05000369/LER-1981-090, Forwards LER 81-090/03L-0.Detailed Event Analysis Encl

Forwards LER 81-090/03L-0.Detailed Event Analysis Encl

ML20009G104
Person / Time
Site:	McGuire
Issue date:	06/25/1981
From:	Parker W DUKE POWER CO.
To:	James O'Reilly NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION II)
Shared Package
ML20009G105	List: 05000369/LER-1981-090, Forwards LER 81-090/03L-0.Detailed Event Analysis Encl 05000369/LER-1981-090-03, /03L-0:on 810530,while Entering Mode 3,S/G 1B Wide Range Level Instrumentation Pegged High.Caused by Equalizer Valve on Transmitter 1CFLT5620 Valving Open,Resulting in Drained HP Ref Leg.Valve Closed & Leg Filled
References
NUDOCS 8108030331
Download: ML20009G104 (3)

LER-1981-090, Forwards LER 81-090/03L-0.Detailed Event Analysis Encl

Event date:
Report date:
3691981090R00 - NRC Website

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Mr. James P. O'Reilly, Director

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Dear Mr. O'Reilly:

(.a l N Please find attached Reportable Occurrence. Report.R0-369/81-90.

This report concerns Technical Specification 3.3.3.5; "The Remote Shutdown. Monitoring In-strumentation Channels shall be Operable with. Readouts Displayed External to the Control Room." This incident was considered to be of no significance with respect to the health and safety.of the public.

V y truly yours,

..._O.g William O. Parker, Jr.

PBN:pw Attachment ec: Director

'Er. Jill 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, California 94303 Ms. M. J. Graham Resident Inspector - NRC McGuire Nuclear Station SI I 1

8108030331 810625 PDR ADOCK 05000369 S.

PDR 1

r-I McGUIRE NUCLEAR STATION INCIDENT REPORT LER/R0 Report Number:

81-090/03L-0 Report Date: June 25, 1981 Occurrence Date:

May 30, 1981 Licensee:

Duke Power Company Facility:

McGuire Unit 1, Cornelius, N. C.

Docket No.:

05000369 Identification of Occurrence:

The Steam Generator (S/G) "1B" level instrumen-tation for Remote Shutdown Monitoring was declared inoperable.

Condition Prjor to Occurrence:

Mode 3, Hot Standby Description of Occurrence:

On May 30, 1981 at 2000 hours0.0231 days <br />0.556 hours <br />0.00331 weeks <br />7.61e-4 months <br />, the S/G "1B" wide range level instrumentation was declared ipoperable.

The S/G "1A" and "1B" widt range level recorder in the Control Room and the S/G 1evel indicators on the Auxiliary Feedwater Pump (AFP) A Panel, Auxiliary Feed. water Pump Turbine Panel and Stsndby Shutdown Facility (SSF) Panel, respectively, had been pegged high.

The instruments were declared inoperable because Unit 1-was entering Mode 3 from Mode 4.

This was a reportable incident pursuant to Technical Specification 3.3.3.5.

Apparent Cause of Occurrence:

S/G."1B" wide range level is monitored by two transmittere, ICFLT5620 and ICFLT6090.

1CFLT5620 supplies a signal (4-20 ma) to the Process Control Cabinets.

From these cabinets, a signal is sent to the AFP Panels indicators, recorder and the computer.

ICFLT6090 provides a signal to the indicator in the SSF Panel.

These indicatars and recorder were pegged high because both of tha level transmitters were valved out.

ii.e equalizer valve on cransmitter ICFLT5620 was open causing the nigh pressure (HP) re-ference leg to drain out.

Both transmitters were supplied by ecmmon HP/LP reference legs.

Analysis of Occurrence: On May 12, 1981, a work request was initiated to in-vestigate and repair the S/G "1B" wide range level instrumentation which had failed high. On May 30, 1981 at 2000 hours0.0231 days <br />0.556 hours <br />0.00331 weeks <br />7.61e-4 months <br />, Unit I was entering Mode 3 from Mode 4 but the S/G "1B" wide range level instrumentation trouble had not been fixed. Hence, the Shift Supervisor declared the instrument inoperable per Technical Specification 3.3.3.5.

On June 1, 1981 at 0239 hours0.00277 days <br />0.0664 hours <br />3.95172e-4 weeks <br />9.09395e-5 months <br />, Unit I went down to Mode 4 from Mode 3 (due to non-related reason).

Personnel found that the equalizer valve on transmitter ICFLT5620 had been valved open.

This re-sulted in draining of the HP reference leg to a level equal to the S/G level which in turn caused the indicators and recorder to fail high.

It is unknown how th? equalizer valve was lef t open. The equalizer valve was closed and the EP reference leg was filled. The transmitters were valved in and the instruments were checked for proper operation. The S/G "1B" wide range level instrumentation was declared operable on June 3, 1981 at 0100 hours0.00116 days <br />0.0278 hours <br />1.653439e-4 weeks <br />3.805e-5 months <br />.

6 LER/R0 Report Number:

81-090/03L-0 Page 2

Safety Analysis

The S/G wide range level transmitters send signals to the remote indicators to provide S/G 1evel indication outside the Control Room.

Thase instruments serve as the only S/G 1evel indicators should it become necessary to evacuate the Control Room to the Auxiliary Shutdown Panel. There are several S/G narrow range level indicators in the Control Room. The narrow range transmitters are also used to provide control signals to the Reactor Prot *.ction ani Control Cabinets and to the accident monitoring instrumentation.

Since the Control Room was available at the time the S/G "1B" wide range level instrumentation was inoperable, the safe operation of the :.3 ant and the health and safety of the public were not affected.

Corrective Action

A work request was initiated to troubleshoot the failed.

instruments.

Personnel filled the partially drained HP reference leg and clesed the equalizer valve.

The instruments were checked for proper operatioa.

The. S/G "1B" wide range level instrumentation was declared operable on June 3, 1981 at 0100 hours0.00116 days <br />0.0278 hours <br />1.653439e-4 weeks <br />3.805e-5 months <br />.

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