ML20211H359

Final Deficiency Rept (55(e)-86-06) Re Rosemount Loose Environ Seal Installations.Initially Reported on 860506. Loose Fittings & All Units w/90-degree Fittings Will Be Modified Prior to Fuel Load

ML20211H359
Person / Time
Site:	Nine Mile Point
Issue date:	06/05/1986
From:	Mangan C NIAGARA MOHAWK POWER CORP.
To:	Starostecki R NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION I)
References
(55(E)-86-06), (55(E)-86-6), (NMP2L-0734), (NMP2L-734), NUDOCS 8606230479
Download: ML20211H359 (2)

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NUMOHAWK NIAGARA MOHAWK POWER CORPORATION /300 ERIE BOULEVARD WEST. SYRACUSE. N.Y.13202/ TELEPHONE (315) 474-1511 June 5, 1986 (NMP2L 0734)

Mr. R. W. Starostecki, Director U.S. Nuclear Regulatory Commission Region I Division of Reactor Projects 631 Park Avenue King of Prussia, PA 19406 Re: Nine Mile Point - Unit 2 Docket No. 50-410

Dear Mr. Starostecki:

Enclosed is a final report, in accordance with 10CFR50.55(e), for the problem concerning Rosemount loose environmental seal installations. This problem was reported via tel-con to G. Meyer of your staff on May 6,1986.

Very truly yours, C

Senior Vice President CVM/GG/cla (1590H)

Enclosure xc: Director of Inspection and Enforcement U.S. Nuclear Regulatory Comraission Washington, DC 20555 R. A. Gramm, NRC Senior Resident inspector NMPC Project File 1

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NIAGARA M0 HAWK POWER CORPORATION NINE MILE POINT - UNIT 2 DOCKET N0. 50-410 Final Report for a Problem Concerning Rosemount Loose Environmental Seal Installations (55(e)-86-06)

Description of the Problem Four Rosemount environmental seals were identified as being loose at the interface with their respective instruments. Due to a concern that this condition was not limited to these four devices, a 100-percent reinspection was performed on all rack-mounted devices with Rosemount seal s presently installed. The inspection identified 77 additional loose seals where 90-deg conduit fittings were utilized.

All of these installations had been previously accepted by Field Quality Control .

The 90-deg conduit fitting utilized has tapered threads with only four threads present. When tightened to the point of seating, the fittings coul d be located in such a direction that the installation is misaligned. In some cases, the environmental seal and flex conduit would be exposed to traffic conditions and which in some cases would interfere with the installation of the adjoining connection. When the environmental seal is installed without this fitting, a loosening condition does not exist.

Analysis of Safety Implications The loose seals could cause degradation of the accuracy of the reactor trip system as well as other related systems due to intrusion of adverse environments into the instruments following an accident. This degradation of accuracy could delay or prevent initiation of protective actions required to mitigate the accident. Thus, if left uncorrected, this condition coul d adversely affect the safety of operations of the plant.

Corrective Action The original 4 loose fittings will be modified per Nonconformance and Dispo-sition Report No. 14791. The 77 additional loose fittings will be modified per Nonconformance and Disposition Report No.15610. Since the rack mounted Rosemount transmitters with 90-degree fittings appear to loosen easily, all these units with the 90-degree fittings will be modified. This modification will be completed prior to fuel load.