sources measurement and transfer - european commission · cea/dam/va ue scientific seminar emerging...

13/11/2007CEA/DAM/VA UE scientific seminar emerging issues on tritium 1

TRITIUMTRITIUM and the ENVIRONMENTand the ENVIRONMENT

SOURCESSOURCES

MEASUREMENT MEASUREMENT

and TRANSFERand TRANSFERPh GUETATPh GUETAT, , CEACEA

Thanks for their help to C Douche, JC Thanks for their help to C Douche, JC HubinoisHubinois, N. , N. BaglanBaglan , ,

D D GaleriuGaleriu, Ph. Davis, W , Ph. Davis, W RaskobRaskob


SOURCES 1 - 1g = 0.358 PBq

• Natural :– 1300 PBq 3.5 kg at equilibrium– 72 PBq/an – 200 g/a -

• Atmospheric nuclear tests – 190 000 PBq north 420kg– 50 000 Pbq south 140kg remain 40kg 2007

• Reprocessing Plants0,4 PBq.(GW.a)-1 = 1 g.(GW.a)-1 as liquid release

• La Hague - sea 10 PBq.an-1 30g - air 0,07• Sellafield - sea 2 to 3 PBq.an-1 8g - air 0,6 to 0,2



• Fission reactors releases (TBq.a-1. GW-1)

Gas liquid– BWR 1 1– PWR 2 = 5 mg 20 = 50 mg

– GCR 4 200-300– HWR 100-1000 = 1g 100-500 = 1g



• Industrial and Small users– Amersham 0.5 PBq.a-1 before 2000 0.1 PBq.a-1

– R&D biology – labelled compounds : french stock 0.5 PBq 1g

• Small amounts, • Incinerators; surface disposal - with14C

– Tritium lighting devices– EXIT – other paintings 0,1-0,5 TBq/device ( 1mg/device)

• Future users– Laser (ie : LMJ) few tritium gas (mg.a-1)– Fusion reactors, use of : JET 20g - ITER 1,5 kg.an-1

EXIT



• Waste and waste disposals– Sea dumping 1967-1982 : 20 PBq 60g– In France very small amounts in surface disposal

• CSM 9 PBq 30 g • CSFMA < 4 PBq <10 g• CSTFA VLLW (ANDRA) low acceptance criteria.

– Graphite : small outgassing (•10-7 a-1?)subsurface

20 000 t - • 5 PBq (2007)

– Hulls & nozzles : 20 TBq / tsmall outgassing (< 10-6 a-1) type B

– CEA tritium waste : 5PBq after treatment + storage

– Rods B4C, sodium cold trap… storage treatment


0,001

0,01

0,1

1

10

100

1000

... CSFM

A AND

RA

... incinerator centraco ... P

WR

900 2 reactors ... PW

R1300 2 reactors

... CEA

Grenoble

... CEA

Cadarache

... ILL HW

R research

... reprocessing LA H

ague Am

ersham C

ardiff... C

EA Saclay (biology)

... CEA

Valduc (defense)... C

EA

Marcoule (defense)

... Pickering A candu

... natural production

g/a gas autorisationliquid autorisation

AUTHORIZED RELEASE TRITIUM [gramme]

358 TBq

4 PBq

4 TBq

2000


Production of tritiated releases and waste in the future

– Depending on : ØConception of processØTreatments of air and waste


In Tritium buildings

• Avoid dilution– Limit volumes of air– Limit water vapor in air => dry air

• Limitation of leaks• Detritiation of air - recycling

• Waste management a major source of Tritium release

• Detritiation of very low activity water not reasonable


DetritiationDetritiation UnitUnit

ProcessProcess in in GloveBoxGloveBox

Tritium BuildingTritium Building

HTOHTO

Tritiated Solid waste treatment on VALDUC

OrganicsOrganicsOrganicsOrganics OvenOven processprocessTreatmentTreatment by by vaporvaporReducedReduced outgassingoutgassing

MLWMLW

Met

allic

sM

etal

lics

2nd barrier

GlowGlow BoxBox LLWLLW

ConfineConfinementment

FE200FE200MeltingMelting furnacefurnace

IngotIngot

DismantlingDismantling

MaintenanceMaintenance

CuttingCutting

<2MBq/<2MBq/D.drumD.drum<50 <50 MBqMBq//D.drumD.drum


TRITIUM RELEASE Ci/Year Fct (Temp. °C) : MA Waste Storage

y = 358,48e0,0762x

R2 = 0,9646

- 100 200 300 400 500 600 700 800 900

1 000 1 100 1 200 1 300 1 400 1 500 1 600 1 700 1 800 1 900 2 000 2 100 2 200 2 300 2 400 2 500 2 600 2 700 2 800 2 900 3 000

-5 -4 -3 -2 -1 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30

Température °C

Rej

ets

annu

els

Ci/a

n


Container for tritiated wasteContainer for tritiated waste

ÅÅ ReversibilityReversibilityÇÇ ConfiningConfiningÉÉ Internal atmosphere Analysis Internal atmosphere Analysis

10-3 Pa.m3/s

overdrumsoverdrums

Elastomer joint10-5 Pa.m3/s

60 € 1 400 € • 1 500 € 5 000 € 12 200 €NB. initial costs of the drum

10-7 Pa.m3/s

FE200FE200EPICEAEPICEA

Metal joint10-9 Pa.m3/s

RCDT2RCDT2

Fût de déchets tritiés223 litres

Ø 690

1020

Ø 730

904

welded

Drum 200 LDrum 200 L

elastomer joint


Prospective cumulated volumes & Tritium activity of waste in France

1 - Small amounts of tritiated waste2 – Program law N° 2006-739 28th juin 2006 - storage solutions…

year

- 1 000 2 000 3 000 4 000 5 000 6 000 7 000 8 000 9 000

10 000 11 000 12 000 13 000 14 000 15 000 16 000 17 000 18 000 19 000 20 000 21 000 22 000 23 000 24 000 25 000 26 000 27 000 28 000 29 000 30 000

2006

2007

2008

2009

2010

2011

2012

2013

2014

2015

2016

2017

2018

2019

2020

2021

2022

2023

2024

2025

2026

2027

2028

2029

2030

2031

2032

2033

2034

2035

2036

2037

2038

2039

2040

2041

2042

2043

2044

2045

2046

2047

2048

2049

2050

2051

2052

2053

2054

2055

2056

2057

2058

2059

2060

Année

Volu

me

Déc

hets

Trit

iés

m3

- 1 000 2 000 3 000 4 000 5 000 6 000 7 000 8 000 9 000 10 000 11 000 12 000 13 000 14 000 15 000 16 000 17 000 18 000 19 000 20 000 21 000 22 000 23 000 24 000 25 000 26 000 27 000 28 000 29 000 30 000

Inve

ntai

re T

ritiu

m T

Bq

ITER ! ! Tonne ! !ILLANDRAVALDUCMARCOULEINVENTAIRE Tritium TBq

Activity

Volumes

Tritiated

waste

volumes M

3

Tritiium

inventoryT

Bq


CONCLUSIONS for SOURCES

• Natural Tritium production is higher than man-made release

• Atmospheric nuclear test multiplied by 100 at world scale and more.

• Reprocessing plants = main sources (sea)

• Heavy water reactor produces much more Tritium (D-T) than PWR,and PWR (boron) more than BWR (ternary fission). T production increases

• Industrial use : – AMERSHAM : specific transfer for dissolved Organic Compounds in estuary

environment– Lighting devices : in US landfills, many places >20000 pCi/L

• Waste :– Tritium in many types of waste : activity and outgassing– Very few in surface disposal in France.– Air tight containers are expensive.

• Fusion use : The use increases but no fundamental change for releasewhat outgassing for waste ?


Measurement


1 - introduction• Preparation of sample depending on the

physicochemical form

– Gas : HT HTO other– Liquide (Water) : pure or not (distillation)– Solid : T2 HT HTO OBT ( E OBT and NE OBT)

• Bio• Metal• Powder - hydrides


2 - Principles - What is measured ?

T e-

W=325 mW/g

3He

electricity

Ionization chamber0.5 MBq/d

photons

Scintillating medium

liquid Scintillation

10 Bq/L

solid Scintillation

10 ppm

permeationin column

Chromatography(gas phase

1 to 10 ppm, 10 mn)

MassH D T He

Mass Spectrometry

Calorimetry 0.1 mg

Activatedcharcoal

Mass SpectrometrySome GBq

Raman Spectrometry

UV excitation


– Inventories :– Calorimetry– solid Scintillation

– Releases : alarm or precision– Ionization chamber – liquid Scintillation

– Isotopy, impurities– Mass spectrometry– Gas chromatography– Raman spectrometry

– Waste : outgassing or inventory– ionization chamber, – He3– Surface contamination, wipe test + scintillation

– Environment : – Liquid scintillation, electolytic enrichment

3 - Objectives of measurements


4 - Liquid scintillation

• Principle : A scintillating cocktail transforms • (e-) in photons,use of gauging curves to determine efficiency of counting before tritiumactivity calculation

• Detection levels :• Survey : 10 Bq.L-1 2 hours for measurement• Very low level : 1 Bq.L-1 NE OBT (1,5day/sample).

• Reference water : A<0,2 Bq.L-1

• Pure Water : no salt, no color, no other nuclides - or distillation

• Contamination problems• Controls for measure, distillation, lyophilisation, burning• Radon, C14…• Chemiluminescence• Static electricity


• Gas : tritiated water vapor HTO; hydrogen gas (HT) and tritiated methane.

– sampling :• Active pump + bubbling

4.1 - Chemical Forms and sampling for tritium measurement in air

Le Marc 7000 ®


4-2 - Organically bound tritium : definition

2 categories of hydrogen

• Bound to C : strong covalent bound, small capacity of exchange with H or T of environment Non Exchangeableorganically bound tritium.

• Bound to O, N or S : weekly bound high capacity of exchange with H or T of environment = exchangeableorganic tritium

Example of the cellulose molecule

n

C O Het


Sample combustion Total tritium Measurement

lyophilisation

Dry matter total organically bound tritium Measurement

Free water

combustion

HTO Measurement

Wash

lyophilisation

Dry matter NE OBT

Pure 2nd free water E OBT

Combustion + distillation of water of combustion

4-3 solid sample Preparation for measurement


5 - Procorad intercomparisons

urine test - sample B not contaminated - procorad 2007

500700900

1100130015001700190021002300

52 53 39 41 59 30 21 16 40 54 58 62 11 29 51 64 13 4 25 63 24 27 65 38 6 15 22 3 18 28 31 19 32 57 2 37 26 68 12 70 36 42 47 44 10 67 7 20 33

n° of the lab

Bq/LUrine sample D - after contamination - procorad 2007

30000

35000

40000

45000

50000

55000

60000

65000

33 68 58 13 12 21 53 40 26 57 7 47 54 62 32 27 10 41 63 22 3 51 59 29 42 16 67 18 19 64 4 31 37 28 30 70 2 65 38 11 6 52 25 15 36 44 24 39 20

n° of the lab

Bq/L

Procorad 1996

pollution

Procorad 2007


6 6 -- INDUSTRIAL EQUIPMENTS FOR WASTEINDUSTRIAL EQUIPMENTS FOR WASTE

e-

12,34 ans

TritiumTritium HHéélium 3lium 3

tritium out-gasing GCCLD = 0,5 MBq/Day/Drum

confining during 30 minutesIonisation Chamber

Total activity LD = some GBq/drum

Method He3confining during some hours


Conclusions for measurement

• Measurement apparatus for large inventories and large volumes toimprove

• Easy to measure at a low level but need to have a good preparation

• Preparation takes time for solid material (case of incident ?)

• Not Easy to reach ANDRA’s requirements for disposal


• LEVELS in ENVIRONMENT


10 –activities of rain and surface waters in the past

100 Bq.L-1

Référence : O. Nitzsche, D. Hebert, proc. Lowrad, p.106, 1996.

In 1963 in Vienna (Austria):150 Bq.L-1 in rain

Activ

itétr

itium

dan

s l’

eau

sout

erra

ine

àFr

eibe

rg (

en U

.T.)

In 1991 in Vienna (Austria):2 Bq.L-1 in rain

1 U.T.(Tritium Unit)= 0,118 Bq.L-1

Effet des essais nucléaires atmosphériques


chanel(surface, 1994):

≈ 0,3 Bq.L-1

Atlantic(surface, 1998):

≈ 0,1 Bq.L-1

c(-1000 m, 1998):

0,005 ± 0,001 Bq.L-1

11. Distribution : sea and oceans

Source: C Taylor, Institute of Geological and Nuclear Science Ltd, Lower Hutt, New Zealand (1997).

Zone demélange

(Pacifique Sud)

Prof

onde

ur (m

)

Activité tritium (U.T.)

1,00

-1000

-2000

-3000

Evolution of tritium activity versus depth:

Repartition of T :• 87% in oceans,• 12% in continental waters,• 1% in l atmosphere ( HT et HTO)

Equateur

Mixingzone


•Tritium transfer in environment– Continuous release– Accidental release

TRS 364


Mechanisms and time scale for equilibrium

Inhalation + transcutaneous : few mn- hAir-vegetable contamination HTO : few h - daysAir-vegetable OBT : few weeksSoil (to reach equilibrium with air) : few months

HTO and OBT in vegetable from soil water : in equilibriumVegetable HTO in equilibrium with soil water within 2 days

Animal products : more or less in equilibrium with fodder – Grass : few weeks of delay


A global IDEA of the tritium (HTO) pseudo equilibrium

AIR

Vegwater

Organicmatter

SOIL

transpirationabsorption

30%deposition

leaching

evaporation 30%

70% 50%

Dry matter content90% to 5%

Animals75%

45%

rain20%

« X% = order of magnitude of water concentration ratio »


HT transfer compared to HTO transfer

AIR

Vegwater

Organicmatter

SOIL

Animals

No depositionby RainDry deposition

(10 times lower)

microorganisms

HTO

No air-leaves transfer


HTO vs. HT Predicted Dose

10g =370 TBq/y; chronic; DCARTχ/Q=1×10-6 s.m-3 total = 9 µSv

For similar source terms, an HT release has a 1-10 % dose impact compared with HTO

29%55%

16%

71%100%

1% 4% 1% 6% 7%0%

20%40%60%80%

100%

Inhalation IngestionVegetable

Ingestionanimal

products

Ingestiontotal

Total

HTHTO

9µSv/an


Concentration and mass balance

Water equivalent factor

1 kg 100g 0.9LFresh weight =dry weight + water

Protein 7 % H => 63% H2OFat 12 % H => 108%Carbohydrate 6 % H => 54%

Weq •50% - 60%

2 to 18


Final assessment for dose assessment

[ ] wairplantpeqplantairrairrtotal

fwplant CHDWHHHC .. ..).1(.)]1(3.0[ +−−+=

[ ]plplair.wairairtotal

fwplant H0..)H(1.)]CH(10.3[HC +−−+= 3.

Cgreen veg =(0.7air+0.09soil) .(0.06obt+0.8HTO) Cair.w

Cgrain cereal =(0.7air+0.09soil) .(0.24obt+0.2HTO) Cair.w

[ ] wairHTOOBTsoilairtotal

fwplant CKKKKC .. ..)][ ++=


Conclusions for normal releases

• IAEA document TRS 364 – 2008 and corresponding tecdoc– an up-to-date synthesis for normal tritium release assessment.

• For HTO : – At each step of the transfer chain, dilution occures– Vegetable Ingestion is clearly dominant– Direct Air-plant pathway dominant

• a HT release has a 1-10 % dose impact compared with HTO• Exposure comes then from HTO converted in soil

• Tritiated water of plant follows air concentration and so is not stable• OBT integrates air concentration


•ACCIDENTAL RELEASE ACCUTE RELEASE

•Dynamic models


The different mechanisms involved in plants contamination : accute release

AIR

Vegwater

Organicmatter

1st Crop

Vegwater

Organicmatter

next Crop

SOIL

harvest

depositionDecrease slope

Incorporation rate

storageHTO


Tritiated particulates – dust & metallic hydrides

• Captation and deposition depending on particles’ size

AIR captation

rain

SOIL

Vegwater

Organicmatter

Dry deposition

??

?

?


Total impact of a 10g HTO release at 1km : effect of the weather

Very sunny Cloud rain Clear night

optimization

intervention

No intervention

Strong influence of atmospheric diffusion conditions

Some conditions where optimization is required

- OK for fine sunny day- Factor 10 for rain- > Factor 10 for night

10 g of HTO = the frontier.optimization limited to few km

6/74/72/7

4/72/7

2/7

6/74/7

6/7

Do we know enough about Tritium impact ?


Dose details by pathway –

(At normalized conc. )

Vegetable Ingestion main pathway

Garden veg or cereal

With rain no change.

At night, still food.


Diurnal and seasonal effects on ingestion dose after an accidental tritium release calculated with RODTRIT)

0 5 10 15 20 25

0.00

0.02

0.04

0.06

0.08

0.10

0.12

0.14

0.16

infant adult

Inge

stio

n do

se (a

.u.)

hour of Sept. 150 50 100 150 200 250 300 350 400

0.00

0.02

0.04

0.06

0.08

0.10

infant adult

inge

stio

n do

se (a

.u.)

julian day

Dose is given in arbitrary units (a.u). The plants and animals were exposed to a constant HTO air concentration for one hour.


Relative importance of mechanisms

• Presently not enough certitude about acute release.

• Strong Rain may increase quite a lot the soil pathway, (but not the total exposure) ?

• Even with a strong rain (15mm), air pathway remains dominant in IAEA-EMRAS exercise.

• OBT generally dominant because of cereals – is that realistic ?

• Dose has to be integrated over one agricultural season because of soil pathway.


Question about scenario :case of wheat

• Ingestion of wheat is a specific problem for tritium :– The effect of cereals is reinforced by the storage and one year of

consumption.

• What is covered by the name Cereals ?

– 260g of cereals : flour, Bread, rice, corn- flakes…– Question of dry or wet weight.

• 260g/d of flouró 430 g/d of bread

– The use of a single point in the wind axe is possible for a gardenbut has to be changed at least to a surface of a field for industrialfood productions. That has a strong effect at short distance.

– Sensible pathway only for few weeks per year.


Example of uncertainties for night assessment

1,00E+02

1,00E+03

1,00E+04

1,00E+05

1,00E+06

1,00E+07

1,00E+08

1,00E+09

0 12 24 36 48

F HTOF OBTF SoilC HTOC OBTC SoilG HTOG OBTG Soil

OBT

HTO

soil

night Case - 3

?

h

Bq/L

- Level reached

- slopes


Agricultural data to develop (sojabean example)

influence of date of contamination on OBT concentration in different parts of the plant at harvest

1,0E-06

1,0E-05

1,0E-04

1,0E-03

1,0E-02

-140 -130 -120 -110 -100 -90 -80 -70 -60 -50 -40 -30 -20 -10 0time between contamination and harvest (days)

incorporation rate (h-1) stem leaf pod grain

sawing 136 days before harvest

flowers at -90 days before harvest July 7th

may 22thharvest october


Regulation : Reference level for food limitation after accident

(calculated for 1mSv in1 year after accident 10%local and 650 kg/y)

107 to define area concerned the 1st day106 to precise area in the following days

104 of Codex alimentariusfar too low

(After 2 days equilibrium reached with soil water)

1,00E+04

1,00E+05

1,00E+06

1,00E+07

1,00E+08

1,00E+09

1,00E+10

sunny 1h rain night sunny48h

rain night

Bq/kg

activity of leaf vegetable at 1 hour after

accident

activity of leaf vegetable at 2 days after

accident


Conclusions for environment : R&D• Tritium does not concentrate in food chainAbout models• Variability remains very large in case of accident especially in rain

and night cases.• Modification needed for wheat modelization - realistic approachAbout experimental Data• Translocation of organic matter from leaves to edible part of the

vegetable.• Case of the night for experimental data.• What about Tritiated particulates ?About modelers• The present Tritium scientific community is very small,• has to synthesize what is absolutely needed in models for acute

release. • This community could disappear from EU in the few next years.


Conclusions for regulation ?

• what level for food trade ?

• 104 Bq/kg is not the right level and is really too low

• Not Consistent with the 10 mSv ICRP level for optimization of interventions (>2 orders of magnitude)

• Not Consistent with codex alimentarius principles 1 mSv + 10% of a huge consumption + level decreasing after an accident + assessment for 1 year.

• Not Consistent with 104 Bq/L for WHO drinkable water in normal conditions.(0,1mSv-100%)

• Transport

4 Bq/cm2 is not reasonable for Tritium

• Drinkable water :

WHO should be kept as reference 104 Bq/L. keep 100 Bq/L as an investigation value but not a definition of drinkable limit. (Cf USA)


Environmental Regulation or reference data

• 109 Bq.kg-1 - European directive radioprotection 1996

• 105 Bq.kg-1 - IAEA clearance level for waste• 105 Bq.kg-1 - Canada OBT food trade value after accident

• 104 Bq.kg-1 - Codex alimentarius proposal after accident

• 104 Bq.L-1 - WHO for drinkable water• 740 Bq.L-1 USA reference value for watertable 20000 pCi.l-1

• 100 Bq.L-1 - EU for distribution water control• 10 to 10000 Bq.L-1 normal T activity in the vicinity of a plant

• 10 Bq.L-1 - reference value for ANDRA storm rain basin• 1 to 10 Bq.L-1 - normal tritium activity of water• 4 Bq.cm-2 - beta value for transport


Thank you for your attention

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