ML20090E166

AO 74-13:on 740918,during Routine Testing,Containment Spray Pump Found Inoperable.Caused by Foreign Object Restricting Suction Flow of Pump.Object Removed

ML20090E166
Person / Time
Site:	Nine Mile Point
Issue date:	09/20/1974
From:	Schneider R NIAGARA MOHAWK POWER CORP.
To:	Skovholt D US ATOMIC ENERGY COMMISSION (AEC)
References
AO-74-13, NUDOCS 8303110617
Download: ML20090E166 (5)

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NIAGARA MOHAWK POWER CORPORATION NIAGARA MOHAWK 300 ERIE BOULEVARD WEST SYRACJSE, N. Y.13202 L* .s h ,* '

September 20, 1974

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Mr. Donald J. Skovholt

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Dear Mr. Skovholt:

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In accordance uith Technical Specifications 1.13d for Nine l Mile Point Unit 1, the enclosed Abnormal Occurrence Report is

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sthmitted. This report is in accordance uith the format set forth in Regulatory Guideline 1.16. Thi.; occurrence vaa reported to l

RO:I on September 18, 1974. \ 1 V

Very taly yours, ,

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• A$: f"?1j'. l m, :ty R.A. Schnes. der i Vice President - Electric Operations ]

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ABNORMAL OCCURRENCE REPORT Report No. 74-13 Date Septembe- 18, 1974  ;

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, , , Occurrence Date September 18, 1974 3, Facility Nine Mile Point Unit 1 i l

4. Identification of Occurrence Inoperable containment spray pump #122.

5. Conditions Prior to Occurrence Unit #1 at steady state 98% power.

6. Description of Occurrence i

During routine testing following a recalibration of the flow trans-l mitter on September 17, 1974, the performance of containment spray pump #122 was found to have varied from previously expected perfor- ,

mance. The three redundant pumps showed expected performance. }

The pump curve for containment spray pump #122 sets design flow at 3000 gpm at a pump developed head of 375 ft. at 60*F. The test data {

e indicated the required developed head but the flow indication was approximately 2600 gpm. The pump was taken out of service and the required surveillance performed on the redundant pu.ap. Technical Specification 3.3.7.b provides 15 days to return the effected pump to service provided the additional surveillance is performed.

Specification 3.~,3 7.b was satisfied, therefore, fulfilling the L.C.O. The pump was disassembled and a piece of wood was found wedged in the " eye" of the pump thus limiting its performance.

Therefore, requiring the reporting of an abnormal occurrence pursuant to Tec'anical Specification 1.13d.

7. Designation of Apparent Cause of the Occurrence

, Restricted suction flow caused by foreign cbject. (1 3/4" x 5 1/4" x 3 1/4" I piece of wood)

8. Analysis of Occurrence  ;

Operation of only one containment spray pump is sufficient-to remove i post accident core energy releases including a substantial chemical i reaction involving hydrogen generation and will also limit pressure and temperature rises in the pressure suppression system to below design values. The containment spray system is designed with four (4) pumps, therefore, providing 400% redundancy. The other three (3) pumps satisfactorily meet the performance requirements, therefore, it can be concluded that no hazard would have been presneted to the general public or station had'the containment spray syste.: been required.  :

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9, Corrective Action The foreign object, a piece of wood 1 3/4" x 3 1/4" x 5 1/4" was removed f rom its lodged location in the " eye of the pump. None of the redundant three pumps has shown any behavior, which would lead to the conclusion that similiar problems with foreign objects have occurred.

- Following removal of the object and reassembly of the pump, its performance was measured and demonstrated the following:

1. Pump discharge pressure was 165 psig or 379 feet of developed head. (required 375 feet)

2. Pump discharge flow was 150 k Ibs / hr or 3000 gpm (required 3000 gpm)

Containment spray pump #122, theref.:re, is returned to service.

10. Failure Data No previous containment spray pump failures.

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28. Occurrence Date_ September 18, 1974

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3. Facility Nine Mile Point Unii; 1 i:p^ ~ 3

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4. I_dentific_a_ tion of Occurrence l{$;3W n.

Inoperable cont inment spray pump #122. )  :. ,-

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5. Conditions Prior to Occurrence 4 ,.l.:{

1 Unit #1 at steady state 98% power

6. Description of occurrence During routine testing following a recalibration of the flow -

transmitter on September 17, 1974, the performance of containment spray pump #122 was found to have varied from previously expected performance. The three redundant pumps showed expected performance.

The pump curve for containment spray pump #122 sets design flow at 3000 gpm at a pump developed head of 375 ft at 60'P. The test data indicated the required developed head but the flow indication was approximately 2600 gpm. The pump was taken out of service and the required surveillance performed on the redundant pump. Technical Specification 3.3.7.b provides 15 days to return the effected pump to servic3 provided the additional surveillance is performed.

Specification 3.3.7.b was satisfied, therefore, fulfilling the L.C.O. The pump was disassembled and a piece of wood was found wedged in the " eye".of the puap thus limiting its performance.

Therefore, requiring the reporting of an abnormal occurrence pursuant to Technical Specification 1.13d.

7. Designation of Apparent Cause of the Occurrence c Restricted suction flow caused by foreign object.(approx. 5-6" long

8. \ Analysis of necurrence Operation of only one containment spray pump is sufficient to .- ,

remove post accident core energy releases including a substantial  ; (,,<>

chemical reaction involving hydrogen generation and will also r' limit pressure and temperature rises in the pressure suppresulon system to below design values. The containment spray system is designed with four (4) puera therefore providing 400% redundancy.

The other three (3) pumps satisfactorily meet the performance requirements, therefore, it can be concluded that no hazard would have been presented to the general public or station had the containment spray system bean required.

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9. Correct _ive Action, '

The iccediate corrective action will involve the removal of the ', '

foreign object from the "cye" of the pump. Tha pump will then be operated and its performance compared to the specifications to assure its operability. '

10. Yailure Data No previous containment spray pump failures.

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