ML20072E300
| ML20072E300 | |
| Person / Time | |
|---|---|
| Site: | Vermont Yankee File:NorthStar Vermont Yankee icon.png |
| Issue date: | 08/15/1994 |
| From: | Pelletier J VERMONT YANKEE NUCLEAR POWER CORP. |
| To: | NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM) |
| References | |
| BVY-94-81, GL-89-10, NUDOCS 9408220197 | |
| Download: ML20072E300 (3) | |
Text
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e:
VERMONT YANKEE i
NUCLEAR POWER CORPORATION l
s Ferry Road, Brattleboro, VT 05301-7002 ENGINE R t OFFICE h
580 MAIN STREET BOLTON, M A 01740 (508) 779-6711 August 15,1994 BVY 94-81 U.S. Nuclear Regulatoy Commission Attn: Document Control Desk Washington, D.C. 20555
References:
(a)
License No. DPR-28 (Docket No. 50-271)
(b)
Letter, USNRC to All Licensees, Generic Letter 89-10, (NVY 89-144), dated June 28,1989 (c)
Letter, VYNPC to USNRC, (BVY 93-14), dated February 5,1993 (d)
Letter,- USNRC to VYNPC, (NVY 93-83), dated June 8,1993 (e)
Letter, USNRC to VYNPC, (NVY 93-84), dated June 8,1993 (f)
Letter, VYNPC to USNRC, (BVY 93-116), dated October 12,1993 (g)
Letter, USNRC to VYNPC, inspection Report No. 50-271/93-16, (NVY 93-227), dated December 29,1993 (h)
Letter, USNRC to All Licensees, Generic Letter 89-10, Supplement 6, (NVY 94-51), dated March 8,1994
Subject:
Generic Letter 89-10: Update of Schedule Commitments in Generic Letter 89-10 [ Reference (b)] and its supplements, the NRC requested licensees to establish a program to ensure the operability of all safety-related motor-operated valves (MOVs) under design basis conditions. The Generic Letter also recommended that each licensee complete all design basis reviews, analyses, verifications, tests and inspections within 5 years or three refueling outages from the date of the letter. The scheduled completion date for the Vermont Yankee GL'89-10 MOV Program is May 1995, following the Spring 1995 Refueling Outage.
In References (c) and (f), Vermont Yankee provided a summary of the status of the Vermont Yankee GL 89-10 Program and a schedule for the completion of the remaining activities.
This status and schedule was also presented to members of' your staff in May 1993 [ References (d) and (e)) and reviewed during an inspection performed at our facility in October 1993 [ Reference (g)]. The purpose of this letter is to provide an updated status and schedule for completion of our remaining MOV activities.
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VERMONT YANKEE NUCLEAR POWER CORPORATION U.S. Nuclear Regulatory Commission August 15,1994 Page 2 With the exception of in-altu differential pressure testing, all items provided in.
References (c) and (f) have been completed or are on schedule for completion by May 1995. As of June 30,1994, procedures were developed or revised as necessary to formalize the details of the MOV maintenance program, including post maintenance testing enhancements and establishment of an MOV trending program. Revision'to the design basis reviews is presently on schedule for completion by December 31, 1994 and preparation of design change documents is presently in progress for margin improvement modifications to be performed during the Spring 1995 Refueling Outage.
1 Vermont Yankee had previously scheduled to perform in-situ differential pressure testing on ten valves prior to June 28,1994. The present schedule calls for the testing to be completed during the Spring 1995 Refueling Outage. In accordance with l
Generic Letter 89-10, Supplement 6 [ Reference (h)), the following information is provided regarding our revised schedule:
1.
The original schedule called for testing of six MOVs prior to and during the Fall 1993 Refueling Outage. This testing of the six MOVs has been completed, with '
the results summarized in Reference (g).
2.
Based on initial reviews performed in 1991, testing of the remaining four MOVs was to be performed during plant operations in the first six months of 1994.
However, further detailed reviews have identified that testing during plant operations would require the plant to be placed in a condition not permitted by Technical Specifications. Therefore, the testing will be performed during the Spring 1995 Refueling Outage when plant shutdown conditions exist.
3.
The purpose of In-situ differential pressure testing was to provide additional' information to support the continued use of the MOVATS Statistical Database and to confirm the conservatism of the existing Vermont Yankee methodology for determining MOV switch settings. As discussed in References (d) and (e),
use of the MOVATS Statistical Database had provided adequate margin when compared to industry equations and differential pressure testing results.
However, References (d) and (e) also requested Vermont Yankee to pay particular attention to gate valves with the lowest calculated margin. Based on -
our review, justification for the use of industry equations and valve factors to determine MOV thrust requirements was completed in August 1993. The valve factors equal or exceed 0.5 for gate valves and equal 1.1 for globe valves. As such, the purpose of in-situ differential pressure testing now is to provide additional information to support the current valve factors and to confirm the conservatism of the existing Vermont Yankee methodologyfor determining MOV switch settings.
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VERMON r YANKu Nucu An Pom.R CORI' ORATION U.S. Nuclear Regulatory Commission August 15,1994 Page 3 This revised schedule is considered acceptable as functionality has been confirmed I
for all MOVs within the scope of our GL 89-10 Program through the combination of static and dynamic testing. All MOVs within the scope of our GL 89-10 Program have been diagnostically tested under static conditions with thrust settings determined from Industry equations and the above valve factors. In-situ differential pressure testing performed to date and industry differential pressure testing results support the current valve factors and confirm the conservatism of our existing MOV switch setting methodology.
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We trust that this information is satisfactory; however, should you have any questions i
or desire any additional information on this issue, please do not hesitate to contact us.
Sincerely, l
VERMONTYANKEE NUCLEAR POWER CORPORATION 1r u James P. Pelletier Vice President - Engineering cc:
USNRC Regional Administrator, Region i USNRC Resident inspector, VYNPS USNRC Project Manager, VYNPS I
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