BVY 11-024, Deviation from BWRVIP-25 Inspection Requirements

Deviation from BWRVIP-25 Inspection Requirements

ML110840044
Person / Time
Site:	Vermont Yankee
Issue date:	03/18/2011
From:	Michael Colomb Entergy Nuclear Operations
To:	Document Control Desk, Office of Nuclear Reactor Regulation
References
BVY 11-024, BWRVIP-25
Download: ML110840044 (5)

Text

Entergy Nuclear Operations, Inc.

Vermont Yankee 320 Governor Hunt Rd

--- ErVernon, VT 05354 Tel 802 257 7711 Michael J. Colomb Site Vice President BVY 11-024 March 18, 2011 ATTN: Document Control Desk U.S. Nuclear Regulatory Commission Washington, DC 20555-0001

SUBJECT:

Deviation from BWRVIP-25 Inspection Requirements Vermont Yankee Nuclear Power Station Docket No. 50-271 License No. DPR-28

REFERENCES:

1. BWR Vessel and Internals Project, BWR Core Plate Inspection and Flaw Evaluation Guidelines (BWRVIP-25), EPRI Report TR-107284, December 1996

Dear Sir or Madam:

BWR Vessel and Internals Project (BWRVIP), BWR Core Plate Inspection and Flaw Evaluation Guidelines (BWRVIP-25) requires that 50% of the core plate rim hold-down bolts of BWR/2-5 plants without repair wedges be examined by enhanced visual testing (EVT-1) from below the core plate (or by ultrasonic testing (UT) from above core plate once the technique is developed).

However, it was determined that the bolts cannot be inspected by UT due to configuration issues and it has been concluded that an EVT-1 exam does not provide meaningful results.

Accordingly, a technical justification for deviation from the BWRVIP guidance was developed to delay implementation of the BWRVIP-25 inspection requirements until the BWRVIP-25 guidance is revised.

The Vermont Yankee Nuclear Power Station (VYNPS) technical justification included an analysis that found that the bolting has a relatively low susceptibility to cracking and a very high flaw tolerance, and 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 will prevent adverse displacement of the core plate.

Furthermore, even with the extremely conservative assumptions of failures of both the bolting and the redundant hardware, thereby potentially preventing all control rods from inserting into the core, the standby liquid control system could be used to bring the reactor to a safe shutdown.

The BWRVIP is currently working on developing revised guidance for the core plate bolts and expects to complete that work, including gaining NRC approval of the revised guidance, by December 31, 2015. VYNPS will implement the revised inspection guidance for the core plate bolts following NRC approval. Given the low likelihood that the function of the core plate will be compromised by bolting failures, there is little risk in postponing UT and EVT-1 inspections of the bolts until such time as the BWRVIP develops revised guidance.

4oz/

BVY 11-024 / Page 2 of 3 VYNPS currently inspects 25% of the top of the core plate hold down bolts every other refueling outage in accordance with the VYNPS Reactor Vessel Internals (RVI) Inspection Program using the VT-3 method. VYNPS will continue to inspect 25% of the core plate hold down bolts every other refueling outage using the VT-3 method in accordance with the RVI Program until the inspection guidance of BWRVIP-25 is revised by the Electric Power Research Institute and approved by the NRC.

This letter is being transmitted for information only and VYNPS is not requesting any action from the NRC staff.

A new regulatory commitment is provided in Attachment 1. Should you have any questions or require additional information concerning this submittal, please contact Mr. Robert Wanczyk at 802-451-3166.

Sincerely,

[MJC/PLC]

Attachment:

1. List of Regulatory Commitments cc: Mr. William M. Dean, Regional Administrator U.S. Nuclear Regulatory Commission, Region 1 475 Allendale Road King of Prussia, PA 19406-1415 Mr. Robert Kuntz, Senior Project Manager U.S. Nuclear Regulatory Commission One White Flint North 11 F1 11555 Rockville Pike Rockville, MD 20852-2738 Mr. James S. Kim, Project Manager Office of Nuclear Reactor Regulation U.S. Nuclear Regulatory Commission Mail Stop 08C2A Washington, DC 20555-0001 Mr. Jonathan G. Rowley, Project Manager Office of Nuclear Reactor Regulation U.S. Nuclear Regulatory Commission Mail Stop 012 Gll Washington, DC 20555-0001

BVY 11-024 / Page 3 of 3 cc (cont'd):

Mr. Matthew Mitchell, Branch Chief Office of Nuclear Reactor Regulation U.S. Nuclear Regulatory Commission Mail Stop 09 H6 Washington, DC 20555-0001 USNRC Resident Inspector Ms. Elizabeth Miller, Commissioner VT Department of Public Service 112 State Street - Drawer 20 Montpelier, Vermont 05620-2601

BVY 11-024 Attachment 1 Vermont Yankee Nuclear Power Station License No. DPR-28 (Docket No. 50-271)

List of Regulatory Commitments

BVY 11-024/ Attachment 1/Page 1 of 1 List of Regulatory Commitments This table identifies actions discussed in this letter for which Entergy commits to perform. Any other actions discussed in this submittal are described for the NRC's information and are not commitments.

TYPE (Check one) SCHEDULED ONE-TIME CONTINUING COMPLETION DATE COMMITMENT ACTION COMPLIANCE (If Required)

VYNPS will continue to inspect 25% of the x Following NRC core plate hold down bolts every other approval of revised refueling outage using the VT-3 method in BWRVIP-25 accordance with the VYNPS Rector Vessel guidance in Internals Inspection Program until BWRVIP- accordance with 25 is revised and approved by the NRC. BWRVIP-94 Rev 1 guidelines.

Following NRC approval, VYNPS will implement the revised BWRVIP-25 inspection guidance for the core plate bolts.