ML20128M742

Requests Concurrence on Deferral of Cold Ref Leg Column Mods Until 1987 Refueling Outage,In Response to Generic Ltr 84-23 & NUREG-0737,Item II.F.2.Deferral Necessary for Completion of Design of Leg Mods

ML20128M742
Person / Time
Site:	Vermont Yankee File:NorthStar Vermont Yankee icon.png
Issue date:	07/18/1985
From:	Murphy W VERMONT YANKEE NUCLEAR POWER CORP.
To:	Thompson H Office of Nuclear Reactor Regulation
References
RTR-NUREG-0737, RTR-NUREG-737, TASK-2.F.2, TASK-TM FVY-85-67, GL-84-23, NUDOCS 8507260062
Download: ML20128M742 (3)

Text

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o VERMONT YANKEE NUCLEAR POWER CORPORATION FVY 85-67

, RD 5, Box 169 Ferry Road, Brattleboro, VT 05301 ,,,ty yo N

p ENGINEERING OFFICE 1671 WORCESTER ROAD

. FRAMINGHAM, M ASSACHUSETTS 01701

. TEL EPHONE 6tT4724100 July 18, 1985 U.S. Nuclear Regulatory Ccamission Washington, D.C. 20555 Attention: Office of Nuclear Reactor Regulation Mr. H.L. Thompson, Director Division of Licensing

Reference:

a) License No. DPR-28 (Docket No. 50-271) b) Letter, USNRC to All BWR Licensees Operating Reactors NVY 84-231, dated 10/26/84, Generic Letter 84-23 c) Letter, VYNPC to USNRC, FVY 84-144, dated 12/6/84 d) Letter, VYNPC to USNRC FVY 85-29, dated 3/28/85 e) Letter, USNRC to VYNPC, NVY 85-101, dated 5/24/85 f) Letter, VYNPC to USNRC, FVY 85-58, dated 6/21/85 g) Letter, VYNPC to USNRC, FVY 85-51, dated 5/31/85 h) Letter, USNRC to VYNPC, NVY 85-111, dated 6/6/85

Subject:

Reactor Vessel Water Level Instrumentation (Generic Letter 84-23) and NUREG 0737, Item II.F.2, Inadequate Core Cooling Instrumentation By Generic Letter (GL) 84-23, dated October 26, 1984 [ Reference b)], the NRC staff provided their conclusions relating Reactor Vessel Water Level Instrumentation adequacy in BWR's and requested Vermont Yankee to provide a description and schedule for proposed improvements. By letters dated December 6, 1984 and March 28, 1985 [ References c) and d), respectively],

Vermont Yankee indicated that the existing Yarway columns and cold reference leg columns would be replaced by a dual cold reference leg arrangement. We proposed to implement this design change during our 1985-86 outage which is scheduled to start in September 1985. Vermont Yankee's proposed modifications and schedule were accepted by the NRC by letter dated May 24, 1985 [ Reference e)].

8507260062 PDR 850718 '

-ADOCK 050002 1 gh Ilo

VEHMONT YANKEE NUCLEAR POWER CORPORATION U.S. Nuclear Regulatory Commission July 18, 1985 Page 2 s !I Vermont Yankee has prcceeded with the preliminary design of the reference leg modifications. We have\ concluded that detailed design requires field verification of the existing drywell configuration prior to finalizing the new reference leg support design. This effectively moves the completion date for this design package well into the' upcoming outage.

Additionally, as you are aware, Vermont Yankee is replacing Recirculation s

System piping in response to IGSCC concerns. Because of the significant work effort in the drywell associated with the Recirculation System piping replace-

, ment, Vermont Yankee is evaluating all drywell work in detail for schedular

-impact on the overall outage.'LWe.have concluded that, due to the need for in-drywell field verification (following shutown), subsequent detailed engineering ,

necessary to produce a final modified reference leg design, and the existing critical path Recirculation System piping replacement schedule in the drywell, '

i installation of reference leg modifications this outage is not achievable under our existing outage schedule.

Therefore, we request NRC concurrence to defer this work effort from our 1985-86 Recirculation Piping replacement outage until the next scheduled refueling outage in 1987. We believe th'is schedule is consistent with schedules established'byother utilities for this effort, and represents Vermont Yankee x

, good faith effort to upgrade our existing installation at the earliest feasible time.

In addition, we will have our upgraded Emergency Operating Procedures (EOP's) in effect prior to 'the startup from the 1985-86 outage. The new E0P's include provisions for operator actions which are specifically intended to address the NRC's concerns relative to reactor vessel water level instrumen-tation. These actions were included in.the BWR Owner's Group Emergency Procedures Guideline and have subsequently been endorsed by the Staff in GL 84-23 as an acc'eptable method for addressing vessel level instrumentation con-cerns until the physical improvements discussed above are implemented.

Therefore, we believe that the continued safe operation of the Vermont Yankee plant is assured during this interim period.

As stated above, we are presently evaluating all drywell-related work in s terms of potential impact on the 1985-86 obtage schedule. Because of the exten-sive resources necessary to complete the pipe replacement task and the inherent physical limitations of the drywell, it may Le necessary for us to defer addi-tional drywell-related design modifications until a future date. We anticipate completing our evaluation by mid-August and will inform our NRR Project Manager of the results. Should any additional design modification deferrals be necessary, we will inform you in writing,

VERMONT YANKEE NUCLEAR POWER CORPORATION U.S. Nuclear Regulatory Commission July 18, 1985 Page 3 We trust that the schedular deferral is acceptable; however, because we are i

in the process of finalizing our outage plans, we would appreciate receiving

{' your concurrence as soon as possible. Should you have any questions regarding this matter or need additional information, please contact us.

Very truly yours, VERM NT YANKEE NUCLEAR POWER CORPORATION Warren P. urphy Vice President an Manager of Operations s

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