ML20086L244
| ML20086L244 | |
| Person / Time | |
|---|---|
| Site: | Peach Bottom  |
| Issue date: | 03/26/1974 |
| From: | Ullrich W PECO ENERGY CO., (FORMERLY PHILADELPHIA ELECTRIC |
| To: | James O'Reilly NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION I) |
| Shared Package | |
| ML20086L241 | List: |
| References | |
| AO-74-16A, AO-74-16B, AO-74-16C, AO-74-16D, NUDOCS 8402070539 | |
| Download: ML20086L244 (2) | |
Text
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- Delta, ylvania g g,337, jj yg March 26, 1974 i
Hr. James P. O'Reilly, Director United States Atonic Energy Com: mission Directorate of Regulatory Operations L 631 Park Avenue 4
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! King of Prussia, Pennsylvania Sabje:t: Abnorm 1 Occurrence 24-Hour Notifiestion Confircing my conversstion with Mr. L A. Feil, A.E.C Region I heguintory Operation's Office on Farch 26, 1974.
Licenso Number DPR ?+h, Arendment Nusber 1
Reference:
A.
Technical Specification 3 6.D.2(a)
B.
Technical Specification 3 5.E.2 C.
Technical Specification 3 5.c.2 D.
Technical Specification 3 6.D.2(b)
I Report No.t 50-277-7!.-16A, B, C and D Report Date:
March 26, 1974 Occurrence Date:
March 26, 1974
- Facility:
Peach Bottom Atoric Power Station
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R. D. 1, Delta,' Pennsylvania 17314 Identifiestion of Occurrence:
A.
Reactor RV 71D bellove assembly leak.
B.
React 6r RV 71X failure to operate mnually.
O.
HICI turbine speed control enlfunction.
l D.
Reactor RV 710 bellove esseebly leak indication.
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Conditions Prior to Occurrenec:
Resetor at approximtely 7f power and 950 pei.
E b Description of the Occurrence:
Tollowing a maintenance outage during which vendor reco: mended r.inor nodifications were rode to the reactor relief valves, each
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relief valve vac cuccessfully operated manually at about 150 psig pressure. Pressure was then increased to about 950 psig and relief valves again tested. Daring this testing period, relief
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valve 71D bellows assenbly leak indication occurred (AO-16A)
E and relief valve 71X railed to open when the canual control switch
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vas pinced in the open position (AO-163).
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An inspection of these two valves inside the dryvell verified a
bellows leak on RV 71D, but did r.ot reveal any cause for the failure I
of RV 71K to operate. The air cupply and electrical connections to R7 71X colenoid valve were verified as being correct dur ng this y(
O inspection.
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1._..,...-.......After determining
. t RV 71K (one of five ADS va1Q vos inoperable, the required system survcillance testing was initiaWd.
A test of the HPCl identified an electrical problem in the turbine control
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system which failed the turbine control valve to the open position (AO-160). Prompt action by the operator shutdown tho turbine before it could trip on overspeed. Repairs were rade within several hours.
Plant shutdown operations were initiated after the EPCI was detemined to be inoperable. Power level was recovered after the HICI i
van successfully retested.
Diortly thereafter. relief valve 71C bellows assembly leak indication occurred (AO-16D) and the decision made to shutdown the reactor.
1 The primary system vna cooled to less than '212 F vithin 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br />.
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Designation of Appirent Cause of Occurrence:
A.
Not known at this time.
B.
Not known at this tice.
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C.
Control system electrical component failure.
D.
Not known at this time.
Analysic of Occurrence:
At the titte of this occurrence., the reactor was operating at a rininum power level sufficient to grupport post caintenance testing of relief valves having previously been shutdown for approximately one week. Decsy heat load in the reactor was minimal. Because sufficient relief valve capscity, and c::ergency core cooling syste=s vere available at all ticce to respond to any plant transient initiated from a full power condition, no safety si nificance is 6
i associated with this occurre'nce.
i Corrective Action:
A. B ar.d D.
Both the valve manufacturer and nuclear steam systes supplier have been inforced of the di'fficulties associated with the reactor relief valves. Following pinnt cooldown, these valves shall f
be disascer. bled and inspected to determine the cause of these difficulties.
Correctivo raintenance operations shall then be initiated.
i C.
Tne electrical calfunction in the HPCI control circuitry was traced The to a local speed control potentiometer which vae open circuited.
open circuit vac caused by the failure of the potentiometer stops to i
limit clide cotion. A potentiometer with proper stops was instelled to correct the deficiency. The EPCI was successfully tested following i
repairs to the control circuitry.
r Failure Date:
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One be13cyc asse:bly leak hss occurred since initial startup. On two occasior.s. relief valves have failed to rescat after manual l
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ir.itiation. On one occasion, e relief valve failed to reseat on the first attempt following ranual initiation but did release on the
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third attempt.
i W N/d l
V. T. Ullrich, Superintendent
[ Peach Bottom Atomic Power Station 5
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