ML083500465

Supplement to Response to NRC Generic Letter (GL) 2004-02, Potential Impact of Debris Blockage on Emergency Recirculation During Design Basis Accidents at Pressurized-Water Reactors, Cover Letter

ML083500465
Person / Time
Site:	Comanche Peak
Issue date:	11/26/2008
From:	Blevins M Luminant Generation Co, Luminant Power
To:	Document Control Desk, Office of Nuclear Reactor Regulation
References
CP-200801606, GL-04-002, TXX-08141
Download: ML083500465 (3)

Text

Mike Blevins Executive Vice President

& Chief Nuclear Officer Mike.Blevins@Luminlant.com Luminant Power P 0Box 1002 6322 Norlh FM 56 Glen Rose, TX 76043 Lw,-ýALým2nt

,T 254 897 5209 C 817 559 9085 F 254 897 6652 CP-200801606 Log # TXX-08141 Ref. #

GL 2004-02 November 26, 2008 U. S. Nuclear Regulatory Commission ATTN: Document Control Desk Washington, DC 20555

SUBJECT:

COMANCHE PEAK STEAM ELECTRIC STATION DOCKET NOS. 50-445 AND 50-446 SUPPLEMENT TO RESPONSE TO NRC GENERIC LETTER (GL) 2004-02, "POTENTIAL IMPACT OF DEBRIS BLOCKAGE ON EMERGENCY RECIRCULATION DURING DESIGN BASIS ACCIDENTS AT PRESSURIZED-WATER REACTORS"

REFERENCE:

1. Letter Logged TXX-05047 from M. Blevins to the NRC dated March 7, 2005, providing a 90-day response to NRC Generic Letter 2004-02, "POTENTIAL IMPACT OF DEBRIS BLOCKAGE ON EMERGENCY RECIRCULATION DURING DESIGN BASIS ACCIDENTS AT PRESSURIZED-WATER REACTORS"

2.

Letter Logged TXX-05162 from M. Blevins to the NRC dated September 1, 2005, providing a response to requested information part 2 of NRC Generic Letter 2004-02, "POTENTIAL IMPACT OF DEBRIS BLOCKAGE ON EMERGENCY RECIRCULATION DURING DESIGN BASIS ACCIDENTS AT PRESSURIZED-WATER REACTORS"

3.

Letter Logged TXX-03130 from C. L. Terry to the NRC dated August 8, 2003, providing a response to NRC BULLETIN 2003-01, "POTENTIAL IMPACT OF DEBRIS BLOCKAGE ON EMERGENCY SUMP RECIRCULATION AT PRESSURIZED-WATER-REACTORS"

4.

Letter Logged TXX-08033 from M. Blevins to the NRC dated February 29, 2008, providing an NRC Generic Letter 2004-02 supplemental response

5.

Letter Logged TXX-08095 from M. Blevins to the NRC dated August 28, 2008, providing an NRC Generic Letter 2004-02 supplemental response

Dear Sir or Madam:

Luminant Power provided responses to NRC Bulletin 2003-01 and NRC Generic Letter (GL 2004-02) in References 1, 2, and 3. Subsequently, Luminant Power provided an update to the modifications and maintenance actions for resolution of GL 2004-02 per Reference 4. Reference 5 stated that all required actions in support of resolution of GL 2004-02 have been completed. In addition, Luminant Power plans on additional enhancements to various procedures and programs related to control of potential debris.

Enclosed, please find Luminant Power's update to the modifications and maintenance actions for resolution of GL 2004-02.

A-1 //0 A member of the STARS (Strategic Teaming and Resource Sharing) Alliance Callaway

• Comanche Peak. Diablo Canyon

• Palo Verde. San Onofre South Texas Project

• Wolf Creek

U. S. Nuclear Regulatory Commission TXX-08141 Page 2 November 26, 2008 For Comanche Peak Nuclear Power Plant (CPNPP), Luminant Power has implemented an overall holistic approach to resolve NRC Generic Safety Issue (GSI) 191. The holistic approach includes:

Implementation of multiple design modifications to substantially increase the size and effectiveness of the containment emergency sump strainers. The new strainers are qualified by prototypical testing for the design.basis debris loading.

Procedures have been implemented to provide clear direction to the operations and technical support staff for monitoring post loss-of-coolant accident (LOCA) long term recirculation operation. These procedures include directions for monitoring system performance and contingency actions in the event that indications warrant the need.

The analyses that support the design modifications include numerous conservatisms to ensure that the overall analyses and modification design include substantial margins to account for uncertainties. CPNPP recognizes that uncertainties exist in various aspects of this issue and has taken adequate measures to accommodate these uncertainties.

Luminant Power has performed numerous additional activities to establish the qualification of the new, strainer system. These activities are:

Containment Condition Assessments Replacement of Radiation Protection Locked High Radiation Doors to the Steam Generator Compartments Redesign of the Drain Path to the Inactive Sump Removal of Radiation Protection Barriers and a Tool Room Enclosure Implementation of Compensatory Actions in response to NRC Bulletin 2003-01 have been implemented as permanent changes in procedures Containment Coatings Assessments 0

Evaluation of the Plant Labeling Program 0

Upstream Effects Evaluation Event Characterization Debris Generation Evaluation Debris Transport Evaluation Debris Load Evaluation Downstream Effects Evaluations - The following evaluations were performed:

Blockage (except for reactor vessel)

Equipment Wear Valve Wear Reactor Vessel Blockage Fuel Blockage Evaluation of Long Term Cooling*

The NRC staff has reviewed Westinghouse Topical Report WCAP-16793, Revision 0, but has not issued a final Safety Evaluation on this report. The CPNPP analysis and licensing basis are in accordance with WCAP-16793. When the NRC final Safety Evaluation on WCAP-16793 is issued, it will be reviewed for impact and the evaluation of long term cooling will be revised as appropriate.

CPNPP performed evaluations of existing engineering design specifications, engineering design standards, engineering programs, modification and maintenance processes and procedures, and station operation processes and procedures. Potential changes were identified and the required changes were implemented. These changes will ensure the inputs and assumptions that support the current analysis

U. S. Nuclear Regulatory Commission TXX-08141 Page 3 November 26, 2008 effort are incorporated into the applicable documents to maintain the necessary attributes fdr future compliance with these requirements.

Changes included:

Revision to design control procedures to explicitly address emergency sump performance impacts Revision to Design Basis Documents and Engineering Specifications to ensure necessary control of existing and future materials that could affect sump performance Revision to the Coatings Program Revision to the Station Labeling Program to ensure control of label materials and locations in containment The supplemental response will be revised and submitted within 90 days after issuance of the final Safety Evaluation on WCAP-16793.

This letter contains the following new licensing commitments regarding Comanche Peak Units 1 and 2.

Commitment No Description 3641550 The CPNPP analysis and licensing basis are in accordance with WCAP-16793. When the NRC final Safety Evaluation on WCAP-16793 is issued, it will be reviewed for impact and the evaluation of long term cooling will be revised as appropriate. The supplemental response will be revised and submitted within 90 days after issuance of the final Safety Evaluation.

Should you have any questions, please contact Mr. J. D. Seawright at (254) 897-0140.

I state under penalty of perjury that the foregoing is true and correct.

Executed on November 26, 2008.

Sincerely, Luminant Generation Company LLC Mike Blevins By Mitchell L. Lucas Vice President, Nuclear Engineering and Support

Enclosure:

ER-ESP-001, Revision 1, Generic Letter 2004-02 Supplemental Response (Luminant Power's Update to the Modifications and Maintenance Actions for Resolution of GL 2004-02) c -

E. E. Collins, Region IV clo B. K. Singal, NRR Resident Inspectors, Comanche Peak clo