ML20093E768
| ML20093E768 | |
| Person / Time | |
|---|---|
| Site: | Nine Mile Point  |
| Issue date: | 07/12/1984 |
| From: | Lempges T NIAGARA MOHAWK POWER CORP. |
| To: | Deyoung R NRC OFFICE OF INSPECTION & ENFORCEMENT (IE) |
| References | |
| IEB-84-02, IEB-84-2, NMP-8954, NUDOCS 8407180105 | |
| Download: ML20093E768 (2) | |
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I Y NIA0 ARA N Li M.AM NMP-8954 l
l NINE MILE POINT NUCLEAR STATION /P.O. BOX 32 LYCOMING, NEW YORK 13093 / TELEPHONE (315) 343-2110 i
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July 12, 1984' l
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I Mr. Richard C. DeYoung, Director j
Office of Inspection and Enforceae,nt USNRC-4 Washington, D.C. 20555
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Reference:
I & E Bulletin 84-02
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Dear Mr. DeYoung:
-IEB 84-02 instructs Nine Mile Point Unit I to:
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" Develop plans and schedules for replacing (1) nylon or Lexan a.
coil spool-type HFA relays used in normally energized a
safety-related applications and (2) nylon coil spool-type HFA relays used in normally de-energized safety-related applications."
I Nine Mile Point plans to replace HFA relay coils or complete relays during the next refueling, which is currently scheduled for the Spring of 1986.
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"During the period before relay replacement, develop and
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implement surveillance plans that include:
(1) Monthly functional tests of all reactor trip system normally energized relays that verify relay contacts change state l
when the relay coil is de-energized; (2) Visual. inspections of all safety-related normally energized
- relays as soon as practical upon receipt of this bulletin.
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Thereafter, similar inspections should be accomplished in
-conjunction with the monthly functional test. These visual I
inspections should verify that relay coils are not i
deteriorating (e.g., inspect coil bobbins for visible cracks or melting), and should confirm cleanliness of the relay pole pieces."'
Nine Mile Point Technical Specifications require checks of most reactor trip functions at.least monthly, and most HFA relays have therefore been verified to, change' state when the relay coil is de-energized. Procedures have been i,
reviewed and will be revised as necessary to assure and provide documentation
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that all normally energized reactor trip system HFA relays are verified to change state when de-energized. These changes will be in effect by September U 1984.
-8407180105 840712 6
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Visual inspedtion of 'e.11 HFA relays, both normally energized an'd normally s,
Ay de-energized', in both*safetyr'and non-safety related systems was completed
'* P prioE to startup;from the'gecent refueling outage..These inspections revealed
@O - no coi1~det9rioration (e.g. no cracks or melting) and confirmed the cleanlinead of relay:yole pieces. This inspection was also performed in 1981
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and 1983.
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'Visuiliinspectionofa11'reactortripsystemnorac11yenergizedrelayswillbe performed monthly. ~Thic procedure will be in effect by September 1, 1984.
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- c. '"Provyde'a basis for continuing operation for the period of time until The n'irmally. energized relays are replaced. This basis
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should include a discussion of those measures addressed in Items
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la and lb and eny sother epreventive and/or. corrective measures taken or planned."-
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!Niss' Mile Point Unit #1 rep 1,iwd safety related HFA relays or coils in 1977 in
.J response to NRC and General Electric concerns. 'Since thatstime, one of these ghas. failed, not due.to the coll, and it failed in the conservative direction.
. NNP-1 Technical Specifications ' require at'least monthly surveillances on RTS
,;-parameters except for Mansa 1 D ram, Main Steam Line Isolation Valve Position,
,' Turbine ~Stop Valve Closure,~tiad Shutdo'wn Positiof of.the reactor mode switch.
[ Of,these, MahayJ : Scram Aces'not utilize HFA relays, and Shutdown Position of
- ) i the ' reactor mode switch] utilizes 'normally de-energized relays. Turbine Stop
% alve ClosureLis tested monthly.. The MSIV_ Position Scram will be checked 7
monthly by pulling affuse to de-energize the HFA relay.. This procedure will C
lbe*in,effectiby, September 1,' 1984.
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- s Based ~on 1) low failure rategof the.RTS and'o'ther safety related HFA. relays at
.Nine; Mile Point Unit'#1, 2). tie lack of evidence of the problem, based on
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~three successive vihkal examinations in 1981, 1983, and 1984, 3) a monthly surveillance interval for test and visual inspection,.4) a failure tolerant
- "one out-of two taken twice"'Idgic system for both RTS and RPS, and 5) the age of thc7HFA relays currently being' about seven years, the anticipated replacement age of nine years,(replacement.two years from now) verses the 10-12 year observed.end of life, continued' operation of Nine Mile Point Unit
- 1 is justified.
Past operating history and manufacturers-recommendationa'on other types of
. relays are reviewed by the Operational' Experience assessment and Equipment
. Qualification programs at Nine Mile Point.
.T e sc e u e for completion of the h
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' Equipment Qualification Replacement Program is March 31, 1985.
s Jtaff time' to perform the review '1s approximately 200 man-hours. Staff time to prepare the. documentation is approximately 80 man-hours.
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Very truly yours,
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w-C Thomas E. Lempges Vice President-- Nuclear Generation
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