ML19326A337

LER 78-050/03L-0:on 780509,excessive Leakage Found in Vacuum Relief Valve Cv 5070 During Leak Rate Test.Caused by Installation of Defective Test Connection Piping.Patch Weld Found Defective.Test Connection Piping Replaced

ML19326A337
Person / Time
Site:	Davis Besse
Issue date:	06/05/1978
From:	David Brown, Cedaz R TOLEDO EDISON CO.
To:	NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION III)
Shared Package
ML19326A305	List: ML19326A304 ML19326A337
References
LER-78-050-03L, LER-78-50-3L, NUDOCS 8002030155
Download: ML19326A337 (3)

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1o: 21l At 1330 hours0.0154 days <br />0.369 hours <br />0.0022 weeks <br />5.06065e-4 months <br /> on 5/9/78, contain=ent Vacuu Relief valve CV 5070 was found to have 3 l

l c 131' l excessive leakage during the perfor=ance of the Local Leak Rate Test. Also, one I o I .: 1 I valve flange bolt was found loose. There was no danger to the health and safety of I l l

l o i s i I the public or unit personnel; The unit was in a shutdown condition. Overall allowa- l  !

i I o I61 I ble leakage for conttin=ent was not exceeded. No core alterations or novement of I I l l o 6 7 I I irradiated fuel within containment took olace while CV 5070 vas inecerable.

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CAUSE DESCRIPTION AND COA AECTIVE ACTIONS l 3 , o g l Initial installation of the test connection piping was defective. The veld had been l 1

.faintenance personnel rer:oved

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[,,,, j ground down too far and the patch veld was defective.

,, ,,, ,the test connection piping, installed a new elbow and replaced the test connection I g,,3g l piping. Valve CV 5070 was retested per the Local Leak Rate Test, and the results l l 1

,. , , , , [were acceptable. CV 5070 was declared operable at 1000 hours0.0116 days <br />0.278 hours <br />0.00165 weeks <br />3.805e-4 months <br /> on Mav 11, 1978. I j 80 7 8 9 F ActuTY ' ETHOO C8 2

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TOLEDO EDISON CO}?ANY A DAVIS-BESSE UNIT ONE NUCL7_AR POWER STATION SUPPLEMENTAL INTORLiTION FOR LER NP-33-78-60 fV) ,

i DATE 07 EVENT: May 9, 1978 TACILITY: Davis-Besse' Unit 1 IDENTITICATION OF OCCURRENCE: Contain=ent'Vacue= Relief Valve CV 5070 was declared inoperable due to excessive leakage Cenditiens Prior to Occurrence: The unit was in Mode 6, with Power (MITI) = 0 and Load'CCiE) = 0.

, Descriotion of Occurrence: At 1330 hours0.0154 days <br />0.369 hours <br />0.0022 weeks <br />5.06065e-4 months <br /> on May 9, 1978, Containnent Vacuum Relief Valve CV 5070 was found to have excessive leakage during the perfor=ance of Surveil-lance Test ST 5061.02, " Local Leak Rate Test". The valve was declared inoperable.

A pin hole leak was found in the weld on the elbow of the 3/4" test connection pip-ing. Also, one valve flange bolt was found loose.

This occurrence is being reported as a co=ponent failure.

Designation of Accarent Cause of Occurrence: Initial installation of the test connec-tion piping was def ective. It could be seen where weld had been ground down too far and the patch veld was. defective.

Leakage was not excessive during initial LLRT (August 1976) or during subsequent LLRT (May 1977), but the leakage did increase.

Analvsis of Occurrence: There was no danger to the health and safety of the public or to unit personnel. The unit was in a shutdown condition. Overall allowable leakage for~containnent was not exceeded. No core alterations or =ovenant of irra-diated fuel within containment took place while CV 5070 was inoperable.

Corrective Action: Maintenance personnel checked the packing and tightened the loose flange helt on CV 5070 and cleaned the valve seat on the boundary check valve CV $080 per Maintenance Work Order 78-1183. Maintenance personnel renoved the test connection piping, installed a new elbow and replaced the test connection piping per Maintenance Work Orders 78-1185 and 78-1189.

Valve CV 5070 was retested per ST 5061.02, " Local Leak Rate Test", and the results

< were acceptable. CV 5070 was declared operable at 1000 hours0.0116 days <br />0.278 hours <br />0.00165 weeks <br />3.805e-4 months <br /> on May 11, 1978. .

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j Failure Data: There hate been no previous similar occurrences.

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