05000280/LER-1979-029-01, /01T-0:on 791011,at Cold Shutdown,Min Wall Thickness Violation Discovered in Reducers Mating w/MOV-1842.Caused by Const Deficiency.Reducers Replaced & Verified to Meet Min Wall Thickness Criteria

/01T-0:on 791011,at Cold Shutdown,Min Wall Thickness Violation Discovered in Reducers Mating w/MOV-1842.Caused by Const Deficiency.Reducers Replaced & Verified to Meet Min Wall Thickness Criteria

ML18136A181
Person / Time
Site:	Surry
Issue date:	11/06/1979
From:	Stewart W VIRGINIA POWER (VIRGINIA ELECTRIC & POWER CO.)
To:	NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION II)
Shared Package
ML18136A180	List: 05000280/LER-1979-029, Forwards LER 79-029/01T-0 05000280/LER-1979-029-01, /01T-0:on 791011,at Cold Shutdown,Min Wall Thickness Violation Discovered in Reducers Mating w/MOV-1842.Caused by Const Deficiency.Reducers Replaced & Verified to Meet Min Wall Thickness Criteria
References
LER-79-029-01T, LER-79-29-1T, NUDOCS 7911140357
Download: ML18136A181 (2)

LER-1979-029, /01T-0:on 791011,at Cold Shutdown,Min Wall Thickness Violation Discovered in Reducers Mating w/MOV-1842.Caused by Const Deficiency.Reducers Replaced & Verified to Meet Min Wall Thickness Criteria

Event date:
Report date:
2801979029R01 - NRC Website

text

NRC FORM 366 17-77)

.ENSEE EVENT REPORT U.S. NUCLEAR REGULATORY COMMISSION e

CONTROL BLOCK: I I 10 lL --'----'----'--'--'-----'6 (PLEASE PRINT OR TYPE ALL REOUiRED INFORMATION)

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19 lo 1014 LICENSE NUMBER 25 26 l1 11 11 h 101 I I 0 LICENSE TYPE 30 57 CAT 58 CON'T [IE]

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~ 17 60 61 DOCKET NUMBER 68 69 EVENT DATE p 1@11 11 Io l 6 I 7 I 9 IG) 74 75 REPORT DATE 80 EVENT DESCRIPTION AND PROBABLE CONSEQUENCES@

jWith the unit at cold shutdown, a possible minimum wall thickness violation was dis-

[§]:TI !covered in the reducers mating with MOV-1842.

Information provided by the Architect-

. ((ill I Engineer determined that the minimum wall thickness had been violated.*'.Th.is is [Q))],reportable in accordance with Technical Specification 6.6.2.a.2.

The health and

[:[I[] !safety of the general public were not affected by this event.

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SYSTEM CODE 1s !FI@

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LEA/RO CVENTYEAR v..y REPORT I 7 19 I NUMBER 21 22

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13 18 SEQUENTIAL OCCURRENCE REPORT NO; CODE l.::=J I O 12,. 9 1 I /j I O I I I 23 24 26 27 28 29 ACTION FUTURE EFFECT SHUTDOWN COMP.

SUBCODE

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19 REPORT TYPE

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30 VALVE SUBCODE L!J@

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31 REVISION NO.

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32 TAKEN ACTION ON PLANT METHOD HOURS SUBMITTED FORM SUB.

SUPPLIER MANUFACTURER ATTACHMENT NPRD-4 PRIME C::.OMP.

COMPONENT I I l.:J@ ~* ~@) **1T*l3 13 *1° I 40' 41 42 43 44 47

~@l~J@ L.:J@ L:J' 1°**1°1° 33 34 35 36 37 CAUSE DESCRIPTION AND CORRECTIVE ACTIONS @

T.Iill I During the repair work on the MOV, the reducers were replaced and verified to CIII] l meet the minimum wall thickness criteria.

This even_t was caused by a construction deficiency.

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STATUS

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10 12 1'.3 ACTIVln CONTENT

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REL~SED OF RELEASE AMOUNT OF ACTIVITY*

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9 10 11 PERSONNEL EXPOSURES

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QNU~ER.Q t:;::;\\ TYPE DESCRIPTION 39 [iliJ I I I * ~~@'--______

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PERSONNEL INJURIES f41) iflU~ER DESCRIPTION~

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I' 44 45 80 LOSS OF OR DAMAGE TO FACILITY '43' TYPE DESCRIW.AON

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NAME OF PRE PAR ER..;Wu.a., _L..a.,__..Sc...t....

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e Attachment (Page 1 of 1)

Surry Power Station, Unit 1 Docket No: 50-280 Report No: 79-029/0lT-O Event Date:

10/11/79 Title of Event:

Minimum Wall Thickness Variance in Reducers to MOV-1842

• 1.

Decription of Event:

With the unit at cold-* shutdown, a. possible minimum wall thickness violation was discovered iri the reducers mating with MOV-1842.

,Infor-mation provided by the Architect-Engineer determined that the minimum wall thickness had been violated.

This event is reportable in accordance with Technical Specification 6.6.2.a.2.

2.

Probable Consequences/Status of Redundant Systems:

It was determined that the wall thickness of the 4" side of the reducers was 0.031" less than the required minimum thickness.

Since no problems were experienced with these reducers, the health and safety of the public were not affected.

3.

Cause

It appears that the reducers (as manufactured) would_ riot mate properly to MOV-1842 and during construction the reducers were machined to insure a proper fit with the valve.

In the course of this modification to the reducers, the minimum acceptable wall thickness was violated.

4.

Immediate Corrective Action

During the repair work on the MOV, the reducers were replaced and verified to meet the minimum wall thickness criteria.

5.

Scheduled Corrective Action:

The reducer replacement was made prior to the unit startup and no further action is deemed necessary.

6.

Action Taken To Prevent Recurrence:

Since the reducers for MOV-1842 were replaced with acceptable minimum wall thickness reducers, no further action will be taken to prevent recurrence.

7.

Generic Implications:

This event was an isolated occurrence with no generic -implications.