05000278/LER-1983-007, Forwards LER 83-007/01T-0.Detailed Event Analysis Submitted

Forwards LER 83-007/01T-0.Detailed Event Analysis Submitted

ML20072Q610
Person / Time
Site:	Peach Bottom
Issue date:	03/17/1983
From:	Cooney M PECO ENERGY CO., (FORMERLY PHILADELPHIA ELECTRIC
To:	Haynes R NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION I)
Shared Package
ML20072Q615	List: 05000278/LER-1983-007, Forwards LER 83-007/01T-0.Detailed Event Analysis Submitted
References
NUDOCS 8304050258
Download: ML20072Q610 (4)

LER-2083-007, Forwards LER 83-007/01T-0.Detailed Event Analysis Submitted

Event date:
Report date:
2782083007R00 - NRC Website

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. l PHILADELPHIA ELECTRIC COMPANY 2301 MARKET STREET P.O. BOX 8699 PHILADELPHIA PA.19101 12158841 4000 March 17, 1983 Mr. R. C. Haynes, Administrator Office of Inspection and Enforcement U.S. Nuclear Regulatory Commission 631 Park Avenue King of Prussia, PA 14406

SUBJECT:

Licensee Event Report Narrative Description

Dear Mr. Haynes:

The following occurrence was reported to Mr. A. R.

Blough, Region I, U.S. Nuclear Regulatory Commission on March 3, 1983.

Reference:

Docket No.50-27A Report No.: 3-83-07/lT-0 Report Date: March 17, 1983 l Occurrence Date: March 3, 1483 Facility: Peach Bottom Atos.ic Power Station R.'J. #1, Delta, PA 17314 Technical Specification

Reference:

Technical Specification 3.8.B.4 states that "During l release of radioactive wastes, the following conditions shall be l met: i

a. The minimum dilution water required to satisfy 3.8.B.1 shall be met.

8304050258 830317 PDR ADOCK 05000279 7 PDR S [J d

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b. The gross activity monitor and flow monitor and their respective recorders on the waste effluent ,

line shall be operable.  !

c. The effluent control monitor shall be set to alarm and autmaatically close the waste discharge valve prior to exceeding the limi5.s specified in 3.8.B.1 above.

I Description of the Event:

a On March 3, 1983,.at approximately 7:07 PM during the Unit 3 refueling outage, an inadvertent initiation of the 3A and 3B RHR pumps transferred approximately 65,000 gallons of water from the torus into the reactor. The initiation was a false low reactor water level signal which was present for less than 3.5 seconds. The protective logic responded as if a true low level signal was present. Therefore, the automatic actions associated with a true LOCA signal occurred. Accordingly, the operating 3B recirculation pump tripped, the El and E4 diesel-generators started, the 3A and 3B RHR pumps started and the injection valves opened, recirculation pump discharge valves closed, and the HPSW pumps trioped. At the time of the occurrence, the E-2 diesel generator was already running, for reliability reasons, with the

E-3 diesel generator blocked for maintenance. Because the

. initiating low level signal cleared within 5 seconds, the LOCA

looic sequence did not continue.

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After the occurrence, the E-2 diesel generator LOCA signal, which can only be reset by removing the diesel from

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service, remained sealed in. This signal also removes the diesel's Cardox system automatic initiation feature. A fire i'

watch was posted when this fact was recognized until the LOCA signal reset was achieved.

Because the unit was in refueling, with the reactor cavity flooded, most of the water overflowed onto the fuel floor-and down the main hatchway to elevation 135 feet where approximately 50 gallons' flowed out of' the building under the railroad door and into the storm drain system.

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i Mr. R. C. Haynes Page 3 Probable Consecuences of the Occurrence:

, Upon discovery of the incident, personnel in the Unit 3 Reactor Building and drywell exited'the area. There were no personnel exposures as a result of the flooding. The man-rem i dose associated with the clean-up effort resulting from this occurrence is estimated to be less than two man rem.

A _ sample of the water taken at' the railroad door measured 1.67x10N3 uCi/ml, with the total release estimated at 316 uCi. The primary isotopes involved were I-131, Zn-65, Cs-134, Cs-137 and Co-60. Concentrations of these isotopes respectively represent approximately 14.5, 14.1, 4.4, 4.3 and 2.9 times the maximum permissible concentrations. Samples taken from the storm drain system along the discharge route to the river indicated decreasing activity. Samples taken at the discharge to the river indicated no detectabis activity due to the dilution cf the small amount of radioactive water by the normal-flow in the storm drain systen.

1 Cause of the Occurrence:

l The cause of the sensed low level which initiated the LOCA signal was a pressure surge in the reference leg of the 2B Yarway Instrumentation loop during surveillance testing.

Corrective Action:

When the water from the reactor cavity-and spent. fuel pool began flooding the refuel floor, personnel in the Unit 3 Reactor Building and drywell exited the area. The 3A and 3B RHR pumps were manually tripped within approximately 4 minutes and the RHR injection valves were manually closed. The torus header valve and full flow test valve were manually opened, along with the manual discharge valve to the condensate storage tank from the reactor water cleanup-system letdown to restore reactor water level to within shutdown range.

l Immediate actions were taken to assess potential leakage l paths to the environment. The water flow to the drain si' stem at the railroad door at elevation 135 ft. was halted. Sampling of the water at various locations along the storm drain flow path i

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• Mr. R. C. Haynes Page 4 was begun. The water in the catch basin at the railroad door was pumped out for processing as liquid radwaste.

Clean-up and decontamination was initiated in the Unit 3 reactor building and refuel floor.

The function of the diesel generator MCA relay upon receipt of a LOCA initiation signal will be discussed with shift operations during the shift meecings.

Very truly yours, h/f y Y M.J. Cooney Superintendent Nuclear Generation Division cc: Document Control Desk Nuclear Regulatory Commission Washington, DC 20555 Mr. A. R. Blough Site Inspector P.O. Box 399 Delta, PA 17314-0399 1

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