ML20039D804

Second Interim Deficiency Rept Re Failure of Reactor Protection Sys Following Secondary High Energy Line Rupture, Initially Reported on 800707.Ref Leg Will Be Insulated to Minimize Heatup.Final Rept Will Be Submitted by 830601

ML20039D804
Person / Time
Site:	Harris
Issue date:	12/23/1981
From:	Chiangi N CAROLINA POWER & LIGHT CO.
To:	James O'Reilly NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION II)
References
10CFR-050.55E, 10CFR-50.55E, NUDOCS 8201060178
Download: ML20039D804 (4)

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' - C96h ' ? t- D e rWetAd.lhht Company December 23i 1981 UI DEC 30 a g *, b 4 File: SH N-2/18 Item 41 Mr. James P. O'Reilly e Q-United States Nuclear Regulatory Canmission g x \

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101 Mariett a Street, Northwest p n, '\\

Atlanta, Georgia 30303 .~ '

JAft e SHEARON HARRIS NUCLEAR POWER PLANT 4 ta; 21 I DOCKET NOS. 50-400 AND 50-401 POTENTIAL SIGNIFICANT FAILURE OF THE REACTOR <

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PROTECTIGi SYSTEM FOLLOWING A SECONDARY HIGH ENERG N LINE RUPTURE (STEAM GENERATOR REFERENCE LEG HEATUP) 4'ITO \ /,

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Dear Mr. O'Reilly:

Attached is the second interim report on the subject item which was deemed as reportable on July 7,1980. As stated in the report, completion of corrective action and submittal of the final report is projected for June 1,1983, for Unit 1. Corrective action date for Ur.it 2 will be provided later.

RDB/gea Yours very truly, Attachment cc: Mr. G. Maxwell W/A .

Mr. V. Stello (2) W/A ,

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N. . Chidngi - Manager Enginee & Construction Quality Assurance / Quality Control s o 00 0FSMAL COPV, .

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411 Fayetteville Street

• Pc O. Box 1551

• Raleigh, N. C. 27602 mm.2WWF.*amwn 0VvE.n7

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SHNPP Unit Nos. l'and 2 Potential Significant Failure of the Reactor Protection System Following a Secondary High Energy Line. Rupture

.(Steam Generator Reference Leg Heatup)

Interim Report'#2 December 15, 1981 Reportable Under 10CFR50.55(e)

Prepared by CP&L t

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SUBJECT:

10CFR50.55(e) Reportable Item Shearon Harris-Nuclear Power Plant Potential Significant Failure of the Reactor Protection.

-System Following a Secondary High Energy Line Break (S/G

_ Reference Leg Heatap)

ITEMS: Steam Generator Level Measurement for SHNPP Units I and 2

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SUPPLIED BY: Westinghouse Water Reactor Division NATURE OF DEFICIENCY: Westinghouse notified the NRC under 10CFR21 in June 1979 of a.potentially significant failure of the reactor protection system following a secondary high energy line break. Such a break within containment could result.in the heatup of the steam generator level measurement reference resulting in the delay of protection signals.

DATE PROBLEM WAS CONFIRMED TO EXIST: Westinghouse Letter CQL-5801 dated March 20, 1980, received March 28, 1980 PROBLEM REPORTED: N. J. Chiangi notified the NRC.(Mr. J. Bryant) that this item was reportable under 10CFR50.55(e) on July 7,1980.

CP&L letter dated July 8, 1980 N. J. Chiangi to J. P. O'Reilly transmitting an interim report.

SCOPE OF PROBLEM: To prevent erroneous signals to the reactor protection system from the steam generator level measurement system due to heatup of the steam generator reference leg.

~ REASON PROBLEM IS REPORTABLE: Potential for the. steam generator level measurement system to provide erroneous signals to the reactor protection system due to severe density changes in the steam generator reference leg. This condition could lead --

to a degraded safety condition.

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' CORRECTIVE ACTION:' Westinghouse advised CP&L that-a hr*Jware fix would be available by. late 1981 and that.the Westinghouse effort was being directed toward a mechanical scheme which involved installing a sealed. reference leg with a spring arrangement that would provide the necessary compensation without external hardware. No such scheme has been

. presented to CP&L by Westinghouse to.date. However, CP&L was advised by Westinghouse (D. McCarthy, CP&L by R. Hayford, Westinghouse)'that the current Westinghouse' recommendation-is for CP&L to insulate the reference leg to minimize the reference leg heatup for at least five (5) minutes following a secondary high energy line' break. The' low-low steam generator-water level trip setpoint would also need to be adjusted to incorporate the additional inaccuracies due to high containment temperatures. A Westinghouse position for the SHNPP project is expected by April 1982, and the completed correction action should be installed on Unit 1-by June 1983.

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