ML20086J074

Telecopy AO 75-5:on 750110,support Flange on Hpsw/Rhr HX Discharge Valve Motor MO-3-10-89B Failed.Caused by High Valve Vibration Due to Throttling Mode of Valve.Motor Casting Will Be Replaced

ML20086J074
Person / Time
Site:	Peach Bottom
Issue date:	01/10/1975
From:	Ullrich W PECO ENERGY CO., (FORMERLY PHILADELPHIA ELECTRIC
To:	James O'Reilly NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION I)
Shared Package
ML20086J073	List: ML20086J071 ML20086J074
References
AO-75-5, NUDOCS 8401230108
Download: ML20086J074 (2)

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PHILADELPHIA ELECTRIC COMPANY Y . , ' . *t. . . c /' " . M I' ~

Peach Botto 2 Atomic Power Sta tion -

Delta. Pennsylvania -- ,

17314

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January 10, 1975

' 'l-Hr. James P. O'Reilly. Director United States Atomic Energy Cor: mission Directorate of Regulatory Operations 631 Park Avenue b King of Pressia, Pennsylvania 19406 g)f Subj ec t : Abno rra l _Oc c_u r,ryn e c 24-Hour Notification Confirming W. T. U11 rich's phone conversation with Mr. Walt Baunac k, A.E.C. Region 1 Regulatory operations Office on January 10, 1975.

Reference:

Licenso Number DPR-56 Technical Specification Fef erence 3.5.B Report No.: 50-270-75-5 Report Date: Janua ry 10, 1975 Occurrence Date: January 10, 1975 Pccility: Peach P,otton Atomic Power Station R. D. 1, Delta, Pennsylvania 17314 Identificatier. cf Occurrence:

Failure of tsupport flange on liPSW/RHR heat exchanger dischargo valve cotor (MO-3-10-893)

Conditions Prior to Occurrence:

Reactor shutdown. Trinary cooling te=perature is approxi.tsately 150*F.

Dnscription of Occurrence:

During routine oporatiur.c of the shutdown cooling code of the RHR nynten, the flange used to bolt the rsocor to the valve oporator gear casing on

, MO-3-10-693 failed. The flango is an integral part of the r:otor end bell

' ca p ting. As found, the valve vac approx.icately 1 1/2" open.

Dasignation of Apparent Cause of Occurrence:

, . High valve vibration due to the throttlin6 c:de of the valve couded * '

the valve stem to horner the pescking out of ponition and cauced a

.fatique failure of the cotor end bell casting.

Analysis of the Occurrence:

Thcae saf ety nignificance of thin occurrence is considered rainical, since no cooling capability of the RHR/HPSW vam lost. The valve failed in the throttled position.

8401230100 750120 C::rrective Action:

PDR ADOCK 05000278 PDR s

Until pernanent repairs can be e.ade and new rotor cas,t ings obtained, the valve was locked in a throttled condition which providen design high prescure servica water flow rate throur;h the heat exchanger when

.ono hi;;h pressure service w.ater puep is placed in r,ervice. In thi,- Sc,2, condition, the operability of the high preuure curvico water systea

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is not effected. PECo Engineering is niitively pursuing other

• slechanisas to reduce vibrationn in this area which are believed to be the cauce of this and similar failures.

Failure Datar Similar dif ficulties have been reported as Abnormal Occurrences on those reports: AO-50-277-74-53 AO-50-278-74-28, A0-50-278-74-35, and AO-50-273-74-36 Very truly yours, .

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W. T. Ullrich, Superintendent Peach Eotten Atocic Fover Station D*

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