ML13267A197

Request for Additional Information, Closure of Option 2a to Address In-Vessel Mitigative Measures for Potential In-Vessel Blockage; Related to Generic Safety Issue 191

ML13267A197
Person / Time
Site:	Comanche Peak
Issue date:	09/30/2013
From:	Balwant Singal Plant Licensing Branch IV
To:	Flores R Luminant Generation Co
Singal B
References
TAC MC4676, TAC MC4677
Download: ML13267A197 (4)

Text

UNITED STATES NUCLEAR REGULATORY COMMISSION WASHINGTON, D.C. 20555*0001 September 30, 2013 Mr. Rafael Flores Senior Vice President and Chief Nuclear Officer Attention: Regulatory Affairs Luminant Generation Company LLC P.O. Box 1002 Glen Rose, TX 76043 SUB,JECT:

COMANCHE PEAK NUCLEAR POWER PLANT, UNITS 1 AND 2 - REQUEST FOR ADDITIONAL INFORMATION REGARDING CLOSURE OPTIONS FOR GENERIC SAFETY ISSUE 191, ASSESSMENT OF DEBRIS ACCUMULATION ON PRESSURIZED-WATER REACTOR SUMP PERFORMANCE (TAC NOS. MC4676 AND MC4677)

Dear Mr. Flores:

By [[letter::CP-201300546, Response to Request for Additional Information for License Amendment Request (LAR)12-007, Revision to Technical Specification 3.8.1, AC Sources - Operating, for Two, 14-Day Completion Times for Offsite Circuits|letter dated May 16, 2013]] (Agencywide Documents Access and Management System (ADAMS) Accession No. ML13149A101), Luminant Generation Company LLC (Luminant, the licensee) provided the U.S. Nuclear Regulatory Commission (NRC) staff with its intended path forward for the resolution of Generic Safety Issue (GSI)-191, "Assessment of Debris Accumulation on PWR [Pressurized-Water Reactor] Sump Performance," for Comanche Peak Nuclear Power Plant, Units 1 and 2 (CPNPP). The licensee stated that CPNPP will follow Option 2a (defined as deterministic approach with additional modeling refinements in SECY-12-0093).

The December 14,2012, Staff Requirements Memorandum on SECY-12-0093, "Closure Options for [GSI-191]" (ADAMS Accession No. ML12349A378), describes three closure options that licensees can follow to resolve GSI-191. The NRC staff has determined that additional information, as requested in the enclosure, is needed from licensees to complete the review of Option 2 plants, including CPNPP, which did not address mitigative measures for potential in-vessel blockage.

Please provide a response to the enclosed request for additional information by October 31, 2013.

R. Flores

- 2 If you have any questions, please contact me at 301-415-3016 or via e-mail at Balwant.Singal@nrc.gov.

Sincerely,

~T~1~~

Balwant K. Singal, Senior Project Manager Plant Licensing Branch IV Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation Docket Nos. 50-445 and 50-446

Enclosure:

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

REQUEST FOR ADDITIONAL INFORMATION CLOSURE OF OPTION 2 FOR GENERIC SAFETY ISSUE 191 LUMINANT GENERATION COMPANY LLC COMANCHE PEAK NUCLEAR POWER PLANT, UNITS 1 AND 2 DOCKET NOS. 50-445 AND 50-446 The December 14, 2012, Staff Requirements Memorandum on SECY-12-0093, "Closure Options for Generic Safety Issue 191 (GSI-191), "Assessment of Debris Accumulation on Pressurized-Water Reactor Sump Performance" (Agencywide Documents Access and Management System (ADAMS) Accession No. ML12349A378), describes three closure options that licensees can follow to resolve GSI-191. The U.S. Nuclear Regulatory Commission (NRC) staff has determined that additional information is needed to complete its review of Option 2 plants, including Comanche Peak Nuclear Power Plant, Units 1 and 2 (CPNPP), which did not address mitigative measures for potential in-vessel blockage.

By [[letter::CP-201300546, Response to Request for Additional Information for License Amendment Request (LAR)12-007, Revision to Technical Specification 3.8.1, AC Sources - Operating, for Two, 14-Day Completion Times for Offsite Circuits|letter dated May 16, 2013]] (ADAMS Accession No. ML13149A101), Luminant Generation Company LLC (Luminant, the licensee) provided the NRC staff with its intended path forward for the resolution of GSI-191 for CPNPP. The licensee stated that CPNPP will follow Option 2a (defined as deterministic approach with additional modeling refinements in SECY-12-0093),

partially due to elevated fiber levels in containment. The licensee also referenced a Nuclear Energy Institute (NEI) letter dated May 4,2012 (ADAMS Accession No. ML12142A316), as one of the documents providing guidance on the contents of the licensee's submittal as a path forward. The NRC staff noted that the May 4, 2012, NEI letter stated that licensees that do not meet very low in-vessel debris limits would provide, as part of the intended path forward, mitigative measures to reduce risk while taking actions to finalize the resolution of Generic Letter 2004-02, "Potential Impact of Debris Blockage on Emergency Recirculation During Design Basis Accidents at Pressurized-Water Reactors" (ADAMS Accession No. ML042360586).

In its [[letter::CP-201300546, Response to Request for Additional Information for License Amendment Request (LAR)12-007, Revision to Technical Specification 3.8.1, AC Sources - Operating, for Two, 14-Day Completion Times for Offsite Circuits|letter dated May 16, 2013]], the licensee stated that it will evaluate, and implement as necessary, recommendations for in-vessel blockage mitigative measures provided by Westinghouse, but the letter did not provide details of Westinghouse recommendations. Also, the licensee referenced Emergency Operating Procedures (EOPs) FRC-0-1A, FRC-0-1B, FRC-0-2A, and FRC-0-2B currently in place for CPNPP, to deal with inadequate core cooling, but did not state the actions of these EOPs. The NRC staff has determined that the following additional information is needed to complete the review of Option 2 plants, including CPNPP, which did not address mitigative measures for potential in-vessel blockage:

1.

Please provide the Westinghouse recommended mitigative measures deemed necessary for CPNPP, and if not yet implemented, the schedule for implementing the Westinghouse recommendations.

2.

Please provide the details of actions performed by EOPs FRC-0-1A, FRC-0-1 B, FRC-0-2A, and FRC-0-2B to deal with inadequate core cooling.

Enclosure

R. Flores

- 2 If you have any questions, please call me at 301-415-3016 or via e-mail at Balwant.Singal@nrc.gov.

Docket Nos. 50-445 and 50-446

Enclosure:

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MMarkley BSingal DATE 9/27113 9/25/13 9/18/13 9/30/13 9/30/13 OFFICIAL AGENCY RECORD