ML13308B800

(VCSNS) - Request for Additional Information

ML13308B800
Person / Time
Site:	Summer
Issue date:	11/07/2013
From:	Shawn Williams Plant Licensing Branch II
To:	Gatlin T South Carolina Electric & Gas Co
Williams, Shawn NRR/DORL 415-1009
References
TAC ME7586
Download: ML13308B800 (4)

Text

UNITED STATES NUCLEAR REGULATORY COMMISSION WASHINGTON, D.C. 20555-0001 November 7, 2013 Mr. Thomas D. Gatlin Vice President, Nuclear Operations South Carolina Electric & Gas Company Virgil C. Summer Nuclear Station Post Office Box 88, Mail Code 800 Jenkinsville, SC 29065 SUB..IECT: VIRGIL C. SUMMER NUCLEAR STATION, UNIT NO.1 (VCSNS) - REQUEST FOR ADDITIONAL INFORMATION (TAC NO. ME7586)

Dear Mr. Gatlin:

By letters dated November 15, 2011, January 26 and October 10, 2012, the South Carolina Electric & Gas Company (SCE&G, the licensee) submitted a license amendment request (LAR) to revise Facility Operating License Number NPF-12 for the Virgil C. Summer Nuclear Station, Unit No.1. The LAR would permit transition of the fire protection licensing basis from Title 10 of the Code of Federal Regulations (10 CFR), Section 50.48(b), to 10 CFR 50.48(c), "National Fire Protection Association Standard NFPA 805" (NFPA 805).

The staff has determined that additional information is needed to continue the review as discussed in the Enclosure. We request that SCE&G respond to these RAls by January 9, 2014. Please note that the staff's review is continuing and further RAls may be developed.

Sincerely,

~lAJ~

Shawn Williams, Senior Project Manager Plant Licensing Branch 11-1 Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation Docket No. 50-395

Enclosure:

Request for Additional Information cc w/encl: Distribution via Listserv

REQUESTS FOR ADDITIONAL INFORMATION LICENSE AMENDMENT REQUEST TO ADOPT PERFORMANCE-BASED NATIONAL FIRE PROTECTION ASSOCIATION STANDARD 805 FOR FIRE PROTECTION FOR VIRGIL C. SUMMER NUCLEAR STATION, UNIT NO.1 DOCKET NO. 50-395 Probabilistic Risk Assessment (PRA) RAt 10.02 In a letter dated October 10, 2012 (Agencywide Document Access and Management System (ADAMS) Accession No. ML2297A218), the licensee responded to PRA RAI10 and provided a detailed description of a series of operator actions to shutdown the facility using a preferred success path after main control room (MCR) abandonment. It appears from the response that this single human error probability (HEP) value is used for every MCR abandonment scenario.

a. Describe whether any values other than 0.05 are used to characterize the HEP following MCR abandonment and whether the 0.05 value also represents the conditional core damage probability (CCDP).

b. If any values other than 0.05 are used, e.g., 1.0, provide the other values, a characterization of the scenarios that these values are used, and a summary of how each value is developed. This information should include explanations of how the following scenarios are addressed.

i. Scenarios where the fire fails few functions aside from MCR habitability and successful shutdown is straightforward.

ii. Scenarios where the fire could cause some recoverable functional failures or spurious operations that complicate the shutdown but successful shutdown is likely.

iii. Scenarios where the fire induced failures cause great difficulty for shutdown by failing multiple functions and/or complex spurious operations that make successful shutdown unlikely.

c. If no values other than 0.05 are used, please explain how scenarios characterized under 10.02.b.i, 10.02.b.ii, and 10.02.b.iii are included in your MCR abandonment evaluations.

PRARAt96 Regarding Fact and Observation (F&O) CF-A 1-01, the licensee applies Option #2 of Task 10 of NUREG/CR-6850, "EPRIINRC-RES Fire PRA Methodology for Nuclear Power Facilities," for circuit analysis, as recommended by the peer review. However, by NRC memorandum, "Interim Technical Guidance on Fire-Induced Circuit Failure Mode Likelihood Analysis," dated June 14, 2013 (ADAMS Accession No. ML13165A209), Option #2 "does not provide an adequate method for quantifying the likelihood of hot short-induced spurious operations." As a result, provide a sensitivity analysis, evaluating core damage frequency (CDF), large early release frequency

-2 (LERF), Delta (~)CDF, and ~LERF, by substituting an acceptable method for Option #2. It should be noted that Option #1 of Task 10 of NUREG/CR-6850, absent control power transformer (CPT) credit, is an acceptable method, as well as the cited staff guidance NUREG/CR-6850.

PRARAI97 Attachment S, Table S-1, Item ECR50799, of the License Amendment Request (LAR), (ADAMS Accession No. ML11332A076) describes a proposed change of providing lower leakage Reactor Coolant Pump (RCP) seals and crediting them in the Fire Probabilistic Risk Assessment (FPRA). The exact RCP seal package is not specified in the LAR; however, the licensee indicated by teleconference that earlier plans to install the Westinghouse passive thermal shutdown seal (SHIELD) had been abandoned for a different RCP seal package.

As a result:

a. Describe the type of seal package modeled in the PRA which supports the risk estimates reported in the November 15, 2011, LAR.

b. If a different seal package is planned to be installed to support transition to NFPA 805 from that which was used in the PRA supporting the November 15, 2011, LAR, identify the new seal package. Also, please answer the following:

i. Provide the revised risk estimates of the impacts, including the basis for any revised assumptions.

ii. If the new seal package model causes the total change in risk from transitioning to NFPA 805 to exceed the acceptance guidelines of RG 1.174, "An Approach for Using Probabilistic Risk Assessment in Risk-Informed Decisions on Plant Specific Changes to the licenSing Basis," describe the plans to demonstrate that the risk increase is acceptable.

iii. Discuss whether any currently proposed license conditions are affected by these changes.

November 7,2013 Mr. Thomas D. Gatlin Vice President, Nuclear Operations South Carolina Electric & Gas Company Virgil C. Summer Nuclear Station Post Office Box 88, Mail Code 800 Jenkinsville, SC 29065

SUBJECT:

VIRGIL C. SUMMER NUCLEAR STATION, UNIT NO.1 (VCSNS) - REQUEST FOR ADDITIONAL INFORMATION REGARDING THE NFPA-805 LICENSE AMENDMENT REVIEW (TAC NO. ME7586)

Dear Mr. Gatlin:

By letters dated November 15, 2011, January 26 and October 10, 2012, the South Carolina Electric & Gas Company (SCE&G, the licensee) submitted a license amendment request (LAR) to revise Facility Operating License Number NPF-12 for the Virgil C. Summer Nuclear Station, Unit No.1. The LAR would permit transition of the fire protection licensing basis 'from Title 10 of the Code of Federal Regulations (10 CFR), Section 50.48(b), to 10 CFR 50.48(c), "National Fire Protection Association Standard NFPA 80S" (NFPA 805).

The staff has determined that additional information is needed to continue the review as discussed in the Enclosure. We request that SCE&G respond to these RAls by January 9, 2014. Please note that the staff's review is continuing and further RAls may be developed.

Sincerely, IRA!

Shawn Williams, Senior Project Manager Plant Licensing Branch 11-1 Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation Docket No. 50-395

Enclosure:

Request for Additional Information cc w/encl: Distribution via Listserv DISTRIBUTION PUBLIC LPL2-1 R/F RidsAcrsAcnw_MailCTR Resource RidsNrrDorlDpr Resource RidsNrrDorlLpl2-1 Resource RidsRgn2MailCenler Resource RidsNrrLASFigueroa Resource RidsNrrDe Resource RidsNrrPMSummer Resource AKlein, NRR JRobinson, NRR

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