05000272/LER-1979-054-01, /01X-2:on 790824,three Snubbers on Main Feedwater Line 14 Found Unable to Rotate Around Spherical Rod End Bearings.Lead Screw & Traveling Nut Assembly Failed Due to Excessive Force.Cause Undetermined

/01X-2:on 790824,three Snubbers on Main Feedwater Line 14 Found Unable to Rotate Around Spherical Rod End Bearings.Lead Screw & Traveling Nut Assembly Failed Due to Excessive Force.Cause Undetermined

ML18085A928
Person / Time
Site:	Salem
Issue date:	02/19/1981
From:	Steele W Public Service Enterprise Group
To:	NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION I)
Shared Package
ML18085A927	List: 05000272/LER-1979-054, Forwards LER 79-054/01X-2 05000272/LER-1979-054-01, /01X-2:on 790824,three Snubbers on Main Feedwater Line 14 Found Unable to Rotate Around Spherical Rod End Bearings.Lead Screw & Traveling Nut Assembly Failed Due to Excessive Force.Cause Undetermined
References
LER-79-054-01X, LER-79-54-1X, NUDOCS 8102270684
Download: ML18085A928 (1)

LER-1979-054, /01X-2:on 790824,three Snubbers on Main Feedwater Line 14 Found Unable to Rotate Around Spherical Rod End Bearings.Lead Screw & Traveling Nut Assembly Failed Due to Excessive Force.Cause Undetermined

Event date:
Report date:
2721979054R01 - NRC Website

text

NRC FORM 366

*771,.. ".*

- LICENSEE EVENT REPORT U.*

UCLEAR REGULATORY COMMISSION

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CONTROL BLOCK: I 1 G)

(PLEASE PRINT OR TYPE ALL REQUIRED INFORMATION)

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LICENSEE CODE 14 15 LICENSE NUMBER 25 26 LICENSE TYPE 30 57 CAT 58 CON'T 0JJ 7

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~~~~~ L!J© I o I s I o Io I o I 2 I 1 l 2101 o I a I 2 I 4 I 1 I 9 I© I o I 2 11 I 9 I a 11 10 60 61 DOCKET l\\IUMBER 68 69 EVENT DATE 74 75 REPORT DAT; 80 EVENT DESCRIPTION AND PROBABLc CONSEQUENCES@

!During the first.refueling outage, as a followup to NRC Inspection 50-311/79-19, three I snubbers on No. 14 Main Feedwater line were found to have failed.

These snubbers

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were included in the stress calculations for the seismic safety analysis of the [Q))J nuclear portion of the main feed water piping.

Stress calculations indicated the I

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increase in stress in the piping is small and remains well below the allowable stress

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I limit.

Seismic stresses would not be affected as the snubbers would be locked under

[£I:[J I that condition.

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SYSTEM CODE le IHI@

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REPORT I 7 I 9 I NUMBER 21 22

CAUSE

CAUSE CODE SUBCODE COMPONENT CODE L!J@ W@ lslulPlolRITI@

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12 13 18 SEQUENTIAL OCCURRENCE REPORT NO.

CODE I

I I o Is I 4 I 1......-1 I 01 ll 23 24 26 27 28 29 COMP.

SUB CODE LEJ 19 REPORT TYPE

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30 VALVE SUBCODE L!J@

20 1=.J 31 PRIME COMP.

ACTION FUTURE TAKEN ACTION ON PLANT METHOD HOURS SUBMITTED FORM liUB.

SUPPLIER REVISION NC.

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• COMPONENT MANUFACTURER I

80 EFFECT.

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CAUSE DESCRIPTION AND CORRECTIVE ACTIONS @

43 44 47 [I))] I Failure of the snubbers appears to be the result of a force applied to the snubbers I

many times greater than their design load.

The force was either an extreme shock load II!IJ or occurred when the snubber was in the fully ret~acted condition.

The exact cause I

and magnitude of the force have never been determined.

Instrumentation was installed to measure and record the acceleration and linear displacement of the piping at the snubber location.

No excessive vibration or displacement was found during the test.

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FACILITY IJi)\\

STATUS

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RELEASED OF RELEASE AMOUNT OF ACTIVITY e EE L!.I@ W(§)I N/A 7

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10 11 PERSONNEL EXPOSURES t:;;:;..

NUMBER t:::;.. TYPE DESCRIPTION~

80 DISCOVERY DISCOVERY DESCRIPTION 32 METHOD OF

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NUMBER

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9 11 12 80 LOSS OF OR DAMAGE TO FACI LITV '4J' TYPE

DESCRIPTION

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ISSUEDt,;:;\\DESCRIPTION ~

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