05000369/LER-1981-071, Forwards LER 81-071/03L-0.Detailed Event Analysis Encl

Forwards LER 81-071/03L-0.Detailed Event Analysis Encl

ML20009F727
Person / Time
Site:	McGuire
Issue date:	05/26/1981
From:	Parker W DUKE POWER CO.
To:	James O'Reilly NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION II)
Shared Package
ML20009F728	List: 05000369/LER-1981-071, Forwards LER 81-071/03L-0.Detailed Event Analysis Encl 05000369/LER-1981-071-03, /03L-0:on 810426,while in Mode 4,initial Fuel Loading,Only Boration Flow Path Extended from Refueling Water Storage Tank to RCS Through Centrifugal Charging Pump 1B.Caused by Fully Open Valve.Valve Repositioned
References
NUDOCS 8107310467
Download: ML20009F727 (3)

LER-1981-071, Forwards LER 81-071/03L-0.Detailed Event Analysis Encl

Event date:
Report date:
3691981071R00 - NRC Website

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DUKE POWER COSIPANY PowEn Brttutxo

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WILLIsM C, PA R e( E R, J A, V<F PSESsDENT TELt#MONE ANCA 704 src.~a cosctc~

May 26, 1981 373-4o83 Mr. James P. O'Reilly, Director fg

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U. S. Nuclear Regulatory Commission

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101 Marietta Street, Suite 3100 g

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Atlanta, Georgia 30303 il J UL S 0 1931 * :T4 i'k u inca,are.s.m Re: McGuire Nuclear Station Unit I a::wmou s.

Docket No. 50-369

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Dear Mr. O'Reilly:

Please find attached Reportable Occurrence Report R0-369/81-71.

This report concerns less than two boration flow paths existing with RCS temperature above 300 F.

This incident was considered to be of no significance with respect to the health and safety of the public.

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V sy truly yours, y_

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William O. Parker, Jr.

RWO:pw Attachment cc:

Director Mr. Bill Lavallee Office of Management & Program Analysis Nuclear Safety Analysis Center U.S. Nuclear Regulatory Commission Post Office Box 10412 Washington, D. C.

20555 Palo Alto, CA 94303 Ms. M. J. Graham Resident Inspector - h1C McGuire Nuclear Station SIf/

8107310467 810526 PDRADOCK05000g S

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a' McGUIRE NUCLEAR STATION INCIDENT REPORT Report Number:

81-71 Report Date: May 26, 1981 Occurrence Date: April 26, 1981 Facility: McGuire Unit 1, Cornelius, N. C.

Identification of Occurrence:

Less than two boration flow paths existed with the Reactor Coolant System temperature above 300 F.

Condition Prior to Occurrence: Mucu 4, Reactor Coolant System temperature about 330 F.

Description of Occurrence:

It was discovered that no operable flow path existed from the Unit 1 Boric Acid Tank (BAT) to the Reactor Coolant System. Centri-fugal Charging Pump (NV) 1A was tagged out to comply with Technical Specification 3.1.2.4.

The only boration flow path was from the Refueling Water Storage Tank (RWST) to the Reactor Coolant System via NV Pump 1B.

Operators found that the boron concentration was decreasing in the Reactor Coolant System using the BAT and blender for makeup. After some investigative manipulations it was found that no boric acid was getting to the blender from the BAT.

The system was then declared inoperable (1730 hours0.02 days <br />0.481 hours <br />0.00286 weeks <br />6.58265e-4 months <br />, April 26, 1981).

Valve 1NV-392 (Boric Acid TK # 1 Recire. Orifice By-Pass) was fully open which reduced the Boric Acid Transfer Pump discharge pressure.

The resulting pressure was insufficient to deliver boric acid to the blender.

INV-392 (Boric Acid TK #1 Recire. Orifice By-Pass) was closed and the flow path from the BAT to the Reactor Coolant System was declared operable.

(1800 Hours, April 26, 1981)

Apparent Cause:

Valve INV-392 (Boric Acid TK #1 Recirc. Orifice By-Pass) was positioned incorrectly when the BAT was aligned for recirculation.

Analysis of Occurrence:

The operating procedure requires that 1NV-392 be throttled to maintain a Boric Acid Transfer Pump discharge pressure of 115 psig I

during recirculation.

This vould provide sufficient head to deliver 30 GPM to the blender if needed.

It appeared that 1NV-392 was placed in the fully open rather than throttled position when the BAT was placed in the recirculation mode earlier in the day.

This occurred shortly after a new batch of acid was i

added to the tank about 1200 hours0.0139 days <br />0.333 hours <br />0.00198 weeks <br />4.566e-4 months <br />.

Once 1NV-392 was closed, the minimum 30 GPM flow was verified to tae blender.

Safety Analysis

At least one boration flow path existed throughout the in-cident (RWST-NV Pump 1B-Reactor Coolant System). Another flow path was available l

until 1650 hours0.0191 days <br />0.458 hours <br />0.00273 weeks <br />6.27825e-4 months <br /> on April 26, 1981 (RWST-NV Pump 1A-Reactor Coolant System).

l Since at least one boration flow path was available and no reactivity changes occurred which required additional boration, the health and safety of the public were not affected by this incident.

If NC temperature had been above 350 F, both NV pumps would have remainc; operable along with their respective boration flow-paths from the RWST.

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Report Number 81-71 Page 2

Corrective Action

Valve INV-392 was repositioned which made the required boration flowpath operable again.

The operation procedure was chan;;ed to lock closed valve INV-392 to prevent a recurrence of this incident.

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