ML20086K508

AO 74-32:on 740612,RHR LPCI Injection Valve MO-2-10-154B Motor Failed.Caused by Rotor Shaft Slippage.Moto Replaced & Valve Stoke Tested

ML20086K508
Person / Time
Site:	Peach Bottom
Issue date:	06/22/1974
From:	Cooney M PECO ENERGY CO., (FORMERLY PHILADELPHIA ELECTRIC
To:	Giambusso A US ATOMIC ENERGY COMMISSION (AEC)
Shared Package
ML20086K512	List: ML20086K508 ML20086K513
References
AO-74-32, NUDOCS 8401270171
Download: ML20086K508 (2)

Text

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June 22, 1974 5 0- 2 r 7 4

Mr. A. Giambusso Deputy Director of Reactor Projects United States Atomic Energy Commission Directorate of Licensing Washington, DC 20545

Subject:

Abnormal Occurrence The following occurrence was reported to Mr. R. A. Feil, A.E.C. Region 1 Regulatory Operations Office on June 12, 1974. Written notification was made to Mr. James P. O'Reilly, Region 1 Regulatory Operations Office on June 13, 1974. In accordanen *lth Section 6.7.2.A of the Technical Specifications, Appendix A of M~.4 for Unit 2 Peach Bottom Atomic Power Station, the following report is being submitted ta 1:a Diroctorate of I. icon =ing ac r.n /4.. . . . -r.1 Occurrone .

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Reference:

License Number DPR-44, Amendment Number 1 i Technical Specification 3.5. A Report No.: 30-277-74-32 Report Date: June 22, 1974 Occurrence Date: June 12, 1974 Facility: Peach Bottom Atomic Power Station I

R. D. 1, Delta, Pennsylvania 17314 Identification of Occurrence:

The RIIR LPCI injection valve MO-2-lO-154B motor failure.

I Conditions Prior to Occurrence:

Reactor operating at appre:imately 705 power.

Description of Occurrence:

During surveillance testing the valve failed to open. In-vestigation revealed that the motor had failed electrically.

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Mr. A.-Giambusso Page 2 June 22, 1974 .

Designation of Apparent Cause of Occurrence: l Rotor shaft slippage resulting in mechanical damage which  !

then caused electrical failure.

Analysis of Occurrence:

Failure of this valve in the closed position resulted in an

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inoperable LPCI system. Surveillance testing was immediately begun on

'the diesel generators and core spray sub-systems as required by the Technical Specifications. Prior to the_ completion of this testing, the valve was opened manually and left open. Because the valve is normally in the open position and is open during LPCI injection it was determined that the LPCI sy tem was then operable. This occurrence, therefore, has minimum. safety s . nificance.

1 I- Corrective Action:

The valve motor was removed and inspected folleving the mi..iual opening of the valve. A shop inspection of the motor indicated that the rotor had slipped along the motor shaft until the rotor cooling blade came in contact with the end bell. This resulted in breaking some of the cooling blades and the removal of significant amounts of material from some blades which did not break. The motor manufacturer was called to the site to aid in the investigation. It is believed that the clip.nage of the. rotor along the shaf t war caused by the vibration ex-1 pu.Ieuwed by t!.c sulvo limitaryuc'Opcrator as cr.bly rehen th valv: 10 used in a throttling mode during shutdown cooling operation. The failure, therefore, has no safety significance since this valve is not used to throttle when the system is performing a safety function. On June 16, 1974, a replacement motor was installed and the valve stroke tested.

Failure Data:

No previous motor failures have been reported for this valve.

liowever, a valve deficiency was discussed in AO (10-15-73),

i p Very truly yours, t

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Cooney Ass t Gen'l Sup'e rintendent Generation Division cc: Mr. J. P. O'Reilly Director, Region i United States Atomic Energy Commission 631 Park Avenue King of Prussia, PA 19046