ML19350C787

LER 81-004/03L-0:on 810324,during Refueling Interval Functional Testing of Hydraulic Snubbers,Snubber RC-21/MUE-43 Discovered W/Shipping Plug Installed in Fluid Reservoir Vent Port.Caused by Procedure Violation

ML19350C787
Person / Time
Site:	Three Mile Island
Issue date:	03/30/1981
From:	Mitchell D METROPOLITAN EDISON CO.
To:	NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION I)
Shared Package
ML19350C778	List: ML19350C777 ML19350C787
References
LER-81-004-03L-01, LER-81-4-3L-1, NUDOCS 8104060699
Download: ML19350C787 (3)

Text

1.nclosure 1 L1L 094 U. S NUCLEAA REGULATO3Y ConansissioN stAC 5OIM 364 O am 1.lCENSEE EVENT REPORT

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o 12 l lWhile in the cold shutdown condition durin2 refueline inte-val functienn! t e e - 4 ~- !

[TTTI pf hydraulic snubbers, it was discovered that snubber RC-2) /vi'r-4 3 knd n shiopine nibg j o i j linstalled in the fluid reservoir vent oort. Because no severe transients occun-ad I no sieniffe,nt occ r-a.cas 1 l o 6 s ! tuhich could have caused unrestrained nine rocion, J

i o g i ]resulted f rom the inoperable snubber.

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cAust ossCRIPTICN ANC CORRECTIVE ACTIONS h The vm + en e h- o % e I I$ i o l 1 Procedure violation was the root cause of this event.

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[TTTl I contractor. The clue was replaced vi*h n va.. ,m, All safety related snubbers will be visua11v insoected 1 g i notified of the event.

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Enclosure 2

. - L1L 094 NARRATIVE REPORT TMI-1 LER 81-04/03L-0 I. Current Activities at the Time of the Occurrence Functional Testing of hydraulic snubbers in accordance with Sur-veillance Procedure 1303-9.9 was in progress.

II. Leading Circumstances While performing testing of hydraulic snubbers on February 23, 1981 in accordance with SP 1303-9.9, snubber RC-21 was discovered to have a shipping plug installed in the fluid reservoir vent port.

III. Description The Unit has been in extended cold shutdown conditions since April, 1979. The snubber failed during refueling interval functional testing which was being performed to satisfy Technical Specification 4.17.4 requirements. Contrary to the Maintenance Procedure checklist, this snubber was reinstalled in 1978, without the proper vent plug being installed. This item is cansidered reportable under Technical Specification 6.9.2.B(2).

IV. Resultant Events Since there has been no earthquake or severe transient which would have caused unrestrained pipe motion under dynamic loading no significant occurrences have taken place as a result of this snubber failure.

Previous Events of Similar Nature V.

None Documented.

. VI . Root Cause The root cause of improper installation has been determined to be a procedure violation. The " Snubber Installation" section of Maintenance Procedure 1410-Y-34 lists several actions to be performed upon installation. Item 3 reads " Remove shipping plug, install vent i plug. ( ) Satisfactory ( ) Unsatisfactory". This form was completed,. Item 3 was checked Satisfactory, and a signature and date was affixed by the maintenance man who performed the installation.

The procedure and training have been reviewed and have been found to be adequate.

VII. Immediate Corrective Action

1) The shipping plug was replaced with a vent plug, other minor repairs and adjustments -were made and snubber RC-21 was func-tionally tested in accordance with the Procedure. Additional

. snubbers were tested to comply with Technical Specification 4.1724.

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2) Management of the Contractor has been informed of this finding.

Although the employee having had committed the violation is no longer employed onsite, the Contractor has committed to require future procedure verification signatures be made only by supervisors (independent of the installer).

Long Term Corrective Action

1) All safety related snubbers which have not been functionally tested recently will be visually inspected by May 1, 1981 to verify that there are no other in-service snubbers with shipping plugs installed in place of vent plugs.

2) The functional testing procedure will be modified by June 1,1981 with instructions to verify that a shipping plug is not installed prior to testing the snubber for personnel safety reasons.

VIII. Component Failure Data Basic Engineers - BE-410 Hydraulic Shock and Sway Suppressor 3/4" x 5" stroke Marl. No. RC-21.

LK. Subsequent Findings As a result of- the inspection begun to comply with long-term corrective action (Item 1) above', Snubber MUE-43 was discovered to have a shipping plug installed in the fluid reservoir vent port on March 19, 1981.

The 'TMI-l Snubber History indicate that MUE-43 was last installed (following removal) on May 12, 1977. At that time, the " Snubber Installation" section of Maintenance Procedure 1410-Y-34 did not exist and there was no formal document that verified removal of shipping plugs other than the work package used for installation.

- The. immediate corrective action for MUE-43 will be to replace the shipping plug with a vent plug. The snubber does not need to be repaired because

the cold piston setting and hot piston setting are the same (meaning the piston does not change positions under normal service). Since there

-is no. thermal pipe movement and since there has been no earthquake or l severe transient which would have caused unrestrained pipe motion under dynamic londing significant occurrences have taken place as a result of MUE-43 vent port condition.

The long-term corrective action of'Section VII above remains unchanged.

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