seismic hazardseismic hazard reevaluationtable 5-1 indicates ‘hard limestone’ below 17 ft...

Seismic HazardSeismic Hazard ReevaluationReevaluation

June 19, 2014

IPEEE Questions

Arkansas Nuclear OneJames A FitzpatrickJames A Fitzpatrick

Arkansas Nuclear One IPEEEArkansas Nuclear One IPEEE

W th E D/G F l il t k d 4160Was the Emergency D/G Fuel oil tank and 4160 v Switchgear upgraded to 0.30 g?

E l i h th i i i t b t tiExplain why there is some inconsistency between section 4.7 of the March submittal compared to RAIs from the IPEEE


W th 4160 S it h d d t 0 30 ? Was the 4160 v Switchgear upgraded to 0.30 g?

4160 Volt Switchgear 2A-3 and 2A-4 4160 Volt Switchgear 2A 3 and 2A 4

Walk down performed during 2R12 outage

3rd set of plug welds observed versus 2 3 set of plug welds observed versus 2

Reevaluated with 3 sets of welds

Switchgear HCLPF to >0 30 g Switchgear HCLPF to >0.30 g

Documented in 96-SQ-2001-01 R. 0


Was the Emergency D/G Fuel oil tank upgraded toWas the Emergency D/G Fuel oil tank upgraded to 0.30 g?

Diesel Generator Fuel Oil Tank 2T-57A&B

• Re-evaluated

• Tanks qualified to 0.30 g

• Documented in 95-SQ-2521-01 revision 0

• Documented in GL 97-02 Completion Letter

Arkansas Nuclear One IPEEEArkansas Nuclear One IPEEE Explain why there is some inconsistency p y y

between section 4.7 of the March submittal compared to RAIs from the IPEEE.

“ fRAI Response “A fault tree was constructed by removing the components not on the IPEEE safe shutdown list…”

March submittal “A fault tree was developed from theMarch submittal A fault tree was developed from the detailed plant fault tree, taking no credit for components on the IPEEE SSEL…”

March submittal is in errorANO – Unit 1 IPEEE meets the requirements of Section

3.2.5.8 of NUREG-1407

J A Fitzpatrick IPEEEJ.A. Fitzpatrick IPEEE

How is the HCLPF calculation for the block walls in the IPEEE adequate?

How was relay chatter addressed?

W EPRI 6041 d f C t II SSC i thWas EPRI-6041 used for Category II SSCs in the Turbine Building?

J A Fitzpatrick IPEEEJ.A. Fitzpatrick IPEEE How is the HCLPF calculation for the blockHow is the HCLPF calculation for the block

walls in the IPEEE adequate?

NRC Bulletin 80-11 and A-46 walk-downsNRC Bulletin 80 11 and A 46 walk downs

3 walls subsequently installed

4 ll t th d4 walls strengthened

EPRI NP-6041-SL

Evaluating damping value used


How was relay chatter addressed?How was relay chatter addressed?

Relay Chatter JAF was a Focused IPEEE 144 Outliers Outlier Seismic Verification Sheets (OSVS) form for each ( )

outlier were filled out. All outliers were resolved in 1998 However, SPID required new relay evaluationHowever, SPID required new relay evaluation

JAF has committed to perform a new relay evaluation


W EPRI 6041 d f C t II SSC i T biWas EPRI-6041 used for Category II SSCs in Turbine Building?

YES

Class I potions designed to both 0.08g for OBE and 0.15g for

DBEDBE

Class II portions governed by 0.08g design.

Class II OBE design controlling for preventing a collapse Class II OBE design controlling for preventing a collapse

affecting Class I portions for DBE

Table 2-3 of EPRI NP-6041 is applicable

Soil Properties

Indian Point Energy Center

Indian Point Energy CenterIndian Point Energy CenterThe new Ground Motion Response SpectraThe new Ground Motion Response Spectra

(GMRS) developed by EPRI and the NRC has some differences.The source of the differences are the result of

different properties assumed for the site amplification.amplification.EPRI used the historical hard rock values which

would result in no amplification.NRC used a softer rock value

Indian Point Energy CenterIndian Point Energy CenterLocated west of the Hudson River in Buchanan,

New York

Th it h th t The site houses three reactors;Indian Point Unit No. 1 (SAFSTOR MODE)Indian Point Units Nos 2 & 3 two PressurizedIndian Point Units Nos. 2 & 3, two Pressurized

Water Reactors

Site Area bedrock is rock of the Manhattan Formation, Limestone, and marble

Indian Point Energy CenterIndian Point Energy Center

The circa 1980 EPRI-SOG Summary Report indicates that the units were founded on ‘basement rock’ with the site underlain by phillite y pand limestone

Table 5-1 indicates ‘hard limestone’ below 17 ft with a 7 ft layer of ‘decomposed rock’with a 7 ft layer of decomposed rock

The regional rock units generally consist of gneiss, schist, granite, quartzite, and marble, all g , , g , q , ,typically associated with high Vs. (Shear Wave Velocity)

Indian Point Energy CenterIndian Point Energy CenterBuilding the three nuclear units required aBuilding the three nuclear units required a

significant amount of rock removal.Rock blasting was used to fragment and remove

the rock to below foundation levels. Native rock elevations in the plant area varied from approximately Elev + 80 ft to Elev + 20 ftapproximately Elev. + 80 ft. to Elev. + 20 ft. towards the western part of the site.

Foundation elevations for the safety related ou da o e e a o s o e sa e y e a edstructures are, in general, 30 feet or more below grade/top of the rock. (final blasted elevation of rock)

Indian Point Energy CenterIndian Point Energy CenterThere were no quantifications for theThere were no quantifications for the

compressional (p-wave) or shear wave velocities

Estimates were based on information suggesting that, for the Indian Point site, shear wave velocities in excess of 9200 fps are appropriate

NOTE 9200 FPS 2 804 16NOTE: 9200 FPS = 2,804.16 mps

Indian Point Energy CenterTypical Wave velocities

Indian Point Energy CenterIndian Point Energy CenterRECENT INFORMATION

The 2010 and 2011 EPRI Reports relied upon the EPRI-SOG information

“The Indian Point Nuclear Generating Station site is considered a hard-rock site because the shear-wave velocity at the surface is > 9200 fps. This is consistent with the hard-rock ground motion equations used here for rock conditions (EPRI 2004) Therefore no site-for rock conditions (EPRI, 2004). Therefore, no sitespecific amplification calculations were made, and hard-rock hazard curves are used to determine the spectra.”

Indian Point Energy CenterIndian Point Energy CenterRECENT EXCAVATION IN THE FUEL STORAGE

BUILDINGA single failure proof crane had to be installed

A h i th i d ti th kAnchoring the crane required excavating the rockRock removal:No blasting allowedNo blasting allowedExtremely difficultNumerous diamond drill bits were broken

Rock samples were categorized as marble.

Indian Point Energy CenterIndian Point Energy CenterRECENT SOIL INVESTIGATIONS AT INDIAN

POINT SITE 2005 thr 2007POINT SITE 2005 thru 2007

Installation of groundwater monitoring wells

Seismic Survey

Work to facilitate movement of Spent Fuel DryWork to facilitate movement of Spent Fuel Dry

Casks

Independent Spent Fuel Storage Installation of

concrete pad


In 2006 a seismic survey was performed at a location


In 2006 a seismic survey was performed at a location approximately 600 feet south of Indian Point 3 VC GPR measurements obtained depth to bedrockS i i f ti t di t i lSeismic refraction surveys to predict compressional

wave velocities in the fill and at the top of the rockSpectral Analysis of Surface Waves (SASW) data

obtained using the ReMI Methodsobtained using the ReMI MethodsThe rock profile in the area is highly fractured and

is not representative of the rock characteristics in pthe plant area.

Fractures in rock result in reduced compressional and shear wave velocitiesand shear wave velocities

Indian Point Energy CenterLarge discontinuities in the rock elevation.

Indian Point Energy Centerg

“AGS noticed several characteristics of the rock b th th it Fi t th t h f thbeneath the site. First, the topography of the bedrock interface ranged from flat to highly variable over relatively short distances. There were a few ylocations where the bedrock interface disappeared and was located greater than 40-45 feet below ground surface(bgs) This occurred on Line 1 fromground surface(bgs). This occurred on Line 1 from stations minus10 to 40, and on Line 5 from stations 12 to 30.”

Indian Point Energy Center(RQD) Rock Quality Designation is and

Indian Point Energy Center(RQD) Rock Quality Designation is and

indicator as to the degree of fragmentation in the rock

Compare Monitoring Well logs along a line close to the

southern part of the plant, i.e.,MWs-41,43,44,45,46, and 47

MWs 48 (and 40), which represent a line in theMWs 48 (and 40), which represent a line in the general area south of the Warehouse (where MW-48 is located).

Indian Point Energy CenterIndian Point Energy CenterMW RQD and Notes

MW RQD41 85 100

48

RQD values of 13, 23, and 58. Fracture zone41 85-100

43 73-10044 80-100

Fracture zoneElev. 25 ft to Elev. 37-6 ft.Fracture zone:

El 28 t 31 ft45 97-10046 68-10047 95 100 40

• Elev. 28 to 31 ft• Angular fragments Elev.

29.5 ft to 32 ft47 95-100 40• Elev. 35 ft to Elev. 38 ft.• 35 ft to Elev. 37 ft

Cl l d f t• Closely spaced fractures Elev. 71-4 to 71-9 ft.

Indian Point Energy CenterMonitoring Well Map

Indian Point Energy CenterBased on the significant fracturing in the MW

Indian Point Energy CenterBased on the significant fracturing in the MW

closest to the seismic survey lines, it is apparent that the area suffered significant erosion and stress levels that caused significant rock fragmentation and discontinuities.

E ti t t th l iti fEstimates as to the wave velocities away from this area of significant discontinuities should be used for Indian Point.used o d a o

Indian Point Energy CenterIndian Point Energy CenterWORK PERFORMED BY GZA TO INSTALL MONITORING WELLS 23+ boreholes installed in the plant area Rock generally characterized as white MARBLE. The Rock Quality Designation (RQD): improves with depth improves with depth improves with distance away from the fragmentation caused by blasting

and weathering generally in the 80 to 100 range

P f b d k f t ( hi h i l d t f t ) Presence of bedrock fractures (which includes transverse fractures) higher near the bedrock surface decreases with depth in the area of the Site

The RQDs are affected by drilling techniques, core breakage during y g q , g ghandling, stress-relief and air slaking, the presence of thinly bedded or closely jointed zone, and the extensive blasting at the site.

Attempts to correlate the RQDs with compressional or shear wave velocities would be questionable at best.

Indian Point Energy CenterIndian Point Energy CenterWORK PERFORMED BY TECTONIC AT THE FUEL STORAGE

BUILDINGBUILDING Eight borings were made inside the FSB and along the road to the FSB. Four of the borings are in the FSB, just south of the Spent Fuel Pool Samples from borings B-1 and B-2 used to perform unconfined Samples from borings B-1 and B-2 used to perform unconfined

compressive strength tests B-1 was taken at a depth of 9.5’ to 10’ B-2 was taken at a depth of 11’ to 12’

The RQDs at the sample locations were 66 and 55 respectively The RQDs at the sample locations were 66 and 55, respectively, indicating significant fragmentation effects from the adjacent blasting

“Results of the unconfined compressive strength testing on the two rock l i ld d h i f i l 10 000core samples yielded strength varying from approximately 10,000 to

20,000 pounds per square inch. These unconfined compressive strengths generally correlate to strong to very strong rock conditions.”

Indian Point Energy CenterIndian Point Energy CenterWORK PERFORMED BY TECTONIC AT THE FUEL

STORAGE BUILDINGSTORAGE BUILDING A seismic refraction study was performed along a 235

ft. long array along the road leading east from the FSB G h l d fi (5) f t t lFSB. Geophones were placed five (5) feet apart along the array.

The Tectonic Report indicates that the rock quality p q yincreases with depth.

The upper portion of the rock in this area is significantly fragmented as a result of the blasting forsignificantly fragmented as a result of the blasting for the FSB to the north and blasting for the Primary Auxiliary Building to the south.


Th P l iti l th t f th k fThe P-wave velocities along the top of the rock vary from 12,500 fps to 13,900 fps.

Indian Point Energy CenterIndian Point Energy CenterWORK PERFORMED BY TECTONIC AT THE

ISFSI PADThe ISFSI pad required the placement of a

carefully engineered fill with properties that matchcarefully engineered fill with properties that match the ones used in performing the Dry Cask drop analyses.y

Up to five (5) feet of rock had to be removed to facilitate the placement of the engineered fill

Rock removal was by mechanical means, significantly affecting the rock upper portion.


ISFSI PADEngineering Properties


ISFSI PADSeismic Refraction Arrays

Indian Point Energy CenterIndian Point Energy CenterWORK PERFORMED BY TECTONIC AT THE ISFSI

PADPAD

Included the characterization of the underlying rocky g Included seismic refraction studies along six (6)

arraysResults from the seismic refraction work were used toResults from the seismic refraction work were used to

verify the predictions as to depth to bedrockSome anomalies existed with the sixth arrayEstimates as to the compressional wave velocities

obtained from the Line 6 array should not be considered

Indian Point Energy CenterIndian Point Energy CenterSEISMIC REFRACTION

Estimates the rock compressional wave velocities along the interface between the engineered fillalong the interface between the engineered fill and the top of the rock

The top of the rock layer is weathered and more f t dfragmented

Measured compressional wave velocities along weathered rock surface do not represent theweathered rock surface do not represent the wave velocities at a depth in the range of 30 ft. below the top of the rock

Indian Point Energy CenterIndian Point Energy Center The mean of the low bound compressional wave velocities from The mean of the low bound compressional wave velocities from

Arrays 1 through Array 6 is 13,217 fps. The mean of the upper bound compressional wave velocities

from Arrays 1 through Array 6 is 15,633 fps. The overall mean of the compressional wave velocities

measured at the ISFSI pad for the rock upper portion is 14,425 fps.

Fractures, more prevalent in the upper portions of the rock, result Fractures, more prevalent in the upper portions of the rock, result in a reduction in the compressional (Vp) and shear wave (Vs) velocities through the rock

Velocities measured by Tectonic represent compressional wave velocities through fractured and weathered rock in the topvelocities through fractured and weathered rock in the top section of the rock and do not represent wave velocities representative of locations 30 feet below the rock surface.

Indian Point Energy CenterIndian Point Energy Center Tectonic observed that: “The presence of bedrock fractures Tectonic observed that: The presence of bedrock fractures

(which includes transverse fractures) is reported to be higher near the bedrock surface and to decrease with depth in the area of the Site (Tectonic, 2004).”

Based on the above observations it may be inferred that the Based on the above observations, it may be inferred that the wave velocities measured by Tectonic represent reduced compressional wave velocities through fractured rock and that at depths of 30 ft. or more below the rock surface, the improved rock quality results in higher wave velocitiesrock quality results in higher wave velocities.

For the purpose of estimating compressional wave velocities away from the fractured, and weathered, rock surface, we shall assume the compressional wave velocity at the foundation level f f fof safety related structures is equal to the mean value of the

wave velocities for the ISFSI arrays, i.e. Vp = 14,425 fps.

Indian Point Energy CenterIndian Point Energy CenterCONCLUSION

The site sits on hard rockhistoric documents

it ti ksite excavation workapplicable well data

Use of selective site data is inappropriateUse of selective site data is inappropriateperimeter well dataISFS Pad surface dataISFS Pad surface data

Seismic Screening


Indian Point Energy CenterIndian Point Energy Center IP3 was screened in as a Priority 1 plant for an SPRA

since the consideration of the more recent re-assessment of the IPEEE was not considered.

The original IPEEE analysis in 1995 was performed to meet the minimum Review Level Earthquake (RLE).

The actual capacity of the plant is much higher.

Demonstrated in recent re-assessment of IPEEE

Indian Point Energy CenterIndian Point Energy CenterIn 2010/2011 the NRC used values for plant p

capacity extracted from the IP3 IPEEE report submitted in 1997. This resulted in the NRC determining a very

conservative SCDF estimate of 1.0E-04 per year, or 1 in 10,000 reactor-years.1 in 10,000 reactor years. NRC has evaluated and stated any plant with a

SCDF value lower than 1.0E-04 per year (or 1 in 10 000 t ) i t bl10,000 reactor-years) is acceptable.

Indian Point Energy CenterIndian Point Energy CenterUsing the improved plant capacities developed by

a Seismic review team a reassessment of the SCDF estimate was performed in April 2011.

This report IP-RPT-11-00012 (ML 13183A280) was transmitted to the NRC by June 2013 letter NL-13-084 (ML 13183A279).NL 13 084 (ML 13183A279).

With the use of the improved plant capacities and EPRI updated 2010 hazard curves;EPRI updated 2010 hazard curves; A new SCDF was estimated at 7.1E-06 per year (or 1 in 140,845 reactor-years).

Indian Point Energy CenterIndian Point Energy CenterAssessment ApproachUnderstanding the current seismic risk to the

station, in terms of SCDF.Identifying potential conservatisms within the IP3Identifying potential conservatisms within the IP3

IPEEE submittal information used by the NRC in the SCDF calculation.Making IPEEE component fragility values more

realistic. The team computed fragility values for a sample The team computed fragility values for a sample

of components that are high contributors to risk using original component design documents

Indian Point Energy CenterIndian Point Energy CenterReducing conservatism in the USGS seismic g

Hazard Curves. the USGS seismic hazard calculations did not include

Cumulative Absolute Velocity (CAV) filtering and groundCumulative Absolute Velocity (CAV) filtering and ground motion incoherence, which tend to reduce the acceleration values.

Developing a more realistic SCDF using the revisedDeveloping a more realistic SCDF using the revised fragilities and hazard curves. It should be noted that the original PRA computer model

S i i H d I t ti P (SHIP) i t il blSeismic Hazard Integration Program (SHIP) is not available to be modified and an alternate approach was developed

Indian Point Energy CenterIndian Point Energy CenterIdentification of Low Capacity Components in

dominant sequencesSeismic-induced loss-of-offsite power (LOSP) and

the subsequent loss of on site AC power from allthe subsequent loss of on-site AC power from all three emergency diesel generators. Loss of secondary side cooling due to depletion of

the condensate storage tank and failure of RHR shutdown cooling due to the seismic event.Loss of component cooling water (CCW) orLoss of component cooling water (CCW) or

containment fan coolers due to a seismic event.

Indian Point Energy CenterIndian Point Energy Center The improved values for the median capacity (Am = 1.27g),

and composite uncertainty (ß 0 4) calculated by theand composite uncertainty (ßc = 0.4) calculated by the review team resulted in a SCDF estimate of 9.4E-06 per year (1 in 106,383 reactor-years) associated with the

t USGS H d C hi h tcurrent USGS Hazard Curves which represents a significant reduction from the GI-199 reported SCDF estimate (1.0E-04 per year or 1 in 10,000 reactor-years)

d i h li i i f h i i i kand is a much more realistic estimate of the seismic risk. It should also be noted that using the improved fragility (Am

= 1.27g, and ßc = 0.4 ) along with the 2010 EPRI updated g, c ) g pseismic Hazard Curves instead of the USGS curves further reduces the SCDF value to 7.1E-06 per year (or 1 in 140,845 reactor-years), y )

Indian Point Energy CenterIndian Point Energy Center The IPEEE and its reassessment were reviewed for

adequacy utilizing the guidance provided in Section 3 3 ofadequacy utilizing the guidance provided in Section 3.3 of the SPID (EPRI, 2013a). A detailed description of the results of the IPEEE adequacy review is included in A di B f th M h S b itt l (ML14099A111)Appendix B of the March Submittal (ML14099A111) .

The results of these reviews have shown, in accordance with the criteria established in SPID (EPRI, 2013a) Section 3.3, that the IPEEE and reassessment of the IHS are adequate to support screening of the updated seismic hazard for Indian Point Unit 3. The review also concluded that the risk insights obtained from the IPEEE are still valid under the current plant configuration.

Indian Point Energy CenterIndian Point Energy CenterScaling the Review level earthquake (RLE)

Am = 0.975g

βc = 0.30

HCLPF = Am x e – (2.3264 x βc ) = 0.975 x e – (2.3264 x 0.30 ) m

= 0.975 x 0.4976 = 0.485g

Scaling factor Scaling factor

0.485/0.23 = 2.11


ConclusionBased on the results of the screening evaluation,

I di P i t U it 3 t f i kIndian Point Unit 3 screens-out of a risk evaluation.

Unit 2 will perform its SPRA in group 1 andUnit 2 will perform its SPRA in group 1 and should show adequate margin based on initial results from Unit 3.

SUMMARYSUMMARYEnsure a complete understanding of the NRC

tiquestions. IPEC is a hard rock site. IP3 Updated IPEEE should be used to evaluate the IP3 Updated IPEEE should be used to evaluate the

new GRMS. IP3 should be screened out of an additional risk

assessment since it has already been performed.Additional confirmation of safety provided by ESEP.

If dditi l ti i d d t i th IPEEE IP3 If additional time is needed to review the IPEEE IP3 should be categorized as a Conditional Priority 3 plant.p

seismic hazardseismic hazard reevaluationtable 5-1 indicates ‘hard limestone’ below 17 ft...

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