05000338/LER-1981-048-03, /03L-0:on 810603,visual Insp Revealed Snubber Reservoir Was Damaged & Empty of Fluid.Caused by Heat Damage to Oil Reservoir.Snubber Replaced & Modified by Moving Fluid Reservoir to Remote Location

/03L-0:on 810603,visual Insp Revealed Snubber Reservoir Was Damaged & Empty of Fluid.Caused by Heat Damage to Oil Reservoir.Snubber Replaced & Modified by Moving Fluid Reservoir to Remote Location

ML20005B094
Person / Time
Site:	North Anna
Issue date:	06/29/1981
From:	Cartwright W VIRGINIA POWER (VIRGINIA ELECTRIC & POWER CO.)
To:	NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION II)
Shared Package
ML20005B090	List: 05000338/LER-1981-048, Forwards LER 81-048/03L-0 05000338/LER-1981-048-03, /03L-0:on 810603,visual Insp Revealed Snubber Reservoir Was Damaged & Empty of Fluid.Caused by Heat Damage to Oil Reservoir.Snubber Replaced & Modified by Moving Fluid Reservoir to Remote Location
References
LER-81-048-03L, LER-81-48-3L, NUDOCS 8107060304
Download: ML20005B094 (2)

LER-1981-048, /03L-0:on 810603,visual Insp Revealed Snubber Reservoir Was Damaged & Empty of Fluid.Caused by Heat Damage to Oil Reservoir.Snubber Replaced & Modified by Moving Fluid Reservoir to Remote Location

Event date:
Report date:
3381981048R03 - NRC Website

text

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U.S. NUCLEAR REGULATORY COMMISSION LICENSEE EVENT REPORT CONTROL BLOCK / / / / / / / (1)

(PLEASE PRINT OR TYPE ALL REQUIRED INFORMATION)

/0/1/

/V/A/N/A/S/1/ (2)

/0/0/-/0/0/0/0/0/-/0/0/ (3)

/4/1/1/1/1 (4)

/ / / (5)

LICENSEE CODE LICENSE NUMBER LICENSE TYPE CAT 0/1/

/L/ (6)

/0/5/0/0/0/3/3/8/

(7)

/0/6/0/3/8/1/

(8) M6 /2 h 4 il / (9)

E DOCKET NUMBER EVENT DATE REPORT DATE EVENT DESCRIPTION AND PROBABLE CONSEQUENCES (10)

/0/2/

/ On Feb. 9, 1981 during Mode 5 operation a visual inspection of hydraulic snubbers /

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/ not accessible during reactor operation revealed that snubber (1-RC-HSS-861)

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/0/4/

/ reservoir was damaged and completely empty of fluid. The snubber was declared

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/ inoperable as required by T.S.3.7.10.

Since the snubber was repaired prior to

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/0/6/

/ Mode 4 operation, the health and safety of the public were not af.'ected.

The

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/ original Deviation Report submitted on 2-9-81 was lost.

It was at er a QC Audit /

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/ on 06-03-81 that this event was determined reportable as per T.S. 6.9.1.9.b.

/

SYSTEM

CAUSE

CAUSE COMP.

VALVE CODE CODE SUBCODE COMPONENT CODE SUBCODE SUBCODE

/0/9/

/C/A/ (11) /B/ (12) /A[ (13) /S/U/P/0/R/T/ (14) /D/ (15)

/Z/ (16)

SEQUENTIAL OCCURRENCE REPORT REVISION LER/R0 EVENT YEAR REPORT NO.

CODE TYPE NO.

(17) REPORT NUMBER

/8/1/

/-/ /0/4/8/

/\\/

/0/3/

/L/

L-f

/0/

l ACTION FUTURE EFFECT SHUTDOWN ATTACHMENT NPRD-4 PRIME COMP. COMPONENT TAKEN ACTION ON PLANT METHOD HOURS SUBMITTED FORM SUB. SUPPL 12R MANUFACTURER

/F[ (18) /Z/ (19) /Z/ (20) /2/ (21) /0/0/0/0/ (22) /Y/ (23) /N/ (24) /A/ (25) /G/2/5/5/ (26)

CAUSE DESCRIPTION AND CORRECTIVE ACTIONS (27)

/1/0/

/ The failure of this snubber was due to heat damage to the oil reservoir. The

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/1/1/

/ reservoir (LEXAN) had been located in a stagnant airflow area close to B Loop

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/1/2/

/ Steam Generator. The snubber was replaced and modified by moving the fluid

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/ reservoir to a remote location.

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/1/4/

/

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FACILITY METHOD OF STATUS

% POWER OTHER STATUS DISCOVERY DISCOVERY DESCRIPTION (32)

/1/5/

/G/ (28)

/0/0/0/ (29) /

NA

/ (30) /B/ (31) / PERIODCC INSPECTION

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ACTIVITY CONTENT RELEASED OF RELEASE AMOUNT OF ACTIVITY (35)

LOCATION OF RELEASE (36)

/1/6/

/Z/ (33)

/Z/ (34) /

NA

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/

NA

/

PERSONNEL EXPOSURES NLMBER TYPE DESCRIPTION (39)

/1/7/ /0/0/0/ (37) [Z[ (38) /

NA

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PERSONNEL INJURIES NUMBER DESCRIPTION (41)

/1/8/ /0/0/0/ (40) /

NA

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LOSS OF OR DAMAGE TO FACILITY 3)

TYPE

DESCRIPTION

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[Z[ (42) /

NA

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PUBLICITY ISSUED DESCRIPTION (45)

NRC USE ONLY

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/N/ (44) /

NA

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NAME OF PREPARER W. R. CARTWRIGHT PHONE (703) on-5151 8107060304 810629 PDR ADOCK 05000338 S

PDR

1 Virginia Electric and Power Ccapany North Anna Power Station, Unit 1 Attachment: Page 1 of 1 Docket No. 50-338 Report No. LER 81-048/03L-0

Description of Event

On February 9,1981 during an 18 month surveillance of inaccessible snubbers as required by T.S. 3.7.10, snubber 1-RC-HSS-861 was found to have a distorted fluid reservoir. As a result, the snubber was completely empty of fluid and was declared inoperable. Since the Deviation Report written at that time was lost, this event was not identified until the QC surveillance of completed maintenance reports was conducted on June 3, 1981. Subsequently, a Lost Document Form was submitted on 6-25-81.

I Probable Cont tences of Occurrence The affected snubber is located on Loop B RTD bypass line 1"-RC-1502-Q.

Without fluid in the reservoir, it was possible that the snubber could have lost it's ability to become a rigid strut when subjected to an excessive rate of movement due to seismic effects. Since the snubber was replaced and the redesign implemented prior to mode 4 operation, the health and safety of the public were not affected.

Cause of Event

The distortion of the Lexan reservoir tube and subsequent loss of snubber fluid was due to the reservoir being placed too close to B Loop Steam Generator. The heat from the Steam Generator support heaters and the RCS piping, combined with a lack of adequate air flow, caused the reservoir to overheat and distort.

Immediate Corrective Action

A spare snubber with a remote reservoir was tested and installed as per Engineering Work Request 81-230.

Scheduled Corrective Action No further corrective cction required.

Actions Taken to Prevent Reccurrence Additional inaccessible snubbers were examined to ensure that recurrence of this event will be prevented.

Generic Implications There are no generic implications resulting from this event.