ML19241B436
| ML19241B436 | |
| Person / Time | |
|---|---|
| Site: | Vermont Yankee File:NorthStar Vermont Yankee icon.png |
| Issue date: | 07/11/1979 |
| From: | Moody D VERMONT YANKEE NUCLEAR POWER CORP. |
| To: | Ippolito T Office of Nuclear Reactor Regulation |
| References | |
| WVY79-80, NUDOCS 7907170149 | |
| Download: ML19241B436 (2) | |
Text
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( h; V EIO10NT Y A N K EM N UCLMAR POW ER COR POR ATION 1
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l SEVENTY SEVEN GROVE STREET RUTI. AND, VEIO10NT 05701 nEety To: B.3.2.1 ENGINEERING OFFICE July ll, 1979 TURNPIK E RO AD WESTDORO. M ASS ACHUSETTS 015 8 f TELEPHONE 617-366 901, WVY79-80 United States Nuclear Regulatory Commission Washington, D.C.
20555 Attention:
T. A. Ippolito, Chief Operating Reactors Branch #3 Division of Operating Reactors
References:
(a) License No. DPR-23 (Docket No. 50-271)
(b) USNRC letter to VYNPC dated January 13, 1978,
Subject:
Acend ent No. 43 to Facility Operating License
Dear Sir:
Subjec t:
Fire Barrier Penetration Seals In reference (b) above, Vermont Yankee committed to a co:pletion date of "end of 1979 refuelir.g outage" for the installation of fire barrier penetratica seals.
We have recently reviewed the coupletien date and our progress toward job completien, and have concluded that we cannot coet the schedule.
Therefore, we must establish a new date for this work.
The date we suggest is the cnd of the 1930 refueling outage.
We realize that this is a significant change, but feel that i.s is justified.
Our bases for this change follow here:
It should be realized that there are presently many different products or systema en the mar,:et for sealing fire barrier penetraticns.
The process of evaluating each of these is a long and arduous one.
The evaluation is made more difficult because no one product rects all criteria developed for the different types of pcactrations in a plant.
These criteria include among others arpacity derating, flexibility, method of application and case of application.
A closer Jock at just one of these, required derating cn cable ampacity, will indicate the problens and decisions i.e are faced with.
A material used as a penetratien seal en electrical cables cust stop a fire frc: going througn a penetraticn.
It nust also stop heat from passing through it and tuilding up the temperature en the non-fire side of the penetration.
This requires that the caterial be a good thermal innulator.
However, this same caterial cust conduct beat away from the cable that it surrounds in thc penetration.
If it does not, a hot spot could develop, causing a fire or a cable failure.
Products have beer developed which claim to meet the crite-ia, but scne are un-tested to date.
Others can be used only en r.ew installations.
This problec of required cable deratin; is a significant one for r cnt fankee and for other older plants.
It cannot he 1:nored; and, in fact, cust be looked at for every penetration.
Tnis is a 22ngthy process.
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ince 2 July 11, 1979 Vermont Yankee is approaching the end of this evaluation process.
It is felt that a decision on the materialt to be used will be made within the next two months, after reviesing the results of tests presently being made.
As you are aware, Vermont Yankee presently has seals on tany penetraticns.
Our uriginal entimate on the time required to either remove these older seals and/or prepare the area for the new seal arrangement was low.
After conferring with contractors that could do that job, our estimate en time has increased substantially.
In additien, all the contracter's tice estit-tes for re-sealing the penetrations are far higher than cur original onu..
The reason for this is readily apparent. Vermont Yankee was one of the first plants to be evaluated by the NRC Fire Hasard Review Team.
Almost no work had been done in the industry using the newly developed seal caterials or systems.
Therefore, estimates were based on theory rather than experience.
As experience builds, time estic.ates increase.
Vermont Yankee is faced with contractors who say they cannot do the work by the prosently scheduled completica date.
We therefore propose a schedule co=pletion date change to the end of the 1980 refueling outage.
We intend to proceed rapidly on this job, and will finish it as soon as practicable.
It is hoped that the actual completica date will be sooner than our new schedule allows.
- However, becauso cf the difficulty in working in some areas of the plant at power, the requested date is necessary.
We wish to point out that other major modifications to the plant fire protection systets have been completed en schedule. We feel this is indicative of the effort we have put on the job to date, and the effort which will be put toward meeting this new date.
If you ha've any question on the above, please contact us.
Very truly yours, D. E. Moody Manager of Operations EAS/dap h
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