ML19210A156

Event Rept 76-2/10:on 760106,pump Discharge Valve to River Pump a Failed to Open Upon Pump Start.Caused by Cracked Spline Adaptor in Valve.Adaptor & Key to Be Replaced & Test Cycled to Assure Operation

ML19210A156
Person / Time
Site:	Three Mile Island
Issue date:	01/16/1976
From:	Arnold R METROPOLITAN EDISON CO.
To:
References
GQL-0054, GQL-54, NUDOCS 7910240881
Download: ML19210A156 (4)

Text

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FILE: INCID:n FIL1 FROM: Met. Edison Co. DATE OF C')C DATE REC'D LTR TWX RPT OTHER Reading, Pa.

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R.C. Arnold 'l-16-76 1-20-76 YY TO:

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CLASS UNCLASS PROPINFO INPUT NO CYS REC'D DOCKET NO:

XXX i l 1 50-289 DESCRIPTION: Ler adv of unusual event 76-2-1 ) ENCLOSURES:

on 1-6-76 re failure of the nuclear services raiver water pump "A" discharge valve to ope t - -

y 4-when the pump was started... M bg sM6 t I L PLANT NAME: Three Mile Ilsnad Unit 1 . _ .

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METROPOLITAN EDISON COMPANY POST OFFICE BOX 542 READING, PENNSYLVANI A 19603 TELEPHONE 215 - 929-36b t January 16, 1976 GQL C05L

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Director of Nuclear Reacter Regulation M - .

U.S. Nuclear Regulatory Cer:=ission

,/ .C-Washington, D.C. 20555 -

S i' ,x 6 /

Dear Sir:

R' - /W Docket No. 50-2d9 Cperating License No. DPR-50 In accordance with the Technical Specifications of our Three Mile Islar.d Nuclear Staticn Unit 1 (D1I-1), we are submitting the iclieving event report.

(1) Report Number: ER 76-2/10 "

g (2a) Report Date: January 16, 1976 4 peerne tg

/ V5hw (2b) Event Date: January 6, 1976 -

IE M 2 0lSZS > $

(3) Facility: Three Mile Island Nuclear Station Unit 1 ' -

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• S"* d (h) Identification of Event:

4 =a

Title:

Failure of the Nuclear Services River Water Pump "A Discharge Valve to Open When the Pu=p was Started.

Type: An abnormal cccurrence as defined by the Technical Specificaticns, paragraph 1.8d, in that the inoperable Nuclear Services River Water Syste= valve threatened to cause an Engineering Safeguards feature er system to be incapable of performing its intended functions.

(5) Conditions Prior to Event:

Fever: Core: 100,5 Elec.: 8h6 MWe (Gross) 6 RC Flow: 138 x 10 lbs./hr.

RC Pressure: 2166 psig RC Temp.. 580CF 1490 084 PEZR Level: 235 inches FRCR Te_:p.. 6500F 554

(6) Description of Event:

At 16CO hcurs en January 6, 1976,while starting the Nuclear Services River Pu=p "A" (NR-PlA) to take vibration readings , the pump discharge valve (NR-VlA) failed to cpen when the pump was started.

At that =c=ent, the NR-P1A vas the designated Engineered Safeguards (ES) Nuclear Services Cooliag 317er Pu=p. Atte= pts to open the valve using the re=cte centrol pushbutten in the centrol rec =

aisc failed. UR-V1A vas then Opened =aaually. It was observed that a greeter than nor=al force was required to cren the valve manually. The valve cycled freely both =anually and electrically after it was manually cpened.

Ir.=ediately, the Nuclear Services River Pu=p "B" (NR-F13) vas selected as the ES pu=p in place of NR-PlA. NR-F13 and its respective discharge valve, NE-V1B, were verified Operable.

The Euclear Services River Pu=p "C" (NR-PlC) and its respective discharge valve, NR-VlC, were also tested and verified operable.

(7) Designatien of Apparent Cause of Event:

The cause of this event has been determined to be caterial in that the Nuclear Services River Pump "A" discharge valve failed to open due to valve binding. Disassenbly of the valve operater revealed a cracked spline adapter that is keyed to the valve stem. The key and keyvay were also damaged. This valve operater damage may have contributed to the valve binding.

(8) Analysis of Event:

It has been determined that this event did not ccnstitute a threat to the health and safety of the public in that:

a. Que Nuclear Service River Water Fu=p is sufficient tu supply emergency ecoling water in the event of a loss cf ecciant accident,

b. NR-P13 was available for cperation.

c. The redundant ES selected pu=p, UR-Plc, and its respective valve, NR-VIC, vere operable.

(9) Corrective Action:

In addition to the i==ediate acticn described abcVe, the NR-VlA operator spline adapter and key will be replaced and the valve cycled to assure that they are opernting preperly. UR-V1A vill be cycled once per week for fcur (h) weeks to assure that the binding does not recur.

The Plant Operatiens Review Cer=ittee and Station Superintendent r have reviewed and approved the abcve corrective acticn and have taken stepr to assure its ec=pletion.

1490 083 (10) Failure Data:

Limiterque Valve Operater

SM3-000 =cter operatcr T;pe H gear driv e Size 13C Material of Splined Sleeve and Key - Steel Valve 16" Butterfly Valve Henry Pratt Cc=pany Max Pressure - 100 psi Body - Cast Ircn Disc - NI-Resist Type 1 Shaft - 30h Stainless Steel Similar Cccurrences:

!cne Sincerely,

(

R. C. A

'rnold Vice President ECA:JMC:ll 1490 086