NOC-AE-10002579, Nine-Month Supplemental Response to Generic Letter 2008-01

Nine-Month Supplemental Response to Generic Letter 2008-01

ML102150419
Person / Time
Site:	South Texas
Issue date:	07/27/2010
From:	Gerry Powell South Texas
To:	Document Control Desk, Office of Nuclear Reactor Regulation
References
NOC-AE-10002579, TAC MD7881, TAC MD7882, GL-08-001
Download: ML102150419 (6)

Text

Nuclear Operating Company South Texas ProjectElectric GeneratingStation PO Box 289 Wadsworth. Texas 77483 A/A --

July 27, 2010 NOC-AE-1 0002579 10 CFR 50.54(f)

U.S. Nuclear Regulatory Commission One White Flint North ATTN: Document Control Desk 11555 Rockville Pike Rockville, MD 20852 South Texas Project Units 1 and 2 Docket No. STN 50-498, STN 50-499 Nine-Month Supplemental Response to Generic Letter 2008-01 (TAC Nos. MD7881 and MD7882)

References:

1 .NRC Generic Letter 2008-01, "Managing Gas Accumulation in Emergency Core Cooling, Decay Heat Removal, and Containment Spray Systems," dated January 11, 2008

2. Letter from Mohan C. Thadani to Edward D. Halpin dated September 22, 2008, South Texas Project, Units 1 and 2 - Generic Letter 2008-01, "Managing Gas Accumulation in Emergency Core Cooling, Decay Heat Removal, and Containment Spray Systems, Proposed Alternative Course of Action and Request for Additional Information" (TAC Nos. MD7881 and MD7882)

3. Letter from G. T. Powell to NRC Document Control Desk dated October 13, 2008, "Nine-Month Response to Generic Letter 2008-01" (NOC-AE-08002355)

(ML082960430)

The Nuclear Regulatory Commission (NRC) issued Generic Letter (GL) 2008-01 (Reference 1) to request that each licensee evaluate the emergency core cooling, decay heat removal, and containment spray systems to ensure that gas accumulation is maintained less than the amount that challenges operability of these systems, and that appropriate action is taken when conditions adverse to quality are identified.

The enclosure provides the results of evaluations performed following South Texas Project Unit 2 refueling outage 2RE14 completed in the spring of 2010 consistent with Reference 2 and committed to in Reference 3.

In summary, STP Nuclear Operating Company (STPNOC) has concluded that, based on the reviews of the plant configuration, plant-specific operating experience, and procedures, the subject systems/functions comply with the current licensing and design bases and applicable regulatory requirements. System piping walk-downs and slope determinations performed have not yielded any information to alter this conclusion. All identified systems are capable of performing their design function.

There are no new commitments in this letter.

STI: 32707888 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 " "I-

NOC-AE-10002579 Page 2 If there are any questions or if additional information is needed, please contact either Mr. Wayne Harrison at 361-972-7298 or me at 361-972-7566.

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

Executed on X0, I 2*7 I ?.MO G. T. Powell Vice President, Engineering JAL/RSE

Enclosure:

Nine-Month Supplemental Response to NRC Generic Letter 2008-01, "Managing Gas Accumulation in Emergency Core Cooling, Decay Heat Removal, and Containment Spray Systems"

NOC-AE-1 0002579 Page 3 cc:

(paper copy) (electronic copy)

Regional Administrator, Region IV A. H. Gutterman, Esquire U. S. Nuclear Regulatory Commission Morgan, Lewis & Bockius LLP 612 East Lamar Blvd, Suite 400 Arlington, Texas 76011-4125 Mohan C. Thadani U. S. Nuclear Regulatory Commission Mohan C. Thadani John Ragan Senior Project Manager Catherine Callaway U.S. Nuclear Regulatory Commission Jim von Suskil One White Flint North (MS 8B1A) NRG South Texas LP 11555 Rockville Pike Rockville, MD 20852 Richard Pena Senior Resident Inspector Ed Alarcon U. S. Nuclear Regulatory Commission Kevin Polio P. O. Box 289, Mail Code: MN116 City Public Service Wadsworth, TX 77483

C. M. Canady Jon C.. Wood City of Austin Cox Smith Matthews Electric Utility Department 721 Barton Springs Road C. Mele Austin, TX 78704 City of Austin Richard A. Ratliff Texas Department of State Health Services Alice Rogers Texas Department of State Health Services

Enclosure 1 NOC-AE-10002579 Page 1 of 3 Nine-Month Supplemental Response to NRC Generic Letter 2008-01, "Managing Gas Accumulation in Emergency Core Cooling, Decay Heat Removal, and Containment Spray Systems" This enclosure describes the results of evaluations performed pursuant to Generic Letter 2008-01 on previously incomplete activities, such as system piping walkdowns, at the South Texas Project (STP). This supplement addresses results of design evaluation reviews conducted since the October 13, 2008 submittal (Reference 3).

The original conclusions documented in the Nine-Month response (Reference 3) with respect to the licensing basis evaluation, testing evaluations, and corrective action evaluations have not changed.

A. EVALUATION RESULTS

1. Design Basis Documents No changes have been made to any STP design basis documents as a result of evaluations performed for this GL response.

2. Confirmatory Walkdowns In the Nine-Month response, (Reference 3), STPNOC committed to complete the following:

0 Complete the slope survey of inaccessible piping in Unit 2 during the spring outage of 2010 and provide a report within 90 days after completion of the outage.

STP slope survey and evaluation of normally inaccessible piping in Unit 2 is complete.

This activity involved slope surveys of applicable GL 2008-01 systems piping in the Unit 2 Reactor Containment Building. Much of the piping required scaffolding to provide proper access to perform the slope surveys.

The piping slope surveys were performed using conventional surveying tools (laser level equipment). The activity involved both insulated and un-insulated inaccessible piping.

On insulated piping, the insulation was temporarily removed as necessary to gain access to the pipe surface. Additionally, ultrasonic examination of selected pump suction piping was performed.

Industry guidance was utilized to determine the applicable acceptance criteria and in the assessment of the data. For pump suction piping, industry guidance provided by the Nuclear Energy Institute (NEI) was utilized to perform the evaluations (Reference 6).

For pump discharge piping evaluations, industry guidance provided by the Pressurized Water Reactor Owners Group (PWROG) was utilized (Reference 7). A PWROG Position Paper providing guidance on the quantities of non-condensable gases that can enter the RCS from the ECCS piping was also utilized as required in the evaluations (Reference 8). The results of the slope surveys, assessment of data, and the evaluations performed on the subject piping were found to be acceptable.

Enclosure 1 NOC-AE-1 0002579 Page 2 of 3 Nine-Month Supplemental Response to NRC Generic Letter 2008-01, "Managing Gas Accumulation in Emergency Core Cooling, Decay Heat Removal, and Containment Spray Systems"

3. Vent Valves No new vent locations or modifications to existing vent valves were found to be necessary as a result of the slope surveys or the evaluations performed.

4. Procedures No additional procedures or additional procedure revisions were considered necessary as a result of the slope surveys or the evaluations performed.

B. DESCRIPTION OF NECESSARY ADDITIONAL CORRECTIVE ACTIONS

1. Additional Corrective Actions As a result of the slope surveys and evaluations performed, no additional corrective actions were required.

2. Corrective Action Updates No updates or changes to previous corrective actions have been identified as a result of the slope surveys and evaluations.

Conclusion STPNOC has completed the slope surveys and evaluations of the normally inaccessible portions of GL systems piping in Unit 2 and has concluded they are in compliance with the current licensing and design bases and applicable regulatory requirements and remain capable of performing their design function.

This completes the STPNOC response to the regulatory commitments described in Reference 3.

Enclosure 1 NOC-AE-1 0002579 Page 3 of 3 Nine-Month Supplemental Response to NRC Generic Letter 2008-01, "Managing Gas Accumulation in Emergency Core Cooling, Decay Heat Removal, and Containment Spray Systems"

References:

1. NRC Generic Letter 2008-01, "Managing Gas Accumulation in Emergency Core Cooling, Decay Heat Removal, and Containment Spray Systems," dated January 11, 2008

2. Letter from Mohan C. Thadani to Edward D. Halpin dated September 22, 2008, South Texas Project, Units 1 and 2 - Generic Letter 2008-01, "Managing Gas Accumulation in Emergency Core Cooling, Decay Heat Removal, and Containment Spray Systems, Proposed Alternative Course of Action and Request for Additional Information" (TAC Nos. MD7881 and MD7882) (ST-AE-NOC-08001809)

3. Letter from G. T. Powell to NRC Document Control Desk dated October 13, 2008, "Nine-Month Response to Generic Letter 2008-01" (ML082960430) (NOC-AE-08002355)

4. Letter from G. T. Powell to NRC Document Control Desk dated January 22, 2009, "Nine Month Supplemental Response to Generic Letter 2008-01" (ML090330142)

(NOC-AE-09002384)

5. Letter from G. T. Powell to NRC Document Control Desk dated February 16, 2010, "Nine Month Supplemental Response to Generic Letter 2008-01 ," (ML100501160)

(NOC-AE-1 0002511)

6. NEI APC 09-20, "Evaluation of Unexpected Voids or Gas Identified in Plant ECCS and Other Systems" from J.H. Riley, NEI, dated May 18, 2009

7. Letter from PWR Owners Group, Transmittal of Revision 1 of Letter Report for Gas Voids Pressure Pulsations (PA-SEE-0451) dated September 08, 2008

8. Letter from Westinghouse, "PWROG Position Paper on Non-condensable Gas Voids in ECCS Piping; Qualitative Engineering Judgment of Potential Effects on Reactor Coolant System Transients Including Chapter 15 Events," dated September 4, 2008