ML19351A169

Significant Deficiency Rept 370/81-05 Re safety-related Containment Isolation Valves 2NI264,2NI266 & 2NI267 Type C Leakage,Initially Reported on 810522.Damaged Soft Seat Disc Assembly or Valves to Be Replaced Before 820601

ML19351A169
Person / Time
Site:	Mcguire
Issue date:	06/19/1981
From:	Parker W DUKE POWER CO.
To:	James O'Reilly NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION II)
References
10CFR-050.55E, 10CFR-50.55E, NUDOCS 8106260175
Download: ML19351A169 (2)

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DUKE power COMPANY Powna Duttonwo 422 SouTn C: Uncu STazer, CilAHLOTTe. N. C. asa4a wiLLaAM O. PA R K ER, J R.

.NoCr P#ttact=, IEkCPmossC: Asta 704 s e c.- P.oosevio- June 19, 1981 3 ' 3-*o e s

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Mr. James P. O'Reilly, Director g

U. S. Nuclear Regulatory Commission _

Region II -

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101 Marietta Street, Suite 3100 p'- u p mances klI Atlanta, Georgia 30303 N '" " '

Re: McGuire Nuclear Station Unit 2 N '

Docket No. 50-370 -

Dear Mr. O'Reilly:

Pursuant to 10CFR 50.55e please find attached Significant Deficiency Report SD 370/81-05.

Ver truly yours,

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William O. Parker, Jr.

RWO:smh Attachment ec: Director Ms. M. J. Graham Office of Inspection & Enforcement Resident Inspector U.S. Nuclear Regulatory Commission McGuire Nuclear Station Washington, D. C. 20555 8106260f${ -

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MCGUIRE NUCLEAR STATION INCIDENT REPORT Report Number SD 370/81-05 Report Date: June 19,1981 Facilfty: McGuire Nuclear Station Unit 2 Identification of Deficiency: Safety Related Containment Isolation Valves 2NI264, 2NI266, 2N1267 Type C leakage deficiency was repcrted to Art Johnson of the NRC Region II on May 22, 1981.

Identification of Deficiency: During the secondary UHI accumulator check valve testing on valves 1NI248 and 1NI249 to verify Reactor Coolant System pressure boundary integrity, the containment isclation valve 1NI264, 1NI266 and INI267 were used as system isolation valves and experienced reverse pressurization of approximately 2485 PfIG. This reverse pressurization resulted in an equivalent seating _ torque in excess of design requirements for the containment isolation function for valves 1NI264,1NI266 and 1NI267. As

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a result,.the soft seats were damaged to a point such that subsequent Type C testing results exceeded containment-isolation leakage criteria. Similar-valves are assigned for the Unit 2 applications and are susceptible to the same cype of damage as experienced on Unit 1.

Analysis of Safety Implications: Had this deficiency not been identified, containment isolation leakage could have exceeded 10CFR50, Appendix J requirements under certain postulated accident conditions.

Corrective Action: This problem will be resolved by replacing the damaged soft seat disc assembly with a new type soft seat disc assembly designed for these conditions or the valves will be replaced with hard seated valves. This action is scheduled to be completed by June 1,1982. Duke is reviewing similar applications on other nuclear stations to preclude this problem. Should any problem be discovered, Duke will notify NRC.

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