ML053490153

Slides - December 8, 2005, Meeting with Energy Northwest on the Risk-Informed Diesel Generator Allowed Completion Time Extension

ML053490153
Person / Time
Site:	Columbia
Issue date:	12/08/2005
From:	Energy Northwest
To:	Office of Nuclear Reactor Regulation
References
TAC MC3203
Download: ML053490153 (15)

Text

Pesoplie,*Vision, S~ollutionxs Columbia Generating Station Diesel Generator CT Extension NRC Public Meeting December 8, 2005

AGENDA 7

• Introductions -

W.S. Oxenford, Energy Northwest M.E. Mayfield, U.S. Nuclear Regulatory Commission

• License Amendment Request for Extension of Diesel Generator Completion Time - G.V. Cullen

• Risk-informed Submittal

• Station Safety Enhancements

• Offsite Power Configuration

• Previously Approved Submittals

• CGS Response to NRC Concerns

• Summary

• NRC Feedback

• Review of Action Items g 2E ERG Y X

ONORT HWE I

ST Page 2 People *Vision *Solutions

Risk-Informed Submittal

• Regulatory Guide 1.200 Pilot Submittal

• Peer Review Team

- Assessed quality of PRA prior to use for the DG CT extension risk-informed application

- Determined modeling assumptions well defined and capture c within base model documentation

- Amendment affecting Facts & Observations (F&Os) resolved

• NRC on-site review of Columbia's PRA

• NRC Review Team comments resolved g 3oENERGY I

v NORTHWVEST Page 3 People-Vision-Solutions

Risk-Informed Submittal

• Regulatory Guide 1.177/1.174

• Risk metrics meet criteria for "very small risk region" (RG 1.174)

• Risk metrics for ICCDP met (RG 1.177)

• Key principles met E-Compliance with existing regulations

- Consistent with defense-in-depth philosophy

- Maintain sufficient safety margin

- No significant increase in core damage frequency

- Use of performance measurement strategies

- maintenance rule Pe 4 PpleiOTHnWS EST

_iPage 4

People *Vision *Solutions

Station Safety Enhancements Plant Modifications Additional 480v AC Source to Battery Chargers (DG-4)

• DG purchased and staged

• Hard wiring installed to simplify and shorten deployment

• Greatly extends power availability to preferred coping equipment (RC

, ADS and Siwitchgear Control Power)

• Battery capacity no longer limits SBO coping duration Pg P

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PageS5 People *Vision *Solutions

Station Safety Enhancements 2

Plant Modifications (continued)

Additional 4.16kv AC Source for Selected Safe Shutdown Loads (Div 3 DG Cross Connect to Div 1 or 2)

• CGS modified to add capability in response to RAI

• Providing procedures and training to facilitate implementation

• Significantly enhances flexibility and safety for LOOP and SBO responses Pag 6ENpERGY

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Station Safety Enhancements Risk Management

• Risk Management Action Commitments for Extended DG CT Include:

• Extended DG CT will not be entered for scheduled maintenance purposes if severe weather or high stress grid conditions are expected

• Verify current grid stability and forecasted grid conditions g 7 P

e NERGY l

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People-Vision-Solutions

Station Safety Enhancements Risk Management (continued)

Greatly restrict maintenance activities on station

• No testing or maintenance on the protected DGs

• No testing or maintenance on plant distribution system connections to off-site power sources

• No testing or maintenance on HPCS and RCIC

• Restricted testing and maintenance on risk-significant equipment

• System load dispatcher contact on daily basis

• Other commitments g 8 NORTHWpEST l

Page 8 People *Vision *Solutions

Offsite Power Configuration Federal Columbia River Power System (FCRPS)

-l Infrastructure includes 500kV, 230kV and 115kV AC Transmission systems Columbia Generating Station interconnections to grid:

Main Generator output is to the 500kV system at Ashe substation (two bus, breaker-and-a-half scheme, 500kv lines to other substations)

Preferred offsite source to CGS is from the 230kV system at Ashe (not connected to 500 kV yard at Ashe)

Backup offsite source to CGS is from the 115kV system at Benton substation (on separate right of way from the 230kV system) l* Regional grid on east side of the state includes significant hydroelectric generating resources to continuously support station service to Columbia

• Diverse Black Start capability in the FCRPS enhances recovery of station service to Columbia during LOOP/SBO events g

ENERGYioSo X

~NORTWS Page 9 People *Vision *Solutions

Industry Precedent

• Columbia Originally Modeled after Clinton Submittal - Approved without Cross Connect

• Columbia Similar to River Bend and Grand Gulf Submittals - Approved with Addition of Cross Connect

• Time frame commitment for implementation of cross connection same as committed by RB and GG

• Defense-in depth and Safety at CGS are Equal or Greater g

ENERGY X NORTHWVEST Page 10 People *Vision *Solutions

In dustry Precedent

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Grand Gulf/River Bend SBO Comparison

• GG and RB Credit RCIC With HPCS as Backup

• Columbia credits HPCS with RCIC as preferred system (in essence HPCS is backup)

- Columbia credits HPCS for 10CFR 50.63 coping

- Columbia committed on docket to have RCIC as preferred SBO response equipment

- FSAR states RCIC is preferred SBO source

- SBO procedures direct operators to RCIC first

- From safety and risk standpoint this makes Columbia similar to RB and GG PENERGY X NORTHWVEST Page 12 People *Vision *Solutions

CGS Response to NRC Concerns

• Using DG-3 for SBO and Cross Connect Does Not Cause Licensing Basis Conflict Unlike PWRs, Division 1 & Division 2 have only LP AC ECCS systems for injection and decay heat removal When cross connection would be used:

- Plant will be at low pressure and high pressure injection is not required or

- HPCS has successfully mitigated the SBO

- Determination that offsite power will not be restored within 4-hour coping time

- Failure of HPCS

- RCIC functioning fully to mitigate SBO (and well beyond coping requirement o f4 hours)

Pg 1ENERGY S

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• Vision

• Solutions

CGS Response to NRC Concerns

• Implementation procedures will provide for swap-over to be accomplished in 2 hours2.314815e-5 days <br />5.555556e-4 hours <br />3.306878e-6 weeks <br />7.61e-7 months <br /> from decision to implement 9 Bus alignment - less than 90 minutes

• Bus energization - less than 30 minutes

• Ability to maintain core cooling and safe shutdown assured by HPCS plus DG-3 cross connect g

ENERGY NORTHWVEST Page 14 People *Vision *Solutions

Summnary Conclusion

• Risk-Informed Process Guidance Followed and Satisfied

• Station Safety Significantly Enhanced to Satisfy Requirements and RAI

• Similar to Precedent Approved Submittals P

ENERGY X NORTHWVEST People *Vision-*Solutions Page 15

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