GO2-15-139, Deviation from BWRVIP-25 Guidance for Inspection Requirements
| ML15287A490 | |
| Person / Time | |
|---|---|
| Site: | Columbia  |
| Issue date: | 10/14/2015 |
| From: | Javorik A Energy Northwest |
| To: | Document Control Desk, Office of Nuclear Reactor Regulation |
| References | |
| GO2-15-139 | |
| Download: ML15287A490 (2) | |
Text
Alex L. Javorik Columbia Generating Station P.O. Box 968, PE04 Richland, WA 99352-0968 Ph. 509-377-8555 l F. 509-377-2354 aljavorik@energy-northwest.com GO2-15-139 U.S. Nuclear Regulatory Commission ATTN: Document Control Desk Washington, D.C. 20555-0001
Subject:
COLUMBIA GENERATING STATION, DOCKET NO. 50-397 DEVIATION FROM BWRVIP-25 GUIDANCE FOR INSPECTION REQUIREMENTS
Reference:
Letter from DA Swank (Energy Northwest) to NRC (GO2-11-093),
Columbia Generating Station, Docket No. 50-397 - Deviation From BWRVIP-25 Inspection Requirements, dated May 6, 2011.
Dear Sir or Madam:
The Boiling Water Reactor Vessel & Internals Project (BWRVIP)-25 inspection guidelines require that 50% of the core plate rim hold-down bolts of BWR/2-5 plants not equipped with repair wedges, such as Columbia Generating Station (Columbia), be examined by enhanced visual method (EVT-1) from below the core plate, or by Ultrasonic method (UT) from above the core plate. However, it was determined that the bolts cannot be inspected by UT due to configuration issues and it has recently been concluded that an EVT-1 exam does not provide meaningful results. Accordingly, a technical justification for deviation from the BWRVIP-25 guidance was developed, and Energy Northwest previously reported to the NRC (Reference) of the need to deviate from the BWRVIP-25 inspection guidelines, with an anticipated deviation closure date of December 31, 2015.
The technical justification included an analysis that found that postulated flaws would not grow to a size that significantly reduces the bolt preload over the life of the plant.
Even if significant cracking did occur in the bolting, redundant structural components would prevent adverse displacement of the core plate. Furthermore, even with the extremely conservative assumptions of failures of both the bolting and the redundant hardware, the Standby Liquid Control (SLC) system could be used to bring the reactor to a safe shutdown.
Columbia has been working with the industry to resolve the issue by December 31, 2015, as stated in the referenced correspondence (Reference). The BWRVIP is currently working on developing revised guidance for the inspection of core plate bolts; however, the BWRVIP has recently informed the industry that revisions to the BWRVIP-25 inspection guidance will not be available in time to support NRC approval by October 14, 2015
DEVIATION FROM BWRVIP-25 GUIDANCE FOR INSPECTION REQUIREMENTS Page 2 of 2 December 31, 2015. Therefore, Energy Northwest has revised the deviation disposition due date and is providing this notification to the NRC that the deviation will remain in place until the revised BWRVIP-25 is approved by the NRC or until some other NRC approved solution is implemented.
This letter is being transmitted for information only and Energy Northwest is not requesting any action from the NRC staff. There are no commitments being made to the NRC by this letter.
Should you have any questions or require additional information pertaining to this report, please contact OM Wolfgramm at (509) 377-4792.
Executed on /4th.of Oefobe(, 2015 Rest;*~~
-1.i.favorik Vice President, Engineering cc:
NRC Region IV Administrator NAO NRA Project Manager NRC BWRVIP Project Manager NRC Sr. Resident Inspector - 988C CD Sonoda - BPA/1399 WA Horin - Winston & Strawn
Alex L. Javorik Columbia Generating Station P.O. Box 968, PE04 Richland, WA 99352-0968 Ph. 509-377-8555 l F. 509-377-2354 aljavorik@energy-northwest.com GO2-15-139 U.S. Nuclear Regulatory Commission ATTN: Document Control Desk Washington, D.C. 20555-0001
Subject:
COLUMBIA GENERATING STATION, DOCKET NO. 50-397 DEVIATION FROM BWRVIP-25 GUIDANCE FOR INSPECTION REQUIREMENTS
Reference:
Letter from DA Swank (Energy Northwest) to NRC (GO2-11-093),
Columbia Generating Station, Docket No. 50-397 - Deviation From BWRVIP-25 Inspection Requirements, dated May 6, 2011.
Dear Sir or Madam:
The Boiling Water Reactor Vessel & Internals Project (BWRVIP)-25 inspection guidelines require that 50% of the core plate rim hold-down bolts of BWR/2-5 plants not equipped with repair wedges, such as Columbia Generating Station (Columbia), be examined by enhanced visual method (EVT-1) from below the core plate, or by Ultrasonic method (UT) from above the core plate. However, it was determined that the bolts cannot be inspected by UT due to configuration issues and it has recently been concluded that an EVT-1 exam does not provide meaningful results. Accordingly, a technical justification for deviation from the BWRVIP-25 guidance was developed, and Energy Northwest previously reported to the NRC (Reference) of the need to deviate from the BWRVIP-25 inspection guidelines, with an anticipated deviation closure date of December 31, 2015.
The technical justification included an analysis that found that postulated flaws would not grow to a size that significantly reduces the bolt preload over the life of the plant.
Even if significant cracking did occur in the bolting, redundant structural components would prevent adverse displacement of the core plate. Furthermore, even with the extremely conservative assumptions of failures of both the bolting and the redundant hardware, the Standby Liquid Control (SLC) system could be used to bring the reactor to a safe shutdown.
Columbia has been working with the industry to resolve the issue by December 31, 2015, as stated in the referenced correspondence (Reference). The BWRVIP is currently working on developing revised guidance for the inspection of core plate bolts; however, the BWRVIP has recently informed the industry that revisions to the BWRVIP-25 inspection guidance will not be available in time to support NRC approval by October 14, 2015
DEVIATION FROM BWRVIP-25 GUIDANCE FOR INSPECTION REQUIREMENTS Page 2 of 2 December 31, 2015. Therefore, Energy Northwest has revised the deviation disposition due date and is providing this notification to the NRC that the deviation will remain in place until the revised BWRVIP-25 is approved by the NRC or until some other NRC approved solution is implemented.
This letter is being transmitted for information only and Energy Northwest is not requesting any action from the NRC staff. There are no commitments being made to the NRC by this letter.
Should you have any questions or require additional information pertaining to this report, please contact OM Wolfgramm at (509) 377-4792.
Executed on /4th.of Oefobe(, 2015 Rest;*~~
-1.i.favorik Vice President, Engineering cc:
NRC Region IV Administrator NAO NRA Project Manager NRC BWRVIP Project Manager NRC Sr. Resident Inspector - 988C CD Sonoda - BPA/1399 WA Horin - Winston & Strawn