ML20155F238

Part 21 & Deficiency Rept Re Failure of Clow Corp Containment Isolation & Vacuum Relief Valves in torus-to-vacuum Breaker Lines.Bearings Being Replaced W/ Different Matl.Related Correspondence

ML20155F238
Person / Time
Site:	Peach Bottom, Limerick, 05000000
Issue date:	03/13/1986
From:	Daltroff S PECO ENERGY CO., (FORMERLY PHILADELPHIA ELECTRIC
To:	Murley T NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION I)
References
CON-#286-511, REF-PT21-86, REF-PT21-86-207-000 OL, PT21-86-207, PT21-86-207-000, NUDOCS 8604210419
Download: ML20155F238 (6)

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. PHILADELPHIA ELECTRIC COMPg .

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P.O. BOX 8699 PHILADELPHIA. PA 19101 E 24 P4 :07' r

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. Docket No. 50-277 "'

50-278 50-352 OL- -

.'. Dr.:T. E.-Murley, Administrator j=

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. -U.S.' Nuclear Regulatory Commission 631' Park Avenue King of. Prussia,'Pa. 19406 ,

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o Subjects iPeach Botton Atomic Power Station Units 2 and 3 '.

~g Limerick Generating Station - Unit 1 s

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' Containment Isolation Valves i Jr

'10 CFR Part 21 Report 4

Dear Dr. Murley:

In accordance with paragraph (3) of 10. CFR 21.21.(b), the . . af,

=following information concerns a recent failure of a combination:

> containment isolation valve and vacuum relief valve in one;of the W

. 4 torus to reactor building vacuum breaker lines at-Peach Bottom. ?hf y

,and potential applicability of this fallure to containment- 5MJ atmospheric control isolation valves at Limerick which were .., 4

supplied by the same manufacturer. -

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1. - Name of individuals informing the Commission:  ;'f y

W. T. Ullrich uN

2. Identification of basic component which contains a defects' Carbon sleeve bearings in Clow corporation butterfly valves - ,@,

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3. Identification of firm supplying the basic component s s.

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C si S Valve Company (Formerly Clow Corporation) .f

! 40 Chestnut Avenue 4 Westmont, Ill. 60559 9604210419 860313 e j '.

PDR ADOCK 05000277 S PDR .

4.- Nature of defect and the safety hazard which could be ,

p 4 created:

l Butterfly valves manufactured by Clow Corporation are , .,

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i installed at Peach Bottom in one of the two redundant torus - '

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reactor building vacuum breaker lines and at Limerick in the .

' Containment Atmospheric Control Systems as containment ,  ;

These valves are exposed to both drywell-a isolation valves. ,

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Land watwell atmospheres, which may experience up to 100%

' - relative humidity. The valves are designed for water, air

, ' dJ and corrosive service. The shaft material is SA,564 Type 630 ,

(alloy.17-4 PH, Cond H-1100). The bearing material is a,

-carbon material of unknown substrate.

• s P :The Clow valves utilized at Peach Bottom were' installed in

.> February, 1985 on Unit 2 (valve AO-2502B) and February, 1983 on' Unit-3'(Valve A0-3502B). Peach Bottom Technical p ' Specifications require stroke testing once per 18 months and 4

additional stroking of these valves is performed during '

"certain surveillance testing, local leak rate testing and following maintenance on the valves. Since installation,lthe

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, LAO-2502B and AO-3502B valves have been full stroke testedj ,

four; times and ten times respectively, with the most recent ,

_ previous testing having been successfully performed on July -

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. 1, 1985 and July 20, 1985 respectively. >

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Maen performing maintenance activities- on valve A0-3502B at l Peach Bottom, this fail.-open valve did not stroke open as it f,

.should have When air was removed from its operator. Upon ic disassembly, significant pitting was observed on the valve y, i shaft. Also, the shaft was found seized to the upper and 3 1 lowerf aleeve bearings such that disc movement was prevented, ,w T i rendering the valve inoperable in the closed position. This *-e "

valve is both-a containment isolation and vacuum relief: valve i on one.of the redundant torus-to-reactor building vacuum .)'

breaker lines. Immediately upon discovery of this condition on, Unit.3, the comparable valve on Unit- 2 ( AO-2502B) was 4," ,

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examined, and it was found to be similarly affected. d'.

Consultation with the manufacturer and metallurgical analyses ,

ij of ' the failed parts performed by PEco Metallurgical ,

Laboratory have indicated that the cause of failure was ar?.

galvanic corrosion between the carbon bearings and stainless steel' shaft. It appears that the corrosion was initiated lc, >

after chloride attack on the shaf t by the bearing material.

! These two valves are normally-closed, fail-open valves Which , cf

operate to limit the differential pressure between the torus 4

' - and reactor building at minus 0.5 i 0.25 paid. The purpose. t of the vacuum relief valves is to equalize the pressure- ,hf; j' f between the pressure suppression chamber and reactor building 7,# ;

WJ' so that the structural integrity of the containment is

maintained. The vacuum relief system from the pressure "l suppression chamber (torus) to reactor building consists of  ;

'two 100% capacity and redundant parallel sets of two vacuum j j' relief breakers in series. Peach Bottom Technical j Specification 3.7.A.3.b allows continued reactor operation .j j for seven days should one of the 100% capacity parallel sets of vacuum relief valves become inoperable. Operation of l

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3Dr'..T. E.'Murley .Page 3 .:

e Es 1 either' redundant system will limit = the containment pressure -

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. odifferentialsto . lass than minus 2 psi, -the design maximum 1

_ pressure differential. One of the two sets of vacuum relief'.

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! .. -valves utilizes a butterfly . valve manufactured by a different

' supplier Which are not subject'to this problem.

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Since the:

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~ redundant set of vacuum relief valves maintains ~.the L , ;3 -  : availability of an additional train of 1004' capacity,;thei ,

safety: significance of -ttus failure related to the Clow l

-Corporation-valves is considered minimal at Peach Bottom.- *

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.; Butterflysvalves manufactured by Clow Corporation areL.,.

- utilized at Limerick Unit 1 as primary containment isolation. / ,

valves in the Containment- Atomospheric Control system. . ,These 3; L~ , valves are -stroked quarterly in accordance with the Technical L s I

Specifications. A review of the stroke time ~ data-fron  ; .

L November, 1984;to the present, demonstrates no degradationiof L . stroke time during_ valve testing indicating that similar

[' . galvanic attack is not occurring in the valves at Limerick.

' The valves at Limerick Which are potentially susceptible to the problem- are 'the containment . isolation valves on the  :  !

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' Containment Atmospheric Control System (Valves HV-57-104,=

1109,.112, 114,~ 115, 121, 123, 124, 131, 135, 147, 161,.162, '4 163, 164). None of these valves are affected by Amendments 1 and 2 to the Limerick Technical Specifications issued l- ' February.6, 1986 and March 3, 1986 respectively. t should an accident occur during primary containment inerting _

or deinerting operations at Limerick, and had the valves ,

experienced a similar degradation as experienced at Peach Bottom, they may stroke closed slower than the time period assumed in analyses of post-accident containment response and post-accident releases, or fail to close,-thereby creating a plant condition Which is unanalyzed. Valves HV-57-104 through HV-57-147 listed above are double containment .

. isolation valves that are normally closed. Primary

' containment integrity can be maintained even if one of the . r two ' containment isolation valves in a specific flow path should fail during inerting or deinerting operations.  !

The containment isolation valves, HV-57-161, 162, 163'and 164, connected to the two post-LOCA hydrogen recombiners are

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normally closed but have a safety function to open after.an '

accident if recombiner operation is required. For each -

recombiner, one valve is in the supply line and one valve is  ;,

in the return line. The only scenario Which would result in D establishing improper flow to either of ' the two 1001 ";

capacity, redundant post-LOCA hydrogen recombiners would be a

. failure to open of one of the two containment isolation V

, valves for both recombiners. These four valves are being T

stroked weekly to ensure that they operate properly.

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Dr.-lT. E. Murley Page 4

5. 'Date onLwhich the information of such def ect was obtained -

--The failure atLPeach Bottom was discovered on January 6,

'1986.- The evaluation to determine reportabililty of this

... -defect'was completed on March 12, 1986.

' 46. The number.and location of the basic component that contains

.q. ,a defect PeachBodton: .

Unit 2 (AO-2502B)' ,

, Unit 3L(AO-3502B)  !

L Both~ valves are containment isolation / vacuum relief

~ valve on one of the 100% capacity redundant torus - reactor

' building vacuum breakers <

F' Limerick Unit 1:

-Primary containment isolation valves in the Containment Atmospheric Control System HV-57-104,112 (Suppression pool to standby gas treatment system)

HV-57-109,121,131 (Nitrogen Supply) .

I HV-57-ll4,ll5 (Drywell to standby gas treatment system) l i HV-57-123,135 (Reactor enclosure supply fan to drywell)

HV-57-124,147 (Reactor enclosure supply fan to suppression pool)

HV-57-161,162 (Containment hydrogen recombiner)

HV-57-163,164

7. Corrective action that has been, is being, or will be taken: .

I the.name of the individual or organization responsible for the action; and the length of time that has been or will be ,

taken'to complete the action:

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l .The PEco Mechanical Engineering Division is currently working l .with.tho' manufacturer to replace the bearings with a

, dif ferent ~ material, possibly bronze, to alleviate the b

chemical and galvanic attack. The shafts and bearings of

-Peach Bottom A0-2502B and A0-3502B valves were replaced in kind, and the valves were returned to service. These are the p only.two valves manufactured by Clow corporation which are in j service at Peach Bottom. Both valves are currently being exercised once per week to verify proper operation.

The four primary containment isolation valves at Limerick which serve the containment hydrogen recombiner are currently being stroked weekly to ensure that they operate properly. ,

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. Dr. T. E. MurleY ,

The ' remainder of the Limerick valves have been verified .

closed. -These valves will be stroked individually prior to

,: their:use.for any inerting or deinerting activities, to

ensure their operability in addition to their normal ,

.;Jquarterly stroking.. Any modifica'tions deemed necessary for t the Peach Bottom valves will also be performed on the*

• ,.Limerick valves.

8. Notifications .

The industry was notified of the valve failure via INPO's ,

Nuclear Network on January 27, 1986.

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Very truly yours,

= l cc: Director, Office of Inspection & Enforcement (3 copies) l.

See Attached Service List .

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cc Troy B. Conner, Jr., Esq. '

Ann P. Hodgdon,' Esq.

, Mr. Frank R. Romano -

. Mr. Robert L. Anthony-

-' Ms. Phyllis Zitzer

.. Charles W. Elliott, Esq. s.

Barry M. Hartman, Esq. .

i Mr. Thomas Gerusky .

. Director, Penna. Emergency Management Apancy ,.

Angus Love, Esq.

David Wersan, Esq.

Robert J. Sugarman, Esq.

, Kathryn S. Lewis, Esq.

Spence W. Perry, Esq.

Jay M. Gutierrez, Esq. .

Atomic Safety & Licensing Appeal Board Atomic Safety & Licensing Board Panel Docket & Service Section (3 Copies)

E. M. Kelly Timothy R. S. Campbell 1~

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t February 4, 1986

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