the center of the core ex-ceeded the critical value and vapor began toform in and around the fuel beads. The vaporformed too fast to escape through core interstices,

19

00! 1’ I 1 I 1 1 I I 1 8 1’ I I ! 1’ !

m%~~ 18—:z

9

,~,Ol!l W.,*

a. Fuel element fragments.

of the core materials. Where the distances be-tween vapor cells were very small, the fuel ele-ment materials that were not vaporized weresubjected to very high pressures from all direc-tions and were probably crushed and ground intovery small pieces. Other portions of the core suchas the support elements did not vaporize, but weresurrounded by vaporizing areas and were subjetted to a second mechanism of destructionvisualized as crushing and grinding. Still otherareas of the core, such as the outer portions,where the fission density rate was below thecritical value, were adj scent to vaporized areasand were subjected to destructive forces of a thirdtype, visualized as an unidirectional explosivemechanism. Thus. at least three tvms of destruc-

101 1 1 1

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II 1 1

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,J A,, ,I 1 1 1 1 ! 1 I 1 ! I I I ! 1 Iaot O.I

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t I 1 1 i I 1 I I ! 1 I 1 I 1 1 I‘L al t to *O so M 09

c. Total fragmenta.Fig. 19. Percent of recovered fragments less than

stated size.

internal pressures quicldy rose above the stresslimits of the reactor materials, and the reactor wasviolently disassembled In those regions where thecritical fission density rate was exceeded, sufficientfission energy was released to vaporize 5 to 20%

The nuclear excursion was terminated asthe reactor became disassociated and the expan-sion of the incandescent vapor and the inertia ofthe rapidly moving incandescent solid piecesproduced an explosive spectacle. Since fission pro-ducts were produced at points most likely to bevaporized, they were probably released to thecloud as vapor rather than as particIes. As thecloud cooled, the fission products condensed ongraphite or entrained desert dust particles in thecloud, accounting for particle activity as a sur-face phenomenon. Uranium, on the other hand,could be expected to be found both adsorbed onparticles by condensation from vapor and inti-mately embedded throughout the volume of frag-ments in the form of unvaporized beads. It doesnot seem unreasonable that many more-or-lessintact beads would be dislodged from the graphitematrix.

The destructive mechanisms just postulatedcan be supported by the fact that 67~o by weightof the support element material in the core wascollected, while only 12~o of the loaded fuel ele-ment material was recovered. Some of the corematerials were marked to identifv their locations.in the reactor. and more Darts from the outer sec-.tions of the reactor were found than from innersections. The data presented in Fig. 13 indicatethat several destructive mechanisms may havebeen operable; a typical plot of the percent byweight of a dust sample less than a given size, onlog-probability paper, lies on or near a straightline. This is almost alwavs so when the dust wasproduced by a single mec~anical operation, such asblasting, grinding, or crushing, acting on a homo-geneous medium. F@n-e 13 shows several distinctregions where the points lie on a straight line,suggesting that there was probably more than onemechanism of breakage.

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CONCENTRATION FOR ANALYZED SECTORS; FRAGMENTWSQ.FT.

Issl

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Fig. 20. DBtribution of fragmentg over recovery area.

21

VI. PROXIMATE NUCLEAR RADIATION MEASUREMENTS

The material in this chapter is largely fromLA-3304, “Integral Gamma and Neutron Measur-ements on the Kiwi-TNT” by Lee and Worman,7and from LA-3446, “Gamma Dose Rate Measure-ments — Kiwi Transient Nuclear Test”, bySanders.12

The devices used by LASL to obtain integralgamma and neutron dosimetric data from theKiwi-TNT experiment differed little from thoseused previously in tests of Kiwi and NRX reactors.

Neutron threshold detectors consisted of 28gPu,~TNp, and ~8U fission foils supplemented by goldand sulfur activation detectors.7 The sets of fissionfoils were encased in cadmium and placed in 10Bballs. The neutron threshold energies measured bythe boron-surrounded foils are 0.004 MeV for239Pu 0.75 MeV for 297Np, and 1.5 MeV forZS8U.’A SZS(n, p) 82Preaction occurs in the stdfurpellet at neutron energies above 2.5 MeV. Gold isactivated by thermal and resonance neutrons. Goldfoils encased in cadmium are activated only byneutrons of greater than 0.3-eV energy because ofthe large absorption cross section of cadmium forneutrons below this energy. Activity differencesof paired gold foils, one bare and one cadmium-encased, indicate the thermal neutron flux. Theintegral neutron fhlx values (nvt) were convertedto neutron doses by factors of

9.3 X 10-10 rad/nvt for neutrons between0.004 and 0.76 MeV;

2.32 X 10-0 rad/nvt for neutrons between0.75 and 1.6 MeV;

2.98 X 10-0 rad/nvt for neutrons between1.5 and 2.5 MeV;

3.63 X 10-’J rad/nti for neutrons above 2.5MeV; and

5.50 X 10-11 rad/nvt for thermal neutrons.

A glass gamma-dosimetry system consistingof two types of glass dosimeters was used to mea-sure gamma doses close to the reactor.’ Gammadoses from 20 to 50,000 rad were measured withsmall rods of AgP08 glass. Cobalt borosilicate glassplates were used to measure gamma doses between1 X 104 and 5 X 108 rads. Both types of glasswere placed in ‘Li-impregnated lead cans to mini-mize the effects of thermal neutrons and low en-ergy gamma radiation.

Doses measured bv the AIzPO, class rods were-“

evaluated by use of ~ speci~lly adapted fluoro-meter. Fluorescent centers produced in the glassby gamma radiation emit visible light when excitedby ultraviolet radiation. The relative intensity ofthe emitted visible light is a measure of the radia-tion exposure of the rod. Fluorometer readingswere converted into gamma dose values by meansof calibration curves obtained by reading rob ex-posed to known gamma doses. Since no gammadoses greater than the detection range of theAgPO, rods were measured, no evaluation of theborosilicate glass plates was required.

Twelve holders containing a full complementof neutron threshold detectors and glass dosimeterswere positioned on free-line pales on the raih-oadtrack along the 270° radial from 50 to i ,430 ftfrom the test point, to measure the variation ofdoses with distance. These holders were recoveredwithin an hour after the event. Thirty-six holderscontaining sulfur and gold neutron threshold de-tectors and glass dosimeters were attached towooden stakes at200 intervals around the test @ton arcs at 100 and 200 ft. This array was used tomeasure the radiation pattern around the reactor.

At 500 ft and beyond, Ilupont type 544 filmpackets were used to measure gamma doses.7 Thesepackets contained a sensitive fihn, type 555, fordoses from 0.01 to 6 R, and an insensitive film,type 834, for doses from 2 to 108 R. A 40-mil leadstrip was placed over the packets to distinguishgamma radiation from beta radiation of less than2.5 Mev. Each film packet was contained in aplastic wrapper to protect against moisture.

Pairs of film packets were located at 50 in-tervals completely around the test point on the500-ft arc, and at 50 intervals between 130 and310° on the 1,000- and 2,000-ft arcs. At 4,000 and8,000 ft, packets were at 5° intervals between 180and 270°. Fihn placement at 3, 6, 12, 24: and 50miles was at approximately 10° intervals between180 and 270°, the stations corresponding to airsampler locations. Integrating dosimetric deviceswere not collected from the field until 24 to 72hours after the event.

Two remote-reading instrument systems wereused to measure gamma dose rates following theexcursion.12 A photomuhiplier/photovoltaic cellscintillator system was used at 500 ft and closer,and an ion-chamber system was used beyond500 ft.

22

Scintillator stations were at O, 90, 180, and270° at 100, 200, and 500 ft. Six ion-chamber in.struments were placed on each of five arcs, con-centrated in the anticipated downwind direction,as listed in Table III.

TABLE HI. LOCATION OF REMOTE READ-ING IONIZATION CHAMBERSTATIONS

Distance Azimuth(ft) (0)

500 45 120 150 210 240 3151000 145 180 210 240 270 3002000 160 190 220 250 2+30 3104000 175 195 225 245 265 2858000 180 200 220 240 260 280

The scintillator system employed fluorescentplastic. light-coupled to either photomultiplier(PM) tubes or to photovoltaic (PV) cells. ThePM tubes were powered by high-voltage batterypower supplies; the PV cells required no externalpower. Each scintillator station had one PM unitand one PV unit connected in parallel to a singlecoaxial signal line. These signal lines were app-roximately 2 miles long, and terminated in areadout facility in the control point area. The cur-rents of the scintillator units” were measured withtransistorized galvanometers whose outputs wereconnected to strip chart recorders. A switchingcircuit allowed either of the two instruments con-nected to the s@al line-galvanometer system tobe read at one time. The PV system produced aconstant signal in the transmission lines; the PMsystem produced a signal only when its powersource was energized. The signals from the twosystems were of opposite polarity. Although aPV signal automatically diminished a PM signal,because the PM signals were about two orders ofmagnitude greater, this interference was negligible.

The ionization chamber system was a com-mercially obtained RAMP 4 system, manufacturedby the Jordan Electronics Division of VictoreenInstrument Company. Each remote station con-sisted of a Nehr-White ionization chamber andbattery power supply. The remote stations wereconnected to the readout system by signal pairs,which were generally more than 2 miles long. Theremote station ion chambers had a logarithmic re..sponse to radiation, and readout units were pro-vided with two logarithmic range scales: 1 mR/hrto l@ mR/hr, and 1 R/hr to 10s R/hr.

After the event, numerous surveys were madewith portable dose-rate survey instruments. Sur-veys by the Radiation Services Department of thePan knerican World Airways, Inc., were largelyconfined to populated areas, such as building com-plexes and roadways, but included some areas a-round the test site. LASL Group H-1 Monitorsconducted surveys to measure the location and ex-tent of contamination around the test site and toaccurately determine its variation with azimuthand distance from the test point.13 Radiationmeasurements by LASL were made at accuratelysurveyed locations, and several serial measure-ments were made to accurately follow the decay ofcontamination. Readings were taken with pairs ofinstruments whose calibration was checked priorto each excursion into the field.

The variation of neutron flux with distance,as measured by the free-line stations along therailroad track, is shown in Fig. 21 and Table IV.The variation of neutron flux with azimuth aroundthe test point is shown in Fig. 22 and Table V.FiOgure 23 shows the variation of neutron andgamma doses with distance along the free line.Figure 24 shows the variation of integral gammadoses with azimuth at 100 to 8,000 ft. Integralgamma doses are listed in Tables IV, V, and VI.

Data obtained from the remote-reading dose-rate systems are shown in Fig. 25. Contaminationpatterns determined by the monitor surveys areshown in Fig. 26. Typical decay data from themonitor surveys are shown in Fig. 27. These datawere processed by electronic computer to obtaindose rate vs. time relationships in the form

DR = At-B (6.1)The values of A and B for representative stationsare given in Table VII. The variations of dose ratewith distance and azimuth as measured by themonitor surveys are shown in Figs. 28 and 29, re-spectively. Values for 1-hour data from monitorsurveys are extrapolated by use of Eq. 6.1 fromdata actually taken several hours later. Values forA and B for representative stations are those pre.sented in Table VfI.

When these experiments were designed, em-phasis was placed on obtaining maximum geo-graphic coverage of the test point area, and onobtaining data from as many locations as possible.Duplication of instrumentation to check on re-liability and accuracy of data, therefore, wassacrificed. Some cross checking of results is possi-ble because of coincidental duplication of instru-mentatio~ and further cross checking can be in-ferred by comparing the data to those obtainedfrom other Kiwi tests.

23

108 i I I I I Io i? 4 6I

6 10 “ 1s2 14

DISTANCE FROM TEST POINT (100 FEET)

Fig. 21. Variation of neutron flux with distance.

1-Z

Illllli llll!l(lllli00 40 02 120 180 Zao ?.40 203 320 3c0

AZIMUTH DEGREE (0”. NORTHI

7 1 I I I I I I I I [ I I I I I I I-1

u. J0x 2–3~ 200 FOOT ARC

~1 –

g

g0 I I I I i I I I I I I

20 40 60 00 IOD 120 MO (w leD ?@ S20

AZIMUTH DEGREE (OO=NORTW

Fig. 22. Variation of neutron flux with azimuth.

TABLE IV. INTEGRALNEUTRONAND GAMMA DATA AT FREELINE STATIONS

Distance

(ft)

50

70

100

140

200

280

IntegralNeummFlux (n/cm’) Rad Doses

p Thermal p PU(J) ~ Npfb) y u(’) ~ S[dJ n~ Rads n~ Rads y Rads

2.88 X 10” 5.74 X 10’2 1.15 X 10” 7.27 X 10’1 Z.91 X I@’ 8.61 x 10S 1,59 x Iv 1.05 x io~

1.70 X 10” 2.95 X 10’2 5.58 X 1011 3.99 X 10” 1.03 X 10*1 3.86 X I@ 9.4 X fo* 1.06 X 10t

8.73 X 101’ 1.47 X 1011 2.61 X 1011 1.53 x lw 5.33 x 1010 1.87 X 109 4.8 X 10’ 5.70 x lIY

4.96 X 10’1 7.87 X 1011 1.42 X 1011 7.41 x 101’J 2.47 x 1010 9.96 X lW 2,7 X 10’ 1.89 X 10s

2.47 X 1011 4.13 x 1011 6.57 X 1010 3.78 X 1010 1.17 x 1010 5.09 x 1P 1.4 x 101 1.36 X lW

1.21 x lo” 2.04 X 1011 3.16 X 1011 1.76 X I(P” 5.35 X 10’ $?.49 X lCP 6.7 7.33 x I@

400 5.51 X- 1010 9.97 X 10’0 1.46 X 1010 7.08 X 10° 2.43 X lIY 1,19 x 102 3 2.82 X lIY

560 !?.22 x 10’0 4.05 x 10’” 7.32 X 10° 3.33 x 100 9.90 x 10s 5.07 x 10’ 1.2 1.30 x lcP

800 8.35 X 109 1.33 X 10’0 2.42 X 10° 8.24 X 10s 4.81 X 10s 1.67 X lW 4.6 X 10’ 6.30 X 101

1000 3.49 x 109 5.55 x 100 1.00 x 100 3.15 x 108 2.44 x lW 6.93 1.9 x 10-1 4.69 X 101

1200 1.63 X IN 2.38 X 109 4.30 x 10S Low 1.91 x 10s 4.00 9.0 x 10.1 5.10 x 10’1400 9.84 X 10s 1.41 x 10’ 2.55 X 102 Law 1.60 X 10s 3.00 5.4 x 10’ 1.00 x 101

(a) J+IPU= Integral neutron fluxes at energies >0.004 NfeV

(b) pNp = Integral neutron fluxes at energies >0.75 MeV

(c) @_J = Integral neutron fluxes at energies >1.50 Mev

(d) & = Integralneu&mfluxesat energies >2.50 MeV

TABLE V. INTEGRAL GAMMA AND NEUTRON DATA AT 100 AND 200 FEET

Dis~@) Bearing S flu(h) nth fhdc)(ft) (0) y rads (n/cm’) (n/cm’) nth rads Cd ratio

3.64 x 10s 6.16 x 101’J 1.19 x 101* 6.57 X 101 —100100100100100100100100100100100100100100100100100100200200

200200200200

200

200

200200200200200

020m.6080

10012014Q160180200$X2324026028030032034Q

o20406080

10012014016018020022Q‘M260280300320340

3.68 X 1P !5.94 x 1010 1.11 x 1012 6.12 X 1013.51 x 10s 5.16 X 1010 1.16 X 1(Y2 6.42 X 1013.16 X I@ 3.98 X 1010 1.03 x lo** 5,69 X 1013.18 X 10s 4.48 X 1010 8.91 X 1011 4.90 x 1011.53 x I@ 7.27 X 109 6,28 X 1011 3.45 x 1013.34 x 109 4.56 X 1010 1.01 x 101* 5.58 X 10’4.24 x 102 5.23 x 1010 1.14 x 1012 6,28 X 1014.43 x lo~ 5.00 x 101° 1.14 x 101’ 6.28 X 1014.93 x 10s 5.49 x 1010 1,04 x 1012 5.76 X 1014.97 x 108 5.35 x 1010 9.99 x 1011 5.49 x 1014.91 x I@ — 9.56 X 1011 5.26 x 1013.97 x 108 4.87 X 1010 9.14 x 1011 5.03 x 1013.62 X I@ 4.95 x 101’J 9.13 x 101* 5.02 X 1013.32 X 108 4.78 X 1010 9.57 x 10’1 5.26 X IN3.12 X I@ 5.00 x 10*O 1.04 x 1012 5.75 x 1014.02 X I@ — 1.11 x lo*’ 6.12 X lW3.94 x 10s 5.38 X I@” 1.13 x 101* 6.24 X 1011.05 x 108 1.32 X I@” 3.04 x 1o11 1.67 X Iw1.09 x I@ 1.25 X 1010 2.97 X 1011 1.63 X 1011.02 x 108 1.26 x 101’J 2.85 X 1011 1.57 x I@8.0 X 102 9.19 x 109 2,59 X 1011 1.42 X 1018.93 X 10’ 1,28 X 1010 2.59 x 1011 1,42 X 1011.01 x 108 1.26 X 1010 2.68 X 1011 1.47 x lW1.11 x 102 1,25 x 101’J 2.78 X 1011 1.53 x 1011.35 x 108 1.32 X I&” 2.78 X 101~ 1.60 X 1011.56 X l@ 1.22 x 1010 2.89 X l@l 1.59 x 1012.09 X l@ 1,26 x lW 2.88 X 1011 1,58 X 1012.71 X I(Y 1.44 x IO*O 2.97 X 1011 1.63 X 1012,23 x l@ 1.57 x l@’J 2.88 x i@l 1.58 X ICP1.48 X I@ 1.10 x Iwo 2.73 X I&l 1.50 x 1011.55 x 103 -- 2.45 X 1011 1.34 x Iw1.00 x 1P 1.55 x 1010 2.67 X 1011 1.47 x 1011,08 X 103 1.56 X 1010 2.87 X 1011 1.58 X 1011.15 x I(Y 1.62 X 1010 2.95 X 1011 1.62 X 1011.09 x 108 3.80 X 1010 2.96 X 1011 1.62 X I(P

(a) Distances are measured from a verticle line through the core center of the reactor.

2.642.542.642.562.422.692.66$2.562.672.58!2.552.512.562.532.592.622.542.582.40!2.392.312.312.292.402.332.472.382.382.472.462.392.372.462.402.362.34

(b) Integral neutron fluxes at energies >2.50 MeV.

(c) Tntegral neutron fluxes at energies <0.3 ev.

26

TABLE VI. GAMMA DOSES OBTAINED BY DOSIMETRY FILMS

Station station

Distance Azimuth(10s ft) (0)

Dose(mR)

00051015

::30

%46

::

%

;:

%90

i%105110115120

:3?135140

i%155160165i 70175180185190195200205210215220!225230235

:5:255

1.18 X 1057.20 x 10’45.00 x 1044.15 x 1041.20 x 1068.35 X 1041.10 x 1061.05 x 1068.40 X 1048.95 X i(Y7.10 x 1048.60 x 1047.7!5 x 1048.46 X. 1045.75 x 1041.03 x 1051.30 x I(Y1.06 X 1051.09 x lVJ1.55 x 1055.30 x 10’48.70 X I(Y7.75 x 1041.14 x ICF1.10 x 1061.21 x 1051.03 x 1058.40 X 1049.70 x 1041.13 x 1051.27 X 1051.21 x 1051.30 x 1061.32 X 1(Y1.72 x lo~2.75 X 1051.65 X 1052.00 x 1011.53 x 1051.60 X 1062.90 X 1054.00 x Ios2.80 X 1062.43 X 1(F2.83 X 1(Y2.25 X 1062.25 X 10S2.20 x lo~2,15 X 1051.50 x 1061.36 X I@1.32 X 10s

(1W ft) (0)Azimuth

g

275280285290295300305310315

:2330335340345350355130135140145150155160165170175180185190195200205210215

:%230235240

250255260

E:2752802a5

(mR)Dose

1.30 x 1051.27 X 1051.40 x I@1.23 x 1051.12 x 1061.69 X I(Y1.09 x 1081.07 x 1051.17 x Iw1.19 x 1051.33 x 1051.30 x 1051.45 x 1051.29 X 1058.40 X 1041.13 x iw1.04 x lob1.07 x I@1.08 X 1051.04 x 1051.33 x 1041.25 X 104

1.17; 1041.00 x I(P1.35 x 1041.33 x 1041.80 X 1041.85 X I(Y2.20 x 1042.60 X 1042.58 X 1042.63 X 1043.03 x 1043.78 X 1041.26 x 1055.60 X 1043.60 X 1042.63 X 1042.55 X 1042.20 x 1042.20 x 1041.53 x 1041.55 x 1045.55 x 1045.15 x 1044.95 x 1045.15 x 1044.85 X 1044.60 X 1041.63 X 1041,53 x 104

26

TABLE VI. CONTINUED

Staticm

I Distance Azimuth(I(YJ ft) (0)

Dose(lnR)

!2!22

290295300305310130135140145;;:

160165170175180185190195

E:210215220225230235

:E250255

E:270275280285290295300305310180185190195200205210215220225230235240245

1.63 X 1041.58 X 1048.35 X IV1.50 x 1041,50 x 1041.65 x 10s1,60 X 10s1.58 X 10s1.45 x 1081.65 X I@1.70 x 1021.85 X I(Y1.99 x lo~2.08 X 1P2.5s X 1093.00 x 1083,38 X I@3.87 X 10s6.30 X I@4.05 x 1041.68 x 1045.55 x 1P4.55 x 1084.05 x Iw3.45 x I@2.99 X I@2.63 X 1062.80 X 10s3.00 x 1092.08 X I@2.03 X I@1.93 x I(Y2.08 X 1031.55 x I@1.30 x 10s1.30 x 10s1.60 X i~1.63 X 10s1.2s x 1081.15 x I(Y9.50 x 1025.95 x 1022.50 X 1012.00 x I@6.50 X 1011.15 x 1021,50 x 1021.90 x 1023.30 x 1022.08 X 1(P3.95 x 1022.25 X 1022.10 x 1021.45 x 1027.00 x 1016.00 X 101

Station

Distance Azimuth(IW+ ft) (0)

——.4 250

:44

:8

:88

:8888888

:16

::161616

::16

::

128256

264

255

E:270i 80185190195200205210215220225

z;

245250255260270180190200210220230240252261270194206219228245260i 72188203211215221230241251268i 80

to280183

to253

LJose(mR)

1.30 x 1024.00 x 1013.00 x 1011.00 x Iw

<lo<lo<lo<lo<lo

1.00 x 1013.00 x 1011.50 x 1022.45 x 1021.35 x 1025.00 x IOJ1.00 x 101

<lo3.00 x 101

<lo<lo<lo<lo<10<lo<lo<10

3.35 x 102<lo<lo<lo<lo<lo<10<lo<lo

1.50 x 102<10<lo<lo<10<lo<lo<lo<lo

1.00 x 101<lo<lo<lo<10

<10

<lo

I0sf

‘ I

F Klwl “TUTINTEQRAL 00SSS AT DISTANCE

< FROM TEST POINT

Id r

g

8~g1-

00SE10 .

I10 I@ lo~

OISTAMX FROM TEST PCJNT (FEET)

Fig. 23. Variation of neutron and gamma doses withdistance.

1 ‘1 I (10’.-

.

\,.

_-- ~~

..$,

100 mm MC‘,..\..

\.lo~130-270 ., no- la

2 \

j100-090

‘\\

1! .,

~. . . .

~ !Q*

Ex,

g \

8

--..

‘\...

10” /,,

\

.. .

\

I [\

‘o’al( ,.

10 10 LOMIWTES

!0 100

TIME. POST EVENT Mouns

a

10’

10 s~2

~

w

n

az

zc1 2000 FOOT ARC

10’=

10*T

4000 FOOT ARC

8000 FoOT ARC10 ‘o ‘

so Iw m 2s0 300 3s0&MUTH (=)

Fig. 24. Variation of integral gamma dozea with

106 —

z

jE.

& 105 —

a

g

10’ —

azimuth, as measured by fii badges.

10’

‘.‘.‘.

‘\\

‘.,‘.,

‘.\

‘,‘.

‘.200-090L,

‘.

‘\‘\

‘.‘,

‘.‘\

‘\200 FoOT ARC ‘\

‘.

103I , ,, t , , I ,0.1

ILO

MINUTES10 Lo

TIME, POST EVENT I HOUR

b.

Fig. 25. Data obtained from remote reading dwe-rate instmments.

!W

0’ ~S00-270

~- K’ ‘ “’”:

500-100

x.

lo~~.

S00 FoOT ARC‘...

500-000 \

‘\ “

~

300-315

‘\\..... ..

1 I I I\\\

‘0’0.1 10I

mJ

Mlwlm 10TIME, POST E&NT HOUR~m

a

10*. , ,*

\

\

2000 FOOT ARC

103 —

‘,

2\.~

E102 —

w-

%m

% 2000-250~

10 ‘ —2000-310

1001.0 10 1.0 10MINUTES

TIME, POST EVENT HOURS

I

I‘o”al I I I I10 10 J

1.0 10MINUTES

TIME, POST EVENT HWi?

d.

“’~

h 4000ANOS000

104 ; -4000-225

,4000-195

\

2 10= T

E ,,

w“

sK

g

-,’f

Io’r8000-240

1001,0 10 1.0NINUTES

TIME, POST EVENT

J

FOOT ARCS

HOUR$’

aFig. %. Ccmtinued.

29

f.

0“.

Ak27 —90”

ICXJR/HR

50 Rlli?

10 RmR

5 R/HR

1.0R/HR

270”

u

Onelw

T5*

%$. IIeo”

a

A

-----irb.

2

d.

7’5.

-—--9U

>LO R/HR

>100mRM7

>10 mR/HR

>10 MRIHR

‘------+””’180”

One Wekk

Fig. 26. Contamination patterna determined by monitor surveys.

30

TABLE VII. COMPARISONS OF DOSIMETRIC DATA

Station

100-000100-080100-090100-100100-180100-260100-270100-280

200-00024N-080200-090200-100200-180200-260200-270200-280

500-000500-040500-045500-050500-090500-120500-180500-240500-270500-310500-315500-320

1000-1401000-1451000-1501000-1801000-2101000-2401000-2701000-300

2000-1602000-1902000-2202000-2502000-2702000-2802OOO-31O

4300-1754000-1954000-220WOO-2254000-230

8000-2008000-2208000-240

Monitor SurveyDecay Constants

Dose Rate = At-B

(ruhr)5.12 X 1041.65 X I&

2.56 X 1042.16 X I(Y9.00 x 102

2.24 X I(Y

2.16 X 1042.17 X I(P2.24 X 1041.25 X lCP4.53 x 1043.39 x 1049.69 X I@2,85 X 104

2.78 X I@2.60 X lW

2.61 X 10s2.59 X 1081.66 x 1025.70 x lo~7.54 x lo~4.62 X 1083.30 x I@

2.!55 X l@

1.78 X 102

1.43 x 1025.39 x 1023.90 x 1022.42 x 1022.08 X 1021.70 x 102

5.521.19 x lo~4.58 X 1012.81 X 101

9,$9

2.71

3.39 x 10-11.723.69 X 101

B

;;E

i .28

;::

1.18

1.391.461.541.331.18i .401.181.41

1.461.54

1.551.47

&1.341.361.34

1.16

1.3

1.3

H1.31.31.3

1.31.3

$::

1.3

1.3

1.31.31.3

J AtiB

Irninto 48 hr

(mR)

‘5.50 x 1051.40 x 1(Y

2.58 X 1062.97 x 1087.21 X 104

1.97 x 105

2.63 X I(Y3.00 x 1053.76 X 1061..35 x 1053.98 X 1054,18 X 1058.53 X 1043.60 X 105

3.90 x 1044.37 x 104

4.41 x 1043.72 X 1041.71 x 1045.57 x 1048.37 X 1045.26 X 1043.67 X 104

9.21 x I(34

1.84 X I@

1.48 x 1025.57 x 10s4.03 x 1042.50 X 1092.15 X 1081.76 X 108

5.71 x 1011.23 x 1044.74 x 1022.91 X 102

9.92 X 101

2.80 X 101

3.501.78 X 1013.82

31

2nlinto 48 hr

(mR)

4.13 x 1051.21 x 105

2.07 x 1052.15 X 1066.73 X IV

1.67 X 10s

1.97 x 1052.16 X 1052,57 X 1061.05 x 1063.38 X lW3.12 X 1057.23 X 1042.70 X 105

2.80 X 1042.98 X I(P

3.00 x 1042.65 X 1041.36 X 1044.51 x 1046.48 X 1044.03 x 1042.84 X 104

1.89 X 104

1.46 x 108

1.17 x 10s4.42 X 10s3.20 X 1041.98 X 1P1.71 x 1021.39 x 102

4.53 x 1019.74 x 1083.76 X 1022.31 X 102

7.87 X 101

2.22 x 101

2.781.41 x 1013,03

Integral ofDose-RateRecording

(mR)

6.20 X 1~

4.49 x 106

1.45 x 106

6,20 X 105

2.78 X 105

1.62 X 105

8.99 X 10s

3.66 X I@

2.18 X IOG

7.36 X I(P

1.89 X 1045.75 x 1081.46 X 1052.28 X 10s9.20 X 104

8.11 X 103

1.33 x 10s

3.86 X I@1.54 x 1041.48 X I(F9.37 x 102

6.54 X 1017.79 x 1013.74 x 1027.02 X 101

1.62 X 1023.48 X 101

4.16 X 1(Y6.02 X 101

1.46 x 10s

2.95 X 1016.20 X 1011.97

IntegralDosimeter

Dose(mR) —.

3.64 X 1063.18 X 106

4.39 x 1063.62 X 106

3.32 X 106

1.05 x 1068.93 X 1(P

1.01 x 1062.09 x 1061.55 x 106

1,00 x 106

1.18 X 1058,4Q X 1048.95 X 1047.10 x 1041.09 x 1051.10 x 1051.65 X I@2.15 X 1051.40 x 1051.33 x lo~1.30 x 1051.45 x 105

1.10 x 1041.00 x lo~2.60 X 1045.60 X 1041.53 x 1044.85 X 1048.35 X I(F

1.85 X lW3.87 X 1084.05 x 1082.08 X 1091.55 x I@1.30 x I(Y5.95 x 102

1.15 x 1023.95 x 1022.25 x 1022.10 x 102

1 x 1011.36 x 1023 x I(P

—

I 1 ! ! , 4 I ${f 1 , i 1 1 1, , I 1

z<

u

%

z810’ ~

OOSE RATE (mRiHR). 1.24x 104t-’”36

10‘~

100I 1#

TIME P’&T EVENT (HOURS)

Fig. 27. Typical monitor survey dose-rate decay data.

10*

CALCULATEO oOsE RATES ! nOUfl

—————%—. 205. R4DIu 1

20G 4.X 600 2.30 ,000 1200 IMW 1600 lKu2 2CO0OISTANCE FROM TEST POINT (FEET)

10 ~“’’’ao’’ o’’”’’’’””’”,. ..,!,, !!

j

CALCULATED00SE UhTE==l HOURSPOST EVENT

200 400 600 803 1000 1200 la 1- Imo 2U

OISTANCE FROM TEST POINT [FEET)

Fig. 28. Variations of dose rata with distance.

Table VIII lists ratios of neutron doses fromKiwi-TNT to those from Kiwi-B4D-202 and Kiwi-B4E-301 at selected distances. All data used tocompute the values in Table VIII were normalizedto rads/MW-sec of reactor energy and it was as-sumed that 3.1 X 1020fissions occurred during theJSiwi-TNT excursion. If 3.4 X 1020 fissions are as-sun+d (the value at the upper limit of error ofthe radiochemical determination of total fissions),

lo~

ULW7E0 OGSC RATCO I WR POET 2VENT

:

x8

m’,

lo~ ~~Ba+az.amloolzolalw 100200220240220280s0 3N340W

AZIMUTH DEGREE (O-. NORTHI

10’

z04060eo lm 120140160 lw200120z4022-a 290w SZOS40S60

AZIMUTH OEGREE (0.. NORTH)

Fig. 29. Variations of dose rate with azimuth.

these ratios are somewhat lower and within therange found in normally operated Kiwi reactors.

TABLE VIII. KIWI-TNT RADIATION MEAS-UREMENTS COMPARED TOIUWI-B4D AND -B4E DATA

Ratios of Dose/MVV-secof Reactor Energy

Distance from ReactorNeutron Doses

(ft) TNT/B4D

5070

10014024)0mo400560800

i 000

1.141.001,011.12i .231.2/31.351.311.110.89

TNT/B4E

1.111,241.171,26i .34i .321.371.X31.070.94

!

a KIWI B-l B

● KIWI B-4Dk

x KIWI B-4E EP5 A\o KIwI B-4E EP6

1“n KIwI TNT FREE LINE

T KIWI TNT DOWNWIND F,LM J

1 KIWI TNT UPWIND FILM x

●

1

I100 I000

DISTANCE, FEET

Fig. 30. Normalized integral gamma doses fromseveral reactor tests.

Figure 30 compares normalized integral gam-ma doses fmm the free line with normalized dose$from previous reactor tests. The Kiwi-TNT valuesare higher than those encount~red with normalreactors except for the very close stations. This canperhaps be explained as follows: Free-line dosesfrom a normal reactor contain a contribution fromprompt gammas (@ose released simultaneouslywith the fission reaction) and a contribution fromdelayed, fission-product decay gammas for about10 to 15 minutes after a run. Normally, bothcontributions are reduced from their theoreticalmaximum value by the shielding provided by thereactor reflector and pressure vessel materials, andby self-absorption within the core. This reductionis about a factor of 5.

Delayed gamma energy in the first minuteafter fission is about 30yo of the prompt gammaenergy, and in the first 10 minutes it is about40% of prompt gamma energy. In the Kivvi-TNTexperimen~ the dosimetric devices were exposedto the prompt gamma energy shielded by the es-sentially intact reactor component5 (as in a nor-mal test), and were also exposed to the largelyunshielded delayed gammas (emanating from thecloud of reactor debris) for about 1 minute. Ap-

proximate calculations show that doses/NIW-secof reactor energy from a Kiwi-TNT type of situa-tion will be about twice those from a normal re-actor. The geometry of the test also shows thatthe dosimeters further from the test point willhave a more constan~ or more slowly changing,source-to-detector distance (when the movingradioactive cloud is the source) than those close tothe test point. Because of the strong wind duringthis test, the influence of the fission-productcloud on the close-in stations diminished rapidly,but its influence on more remote stations changedlittle during the first minute or so. Therefore, thefarther-out stations could be expected to registerproportionately higher integral doses than thoseat closer range. Since the free-line dosimeterswere recovered from the field within an hourafter the event (all but the innermost few within15 minutes), they were not unduly influenced byradioactive contamination.

Dosimeters other than those on the free lineremained in the field, under the influence of radia-tion from contamination, for 24 to 72 hours. Todetermine the fraction of total dose due to radia-tion from contamination, Eq. 6.1 was integratedwith respect to time over the interval from 1 or2 minutes to 48 hours, for which time a dosimeterremained at each station. Table VIII comparesdoses measured by glass rods and film badges withintegrations of Eq. 6.1. Included for comparisonare numerical integrals of the dose-rate recordspresented in Fig. 25. With a few exceptions, thedoses measured by the integrating devices aresubstantially greater than the integrals of doserates. This is to be expected since the integratingdevices readily responded to the prompt radiation,whereas the dose-rate recorders, because of theirresponse times, could be used only to measure de-layed radiation. Because of saturation problems,most of the ion chambers did not provide any in-formation until 2 minutes after the event, bywhich time the cloud was nearly 4,000 ft from [hetest point. Therefore, except for the 4,000- and8,000-ft data, ion-chamber data are considered tobe solely a measure of radiation from ground con-tamination.

Scintillator system data are considered to bereasonably reliable after about half a minute, butvalues for earlier times are merely extrapolations.Numerical integrations of the scintillator data arepresented for times beyond 1/9minute, and are alsoconsidered to represent only radiation from groundcontamination, although there may still have beena small influence from the cloud at very earlytimes. The severe fluctuations of dose with azimuth

33

as measured by film badge are consider@ to bedue largely to radiation from ground contamina-tion. Correlation between film badge doses andintegrations of dose rates is poor, even allowingfor the discrepancy due to prompt and cloud radia-tion; this is attributed to the fact that doses anddose rates were measured at slightly different lo-cations at the same station. Since ground con-tamination included discrete fragments with highspecific activity, the dose rate at some stations wasfound to vary considerably for two points separatedby only a few yards.

That film badge doses were perturbed byground contamination or other causes is indicatedin Fig. 24. The peak doses registered along thedeposition pattern center line at 200 to 215° couldnot have been caused by radiation from the cloudalone, unless the cloud behaved as a point sourcetraveling at ground level, which photographicevidence contradicts. A calculation of radiationdose from an elevated source of reasonable geo-metry (e.g., sphere, point, line, sausage, or ameo-ba) yields doses much more uniform with respectto azimuth than those measured.

The accuracy of data collected by the dose-rate systems is also subject to question. The plotsof dose rate versus time on the log-log scales usedin Fig. 25 should have yielded nearly straightlines a; is the case when activities of theoreticalfission product mixtures are plotted in this fashion.Some variations are expected, but the deviationsin some of the lines in Fig. 25c are strongly sus-pected of being due to meter error, especially sincethey occur around a scale-shift point. Also, theplot for the recorder at Station 500-240 representsthe lowest dose rates measured at that distance al-though that station was more coincident with thecloud path than any other at that distance.

It is also recognized that values extrapolatedto 1 hour from data actually obtained a day ormore after the test as is the case for the monitorsurvey data, must be used with reservation. Thiswas, however, information collected during thetest and should be used only for what it is worthin checking the accuracy of other data.

Although much criticism has been leveledherein at the instrumentation systems used, itmust be recognized that they are representative ofcarefully calibrated instrumentation used in nu-clear radiation measurements, and they are littleworse, and probably better, than most. In addition,although individual data pointa are questionable,the aggregate is highly useful in determining theexposures and hazards to be encountered in anexcursion such as the Kiwi-TNT.

Todividual

determine the contribution of each in-source of radiation (i.e., prompt, neutron,

cloud, or contamination) to ~e to_talpersonnel ex-posure at given distances in the vicinity of an ac-cidental excursion similar to the Kiwi-TNT, thefollowing exercise was performed. Reference toTable IX will aid in following this discussion. Thedose measured by the integral dosimeter at eachstation was recorded. From this was subtracted acontribution attributable to prompt gamma radia-tion derived from previous tests of Kiwi reactors(Fig. 30). The value of rads,@fW-sec was 70%of the total rads/MW-sec measured on previoustests. The difference between the total dose andthe prompt gamma dose is then due to doses fromthe debris cloud and ground contamination. Thenumerical integral of the dose-rate data (beyond~,$ minute for scintillator stations, beyond 2 min-utes for other stations) was taken as the contribu-tion from ground contamination. Some loss ofprecision is involved in this step, since the in-tervals of integration varied and did not Corres-pond to the times the integrating dosimeters wereact ually in the field. However, these integrals arelargely representative of the dose from groundcontamination, since the major fraction was re-ceived during the earliest minutes. Subtractingthe dose rate integral from the cloud and deposi-tion dose yields the cloud dose. The values ob-tained are given in Table IX. Plots of these in-dividual e~posures for the downwind and up-wind directions are given in Fig. 31, where theprompt gamma dose is that obtained, as explained,from previous Kiwi reactor tests. The neutron doseis that actually measured during this test, since itis relatively free of the influence of such factorsas weather, cloud, and deflagration. The clouddose is largely either the maximum or minimumvalue derived in Table IX. Sometimes this valuewas modified to make it consistent with all dosesmeasured at a given distance or other geometricalfactor. The deposition dose given in Fig. 30 is de-rived by taking the numerical integral of the doserate at the various stations from time of arrivalof the cloud until 5 minutes after the excursion.This value was considered representative of theexposure one would receive from deposited activityif he were caught in an accidental excursion andh?d to evacuate the area.

Personnel hazards are summarized as follQws:Out to approximately 300 ft, almost all radiationexposures wouId be fat.d, being in excess of i ,000rads. Between approximately 300 and 600 ft,varying degrees of radiation injury including somefatalities, would occur as exposures would be be-tween 200 and 1,000 rads. Between approximately600 and 750 ft+ exposures would be between 100and 200 rad, producing slight illness. From 750 to

34

TABLE IX. CALCULATIONS OF COMPONENTS OF TOTAL EXPOSURE

100-090

100-180

100-!270

200-000

200-090

200-180

200-270

500-000

500-090

500-180

500-270

500-045

500-120

500-240

500-315

1000-145

1000-180

1000-210

1000-240

1000-270

1000-300

2000-160

2000-190

2000-220

2000-250

2000-280

2000-310

Integral

lhsimeter Prompt DoseDose (from Fig. 6.10)(d) (mR)

3.2 X 108- ‘- ““ “--

4.9 x 106

3.5 x 106

1.0 x 106

9.4 x 106

2.1 x 106

1.3 x 106

1.2 x 106

1.1 x Iw

1.6 X I@

1.4 x I(Y’

8.9 X I(Y

1.1 x I@

2.1 x lo~

1.3 x lo~

1.1 x 104

2.6 x 104

5.6 X 104

1.5 x 104

4.8 X 104

8.4 X I@

1.8 X 108

3.9 x 102

41.0 x 1(Y

2.1 x 108

1.3 x 102

6.0 X IV

23 x 1u“

2.3 X I(Y

2,3 X I@

4.5 x I@

4.5 x 105

4.5 x 1(F

4.5 x 106

5,2 X I@

5.2 X 104

5.2 X I@

5.2 X IV

5.2 X I@

5.2 X 104

5.2 X 104

5.2 X 104

1.0 x 104

1.0 x 104

1.0 x 104

1.0 x 104

1.0 x 104

1.0 x 104

7.0 x 102

7.0 x 102

7.0 x 102

7.0 x 102

7.0 x 102

7.0 x 102

integralofDose Rate

Cloud + RecordDeposition (Deposition)

(mR) (mR)

9 x 106

2.6 X 108

1.2 x 106

6 X’ I@

4.9 x lW

1.6 X lV

8.3 X I@

6.8 x 10’

5.7 x’ 104

1.1 x I(P

8.8 x 10’4

3.7 x 104

5.8 X 104

1.6 X 106

7.8 X 104

1.0 x 1(Y

1.6 X 104

4.6 X 1(Y

5.0 x 1P

3.8 X I@

—

1.1 x 108

3.2 X I(P

3.3 x 102

1.4 x I@

6.0 X 102

—

1.2 x I(Y

9.1 x I@

3.5 x 106

3.4 x 104

2.5 X 104

3.8 X 105

5.0 x 104

6.2 X 108

6.7 X 108

3.2 X 104

9.9 x 108

7.4 x 108

!5.8 X 108

2.3 X 1(F

8.1 X I(Y

1.3 x I&

3.9 x l@

1.5 x 104

1.5 x 10’

“9.4 x 10’

1.3 x 1P

6.5 X 101

7.8 X 101

3.8 X 102

7.0 x 1(P

1.6 X 102

3.5 x 101

Cloud Dose(mR)

5 minDeposition

Dose(mR)

7.8 X 106

1.7 x loo

7.7 x ICF

5.7 x I@

4.7 x I@

1.2 x 108

7.8 X lW

6.2 X 104

5.0 x 104

8.0 X 1~

7.8 X 104

3.0 x 104

5,9 x 104

1.6 X I&

7.0 x 104

—

1.2 x 104

3.1 x 104

3.5 x l@

2.9 X I&

—

1.1 x lN

3.1 x 108

2.9 x I@

1.3 x 108

4.4 x 102

—

1.2 x 105

3.3 x I(P

1.5 x 105

2.4 X 1~

2,0 x 104

2.2 x I(Y

4.6 X I@

3.0 x I@

4.3 x i@

3.0 x 104

9.5 x 102

2.4 X 108

—

3.5 x 102

2.5 X 108

4.8 X I@

1.8 X 108

6.7 X I@

6.2 X lCP

—

4.8 X IW

4.3 x 101

1.8 X IW

1.5 x 102

2.1 x I@

9.5 x 101

1.2 x Iw

35

l\\ UPW[ND

“4,10= TOTAL EXPOSURE

-.,h.

h. PROMPT NEUTRON

\.

‘.

J%$, PROMPT GAMMA\

‘\

‘/\, ‘l\In = I I I.-

100 200 500 1000 2000

DISTANCE, FEET

J4000 0000

!- -/

00WNWINO

106

~.E

PROMPT NEUTRON

w- 10’

5

assaoA< 104g

ug

103 :

102 1 1 1 I

100 200 500 1000 2000 4000 8000

DISTANCE, FEET

Fig. 31. Components of radiation exposure vs. distance.

1,200 ft, exposures would range from 25 to 100 any, injury or clinical effects, but exposures woularad, producing some very slight hemotological exceed approximately 3 rads and would requirechange, but no ilhess. Beyond 1,200 ft, out to administrative investigation and reporting. Beyondapproximately 2,000 ft, there would be little, if 2,000 f~ there would be no hazard.

VII. THE CLOUD GROWTH AND ASCENT,

Effluent clouds from instantaneous reactor dis-asters have been a subject of some speculation be-cause their behavior is an important factor in re-actor siting and hazard evaluations. Cloud be-havior is not well understood and, since Kivvi-TNT afforded an opportunity to observe an efflu-ent cloud from a simulated uncontained reactordisaster, efforts were made to document it to thefullest practicable extent. This chapter discussesthe visually recorded behavior of the effluentcloud; radiological effects are discussed later.

Continuous photographic sequences of thecloud were taken from five locations around thetest point from the instant of the excursion untilthe cloud was out of photographic view, approxi-mately 10 minutes later. The Appendix containsthe tabulated data obtained from these photo-graphs and discusses the methods of analysis. Thismaterial is available in no other publication.

Figure 32 shows the cloud rise, plotted linear-ly as mean altitude vs. distance. Figure 33 showslogarithmic plots of cloud mean altitude and topaltitude vs. time. Figure 34 logarithmically de-picts cloud vertical and horizontal diameter.

Figures 32 and 33 indicate that the cloud roserapidly for about 3 minutes to a mean altitude ofabout 2,500 f~ presl.unably under the influenceof the thermal disequilibrium between it and thesurrounding atmosphere. It then apparently stabil-ized; the mean and top altitudes continued to in-crease, although much more slowly, while thebottom altitude remained essentially constant. Thecontinued increase in cloud size after stabilizationcan be attributed to atmospheric dispersion, butthe slow increase in altitude after stabilization isdifficult to explain.

The continued increase in the top altitude led

36

I10=

, I I , , , t I 1 , , I , I IN lw

TIME. SECONOS

1“’’’”

I I , , Ivi ~

Fig. 32. Cloud center altitude w. distance. —

t w2RIZONTALDIAMETER/1

lo~ t I 1 I , , 1 , , 1 i , 1 I10 100

TIME, SECONOS

Mean Altitude

I 1 I 1111 i I I I I 1111 I 1 I

~

IllIl.

.103 —Illo

:ij

a

K+ I I I I Ill I I I I I 1111 I I 1 I 1

10’ 102TIME, SECONDS

Top Altitude

Fig. 33. Cloud altitude vs. time (logarithmic plot).

to the belief, on an earlier, less thorough, examina-tion of the data, that the cloud did not stabilizeuntil about 10 minutes after the event. However,Figs. 32 through 34 indicate a clear change in mo-tion very close to 3 minutes after the event, lead-ing to the conclusion that the cloud stabilized atthat time. All further discussion will assume cloudstabilization 180 seconds after the excursion.

2

t-~ 103—t!s

‘tjs

Ioc– t 1 , I , ! , I , I , !10 100

TIME, SECONOS

Fig. 34. Cloud diameter vs. tinm

Straight lines were fitted by means of least-squares techniques to the data plotted in Figs. 33and 34, yielding the following relationships:

For cloud mean altitude before stabilization,An = 58.0 t0724. (7.1)

For cloud mean altitude after stabilization,A. = 925 iY-lse. (7.2)

For cloud top altitude before stabilization,A, = 118 tO.648. (7.3)

For cloud top altitude after stabilization,A, = 863” t“.zso.

For cloud vertical diameter,H = i62 tO.4611

For cloud horizontal diameterzation,

W = 61.6 t“”oal.

(7.4)

(7.5)

before stabili-

(7.6)

For cloud horizontal diameter after stabiliza-tion,

W = 8.94 t. (7.7)

37

In these relationships, length is in feet and timeis in seconds. Another relation between cloud al-titude and time that can be observed from thesedata is

A = Af (1 — ep’). (7.8)

This relation has an advantage for some computa-tional purposes in that it and all its derivatives arecontinuous, whereas there are discontinuities inthe derivatives of the first set of relations. Valuesof AC and p were found using least-squares curvefitting techniques, and yield the following equa-tions,

A – 2880 (1 –m— e-0.490T) + 7~ (7.9)

At = 4218 (1 – e-0”418’) + 194 (7.10)

where Am and A; are mean altitude and top alti-tude in feet, as before, but T is now expressed inminutes. The fit of the data to Eqs. 7.9 and 7.10is shown in Fig. 35.

One particularly interesting aspect of cloudbehavior was the correlation between the actualheight of stabilization and heights of stabilizationpredicted by, the few available models using knownor assumed meteorological conditions. The firstreported comparison, made without detailed exam-ination of the actual weather parameters, bhtrather with assumed “usu”d” or “typical” values,gave a value lower than the actual cloud top al-titude at 10 minutes, but very near to its mean al-titude at 3 minutes. This particular example used

CLOUD CENTER ALTITUDE Vs TIME

30W0

0

2w- —1-Wf

z

[!111,111!1111111

o , Expulman?al pdnlg0

$— . h. 2ESO(I.,-.49Ot )+ 70

3aooo

0

0

0 2 4 6 6 10

the Sutton model for cloud rise as discussed in“Meteorology and Atomic Energy.”14

A more careful consideration of the threemodels for cloud height prediction discussed inReference 14 reveals that all three involve theuse of an actual or implied gradient of potentialtemperature and, if there is no gradient of po-tential temperature, no rise can be defined bythese models. The temperature profile actuallymeasured near the test point a few minutes afterthe Kiwi-TNT excursion showed a lapse ratenearly equal to the dry adiabatic lapse rate inmost of the atmosphere through which the cloudrose; therefore, the potential temperature gradientin this atmosphere was very nearly zero, andcalculations of cloud rise using these models werenot very meaningful. (As a matter of interest, atemperature profile nearly equal to the ~ adia-batic lapse rate has been frequently measuredwhen nuclear rocket reactors have been tested. )Another difficulty would have arisen with thesemodels even had the potential temperature gradi-ent not been zero, in that some of the other para-meters are difficult or impossible to measure, evenwith the extensive equipment utilized for theKivvi-TNT experiment, and resort must be madeto assumed typical values for these parameters.

Finally, these models also require a knowl-edge of the thermal energy contained in, and thetemperature of, the embryo cloud. Both thesequantities can be only crudely estimated for thisexperiment. An instant after the excursion, anincandescent ball appeared where the reactor

CLOUD TOP ALTITUDE Vs TIME

TIME IN MINUTES TIME IN MINUTES

I?lg. 35. Cloud altitude va time (least-equarea plot).

38

stood, which rapidlythe cloud. The rate of

coded and developed intoheat transfer from this ball

by radiation was sufficient to cool it from whiteincandescence, through dull red, to a black cloud,in approximately i second. It therefore seems ap-propriate to assign an initial temperature to thecloud of perhaps a few hundred degrees centi-grade, since incipient red heat occurs at approxi-mately 500 to 550°C. What constitutes a “few”in this case is subject to guesswork. The amountof energy liberated during the excursion is rela-tively well known, being approximately 104MVV-sec, 10~0J, 2.5 X 10e g-cal, or 107 Btu. Only about1~0 of this was lost as kinetic energy, an incon-sequential amount for purposes of this discussion.The amount of energy lost by radiation can beapproximated if it is assumed that the specificheat of the incandescent ball remained essentiallyconstant from 3,000 to 800”K, in which case ap-proximately 70% of the energy would be lost byradiation, leaving about 3 X 109 J, 7 X 108 g-cd,or 3 X 106 Btu. Corrections could be entered fornonconstant specific heat, bu~ as will become ap-parent, other difficulties and uncertainties makesuch a refinement extraneous to this discussion.An additional complication is that samples of thecloud for radiochemical analysis collected a fewminutes after the event by aircraft contained verylittle graphite.]6 This can be explained by assum-ing that the hot, highly fra=gented graphiteoriginally in the reactor core was oxidized duringcloud development. Radiochemical analyses of

cloud samples indicate that at least half of thecore was present in the cloud. (Approximatelyhalf of the unfissioned uranium, and two-thirdsof the resultant fission products were calculated tohave been released to the cloud.) The reactor corecontained approximately 1,000 kg of graphite. Thisamount of graphite, if oxidized to carbon dioxide,would liberate approximately 3 X 1010 J, 7 X 10°g-cal, or 3 x 107 13tu. It is apparent that the a-mount of heat energy that could be liberated byoxidation of core graphite during cloud rise isappreciable — of the same magnitude as the nu-clear energy released during the excursion. Anestimate of the actual thermal energy, and its rateof release, is therefore very difficult to make, as isa meaningful comparison of the actual cloud riseduring this experiment with predictions of risemade using any of several available models.

A rule of thumb is that the height of a reactordisaster effluent cloud may be estimated by as-suming that it will rise 300 to 500 meters above theaverage base of fair weather cumulus clouds whena dry adiabatic lapse rate exists. This altitudewould be at the base of an upper stable layer,such as occurred at approximately 9,000 feet MSLon the day of the Kiwi-TNT event. By this ruIe,the cloud should have risen to 6,500 to 7,OOOft a-bove terrain. Its altitude at stabilization was sub-stantially below this, in fact it stopped rising a fewthousand feet below the base of the stable layer.

VIII. THE CLOUD WAKE

Information used in this chapter is takenfrom “Nevada Aerial Tracking Syste~ Very Pre-liminary Report of Kivvi-TNT Event,” EG&G, Inc.,Santa Barbara, California,e and from LA-3395-MS, “Radiation Measurements of the Effluentfrom the Kivvi-TNT Experiment,” by Hendersonand Fultyn.le

Because the Kivvi-TNT was a unique, con-trolled simulation of a phenomenon frequentlycalled a maximum credible reactor accident, therewas great interest in the radiological characteristicsand effects of the effluent many miles from thetest point. The interest of LASL was to measurethe levels of airborne radioactivity and grounddeposition, to try to determine its isotopic con-centration, and to relate this information to cur-rent atmospheric dispersion models to test theirvalidity. The USPHS documented the effects ofthe long-range effluent cloud on the people andagriculture dovvnvvind.b The results of the LASL

investigation are given in this and the next chap-ter. The USPHS results are in Chapter X.

A general understanding of the cloud pathwas obtained by aerial tracking. The NevadaAerial Tracking” System (NATS) aircraft mannedby personnel from EG&G observed the radioactivecloud shortly after it reached California and againas it reached the Pacific 0cean.8

The LASL effluent cloud sampling stationsblanketed a quadrant downwind from 4,000 ft to50 miles from the test point.le Portable trailer-mounted sampling equipment was used as de-scribed in Chapter II. Figure 36 shows the loca-tion of LASL sampling stations for this event. Be-cause of the proximity of the Kiwi-TNT test pointto Reactor Test Cell C at Jackass Flats, stationplacement was on arcs previously established forthe normal reactor test point at the test cell. Allresults presented here use the station designations

39

.

a. Close range. \

t ‘ =—~

LJ!Q!i’(lz. zrx.

\ 9-2,0.114T SITE

-/”,6.270. 8.27..

,.260.

‘. ,6-2s0. ,.25

‘. ,..

8.% v

,e,,u,. *,54

,Z ?s7.*%O”

., $.

-.? ~o ~

,. \. .

‘~b. Intermediate.

Fig. 36. Air sampling stations.

40

c. Long range.

~g. 36. Collti.rud,

of these areas. Because these previously established each fitted with a transition piece to accommodatearcs were not exactly concentric with the Kivvi- a 6 X 9-in. Whatman No. 41 filter paper. ThisTNT test point, Table X is provided to show the particulate filter was backed up by a parallel pairtrue azimuth and distance from the test point for of organic vapor type respirator cartridges packedeach station on the 41,000-, 8,000-, and 16,000-ft with activated charcoal, which allowed for thearcs. gross separation of the airborne material into two

distinct fractions. The material collected on the

The Staplex* high-volume air samplers were *The Staplex Co., New York, N. Y.

41

TABLE X. SAMPLER LOCATIONS*

TNT Location TNT Location

Test Cell CLocation

4180

4185

4190

4-195

4200

4205

4-210

4-215

4220

4-925

4-230

4-235

4-240

4245

4260

4-255

4-260

44?65

4-270

8-180

8-185

8-190

8-195

8-200

Distance Azimuth(’) Test Cell C Distance &&ufi(a)

(ft)——

4,000-ft arc

4,540

4,520

4,490

4,460

4,420

4,390

4,350

4,310

4,260

4,220

4,170

4,12Q

4,060

4,010

3,960

3,910

3,860

3,800

3,760

8,000-ft WC

8,530

8,510

8,480

8,450

8,410

(0) Location (ft) (0)

8,000-ft arc (continued)

176

181

186

190

194

199

2U3

238

212

217

222

226

231

236

241

251

256

262

178

183

188

192

198

8-205

8-210

8-215

8-220

8-225

8-230

8-235

8-240

8-245

8-250

8-255

8-260

8-265

8-270

16-180

16-190

16-200

16-210

16-220

16-230

16-240

16-252

16-261

16-270

8,370

8,330

8,290

8,240

8,200

8,150

8,100

8,0W

7,980

7,940

7,890

7,840

7,790

7,74Q

16,000-ft arc

16,500

17,800

18,800

18,000

17,700

19,100

16,000

15,900

16,800

14,400

202

2U7

212

216

222

226

231

236

241

246

251

256

261

266

179

188

198

209

219

228

237

249

258

!%7

(a) North= O.

*The Kiwi-TNT test point was N 28° W at 600 ft from Test Cell C. The locations of the stations at

32,000 ft and beyond are not known precisely enough to make calculations of exact position in re-

lation to the test point worthwhile.

4Q

filter was assumed to be entirely particulate, andthat on the charcoal was assumed to be entirelygaseous at the time of collection. (These assump-tions, as well as the assumption that noble gaseswould not be collected on either medium, are notentirely true, but departures from them are most-ly small, although at times troublesome and notentirely resolvable. ) The nominal sampling rateof this system is 1 meter3 of air per minute.

The cascade impactors were of the Unico*design, selected on the basis of previous field ex-perience with several designs. Nondrying resin-coated plastic slides were used for the four im-paction stages and a membrane filter was placedafter the fourth stage as a fifth and final collector.The units were used to measure the radioactivityassociated with particles of sizes characterized bytheir effective aerodynamic diameters.

The sequential samplers consisted of eightStaplex sampler heads, each fitted with a 4-in. -diameter Whatrnan No. 41 filter paper. Thesampling sequence was initiated by radio com-mand, but was manually preset to sample duringthe total estimated time of cloud passage. Run-ning times per, sampler varied from 5 minutes onthe close-range arcs to 30 minutes on the distantarcs. Although the samplers were intended tocollect information regarding cloud arrival timeand longitudinal concentration profile with re-spect to time, the sequencing mechanisms did notall function properly and meaningful samples werenot collected. Because analysis of the data revealedthem to be clearly absurd (several stations indi-cated that the cloud passed before the excursion),they are not presented here.

Samples of deposited activity were collectedon paired 7 X 10-l/g-in. Lucite trays coated witha clear, nondrying alkyd resin. The txays wereplaced horizontally, face up, on stakes approxi-mately 30 in. above grade at all trailer locations.Acrylic plastic trays were used to avoid thetrouble previously encountered with neutronactivation of metallic trays and to permit micro-scopic examination of the collected material.

Film packets of the type described in ChapterVI were also placed at each trailer location onthe stake supporting the resin-coated trays. Themethods employed and results obtained from thisplacement are given in Chapter VI.

The radioactivity associated with each high-voltime air sample and resin-coated tray was de-

*Union Industrial Equipment Company, Port Chester,N. Y.

termird using simultaneous beta-gamma detec-tors housed in a common shield. Beta countingwas done using one of several 7 X 10-l/z-in.methane gas flow proportional counters, each lo-cated at the top of its iron counting shield. Thegamma counting probes consisted of a 10-in. di-ameter by 5-in. -thick plastic phosphor coupled tofive photomultiplier tubes. The gamma probe out-put was fed into a standard single-channel ana-lyzer ‘operated in the integral mode with thethreshold set at approximately 100 keV. Themechanical arrangement of the components allowsfor variation of counting geometries inside theshield. Specially desiamed beta proportional count-ers were used to count the cascade impactor stagesand sequential samples. Quantitative isotopic in-formation about selected samples was derived byuse of multichannel gamma pulse height analysis,discussed in the next chapter.

Table XI shows the total dosages (pCi-sec/m8)and deposition concentrations (pCi/m2) with theactivity corrected to estimated time of cloud pas-sage. Airborne particle dosages were calculatedfrom data generated by the analysis of fiiterpapers, and the airborne gaseous dosages fromanalysis of the charcoal cartridges. The depositedactivity per unit area was determined by assumingthat the ground deposition was the same in com-position and magnitude as that collected on theresin-coated trays. Extrapolations of radioactivitywith respect to time were performed using theisotopic compositions of samples presented in thenext chapter.

Table XII shows measured deposition vel-ocities at the stations where there was significantsample activity. Values for airborne particulatematerial were obtained by dividing the depositionconcentration measured by the resin-coated tray(Ci/m’) by the airborne particle dosage measuredby the filter paper only (Ci-sec/ 9,. Values for

r

total airborne material were obta ned by dividingtray activity by total airborne d sage (filter ph.Lscartridge dosage). These values are questionablebecause the isotopic composition of the depositedactivity is different from that of the airborneactivity. The large variations in deposition velocityfrom station to station are not unusual, however,as this phenomenon is also noted in data for allthe normal reactor runs. This suggests that theconcept of a constant deposition veloci~ is gross-ly in error, and that the “constant” should bereplaced by a statistically varying quantity.

Table XIII shows the results of the analysisof samples collected by the cascade impactors.These results were derived using the activity on

43

TABLE XI. MEASURED DOSAGES AND DEPOSITION CONCENTRATIONS

Station

4-18041854-190419542004-2054210421542204-2254-23042354-2404-2454-2504-2554-2604$X554-270

8-1808-1858-1908-1958-2008-2058-2108-2158-2208-2268-2308-2358-2408-2458-2508-2558-2608-2658-270

16-18016-19016-20016-21016-22016-230

Dosage(pCi-sec/ma)

Airborne Particulate Airborne Gaseous

;.: ~ :(I;

1:6 X 1017.1 x 1013.2 X 1021.0 x 1016.0 X I@3.1 x 1041.2 x 1082.2 x 1041.4 x 1048.3 X I@4.8 X I@4.6 X I@1.9 x 1026.8 x 1017.1 x lW8.7 X I@1.0 x 101

2.6 X 10-13.6 X 10-11.6 X 10°1.1 x 1011.6 X 1012.0 x 1024.5 x 10s1.5 x 1049.3 x 1084.2 X I@1.6 X 1012.3 X I@5.6 X 1021.8 X 10’4.2 X 10°6.7 X 1011.7 x 10-13.9. x 10-13.8 X 10°

3.0 x 10-11.8 X 10-12.1 x 10’J6.7 X I(Y1.6 X 1098.3 X 102

4,000-ft arc

Bkgd1.1 x 1008.2 X 10°1.1 x 1013.2 X 1011.1 x 1004.3 x 1021.4 x 10s3.1 x 1012.0 x 1081.6 X IN1.1 x 1025.0 x. 1024.6 x 1027.8 X 10°4,4 x 1002.8 X 10-11.1 x 10’J3.7 x 100

8,000-ft arc

5.3 x 1008.1 X 10-19.0 x 10-11.8 X 1(P2.7 X 1015.2 X 1015.3 x 1021.7 x I(Y2.1 x 1027.2 X 1024.5 x 1005.2 X 10°1.4 x 1027.4 x 1001.8 X 10-29.1 x 1007.1 x 10-14.6 X 10-11.4 x 10-1

16,000-ft aI’C

2.1 x 1008.5 X 10-21.6 X 1002.0 x 1021.9 x 1021.6 X I&

Total

1.4 x 10-12.7 X 10°2.4 X 1018.1 X 1013.!5 x 1021.1 x 1016.4 X I@3.2 X 1041.2 x I(Y2.4 X 1041.6 X 1049.4 x I&5.3 x 102’5.0 x lo~2.0 x 1027.2 X 1017.1 x 1019.8 X 10°1.4 x 101

5.5 x 1001.2 x 1002.5 X 10°2.9 x 1014.3 x 1019.5 x 1025.1 x I@1.7 x 1041.1 x 1044.9 x 1022.0 x 1012.8 X 1017.0 x 1022.6 X 1014.9 x 1007.6 X 1018.8 x 10-18.5 X 10-13.9 x 100

2.4 X 10°2.7 X 10-13.7 x 1006.9 X I@1.8 X I(Y9.8 X 102

GroundDeposition(pCi/m2)

2.3 X 10-21.5 x 10-21.6 X 10-24.9 x 10-22.5 X 10-11.8 X 10°7.8 X 10°6.6 x 10’3.4 x I&9.3 x 1002.8 X 10°5.2 X 10°4.4 x 1001.3 x 1005.6 X 1011.6 X I&l4.8 X 1021.1 x 10-27.2 X 10-B

BkgdBkgdBkgd

1.0 x 10-21.9 x 10-21.0 x 10-12.0 x 1002.1 x 1013.1 x 1008.7 X 10-18.2 X 10-11.4 x 1002.2 x 10-19.6 X 10-s9.7 x 10-2

BkgdBkgd

1.0 x 10-s7.9 x 10-8

9.6 X 10-46.9 X 10a8.5 X 10-a4.6 X I&4.7 x 10-12.0 x 10-1

44

I

TABLE XI. CONTINUED

Dosage(pCi-sec/ma)

Station ‘tiborne Particulate Airborne Gaseous

16-WI 2.9 X I& 7.6 X 10116-252 4.8 X 10-1 2.7 X 10016-261 2.2 x 10-1 1.5 x 10-116-270 7.4 x 10-1 5.5 x 101

32-19432-20632-2193%22832-2453 258

%3 273

6417264188642036421 i6421564221642306424164-251

128-180128-190128-24)012$-211128-225128-236128-250128-263128-266128-280

256-183256-190266-200256-210256-217256-225256-236256-240

32,000-ft arc

1.8 X 10° 8.4 X 10-11.1 x 100 9.0 x 10-11.8 X I(V 6.9 X I(P5.5 x 102 7.2 X 1012.2 x 101 6.6 x 1002,8 X 101 Bkgd2.0 x 100 8.1 X iO_l

BkgdBkgdBkgd

8.7 X I(P6.2 X I(Y1.1 x lW1.1 x 10-1

BkgdBkgd

2.1 x 10-17.4 x 10-22.4 X 1011.7 x 1(Y1.0 x 1024.6 X 10-15.6 X 10-12,1 x 10-11.5 x 1012.0 x 10J

Bkgd4.8 X I(P7.4 x lo~1.7 x 1021.8 X 10-11.2 x 10J2.3 X 10-12.2 x 10J

64,000-ft =C

7.3 x 10-21.5 x 10-16.4 X 10-12.7 X I@2.5 X I@3.7 x 1003.1 x 10-11.0 x 1001.6 X I@

128,000-ft arc

3.3 x 10-11.5 x 10-11.4 x 100!5.2 x 1(P2.5 X 10°2.3 X 10-21.5 x 10-12.2 x 10J2.4 X 10-12.1 x 10-1

256,000-ft WC

Bkgd1.6 X 1012.4 X I@6.7 X 1009.9 x 10-2

BkgdBkgdBkgd

GroundDepmition

Total (pCi/m2)

3.6 X 102 6.2 X 10-23.1 x 100 5.0 x 10-23.7 x 10-1 4.3 x 10-s1.3 x 100 1.1” x 10-2

2.7 X 10° 1.3 x 10-12.0 x 100 6.9 X IIY1.9 x 104 2.8 X 1016.2 X 102 2.5 X 10-12.8 X I(Y 2.0 x 10-12.8 X 101 3.5 x 10-22.8 X 10° 1.2 x 10-2

7.3 x 10-21.5 x 10-16.4 X 10-19.0 x 1026.4 X IN1.2 x 1024.2 x 10-11.0 x 1001.6 X 10°

5.3 x 10-19.3 x 10-12.5 X 1011.7 x 1081.1 x 1024.8 X. 10-17.1 x 10-14.3 x 10-14.0 x 10-14.1 x 10-1

BkgdBkgd

2.3 X 10-2Bkgd

3.7 x 1001.9 x I@6.5 X 10-81.1 x 10-1

Bkgd

Bkgd4.0 x Iw4.8 X 10-12.4 X 10°3.7 x 10-2

13kgd4.2 X 101

BkgdBkgdBkgd

Bkgd 4.3 x 10-84.9 x 102 5.1 x 10-17.6 X 102 3.8 X 10-11.8 X 102 Bkgd2.8 X 10-1 5.2 X 10-41.2 x 10-1 Bkgd2.3 X 10-1 Bkgd2.2 x 10-1 Bkgd

46

TABLE XII. DEPOSITION VELOCITIES IN CENTIMETERS PER SECOND

StationTotal Airborne Material(gaseous + particulate)

4-1804-1854-1904-1954-2004-20542104$?1542204225423042354-24042454%042554-26042654270

8-1958-2008-2058-2108-2158-2$M8-2258-2308-2358-24Q8-2458-2508-2558-2608-2658-270

ParticulateMaterial Station

4,000-ft arc

16.0.560.0670.0600.071

16.0.122.12.80.0390.0180.0550.0830.0260.280.220.0680.110.051

8,000-ft arc

160.940.100.0690.078

18.0.132.12.80.0420,0230.0630.0920.0280.290.240.0680.130.072

0.0340.0440.0430.0390.120.0280.0184.15.00.0310.0370.23——

0.120.20

0.0910.120.0500.0440.140.0330.0215.16.10.0390.0530.23——

0.260.21

Total Airhmne Material(gaseous + particulate)

16,000-ft arc

16-18016-19016-20016-21016-22016-23016-24016-26216-26116-270

0.04)2.60.236.70.0260.0200.0171.60.0120.85

32,000-ft WC

32-1943232063%21932-2283%24532-25832-273

4.8350.

0.150.0400.71

13,0.43

64,000-ft WC

64-203642116421564-22164-23064241

3.6—

0.05816.1.5

11.

12&OO0-ft arc

128-190128-200128-211128-225128-!236128-250

1.7i .90.140.034—

59.

256,000-ft WC

256-190256-200256-210256-217

0.100.05—

0.19

ParticulateMaterial

0.323.80.406.90.0290.0240.021

10.0.0201.5

7.2630.

0.160.0450.91

13,0.60

——

0.06017.5.9—

5.42.00.140.037—

75.

0.110.051—

0.29

46

TABLE XIII. AIRBORNE PARTICLE SIZE DATA, ACTIVITY ON UNICO IMPACTC)R STAGESAT COUNT TIME (PICOCURIES)

MedianDiameter

Station Stage 1 Stage 2 Stage 3 Stage 4 Stage 5 (P)

GeometricStandardDeviation Comments I

4,000-ft arc

4-210 568 695 1$25 530 23,3074-215 134,172 200,034 14,537 114,340 126,641

92% < t,U

5.466% >5fL86% <Ip

84% <1P82% <1P I

3.8

2.6

1.6

,,..

4.84.8

4-22Q 11,9414-225 1,2864-230 32,5554-235 6,42442443 1,7314245 1,5854250 i ,647

6;2$12,851

9943,051

783226141

2’%329

2,47!31,577

392299

77

5;366 “2632,972 47,641

713 33,4336,040 85,7041,222 18,8802,649 24,0692,084 437

8,000-ft WC

1,471 22,9844,988 131,1824,965 4,726

1,102 37,703

16,000-ft arC

88% <Ip6.6

1,2532,!5952,153

568

80% <lP83% <1P

7.288% <lp

8-210 3,2708-215 17,4378-220 3,1738-225 3,028

220797275332 I

95% >5p72% >5P89% <Iw87% <Ip

16-210 27,97816-220 11416-230 10716-240 125

1,306134821

193153734

9,988 023 6

145 2,417169 1,900

32,000-ft -C

32-219 161,930 8,230 53,915 23,940 23,892

64,000-ft arc

120 2,2361,515 31,910

914 11

128,000-ft EWC

219 7,515

256,000-ft arc

62% >5P

167,730

765

148694316

81% <lP69% <l~t84% >5P

64-211 11964215 35364221 8,018

91% <Ip128-211 81 262 64

256-190 886266-200 1,897

6,277536

16271

262 1,6501,413 4,191

3.6 55% <Ip3.6 55% <Ip

47

the impactor stages at the time the samples werecounted, and a calibration of a typical impactorfor particles with a specific gravity of 2.6. Thestages of a single unit were counted sequentiallywithin 10 minutes of each other; corrections fordecay within this period were negligible. Thesedata allow one to approximate the aerodynamicsize characteristics of the airborne particulate ma-terial. In general, the isotopic composition of thematerial on the early stages (when sufficientactivity was available to analyze) was similar tothat found on the resin-coated trays, whilq thecomposition of the activity on the final stages

,approxirnated that collected on the high-volumefilter papers.

Table XIV shows the results of calculationsbased on the analysis of the air samples collectedduring the experiment. It gives for each samplestation the hypothetical whole-body gamma dosefrom the radioactive cloud. This dose is calculatedassuming that the station was immersed in ahemispherical cloud of infinite extent and of uni-form concentration equal to that measured at thestation and extrapolated to time of cloud passage.It is also assumed that, on the average, one photonwas emitted per nuclear disintegration, with aver-age photon energy of 0.7 MeV. It is recognizedthat the validity of the assumption of an infinitehemispherical cloud is poor for stations within afew miles of the test point; validity should im-prove as the distance increases but the assumptionis still dubious even at long distances. However.in spite of its shortc:,rnings, this assumption isfrequently made in dermng doses from radioactiveclouds for hazards evaluations and other argu-ments. Although sufficiently sensitive dosimetricequipment for accurate measurement of cloud dosewas not available at any of the trailer locations,these calculations give some estimate of the hazardthat might have been encountered. For the fewlocations where direct comparison of these hypo-thetical doses with measured doses can be made,discrepancies must be attributed to the dubiousvalidity of the premises of the calculation, ordosimetric errors, or both.

Table XIV also lists a hypothetical adult thy-roid dose due to iodine inhalation at each samplingstation. These data arise from the actual iodineisotope dosages measw”kd at each station by theair sampling equipment. The factors at the rightfor exposure to 1 Ci-sec/ms of a particular iodineisotope were used to calculate the thyroid dose.These dose factors have been derived using Na-tional Council for Radiation Protection criteriafor organ size, breathing rate, and fraction of iso-tope retained.

Table XV presents some hypothetical resultsof calculations based on the analysis of the resin-coated trays. The hypothetical ground depositiondose rate was calculated by assuming that the sta-tion was located above an infinite plane with uni-form deposition of material of the same concen-tration as that measured on the resin-coated trayextrapolated to the time of cloud passage; that, onthe average, one photon was emitted per nucleardisintegration; and that the average photon energywas 0.7 MeV. The i-year integrated depositiondose was calculated assuming a clean area beforethe arrival of the cloud and no subsequent con-tamination. The integration was performed usingonly the decay of the isotopes identified as beingpresent. One year was selected for the integrationto attempt to account for leaching and other re-moval processes.

Figures 37 through 39 show isodosage andisoconcentration contours plotted from the mea-surements discussed above. Figures 40 through 46show crosswind (azimuthal) profiles of exposuredosage, ground deposition, and deposition veloci-ties. Figure 47 shows the cloud centerline (maxi-mum) dosage, deposition concentrations, and de-position velocities measm-ed on each arc vs. dis-tance. Figures 48 through 50 show cloud centerlinecalculations of whole-body dose, adult thyroid in-halation dose, and deposition dose rate, fromTables XIV and XV.

The “notch,” or relative minimum, at 16,000ft in the plot of cloud centerline dosage vs. dis-tance (Fig. 47) is typical of concentration datafrom normal, nondestructive reactor runs. Severalspeculations as to its cause are available, but ithas not been soundly explained. One of the firstthings that comes to mind is that the concentra-tions at long distances (6 miles and beyond) aredue to the material in the elevated cloud, whilethe concentrations at close range are due to ma-terial in the stem, which behaved as a theoreticalground-level release. Figure 47 implies that thestem contained about 10~0 as much actitity as theelevated source, if both are considered to be pointsources.

Thyroid Dosein Rads

Due to 1 Ci-sec/maIsotope of Isotope1811 3291821 12.41881 92.31841 5.618SI 25.3

48

TABLE

Station

4-180418541904-1954-2004-2054-2104-2154-2204-2254-2304-2354-24042454-2504-2554-2604-2654-270

8-1808-1858-1908-1958-2008-2058-2108-2158-2208-2258-2309-2358-2408-2458-2508-2558-2608-2658-270

16-18016-19016-20016-21016-220

XIV. CLOUD PASSAGE EFFECTS

Whole-Body Dose Adult Inhalationdue to Cloud Passage Thyroid Dose

(rads) (rads)

4,000-ft arc

3.16 X 10-85.68 X 10-74.90 Y 10-61.71 x 10-67.77 x 10-~2.02 x 10-u1.22 x 10-38.25 X 10-s2.26 x 10-45.42 X 10-s3.26 x 10-31.91 x lo~1.09 x 10-39.13 x 10-44.33 x 10-61.66 x 10-61.53 x 10-62.16 X 10-62.86 X 10-6

8,000-ft arC

9.96 X 10-72.29 X 10-75.14 x 10-75.50 x 10-’J8.28 X 10-64.89 X 10-59.51 x 10-43.44 x 10-82.30 X 10-89.15 x 10-44.26 X 10-65.73 x 10-61.36 X 10-45.63 X 10-”8.93 X 10-71.70 x 10-51.64 X 10-T1.74 x 10-’8.74 X 10-7

16,000-ft aI’C

4.03 x 10-81.89 X 10-51.36 X 10-41.89 X 1045.99 x 10-42.06 x 10-68.41 X 10-83.31 x 10=7.78 X 10-43.89 X 10-22.88 X 10-21.92 X 10-29.26 x 10-38.43 X 10*1.78 X 10-49.10 x 10-62.39 X 10-52.07 X 10-56.16 x 10-6

5.4?3 x 10-58.57 X iO-”9.82 X 10-61.88 x 10-42.90 X 10-46.02 X 10-46.88 x lo~2.17 X 10-22.50 X 10-28.61 x 10-s5.22 X 10-56.08 x 10-61.62 X 10-88.34 X 10-61.45 x 10-61.16 X 10-47.42 X 10-”4.95 x 10-62.70 X 10-6

4.40 x 10-7 2.57 X 10-’5.73 x 10-8 1.11 x 10-67.64 X 10-7 2.01 x 10-61,27 X 10s 4.55 x 10-83.26 x 10-4 2.78 X 10-3

Whole-Body Dose Adult Inhalationdue to Cloud Passage Thyroid Dose

Station (rads) (rads)

16-23016-24016-25216-26116-270

16,000-ft arc (continued)

1.70 x 1047.93 x 10-~5.79 x 10-7’7.84 X 10-s2.63 X 10-7

32,000-ft arc

32-19432-20632-21932-2283%24532-2583%273

41.80 X 10-73.59 x 10-73.79 x 10-31.06 X 10-45.07 x 1o-?4.96 X 10-s4.93 x 10-7

64,000-ft arc

64-17264-1886420364211642156422164-23064-24164-251

1.29 X 1082.63 X 10-81.14 x 10-71.34 x 1041.11 x lo~1.82 X 10-57.24 x 10-81.81 X 10-72.92 X 10-7

I$xl,ooo-ft arc

128-180128-190128-200128-211128-225128-236128-250128-263128-266128-280

8.58 X 10-83.70 x 1o-~3.55 x 10-62.39 X 10-41.45 x 10-66.68 x 10-81.03 x 10-76.79 X 10-86.38 X 10-86.48 X 10-s

266,000-ft WC

256-190256-200256-210256-217256-225266-236256-244)

6.08 x 10-69.40 x 10-52.20 x 10J3.96 X 10-81.51 x 10-s2.86 X 10”s2.63 X 10-8

2.14 X 10-31.04 x 10-23.26 x 10-61.91 x 10-66.95 X 10-8

1.13 x 10-61.17 x 10-61.72 X 10-21.12 x 10-39.11 x 10-61.14 x 10-71.09 x 10-5

9.85 X 10-72.01 x 10-68.70 X 10-68.47 X 10-47.24 x 10-31.14 x 10-44.25 X 10-”1.39 x 10-52.23 x 10-6

5.24 X 10-”2.43 x 10-64.48 X 10-52.38 X 10s1.36 X 10-17.93 x 10-72.81 X 10-63.63 X 10-03.92 X 10-83.50 x 10-6

1.19 x 10-31.84 X 10-34.47 x 10-42.32 X 1062.27 X 10-74.32 X 10-?3.97 x 107

49

TABLE XV. HYPOTHETICAL GRtNJND DEPOSITION EFFECTS

station

41804-1854-19041954-2004-2054-210421542204225423042354-2404-245425042554-2604-2654-270

8-1958-2008-2058-2108-2158-2208-2258-2308-2358-2408-2458-2608-2558-2608-2658-270

16-18016-19016-200

Deposition l-Year IntegratedDo~e Rate Deposition ‘Dose

(rads) (rads)

4,000-ft arc

2.85 X 10-7 6.96 X 10-81.91 x 10-7 4.66 X 10-62.03 X 10-7 4.95 x 10-66.07 X 10-7 1.48 X 10-53.10 x 10-6 7.56 X 10-52.23 X 10-s 5.44 x 10-49.79 x 10”5 2.39 X 10-88.15 X 10-8 1.99 x 10-14.26 x 10”4 1.04 x 10=1.16 X 10-4 2.84 X 1043.53 x 10-6 8.61 x 10-46.48 X 10-5 1.58 X IW5.45 x 10-6 1.33 x 10-s1.63 X 10-5 3.97 x 10-46.96 X 10-” 1.70 x 10-42.00 x 10-6 4.86 X IOJ5.95 x 10-7 1.45 x 10-61.40 x 10-7 3.42 X 10-69.01 x 10-8 2.20 x 106

8,000-ft WC

1.28x 10-7 3.13 x 10-62.42 X 10-7 5.91 x 10-61.27 X 10-6 3.10 x 10-62.57 X 10-s 6.26 X 1042.63 X 10-4 6.42 X 10-83.94 x 10-5 9.61 X 10-41.09 x 10-~ 2.65 X i 0-41.03 x 10-5 2.51 X 10-41.75 x 10-5 4.27 X 10-42.79 X 10-” 6.82 X 10s1.21 x 10-~ 2.94 X 10-”1.21 x 10-7 2.95 X 10-”

— —— —

1.26 x 10-8 3.06 X 10-79.92 X 10-8 2.42 X 10-”

16,000-ft =C

1.19 x 10-8 2.92 X 10-78.69 X 10-8 2.12 x 10-61.06 X 10-7 2.59 X 10-6

Deposition 1-Year IntegratedDose Rate Deposition Dose

Station (rads) (rads)

16,000-ft arc (continued)

16-21016-22016-23016-24016-25216-26116-270

321943X2Q63%2193%22832-24532-2583%273

64-2036421164-21564-2216423064-24164261

128-190128-200128-211128-225128-236128-250

256-183256-190256-200256-210256-217

5.71 x io=8.85 X 10-”2.49 X IO-67.79x 10-76.22 X 10-75.36 X 10-101.38 X 10-T

32,000-ft WC

1.40x 10-11.43 x 10-46.10 X 10-51.90 x lo~1.52 X 1051.31 x 10-S3.38 x 10-6

1.68 x 10-68.56 X 10-53.55 x 10-43.08 X iO-”2.52 X 10-”4.35 x 10-71.54 x 10-7

64,000-ft ilrC

2.87 X 10-7—

4.64 x 10-62.33 X 10-48.07 X 10-81.33 x 10-6

—

128,000-ft arc

4.14 x 10-62.10 x 10-88.71 X 10*7.56 X 10-56.19 X 10-51.07 x 10-63.79 x 10-6

7.12 X 106—

1.15 x 10-85.77 x 10-82.00 x 10-63.24 x 10-6

—

5.01 x 10-85.97 x 10-64.58 X 10-74.58 X 10-7

—

5.26 x 10-1

256,000-ft WC

1.26 X 10-81.50 x 1041.15 x 10-61.15 x IO-5

—

1.33 x 101

5.36 X 10-s6.32 X 10°4.79 x 10-6

—

6.50 X 10-a

1.44) x 10-61.65 X 1041.25 X 10-4

—

1.69 X 10-7

50

270=

do”

MICROCURIE SEC./M3

210’ -

lo=- Id

10’-10’ lzzza

10’-10’ !zzzz

KP- 10’

16’-10° m

270”—

32,000’ ARC

64,000’ ARC

128,000’ARC

256,000’ ARC

160”

MICROCURIESSEC./M3

.,04 -

103-104 m

102-103 lzzzzzi

10’-10’ zzzzzI

18-10’

d-lo” m

Fig: 37. Dosage from airborne particulate activity. Beta activity corrected to estimated time of cloud passage.

270”—

I

27CP

4,000’ ARC

8.000’ ARC

16,000’ ARC

32,000’ ARC

,.

MICROCURIE SEC./M3

.?10’

10’-10’

10’-10’ v2z//410”-10’

Id -10” Lzza

32,000’ ARC

64,000’ ARC

128,000” ARC

256,000’ ARC

,.

MIcROCURIE SEC./M3

2102 Izzzzn

,01-,0’ ezzz?

ICP-1o’

Id -d Dzl

Fig. 38. Dosage from airborne gaseous activity. Gamma activity corrected to estimated time of cloud passage.

51

I

4,000’ ARC

S,000’ ARC

16,000’ ARC

32,000’ ARC

.

27(Y

32,000’ ARC

64,000’ ARC

12WO0’ARC “

256,000’ ARC

●

MICROCURIEWM2

,0’-,02 m

,0”-,0’ m

d-d rzzzl

,62-,6+ m

Fig. 39. Activity on resin-coated trays. Beta activity corrected to estimated time of cloud passage.

I I It : i

AZIMUTH (“)

Fig. 40. Crosswind dosage, deposition, and deposition velocities — 4,000-ft arc.

52

I 1’ I I 1 L“’’’’’’”-l\

1-

1

+’ L DOSAGE

A ● TOTAL

A PARTICULATE

D GASEOUS

,f, ,,,IC3 I I I I I

ISO 190 200 ZIO 2S0 230 240 250 260 270 260

AZIMUTH (“) AZIMUTH (“)

Fig. 41. Crosswind dosage, depoaitiq and deposition velocities — 8,000-ft arc.

10+

AzlkklTH (“1

● 3

AZIMUTH (*)Fig. 42. Crosswind dosage, deposition, and deposition velocities — 16,~:ft arc.

53

1“’’’’’”; t I I I Ii

DOSAGE

10’ — ● TOTAL

a PARTICULATE

~ GASEOUS

%

~ 103—

0

ua

zoK 102—g~

u

203g 10‘—

uaz0axw 100

10‘—

16z I I I I I I I200 210 220 23o 240 2S0 26o 270 260

AZIMUTH (“)

10’

A OEPOSITION VSWCITY

2

uE

z %/occ2 10°~

zg~a1-2w0

~ ,04

z0~

;

w0

10*—

I I I I200 220 240 260

AzIMUTH (“1

Fig. 43. Crosswind dosage, deposition and deposition velocities — 32,000-ft arc.

I

+

,J\,1:R%’:c%qT’’N,,63210 220 2KI 240

AZIMUTH (“) AZIMUTH (“)

Fig. 44. Crosswind dosage, deposition, and deposition velocities — 64,000-ft arc.

54

OOSAGE

● TOTAL

A PARTICULATE

■ GASEOUS

I I 1 I I [ I I

162 I I I I I I 1180 190 200 210 220 230 240 25o 2S0 2T0 280

1● OPPOSITION CONCENTRATION

A OPPOSITION VELOCITY

AZIMUTH (“)

Fig. 45. Crorsvind dosage, deposition, and deposition velocities — 128,00CS-ftarc.

If DOSAGE

● TOTAL

~ A PARTICULATE

■ GASEOUS

U)

QJKao0ag

~1

<

~auKamon

ti100—

10-’ I I200 210 -220 230 240

AZIMUTH (“)

I I

● DEPOSITION WNCENTRATKIN16’— Oo

A DEPOSITION vELOCIT;

“s.

$

zg

4

g~

z9.1- 102—aK1- 1

Eu

;

$

Gg

u .3a 10

164 I I 1, I190 200 210 220

10*

AZIMUTN (“)

Fig. 46. Crosswind dosage, deposition, and deposition velocities - 256,00@ft zll’C.

55

II I I I

● DEPOSITION CONCENTRATION

A OPPOSITION VELOCITY

I I I I I4 e 16 32 64 128

OISTANCE (FEET x l&)

I

● ToTAL AIRBORNE

A PARTICULATE

_ GASEOUS

t I I I I I4 8 16 128

DISTANC: FEET x%

Fig. 47. Cloud centerline dosage, deposition, and deposition velocities.

II

0 Id .—s

~ MEASURED BY FILM

i~ CALCULATE FROM

MEASURED AIRBORNE>nom l& —

u 4

d

s

163 :

1644 I I I I I8 16 3t? 64 128 2s6

DISTANCE (FEET x I 0-3)

Fig. 4S. Centerline whole-body dose.

6

,6’4,6DISTANCE (FEETxld3)

Fig. 49. Centerline adult thyroid inhalation dose.

56

162 I [ [ I I -1

t\A

I I I I I4 8 [6 32 64 128 256

DISTANCE (FEET X 163)

Fig. 60. Centerline deposition dose rate.To obtain an estimate of the source term, or

amount of radioactive material released to thecloud, calculations were made using the measuredairborne activity concentrations and the dispersionequations of Sutton’? and Pasquill.18 Table XVIshows the values of source term vs. distance ob-tained. Only distances of 16,000 ft and beyondwere used, since both models predict negligibleground concentrations from a perfect elevatedpoint source at shorter distances. Even ignoringthe two close-range arcs, one obtains an appreci-able spread of values for the percentage of fission-product material released. Ignoring the value for256,000 ft in the Sutton group, one gets as anaverage about 70 Y. of the fission products released.

TABLE XVL

Distance

(ft)

16,00032,00064,000

128,000256,000

CALCULATED SOURCESTRENGTH VALUES VS. DIS-TANCE

Percent of Fission ProductsReleased to Cloud

Sutton Pacquill

33 161092 8276 1962 31

284 103

Ignoring the 16,000-ft value in the Pasquill group,one gets as an average about 60~0. These averagevalues agree fairly well with the figure of 73, ob-tained independently by radiochemical analysisof cloud samples taken by aircraft a few minutesafter the test and of debris samples recoveredfrom the test site.

Figure 51 compares pretest predictions ofcloud centerline dosages, Sutton and Pasquill esti-mates using parameters measured during the test,and measured centerline dosages. For the pretestestimate, a 40% release of 1021 fissions was as-sumed, with 15-mph winds and neutral conditions.The posttest exercise used a 67% release of3 X 1020 fissions and 25-mph winds. Calculationsof Sutton’s parameters were attempted using themeteorological data from the test, but gave an un-satisfactory spread of values. However, a judg-ment evaluation of those values resulted in a se-lection of n = 0.18 and C2 = 0.067 for the Suttonparameters. Pasqui.11’s stability category C wasused for that part of the exercise. It is evidentfrom Fig. 51 that the uncertainty in the pretestparameters led to an erroneous, but comfortablyconservative, prediction. The calculations usingthe posttest data, (and also giving the models thebenefit of every doubt) produced better, but stillconservative, results. Even this extent of agree-ment is noteworthy in view of the distances in-

t

L4K

I — S A R PREDICTIONBEFORE TEST

‘- SUTTON,USING TEST DATA

— PASQUILL,USING TEST DATA

● MEASURED CLOUOCENTERLINE DOSAGE

~~;TSK 16K 64K 12 K 2SSK

I1 [ 1 1 1 Ill 1 I 1 I I 1 1 r

1000 10000METERS

DISTANCE

Fig. 51. Comparison of cloud data with theoreticalpredictions.

57

volved, however, and leads one to conclude thatthese two popular dispersion models are useful forpredicting downwind radioactivity patterns, par-ticularly since no better model appears to be avail-able.

Beyond the 60 miles or so covered by theLASL array, the cloud wake was observed by theNATS aerial tracking aircraft,’e and later byBureau of Radiological Health of the State ofCalifornia and U.S. Public Health routine airmonitoring stations.6

The NATS aircraft was airborne approxi-~ately 21/2 hours after the event, and the radio-active cloud was intercepted 1 hour 45 minuteslater at an altitude of 9,000 ft near Pyramid Peak,on the western side of Death Valley, approximate-ly 60 miles southwest of the test point. Figure 52shows the subsequent track mapped by the air-craft. Preliminary analysis of the gamma pulseheight spectra taken near the cloud indicated thepossible presence of 1s51, 1s41, 8*Rb, and ‘%-r. Thealtitude of maximum activity appeared to be7,000 ft MSL. The terrain prohibited the aircraftfrom descending below 7,000 ft MSL. Darknessand the mountainous terrain ended this first track-~g procedureapproximately 6 hours 30 minutesafter the event.

At 11 hours 20 minutes after the Kiwi-TNTevent. the NATS aircraft again attempted to lo-cate the effluent cloud. Searching procedures wererestarted near Daggett, California, at 2310 PST,12 hours 10 minutes after the event. The actualflight path is shown in Fig. 53. Positive signalswere received over the ocean from Los Angelesto near. Santa Barbara. Gamma pulse heightspectral data obtained in this area differed fromnormal background, and indicated the presence ofphotopeaks that would have been expected at thattime after the Kiwi-TNT event. The aircraftstopped tracking at 0205 PST to refuel near LosAngeles. After refueling, it returned to the previ-ous search area and again detected weak, but posi-

tive signals, indicating that the efflue~t was con-tinuing to move farther out to sea.

A few days after the Kiwi-TNT event, Pub-lic Health officials observed increased radioactivityin routine air samples from the Barstow, SanBernardino, Los Angeles, and San Diego, Cali-fornia, areas on January 13 and 14, 1965. Thesesamples helped to confn-zn the presence of thecloud wake out to the Pacific Ocean.

ATS-NTS, NVOO SURVEYS BY: E. c 80 INC., SANTA MRAARA u/ r

/ EQUAL COUNT RATE j/ (S00-1500 CPS OVER \

/ OACK13ROUNO) t )

JILLARAT APPROXIMATE SHAPE ANOo SIZE OF CLOUO Al START

I

/DAGK-

CNECK

A

I

E

W OM =l/AR/HR o CAMP

d

BAKEF

SFECTRAL OATALoUTIONS ~ IRWIN

* 460ALTITUOE9PIRALLOCATIONO

GROUNOZERO @~o 10 40 MILES

Fig. 52. Cloud track.

IX. THE RADIOLOGICAL COMPOSITION OF THE CLOUD

The qualitative analysis of the effluent sam- Samples are selected on the basis of initialpies collected by LASL used the method developed activity, location in the array, and type. Theseduring normal tests in the Rover series. The samples are repeatedly counted for an extendedmethod. described in detail in LA-3397-MS,1° con- period at intervals that depend upon the age ofsists basically of following the decay of selected he sample. At each counting, a- gamma ~ulsesamples, and, after all data are collected, segment- height spectrum is also obtained for each of theseally subtracting out (stripping) the activity of samples. The number of samples is reduced, whenprogressively shorter-lived isotopes from the possible, by cross-comparison and elimination ofactivity of the mixture. all but one of any group exhibiting identical

58

I

SCALE

1~o 20 40 80 80 MILES Q BAKERSFIELD

START OF SEAROH

1200

dEDWARDS AFB

*o o VANDENBERG AFB

#e

SANTA o VICTORVILLE

SAN

SANTA CRUZSAN MIGUEL

SAWfA~:SA ISLAND /> “Oe4-

e. chbo%.-”ULRAOIATKNLEVELS INDICATED ARE NET

-u~ -,Cba,

NGREASEOVER SMKQROUNDOOCPS. lpR/NR 1200

=.~TAFLT. LIWS~+~3030’ ~

.~ ~~o ~“ ‘ II r“

(ce

\

+ 33°30’

m

SANTA0S. OATA FLT. LINES ~ ~ ~ 84 CATALINAIPECTRAL OATALOCATIONS~ ISLAND

iLT. SPIRAL LOCATIONS ~ \

z<00

m-c

Fig. 53. Flight path of cloud-tracking aircraft

characteristics. This process is continued until thelongest-lived isotopic component can be identifiedand measured, or until the activity level of thesample becomes insignificant. The process ofcurve stripping is then employed to quantitativelydetermine the isotopic composition of the sample.

In the ideal strip analysis, the decay of thesample is followed until only a single long-livedisotope is present. ‘The activity of this isotope isthen subtracted from the activity of the mixture.The resultant curve is then plotted, and the pro-cess is repeated, subtracting this time the isotopeof next-longest half life. Progressive subtractionis repeated L1.tlti] all isotopic activities have beendetermined. During the process, the gamma pulseheight spectra are used to identify the isotopespresent in significant quantities during selectedperiods of the decay. In practice, the ideal case isseldom encountered and the isotopic contributionsto the activity must be subtracted in pairs or trip-lets. When this is necessary, a least-squares tech-nique is employed to fit the activities of the appropnate pair or triplet to the tail of the residualcurve. As a check on each analysis, a synthesizedplot is made of the theoretical decay of the iSO-

topes determined during the analysis, and this is

compared for goodness of fit with the originalcurve of sample decay data. The deter@ned iso-topic composition is also checked for consistencywith gamma pulse height spectra for the sample.

For the Kiwi-TNT event, this method wasused only for the charcoal cartridge and resin-coated tray samples. The gamma ptdse heightspectra for the filter samples revealed that thesesamples contained essentially gross fission pro-ducts. This was confirmed by constructing hypo-thetical curves of gross fission-product activities,less those isotopes and their daughters which wouldhave been gaseous at the time of collection, andcomparing these curves to the sample decaycurves. Detailed radiochemical analysis of cloudsamples collected by aircraft a few minutes afterthe event further confirmed the comparison. Theratios of activity of the various fission productswere found to be no more than 1.5 times thetheoretical ratios of these products.

The analysis of the charcoal cartridges in-dicated that the gaseous material was mostlyiodines and not greatly different from what wouldbe expected from sampling a cloud of unfraction-ated fission products with the iodines still largely

59

in the gaseous state. The deposited activity wasquite different from the airborne particulate ac-tivity, containing predominantly refractory iso-topes. Iodine-135 was the only isotope of iodineidentified in these samples.

Table XVII lists the apparent zero-time comp-osition of the material collected by the charcoalcartridges and resin-coated trays as determined bythe curve stripping technique. The activity, A,.of any sample at any time, t, may be determinedby

At = ZiA~e-W,

where Al is the value given in Table XVII for theith isotope, and ~i is its decay constant. Whereparent-daughters are presen4 the appropriateBateman equation should be used in the sum.

TABLE XVII. DECAY CURVE DATA

Airborne Gaseous Material4,000-ft arc

Theprobably

presence of lssxe on the cartridges is

due to ingrowth from the 1351. When~his growth begins ~ not precisely known, but azero-time value of ‘35Xe activity is given whichproduces an excellent fit to the data. The 136Xe isprobably completely swept out of the cartridgesduring sample operation, and is allowed to diffusefreely from them after active sampling but beforethey are packaged for counting. Xenon-1 33 doesnot similarly appear. because its gamma energy,80 keV, is below gamma-counting system thresh-old of 100 keV. (Gamma counting must be LISd

on the charcoal cartridges because their structureresults in ahnost complete beta self-absorption. )The presence on the cartridges of the solid iso-topes, lBzTe and lW3a-La is not well understoodexcept that they exist as extremely fine particles,but this phenomenon has frequently been ob-served in other studies of fission products releasedto the atmosphere.

Airborne Gaseous Material8,000-ft arc

Isotope % at Zero Time

1-134 48.21-132 1.501-135 44.8Xe-i35 3.641-133 1.78Te 1-132 0.02301-131 0.0392

Airborne Gaseous Material16,000- to 256,000-ft arcs

Isotope ~ at Zero Time

1-134 81.11-135 10.6Xe-135 7.381-133 0.923Te I-132 0.01791-131 0.0340Ba-La-140 0.00640

Deposited ActivityAll Arcs

Isotope

1-1341-135Xe-1351-133Te 1-1321-131Ba-La-140

% at zeroTime

76.315.8

5.91.800.02880.07120.0132

Isotope % at Zero Time

1-135 59.9Zr Nb-97 32.8Mo-99 6.65Ba-La-140 0.554Ru-103 0.0444Zr Nb-95 0.0444

X. THE IMPACT ON THE NEIGHBORHOODThe material in this chapter is largely from the Atomic Energy Commission, SWRHL con-

the USPHS “Final Report of Off-Site Surveillance ducts a program of radiological monitoring andfor the Kiwi-TNT Experiment.’yr environmental sampling in the off-site area sur-

rounding the Nevada Test Site and the Las VegasUnder a Memorandum of Understanding with Bombing and Gunnery Range. In addition to their

60

routine sampling network, the USPHS placed addi-tional monitors and sampling stations in the an-ticipated downwind direction from the Ifiwi-TNTevent to better document the impact of the teston the neighborhood.

Twelve ground monitoring teams txacked thecloud passage with portable instruments. Eachteam was equipped with an Eberline E500B[0-2,000 mlljhr on five scales), a Precision ModelIII Scintillator (O-5 mR/hr on six scales), and aVictoreen Radector Model No. AGB-50 B-SR(0-50,000 mR/hr on two scales). Positioning ofthe ground monitors was assisted by aerial dose-rate readings made by two PHS monitors in an AirForce U3-A aircraft, which was primarily engagedin aerial cloud tracking and sampling. Forty-fiveroutine air samplers were operated in Nevada,Utah, Arizona, and California. In addition, 18supplementary air samplers, and eight EberlineRM-11 dose-rate recorders (0.1 to 100 mR/hr on asingle logarithmic scale) were placed in the an-ticipated downwind sector. All air samplers wereequipped with Whatman No. 41 filters backedwith MSA charcoal cartridges. Film badges wereissued to 157 people off site, including 67 atLathrop Wells, 30 in the Amargosa Farm area, andfive. at Death Valley Junction. The film badge

\v\

>FUR’’’C’R9R!+{

AlR SAMPLERS (ALL WITHCHARCOAL CARTRIDGES )

DOSE RATE RECORDERS I “: “b

-cMILK SAMPLING LOCATIONS

\\

SHOSHONE ~

Fig. 54. Downwind USPHS sampling and monitoringlocations.

used was the DuPont type 555 film packet, withtwo films, 20- to 100-mR range and 100- to 2,000-mR range. Nine of the film badges were in ornear the downwind sector. Seventy-four milksamples were collected and analyzed for fissionproducts following the Kiwi-TNT event. Thesamples were collected from two ranches in theAmargosa Farm area and from 14 locations insouthern California. Vegetation samples were col-lected from most milk sampling locations. Watersamples were collected from two open ponds, atDeath Valley Junction and at Shoshone, Cali-fornia, the day following the test. Figure 54shows the downwind USPHS sampling and mon-itoring locations within approximately 75 milesof the test site. Figure 55 shows a larger area, outto the Pacific Ocean, where milk samples werecollected in southern California.

All air samples were counted for gross betaactivity immediately upon receipt at SWRHL.Samples exhibiting significant radioactivity werethen further anal yzed as described in Reference 5.All charcoal cartridges and filters were also ana-lyzed by gamma pulse height analysis. The mini-mim detectability of this analysis for lBIT, l~ZI,1s31, and 1351 is approximately 200 pCi. Milk,water, and vegetation samples were analyzed bygamma pulse height analysis. The lower limit ofdetection for gamma emitters in milk samples inthis system is 20 pCi/liter.

A summary of positive gamma dose-ratemeasurements made by the monitoring teams anddose-rate recording instruments is given in TableXVIII. The data indicate a measurable cloudwidth of approximately 5 miles by the time itreached Highway 95, just south of the Test Siteborder; the eastern edge of the cloud was approxi-mately at Lathrop Wells. Farther downwind,measurable does rates occurred in the AmargosaDesert to the west of Highway 29. No activity wasmeasurable in the Furnace Creek area of DeathValley. The maximum dose rate measured by aground monitoring team was 70 mR/hr, approxi-mately 1.5 miles west of Lathrop Wells on High-way 95. A numerical inteawation of dose rates vs.time gave a calculated external exposure dose of5.7 mR for this location. This location is normallyunpopulated, but there were eight persons en-gaged in sampling experiments there during thetest. A similar calculation was made for the Amar-gosa Farm area and Death Valley Junction. Theexternal gamma dose calculated for these popu-lated locations did not exceed 0.5 mR. Hi@way95 was remonitored at about 0900 the morningafter the test. Some small residual contaminationwas found between Lathrop Wells and a point 4

61

A AESCCWIOO

0 “w w w 7,N% ~#

n

RCWLEY \

U. 65. Milk HI@@ kxXtiOIK4.

miles to the west. A maximum net peak dose rate Table XX summarizes PHS air sampIes thatof 0.05 mR/hr was found 2.6 miles west of Lath-on exhibited Dositive activitv. Because most of theseWells. A similar survey of Highway 29 and th~Amargosa Farm area found no readings abovebackground.

A summary of the milk sampling locations isshown in Table XIX. The Amargosa Desert loca-tions and 14 California locations were sanpled forapproximately 1 week starting the day after thetest. None of the 74 milk samples contained de-tectable quantities of fresh fission products. Ani-mals at all but one location were being fed baledhay; the cows at 13rawley, California, were fedgreen fodder. Natural vegetation samples from theSaticoy-Fillmore-Newhall area in California con-tained fresh fission products. However, cow feedand milk at these locations did not contain de-tectable quantities of fresh fission products, nordid vegetation samples from an area extendingfrom Barstow to Santa Barbara, California. Neitherof the water samples collected contained freshfission products.

samplers &ere in the same area as the LASL ar-ray, but not at identical locations, and were col-lected and analyzed in similar, but not identical,fashion, the temptation to compare airborne ac-tivity dosages measured by the two systems is over-whelming. Such a comparison reveals that order ofmagnitude discrepancies exist between sampleswhich were not far apart. However, the consist-ency (or lack thereof) between the two sets ofdata appears to be about the same as that withineach set.

The Bureau of Radiological Health of theState of California routinely operates 14 airsamplers within the state. Kiwi-TNT effluentpassage was noted on several samplers whose lo-cations are given in Table XXI. The results ofthese analyses were supplied to SWRHL. Thesamples were counted within 2 days followingcollection, and the results were extrapolated to endof sample collection assuming a t-lz decay. Natural

TABLE XVIII. DOSE RATES MONITORED OFF THE TEST RANGE COMPLEX ON JANUARY12, 1965.

Time During Net PeakTime of Peak Which Dose Rates Gamma

Dose Rate Were Greater Dose RateLocation* (PST) than Bkgd (mR/h.r)

3 mi. N of Hvvy. 95 on Lathrop Wells-NRDSRoad (NRDS Boundary) 1143 1130-1207 70

Lathrop Wells 1146 1125-1148 2.0

1.5 mi. W of Lathrop Wells 1147 1138-1158 70

5 mi. W of Lathrop Wells 1207 1200-1220 0.18Dansby’s Ranch (5 mi. S of Lathrop Wells onRt. 29 and 6 mi. W on Amargosa Farm road) 1262 123%1324 0.6715.3 mi. S of Lathrop Wells on Hvvy. 29 1328 1305-1345 0.2$

Death Valley Junction 1349 1315-1428 0.11

7.5 mi. W of Death Valley Jet. on Hwy. 190 1335-1415 1300-1440 0.23

Dose Rate Recorder Data on January 12, 1965

Time During Net PwkTime of Peak Which Dose Rates Gamma

Dose Rate Were Greater Dose RateLocation” (PST) than Bkgd (mR/hr)

Lathrop Wells 1146 IIW1250 2.0

Dansby’s Ranch 1252 1145-1335 0.67

Death Valley Jet. 1349 1250-1430 0.11

Recorde~ at Beatty, Nevac& and Stovepipe Wells, Furnace Creek Ranch, and Shoshone, Califo~ did notindicate activity above background.*See Fig. 54.

TABLE XIX. USPHS MILK SAMPLING ACTIVITY FOLLOWING KIWI-TNT

Number of DaysLocation Sampled Inclusive Dates

Lathrop Wells, NevadaDan.sby’s Ranch 6 1/13/65 to 1/19/65Selbach Ranch 6 1/13/65 to 1/19/65

Barstow, California 8 1/14/65 to 1/22/65Bakersfield, California 7 1/14/65 to 1/20/65Cantil, California 1 1/15/65Lancaster, California 1 1/15/65Glendale, California 1 1/15/65Lucerne Valley, Califorrlia 1 1/14/65Los Angeles, California 7 1/14/65 to 1/20/65Riverside, California 6 1/15/65 to l/W/65Escondido, California 6 1/15/65 t.O 1/21/65San Luis Ohispo, California 7 1/14/65 to 1/20/65Saticoy, California 2 1/15/65 to 1/18/65Newhall, California 7 1/14/65 to l/2U/65Fillmore, California 1 1/16/65Brawley, California 7 1/15/65 to 1/21/65

63

2!2

!2!2

!2!2

!2!2

P’lu

TABLE XXI. CALIFORIVL4 STATE AIR SAMPLER LOCATIONS REPORTING EVIDENCE OFKIWI-TNT CLOUD PASSAGE.

Prefilter Gross Beta24Hour Sample Volume Concentration atEnding 0800 PST sampled End of Collection

Location on Date Shown (m8) (pCi/m8)

Barstow 1/13/65 64.4 360Barstow 1/14/65 63.3 6.9San Bernardino 1/13/65 60.1 16.4San Bernardino 1/14/65 64.5 6.2Los Angeles 1/13/65 58.1 6.3Los Angeles 1/14/65 63.3 8.8San Diego 1/13/65 81.8 3.3San Diego 1/14/65 80.3 6,2

levels of radioactivity in air at the sampled loca-tions generally do not exceed 2 pCi/m8. In addi-tion, the Los Angeles station of the USPHS Radia-tion Surveillance Network reported fresh fission-product activity in samples collected following theKiwi-TNT event. Twenty-four-hour samples end-ing on the mornings of January 13 and 14 at LosAngeles indicated gross beta concentrations of 0.93and 1.82 pCi/m8, respectively, extrapolated tocollection time. A gamma-ray analysis of thesetwo samples indicated unquantitated traces ofw&~ and log. 1OORU-Won both days and 1811on January 13; 1’ZTC-I leveb of 1.5 pci/m3 werereported on both days.

Thyroids of several members of the USPHS

off-site survey teams were counted at the USPHSWhole-Bmly Counting Facility to determine iodineuptake following the Kiwi-TNT event. All thyroiddoses due to iodine were less than 3,3 k 1 mand were due to the 131 and 135 isotopes. Themonitor 1.5 miles west of Lathrop Wells who ex-perienced a dose rate of 70 mR/hr was includedin the study, and received the peak thyroid doseof 3.3 rnR. Comparison of measured thyroid dosewith that calculated from LASL air samplingdata is quite good. Data from Table XIV andFig. 49 indicate that a thyroid dose calculatedfrom air sampling data for a monitor approxi-mately 15 miles from the test point would be 4rnR.

Xl. CONCLUSIONS

The Kivvi-TNT was a successful simulationof a maximum credible accident due to extremelyrapid reactivity insertion into the core of a nu-clear rocket reactor. This type of accident was ofmajor concern at the time of its conception andplanning; emphasis is now on the loss-of-coolantaccident,

In the reactivity insertion acciden~ the fis-sion process and deflagration occur essential] y imstantaneously. The fission products are producedand released at almost the same instant. Althoughpostulation of the reactor core inventory of pro-ducts due to any previous fissions is complicatedbecause an infnnte variety of fission-product in-ventories can be conceived, their effects can beextrapolated from the results of this test.

In the loss-of-coolant accident many moreparameters are involved than in the fission-pro-

duct release. Fission-product release would not beinstantaneous, and the release rate would dependupon whether the reactor was critical or sub-critical at the time of the collant loss; it would de-pend upon the power level and previous powerhistory of the core; each chemical element wouldbehave differently, rather than all fission pro-ducts being released in about equal proportions.Consideration of all these factors is appropriateonly for particular cases and is too extensive forinclusion here. Therefore, only conclusions perti-nent to the Kiwi-TNT and similar reactivity in-sertion incidents occurring with uncontaminatedfissionable assemblies will be stated.

Severe property damage to normal objectsand structures by the blast from the eruptionwould probably be limited to a radius of about100 ft. Minor blast damage, such as windowbreakage, would be confined to about a 1,000-ft

65

radius. Personnel injuries from blast and heatwould be almost inconsequential as compared toradiation injuries.

Out to approximately 300 ft, which is be-yond the range of probable blast injury, radiationexposures would probably be fatal, being in excessof 750 rads. Between approximately 300 and 750ft, varying degrees of radiation injury, includingsome fatalities, would occur as exposures wouldbe between 100 and 750 rads. From 750 to ap-proximately 2,000 ft downwind, little, if any, in-jury or clinical effects would occur, but exposureswould exceed 3 rads and would require adminis-trative investigation and reporting. Beyond ap-proximately 1.5 mile, doses even in the path ofthe cloud would be below a few hundred millirad,and should present no problems.

The seriousness of radioactive contaminationis difficult to assess, since it depends so heavily onthe value and potential uses of the contaminatedreal estate. However, 1 day after the Kivvi-TNTevent, contamination exceeding 100 mR/hr waswithin 1.200 ft downwind and 300 ft umvind of

300 ft downwind1 week after the

and less than 100 ft upwind. Byeven~ the 100 mR/hr area was

the test point; the 1 R/hr line at this &e was

REFERENCES

300 ft downwind and less than 100 ft upwind ofthe test point. Within a few hours of the test,contamination above 1 mR/hr was difficult tofind beyond 2 miles, although a few “hot spots”of several mR/hr were discovered out to 10 mileson the day of the test. These rapidly decayed a~vayto insignificance. Beyond 12 miles, no con lamina-tion above I mR/hr was found.

No radioiodine was discovered in milk fol-lowing Kiwi-TNT; however, cows downwind dur-ing cloud passage vvere not grazing but were beingfed baled fodder. Nevertheless, the minimal radio-iodine found in samples of deposited activity andvegetation indicates that radioiodine contaminationin milk, even if encountered, would have beenwell below levels of concern.

In the briefest summary, a Kiwi-TNT typeof excursion, without a fission-product inventoryin the reactor, creates inconsequential hazards topersonneI and property beyond about 2 miles, adistance that can be reasonably expected to lieoutside test areas,

1.

2.

3.

4.

L. D. P. King (cd.), “Description of theKiwi-TNT Excursion and Related Experi-ments,” LA-3350-MS (Confidential RD),Los AJamos Scientific Laboratory (July1966).

C. A. Fenstermacher, L. D. P. King, andW. R. Stratton, “Kiwi Transient NuclearTest” (p. 226); and W. R. Stratton, C. A.Fenstermacher, L. D. P. King, D. M. Peter-son, and P. M. Altomare, “Analysis of theKivvi-TNT Experiment” (p. 250); AIAAPropulsion Joint Specialist Conference, June14-18, 1965, Colorado Springs, Colo., AZAABzdl., 2,5 (1965).

L. D. P. King, “Description of the Kiwi-TNTExcursion” (p. 126); W. R. Stratton, D. M.Peterson, and P. M. Altomare, “Analysis ofthe Kiwi-TNT Experiment” (p. 126); andBeverly Washburn and Charles Hudson, “PinTechnique for Displacement Measurementsin Kiwi-TNT” (pp. 127-128); Trans. Am.Nud. SOC., 8, i (1965).

L. D. P. King, “Safety Neutronics for RoverReactors,” LA-3368-MS (Confidential RD),

5.

6.

7.

Los Alamos Scientific Laboratory (October1965).

“Final Report of Off-Site Surveillance for theKiwi-TNT Experiment,” SWRHL-17r, South-western Radiological Health Laboratory,U. S. Public Health Service, Las Vegas,Nevada (August 6, 1965).

“Nevada Aerial Tracking System, Very Pre-liminary Report of Kiwi-TNT Event,” EG&G,Inc., Santa Barbara, California (January 21,1965).

P. K. Lee and F. C. V. Worman, “IntegralGamma and Neutron Measurements on ‘theKiwi-TNT,” LA-3304, I.os Alamos ScientificLaboratory (May 1965).

8. F.. E. Campbell (com~.), “Kiwi-TNT Parti-cle Study,” ‘LA-3337-MS” (Confidential RD),Los Alamos Scientific Laboratory (August

9.

1965).

R. V. Fult-yn andment and Support—Kiwi Transient

C. J. Boasso, “Fuel Ele-Element Fragment StudyNuclear Test,” LA-3445-

66

10.

11,

12.

13.

14.

MS (Confidential RD), Los Alamos ScientificLaboratory (December 1965).

H. F. Mueller and D. A. Wilson, “Analysisof Meteorological Data for the Kiwi-TNT 15.Reactor Test,” WBRS-LA-9, Weather BureauResearch Station, U. S. Department of Com-merce, Las Vegas, Nevada (February 24,1965).

R. Reider, “Kiwi-TNT ‘Explosion’,” LA-3351 16.(Official Use Only), Los Alamos ScientificLaboratory (July 1965).

F. W. Sanders, “Gamma Dose Rate Measure-ments—Kiwi Transient Nuclear Test,” LA- 17.3446, Los Alamos Scientific Laboratory(December 1965).

18.P. K. Lee and R, V. Fultyn, ‘~Kivvi TransientNuclear Test Dose Rate Survey,” LA-351 9-MS, Las Alamos Scientific Laboratory 19.(March 1966).

U. S. De~artment of Commerce. Weather

(prepared for U. S. Atomic Energy Commis-sion), U. S. Government Printing Office,Washington, D. C. (July 1955).

E. A. Bryant, J. E. Sattizahn, and G. F.Wagner, “Radiochemical Measurements onKiwi-TNT,” LA-3Q90 (Confidential RD),Los Alamos Scientific Laboratory (May1965).

R. W. Henderson and R. V. Fultyn, “Radia-tion Measurements of the Effluent from theKiwi-TNT Experiment,” LA-3395-MS, LosAlamos Scientific Laboratory (October 1965).

O. G. Sutton, Micrometeorology, McGraw-Hill Book Co., Inc., New York (1953).

F. Pasquill, Atmospheric Diffusion, D. VanNostrand Co., Ltd., London (1962).

R. W. Henderson and R. V, Fultyn, “Radia-tion Measurements of the Effluent from theKiwi-B4D-202 and -B4E-301 Reactors,” LA-3397-MS, Los Alamos Scientific Laboratory/

Bureau, “Meteorology and Atomic Energy,” (August 196!5) .

APPENDIXCloud Dimension Data Analysis

The locations of the cameras used exclusivelyto photograph the cloud for dimensional analysiswere as follows:

East camera tower, 95.5”, 10,000 ft, 16-mmfilm, 12 frames/see.

Control Point Building roof, 168°, 10,200 ft,16-mm film, 24 frames/see, and 70-rnmfib i frame every 2 seconds.

North portable camera station, 29.5°. 11,200ft, 1G-mm fihn, 24 frames/see.

R-MAD Building roof, 117.5°, 13,100 ft,70-mm film, 1 frame every 2 seconds.

South portable camera station, 210°, 11,554ft, 70-mm film, 1 frame every 2 seconds.

The azimuths and distances are from theKiwi-TNT test point. All cameras were operatedby EG&G personnel.

Analysis of the 16-mm film used a speciallymodified projector which allowed the film to be

studied a frame at a time. This projector also con-tains a frame counter which allowed accurate de-termination of the time a specific frame was made.

The camera-projector system was treated asa simple lens system of unknown focal length. Toobtain correct cloud dimension data, it was there-fore necessary to have a reference object, ofknown size and distance, in the photograph.Fortunately, there were a meteorological towerand water tower at the test cell complex, and atleast one of these appeared in all photographsused to obtain dimensional data. The analysis wasas follows (see Fig. A.1 ).

Fig. Al. Geometric re]ationsfips aAed in de-termining cloud dimensions.

67

H = actual height of cloudh = height of cloud on projection screen

D = actual height of reference objectd = height of reference object on screenL = distance from camera to reference objectR = distance from camera to cloudf = equivalent focal length of optical system.

Using the simple lens formula,

Lf Rf~;and ——=—

D~ .~ (Al)

RDh

“m(A.3)

The heights and distances of the referenceobjects were known. The distance to the cloudwas calculated using the meteorological data givenin Chapter III. From the photographs, a prelimin-ary estimate of cloud altitude vs. time was made.An accurate track of the cloud was made usingthe ,svind speed and direction for each altitude, andfrom this track the cloud-to-camera distance couldbe ascertained.

Ld Rh Data obtained in this fashion are Listed inT=f==

(A.2)Table A.1, and plotted in Figs. 2, 3, and 4.

TABLE A.I. CLCNID DIMENSION DATA

TimeAfter Event

(see)

123456789

102030456090

124)1501802102’KI270300330360390420450480510540

Distance fromTest Point

to Cloud Center(feet)

%762.496.1

130164197231265298332669

1024155620893256442350835743640370637723838390439805

105701133012Q9012a501362014380

HorizontalDiameter

(feet)

VerticalDiameter

(feet)

‘r~Altitude

(feet)

CenterAltitude

(feet)

BottomAltitude

(feet)

168158158175192208225

42361264il727.979

1017172819891812203421592567272229413%3235963979437946555665

243275318306338347357337644768927853

10961429172819151987197321752202222362418270726402618281329002986

11119924328632937!2414456476518873

10341329156020022610307234313472351736433717385740464Q8741724199427644074459

121148170219

2a2298349551650865

113314-54189622082474%792530255226152714283827332851%390286929572966

011116676

109119180229266

706906

1181134415161486154414651514157216281380153115811463ifio71473