ML091970578

Summary of Category 1 Meeting with Luminant Generation Company LLC, Resolution of Generic Letter 2004-02, Potential Impact of Debris Blockage on Emergency Recirculation During Design Basis Accidents at Pressurized-Water Reactors

ML091970578
Person / Time
Site:	Comanche Peak
Issue date:	07/31/2009
From:	Balwant Singal Plant Licensing Branch IV
To:
Singal, Balwant, 415-3016, NRR/DORL/LPL4
References
TAC MC4676, TAC MC4677
Download: ML091970578 (7)

Text

UNITED STATES NUCLEAR REGULATORY COMMISSION WASHINGTON, D.C. 20555-0001 July 31, 2009 LICENSEE: LUMINANT GENERATION COMPANY LLC FACILITY: COMANCHE PEAK STEAM ELECTRIC STATION, UNITS 1 AND 2

SUMMARY

OF JULY 9,2009, CATEGORY 1 MEETING WITH LUMINANT GENERATION COMPANY LLC ON RESOLUTION OF GENERIC LETTER 2004-02 (TAC NOS. MC4676 AND MC4677)

From 8:00 AM to 12:00 PM on July 9, 2009, a public meeting was held between the U.S.

Nuclear Regulatory Commission (NRC), and representatives of Luminant Generation Company LLC (Luminant, the licensee), at NRC Headquarters, One White Flint North, 11555 Rockville Pike, Rockville, MD. The purpose of the meeting was to discuss the resolution the draft NRC request for additional information (RAI) regarding Generic Letter (GL) 2004-02, "Potential Impact of Debris Blockage on Emergency Recirculation during Design Basis Accidents at Pressurized-Water Reactors," for Comanche Peak Steam Electric Station (CPSES), Units 1 and 2.

A list of meeting attendees and the Nuclear Energy Institute (NEI) bridge line participants is enclosed. During this meeting, representatives from Luminant, AREVA NP Inc. (AREVA), Alion Science and Technology Corporation (Alion), Alden Research Laboratory, Inc. (Alden), and Performance Contracting, Inc. (PCI), presented slides discussing the common understanding and proposed path forward regarding the draft GL 2004-02 RAI.

Presentations The following meeting slides are located in the Agencywide Documents Access and Management System (ADAMS):

• Meeting Agenda (ADAMS Accession No. ML091940275)

• NRC Introductory Remarks (ADAMS Accession No. ML091940276)

• Luminant Holistic Analysis (ADAMS Accession No. ML091940277)

• Alion, discussion on RAI 9 and 6 (ADAMS Accession No. ML091960449)

• Alden discussion on RAI 10 and 11 (ADAMS Accession No. ML091940278)

• AREVA and PCI discussion on RAI 15, 8 and 20 (ADAMS Accession No. ML091940083)

• Luminant discussion on RAI 22 and 23 (ADAMS Accession No. ML091940084)

• Luminant discussion on RAI 24 and 37 (ADAMS Accession No. ML091940085)

Results of Discussion RAI #2: The licensee discussed the potential for destruction of lead blankets during a loss-of coolant accident (LOCA) and the expected characteristics of the lead blanket debris. The NRC

-2 staff was able to determine that the debris usec;! during head loss testing likely provided a conservative representation of the debris that would be created in the plant during a LOCA.

This item should be able to be satisfactorily addressed.

RAI #9: The licensee discussed the analytical pool-fill transport model for CPSES, Units 1 and

2. The NRC staff stated that the discussion was not sufficient to resolve the issue, in part, because the issue actually concerned the modeling of pool-fill transport in the test flume, which did not appear to have been performed prototypically. The licensee agreed to provide additional explanation and justification for its analysis methods, physics, and modeling conservatisms during the pool-fill phase.

RAI #6: The licensee discussed the testing that formed the basis for the assumption that 10 percent fiberglass materials settled in the containment pool will be eroded to fines. The NRC staff is currently reviewing the erosion test report to determine whether this assumption is justified.

RAI #8: The licensee stated that adding fine debris to the test flume to account for the erosion of settled debris pieces in the flume is unnecessary and that fines are released from small and large pieces of debris added to the test flume. The NRC staff stated that the information presented by the licensee to provide sufficient confidence that a representative quantity of fine debris is released to account for erosion. The licensee agreed to provide additional information on this subject, explaining and documenting known conservatisms in this area.

RAI #15: The licensee discussed the basis for the addition of approximately two-thirds of the latent fibrous debris prior to starting the test flume recirculation pump. The NRC staff stated that this practice appears inconsistent with the head loss testing review guidance but agreed that a video taken of latent debris transport in the small flume at Alden would be helpful in assessing the significance of the issue. The licensee stated that it plans to provide additional information, including the video discussed.

RAI #20: The licensee stated that the transport of large debris pieces in the test flume was not affected adversely by its narrowness. The NRC staff stated that it is likely that the addition of large pieces adversely affected debris transport in the flume, but noted that the significance of the issue may be limited if the licensee could demonstrate that the debris pile on the flume floor was relatively non-porous. The licensee informed the staff that it plans to provide additional supporting information, including a description of fiber preparation and supporting photos.

RAls #22 and 23: The licensee stated that the minimum submergence of the strainer had been recalculated and determined to be significantly greater than previously determined. The licensee also stated that the strainer would be fully submerged within 5 to 15 minutes of the initiation of emergency core cooling system recirculation and that, for full recirculation, the strainer would be fully submerged. The licensee agreed to provide the NRC staff with supplemental analysis of revised small-break LOCA analysis which revised the minimum sump water level. Based on the information provided, or expected to be provided, the NRC staff expressed the belief that the licensee is likely to be able to demonstrate adequate strainer performance in the areas of air ingestion, voiding, vortex formation, and flashing.

-3 RAI #37: The licensee stated that strainer testing had been performed conservatively for the limiting secondary line break location, even though the licensing basis does not require consideration of this break location. The NRC staff expressed the view that the test methodology used for the strainer test for this break does not appear conservative and that the licensee's argument concerning the exclusion of this break location from the licensing basis had not been sufficiently justified. NRC Regulatory Guide 1.82, "Water Sources for Long-Term Recirculation Cooling Following a Loss-of-Coolant Accident," dated November 2003, and the NRC staff's safety evaluation dated December 6, 2004 (ADAMS Accession No. ML043280641),

on NEI 04-07, "Pressurized Water Reactor Sump Performance Evaluation Methodology," dated May 28, 2004 (ADAMS Accession No. ML041550661), indicate that the limiting secondary line break locations for strainer performance should be considered, and General Design Criterion 4, "Environmental and dynamic effects design bases," in Appendix A to Part 50 of Title 10 of the Code of Federal Regulations, does not address the generation of debris by high-energy line breaks. The licensee stated that it planned to provide NRC staff with an improved basis regarding the acceptability of test design and results.

Due to time constraints, the NRC staff and the licensee agreed to have a wrap-up phone call within 2 weeks of the meeting.

As a Category 1 meeting, the public was invited to observe and was given an opportunity to communicate with the NRC staff after the business portion, but before the meeting was adjourned. Public Meeting Feedback forms were not received.

Please direct any inquiries to me at (301) 415-3016, or Balwant.Singal@nrc.gov.

Sincerely,

~~, u-..} \c..b l ~~

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:

List of Attendees and NEI Bridge Line Participants cc w/encl: Distribution via Listserv

ENCLOSURE LIST OF MEETING ATTENDEES AND NEI BRIDGE LINE PARTICIPANTS JULY 9, 2009, PUBLIC MEETING WITH LUMINANT GENERATION COMPANY LLC

LIST OF ATIENDEES FOR JULY 9, 2009 PUBLIC MEETING WITH LUMINANT GENERATION COMPANY LLC NAME ORGANIZATION M~ES W CA/o(

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th Meeting on July 9 , 2009 between Luminant and the NRC NEI Bridge Line Participants Russ Lytton McGuire Nuclear Station, Duke Energy 980-875-5421 Russell. Lytton@duke-energy.com Andrew Kaufman Continuum Dynamics, Inc 609-538-0444 x 111 andy@continuum-dynamics.com Mark Harriman Ginna Station, Constellation Energy 585-771-3251 Mark.Harriman@constellation.com Paul Leonard Cook Station, AEP 269-697-5668 pwleonard@aep.com Wendi Croft Three Mile Island, Exelon Nuclear 610-765-5726 Wendi.Croft@exeloncorp.com Rich Sievers Three Mile Island, Exelon Nuclear 717-948-8398 Richard.sievers@exeloncorp.com Pete Wilkens Southern California Nuclear 949-368-2234 peter.wilkens@sce.com Ed Kimoto Southern California Nuclear 949-368-2114 edwin.kimoto@sce.com

ML043280641),

on NEI 04-07, "Pressurized Water Reactor Sump Performance Evaluation Methodology," dated May 28, 2004 (ADAMS Accession No. ML041550661), indicate that the limiting secondary line break locations for strainer performance should be considered, and General Design Criterion 4, "Environmental and dynamic effects design bases," in Appendix A to Part 50 of Title 10 of the Code of Federal Regulations, does not address the generation of debris by high-energy line breaks. The licensee stated that it planned to provide NRC staff with an improved basis regarding the acceptability of test design and results.

Due to time constraints, the NRC staff and the licensee agreed to have a wrap-up phone call within 2 weeks of the meeting.

As a Category 1 meeting, the public was invited to observe and was given an opportunity to communicate with the NRC staff after the business portion, but before the meeting was adjourned. Public Meeting Feedback forms were not received.

Please direct any inquiries to me at (301) 415-3016, or Balwant.Singal@nrc.gov.

Sincerely, IRA!

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:

List of Attendees and NEI Bridge Line Participants cc w/encl: Distribution via Listserv DISTRIBUTION:

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