GO2-08-147, Response to Request for Additional Information Regarding Request 3ISI-08

Response to Request for Additional Information Regarding Request 3ISI-08

ML083030047
Person / Time
Site:	Columbia
Issue date:	10/20/2008
From:	Gambhir S Energy Northwest
To:	Document Control Desk, Office of Nuclear Reactor Regulation
References
3ISI-08, GO2-08-147
Download: ML083030047 (2)

Text

Sudesh K. Gambhir ENERGY Vice President, Technical Services P.O. Box 968, Mail Drop PE04 NORTHWEST Richland, WA 99352-0968 Ph. 509-377-8313 F. 509-377-2354 sgambhir@energy-northwestcom October 20, 2008 G02-08-147 10 CFR 50.55a U.S. Nuclear Regulatory Commission ATTN: Document Control Desk Washington, D.C. 20555-0001

Subject:

COLUMBIA GENERATING STATION, DOCKET NO. 50-397 RESPONSE TO REQUEST FOR ADDITIONAL INFORMATION REGARDING REQUEST 3ISO-08

Reference:

Letter dated December 13, 2007, SK Gambhir (Energy Northwest) to NRC, "Request 31SI-08 for Approval of Alternate Risk-Informed Inservice Inspection (RI-ISI) Requirements for the Third Ten-Year Interval Inservice Inspection Program Plan" .

J.

Dear Sir or Madam:

On September 23, 2008 Mr. Fred Lyon, NRC, forwarded (via e-mail) a request for clarification from the reviewer of Energy Northwest's Request 31SI-08 (Reference) regarding two contradictory statements. This request identified the two statements as follows:

In the summary list of changes made to the second RI-ISI program, on page 3 of 5 of Attachment 1, the licensee states "incorporated one

.deviation to EPRI TR-1.12657 for failure potential assessment for Thermal Stratification, Cycling and Striping (TASCS)."

Then in the paragraph entitled Summary TASCS, on page 11 of 29 in:

Attachment 2, the licensee states "the above criteria were incorporated into the degradation mechanism assessment for the first RI-ISI submittal and have not changed for this submittal. Therefore there is no change in risk due to the assessment of the TASCS degradation mechanism."

14ow7

RESPONSE TO REQUEST FOR ADDITIONAL INFORMATION REGARDING REQUEST 31SI-08 Page 2 To address the contradiction, Energy Northwest provides a revision to the quoted statement in the summary list of changes made to the second RI-ISI program on page 3 of 5 of Attachment 1 of the reference as follows:

"Identified one deviation to the EPRI TR-1 12657 methodology for application of additional criteria in the degradation mechanism assessment for Thermal Stratification, Cycling, and Striping (TASCS). These additional criteria were applied in the TASCS assessments for both of Energy Northwest's RI-ISI requests (i.e., the initial RI-ISI request of August 16, 2000 and this 31SI-08 request). Application of the additional criteria was not identified as a deviation to the EPRI methodology in the initial RI-ISI submittal."

The additional screening criteria for assessing the TASCS damage mechanism described on page 10 and 11 of Attachment 2 were provided to the staff in a letter from Electric Power Research Institute's (EPRI), Pat O'Regan to NRC's Dr. Brian W. Sheron, dated March 28, 2001 (ADAMS ref: ML011070238). As stated in this letter, the criteria are consistent with EPRI TR-1 000701, "Interim Thermal Fatigue Management Guidelines," (MRP-24) which was published in January 2001. Energy Northwest cannot state with certainty why application of the criteria was not identified as a deviation in its first RI-ISI submittal. It may be in part because the criteria were draft only, and had not been published at the time of Energy Northwest's August 16, 2000 submittal.

There are no new commitments made in this submittal. If you have any questions or require additional information, please contact MC Humphreys at 509 377-4025.

Respectfully, SK Gambhir Vice President, Technical Services cc: EE Collins, Jr. - NRC RIV NRC Senior Resident Inspector/988C RN Sherman - BPA/1 399 CF Lyon - NRC NRR WA Horin - Winston & Strawn