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NRR E-mail Capture - Nei/Epri Presentation Slides for Jan 18, 2018, Public Meeting to Discuss Licensee Methods of Accounting for Seismic Risk in 10 CFR 50.69 Applications Without Using a Seismic Probabilistic Risk Assessment
	ML18022A111
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Issue date:	01/22/2018
From:	Ed Miller; Special Projects and Process Branch
To:	Ed Miller; Special Projects and Process Branch
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Slides for Jan 18, 2018, Public Meeting Attachments:

50 69 Seismic Alternatives 18-18 Public Meeting.pdf Attached are the NEI/EPRI presentation slides for the January 28, 2018, public meeting to discuss seismic approaches to 10 CFR 50.69 LARs.

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Greg Krueger, NEI Partha Chandran, Southern Nuclear Greg Hardy, SGH Pat ORegan, EPRI NRC Meeting January 18, 2018 50.69 Seismic Categorization Options

2

50.69 Seismic Categorization Options

Review of October 23, 2017 meeting

Results from additional sensitivity study

Proposed Path Forward

Discussion

3

Summary of October 23, 2017 Meeting

Provided background on seismic risk inputs to the 50.69 Categorization process

Presented results to two sensitivity studies at high seismic plants with new Seismic PRAs

Described insights from the sensitivity studies and how those insights could affect the 50.69 categorization process

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NEI 00-04 Risk Informed Categorization - Seismic Inputs

Gap in information available to implement NEI 00-04

- Some plants dont fit within any of the three available options

- Includes plants that did not perform an SMA for IPEEE, and were not required to perform an SPRA in response to Fukushima

Key question is whether seismic considerations provide unique risk insights in the 50.69 categorization process

Would such insights drive SSCs to be HSS?

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Premise

Categorization process is robust and integrated methodology

- Ensure all functions (system-level attribute) are considered

- Includes risk insights, Defense-in-Depth reviews and IDP

- Integral Importance Assessment (weighted average of importance measures)

Extensive seismic reviews performed over the last 5 years

- Plant walkdowns performed to validate design basis compliance

- New site-specific seismic hazard estimates

- NRC grading of plants based on comparisons of design vs. new hazards

Limited unique component insights, even for high hazard sites

- Sensitivity studies show SPRAs produce few (if any) unique HSS components

- Insights for low and medium hazard plants expected to be more limited

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50.69 Seismic Categorization Sensitivity Studies

High seismic ground motion plants with new SPRAs as test cases

Determine how many/what kinds of SSCs are categorized as HSS

Identify HSS components using FPIE, Fire and Seismic PRA models

Compare HSS seismic components to those derived from other models

Studies for 4 plants with high seismic hazards and new Seismic PRAs

7

50.69 Categorization - Sensitivity Studies Plant A Plant B Plant C Plant D Results from Plants A and B were presented at the October 23, 2017 meeting Results from Plant C will be presented today Results from Plant D are under review and will be presented in a later meeting

8

Plant C Sensitivity Study

Use risk evaluation criteria in NEI 00-04

Fussell-9HVHO\\RU5$:!LGHQWLILHGDV+66

Performed for all three models (internal, fire, seismic)

Did not consider Integral Importance Assessment

9

Plant C Sensitivity Study, Fragility Groups F-9RU5$:!

Fragility Group ID Fragility Group Description HSS for FPIE or Fire PRA 1ACCBAA0205--D INCOMING 1AA02 FDR BKR Yes

1ACCBBA0301--D INCOMING 1BA03 FDR BKR Yes

1AFXV015-----P AFW,TDAFW PUMP,DISCH, ISOLATION Yes

1DCBYDD1B----F 125 VDC BATTERY 1DD1B Yes

1LPMVHV8702A-D RCS TO RHR PUMP B SUCTION MOV Yes

1RCPOPV0455A-U, 456-U PRESSURIZER PORVs Yes

1RPCBS6---RTAD, RTBD REACTOR TRIP BREAKER 'A, BREAKER B Yes

1SWFN1-F01---X to F04--X BREAKER to A TRAIN NSCW FAN #1, #2, #3, #4 Yes

1SWFN2-F01---X to F04--X BREAKER to B TRAIN NSCW FAN #1, #2, #3, #4 Yes

S_1ACBS-120PN-CB180 120 VAC PANEL CB 180 Yes

S_1ACIV-120-CB180 AC INVERTER CB180 Yes

S_1ACSD-SEQ SFTY FEATURES SEQUENCER Yes

S_1AFPM-MDP BOTH AFW MDP Yes

S_1AFPM-TDP AFW TDP Yes

S_1AFW-AOV-RLY RELAY FOR AFW PUMP TURB TRIP & THROTTLE VLV Yes S_1CCTK-4 CCW SURGE TANK S_1DCBC-CB180 BATTERY CHARGER CB180 Yes S_1DCBS-MCC-AB 125 VDC MCC 1AD1M AND 1BD1M Yes

S_1DCBS-MCC-ALL ALL 125 VDC MCC Yes

S_1DCBS-PN-CB180-1E 125 VDC 1E DISTR. PANEL - CB180 Yes

S_1DCBS-SGR-CB180 125 VDC SWITCHGEAR CB180 Yes

S_1DCBY-CB180 125 VDC BATTERY CB180 Yes

S_1DG DIESEL GENERATOR Yes

S_1DGDM-VENT DG VENT DAMPER FOR FANS 1-4 Yes

S_1DGFN-FAN DG BLDG ESF SUPPLY FAN

S_1FC-ACU-FLD ANCHORAGE FAILURE OF ACU WITH NSCW FLD

S_1SWFN-NSCW-FANS NSCW TOWER FANS Yes

S_1XCTK-4 ACCW Surge Tank S_CB-CHLR-NSCW-FLOOD SEISMIC FAILURE OF CB ESF CHILLERS CAUSE NSCW FLOOD ON CB 260

Notes:

Components are HSS due to seismic correlated failures Several components would be HSS due to 50.69 Passive Categorization One component would be HSS due to implicit inclusion in FPIE HSS D/G components

10

50.69 Seismic Categorization Sensitivity Studies Sensitivity studies from high seismic hazard sites show limited unique insights at the component level

HSS SSCs identified in the seismic PRAs are also identified as risk significant in the FPIE PRA and/or Fire PRA

In certain limited cases, correlated failures in the Seismic PRA can lead to different categorization results

Only a handful of such unique components are expected

Unique seismic HSS components expected to be even fewer at low and medium seismic hazard plants

11

Relay Considerations

Relays can be important components in SPRAs (e.g. EDG control cabinets, chargers/inverters, 4kV switchgear)

FPIE PRAs typically do not explicitly model relays; contributions implicitly modeled

Backup power system functions are modeled

Based on functional reviews, typically cabinets housing important relays identified HSS in FPIE PRA and by default, subcomponents in those cabinets considered HSS

Subsequent categorization of subcomponents in enclosures would need to consider the functions of the subcomponents

12

50.69 Seismic Categorization Proposed Path Forward Low hazard plants, with new GMRS generally below SSE

- SPRAs provide very limited unique insights to 50.69 categorization and explicit consideration of seismic risks in the 50.69 categorization process is not necessary 0RGHUDWHKD]DUGSODQWVZLWKQHZ*056!66(EXWQRW

required to perform an SPRA for NTTF 2.1 response

- Sensitivity studies have shown that seismic correlated failures may contribute to 50.69 categorization decisions

- Consider correlated failure sensitivity studies using the FPIE PRA for moderate seismic hazard plants High seismic hazard plants performing SPRAs

- Use SPRA or SMA component list consistent with NEI 00-04

13

Summary

Confidence that SCCs are categorized in robust, integrated process

- Defense-in-Depth reviews

- All functions (system-level attribute) are appropriately considered

- Multi-discipline panel of experts reviews/approves the results

Formalized 3-tiered approach allows efficient review process

- Seismic considerations not expected to provide unique risk insights

- Examining results of 4 sensitivity studies to define correlated failure insights for possible use by moderate hazard sites

Submittal strategy under development

14

TogetherShaping the Future of Electricity

15

Backup Slides

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Sensitivity Study - Plant C, Fragility Groups F-9

Fragility Group ID Fragility Group Description HSS for FPIE or Fire PRA Comments 1ACCBAA0205--D INCOMING 1AA02 FDR BKR Yes

1ACCBBA0301--D INCOMING 1BA03 FDR BKR Yes

1AFXV015-----P AFW,TDAFW PUMP,DISCH, ISOLATION Yes

1DCBYDD1B----F 125 VDC BATTERY 1DD1B Yes

1LPMVHV8702A-D RCS TO RHR PUMP B SUCTION MOV Yes

1RCPOPV0455A-U, 456-U PRESSURIZER PORVs Yes

1RPCBS6---RTAD, RTBD REACTOR TRIP BREAKER 'A, BREAKER B Yes

1SWFN1-F01---X to F04--X BREAKER to A TRAIN NSCW FAN #1, #2, #3, #4 Yes

1SWFN2-F01---X to F04--X BREAKER to B TRAIN NSCW FAN #1, #2, #3, #4 Yes

S_1ACBS-120PN-CB180 120 VAC PANEL CB 180 Yes

S_1ACIV-120-CB180 AC INVERTER CB180 Yes

S_1ACSD-SEQ SFTY FEATURES SEQUENCER Yes

S_1AFPM-MDP BOTH AFW MDP Yes

S_1AFPM-TDP AFW TDP Yes

S_1AFW-AOV-RLY RELAY FOR AFW PUMP TURB TRIP & THROTTLE VLV Yes

S_1CCTK-4 CCW SURGE TANK

Addressed by 50.69 Passive Categorization Process S_1DCBC-CB180 BATTERY CHARGER CB180 Yes

S_1DCBS-MCC-AB 125 VDC MCC 1AD1M AND 1BD1M Yes

S_1DCBS-MCC-ALL ALL 125 VDC MCC Yes

S_1DCBS-PN-CB180-1E 125 VDC 1E DISTR. PANEL - CB180 Yes

S_1DCBS-SGR-CB180 125 VDC SWITCHGEAR CB180 Yes

S_1DCBY-CB180 125 VDC BATTERY CB180 Yes

S_1DG DIESEL GENERATOR Yes

S_1DGDM-VENT DG VENT DAMPER FOR FANS 1-4 Yes

S_1DGFN-FAN DG BLDG ESF SUPPLY FAN

Function associated with loss of D/G, there would be identified as HSS due to its association with D/G S_1FC-ACU-FLD ANCHORAGE FAILURE OF ACU WITH NSCW FLD

Addressed by 50.69 Passive Categorization Process S_1SWFN-NSCW-FANS NSCW TOWER FANS Yes

S_1XCTK-4 ACCW Surge Tank

Addressed by 50.69 Passive Categorization Process S_CB-CHLR-NSCW-FLOOD SEISMIC FAILURE OF CB ESF CHILLERS CAUSE NSCW FLOOD ON CB 260 One train by itself would not make the loss of NSCW critical; Seismic correlated failure of both trains is assumed leading to NSCW flooding;

ML18022A111

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