ML20010H543

Forwards LER 81-142/03L-0.Detailed Event Analysis Encl

ML20010H543
Person / Time
Site:	McGuire
Issue date:	09/18/1981
From:	Parker W DUKE POWER CO.
To:	James O'Reilly NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION II)
Shared Package
ML20010H544	List: ML20010H543 ML20010H545
References
NUDOCS 8109240605
Download: ML20010H543 (2)

Text

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I DUKE POWER COhiPAN "IT POWEH UU11. DING 422 Sourit CnUHcu STHEET, CHAH1DTTE, N. C. as24a wf L LI AM O. PAR M E R, J R.

Vice P~tsscr~v TELt p.eo m t:Anta 704 s et.- e.oeuctio~ September 18, 1981 3 73-4c 83 Mr. J. P. O'Reilly, Director ,

U. S. Nuclear Regulatory Commission p Region II s/ g',@ '/'g 58 Tf,'hA 101 Marietta Street, Suite 3100 2/ q -}_t Atlanta, Georgia 30303 &l c.?

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Re: McGu.* e Nuclear Station Unit 1 -1bx g %, r

, Dock. No. 50-369 MY/ '

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Dear Mr. O'Reilly:

Please find attached Reportable Occurrence Report R0-369/81-142. This report concerns T.S.3.3.3.6, "The Accidents Monitoring Instrumentation Channels Shown-in Table 3.3-10 Shall Be Operable." This incident was considered to be of no significance with respect to the health and safety of the public.

Very truly yours,

/ '

William O. Parker, Jr.

PBN/smh Attachment cc: Director Mr. Bill Lavallee Office of Management and Program Analysis Nuclear Safety Analysis Center U. S. Nuclear Regulatory Commission Post' Office Box 10412 Washington, D. C. 20555 Palo Alto, California 94303 Ms. M. J. Graham Resident Inspector-NRC McGuire Nuclear Station

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8109240605 810918 PCR ADOCK 05000369 '

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McGUIRE-NUCLEAR STATION l

i REPORTABLE OCCURRENCE 1

REPORT NUMBER: 81-142 REPORT DATE: September 18, 1981-OCCURRENCE DATE: August = 19, 1981

FACILITY

McGuire-Unit 1; Cornelius, N.C.

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IDENTIFICATION OF OCCURRENCE: Both Channels of-the Post-Accident ContainmentL

• Sump Level Instrumentation indicated water levels when no water was in the sump, and were subsequently declared inoperable. The incident is reportable under the provisions of Technical Specification 3.3.3.6.

CONDITION PRIOR TO OCCURRENCE: Mode 2, Startup; conducting low power testing.

DESCRIPTION OF OCCURRENCE: Technicians found that the zero level outputs of the Barton,.Model 386 transmitters varied with the bellows sensor housings installed <

and removed. The bellows were noted to be expanded excessively such that the walls of the housing prevented'the free movement of the bellows.

APPARENT CAUSE OF OCCURRENCE: The zero level outputs of the containment' sump level transmitters had shifted and caused the transmitters to-be out of cali-

.bration over their entire range.

ANALYSIS OF OCCURRENCE: The instruments were functioning in a much higher tem-

. perature environment than the original installation conditions; this caused the I fluid filled bellows assembly to expand and contact the housing walls.

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SAFETY ANALYSIS: This was a common cause failure of accident monitoring instru-mentation. The transmitters involved provide no safety related function and are not necessary for accident mitigation; therefore, the inoperability of this equip-ment had no effect on safe plant operation, or the health and safety of the public.

The operability of accident monitoring instrumentation ensures that sufficient in-formation is available on selected plant parameters to monitor and assess the variables following an accident. The containment sump level transmitters failed j at near normal containment operating conditions. The question rises as to whether

! these instruments can survive the extreme conditions postulated for a post-accident environment. The matter has been referred to~ Duke Power Company Design Engineering

-Department--for further analysis and determination of the necessity for a nuclear i station modification considering the immediate corrective action that was taken.

CORRECTIVE ACTION: The interiors of the sensor bellows housings were bored or machined down to a tolerance necessary for.the free movement of the bellows.

This action proved successful in relieving the interference problem. The instru-ments were then recalibrated and placed back in service on August:21, 1981.

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