PNO-III-87-031A, updates Four Possible Equipment Tampering Incidents at Plant.No Final Conclusions Reached Following Interviews W/About 140 Plant Workers.On 870306,mgt Reacted to Rept of Hoax Explosive Device at Plant.Workers Suspended

PNO-III-87-031A:updates Four Possible Equipment Tampering Incidents at Plant.No Final Conclusions Reached Following Interviews W/About 140 Plant Workers.On 870306,mgt Reacted to Rept of Hoax Explosive Device at Plant.Workers Suspended

ML20205J668
Person / Time
Site:	Dresden
Issue date:	03/27/1987
From:	Axelson W, Creed J NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION III)
To:
References
PNO-III-87-031A, PNO-III-87-31A, NUDOCS 8704010381
Download: ML20205J668 (2)

PRELIMINARY POTIFICATION OF EVENT OR UhUSUAL OCCUPPENCE--PNO-III-87-31A Date March 27, 1987 ,

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This preliminary r.otification constitutes EARLY notice of events of POSSIBLE safety or public interest significance. The information is as initially received without varification or evaluation, and is basically all that is known by the Region III staff on this date.

Facility: Ccnronwealth Edison Company Licensee Emergency Classification:

Dresden Unit 2 Pctification of an Unusual Event Morris, IL 60450 Alert Site Area Energency Pocket No. 50-237 Ger.eral Emergency X Not Applicable

Subject:

FOSSIBLE EQUIPPENT TAMPERING----(UPDATE)

The licensee is completing its investigation of circumstances surrounding potential tampering incidents that were identified at the plant (see PNO-III-87-31). In sumary, the licensee's team investigation reviewed four events initially. One event involved loose bolts on a diesel generator cooling pump being found twice; and the second involved loose bolts on the diesel generator heat exchanger. Later, the licensee included a review of a mispositioned breaker on a reactor protecticn PG set and loose bolts on a drywell hatch. l The unit was in cold shutdown for a refueling outage throughout the investigation.

Most of the investigation has been completed, including interviews with about 140 plant workers. The licensee has indicated that no firal conclusions have been reached. However, two incidents (the heat exchanger loose bolts and the drywell hatch bolts) appear to have explanations that discount tampering. The two other incidents have less clear explanations, so the possibility of deliberate tampering has not been ruled cut. The remaining incidents, wh ther tarrering or pccr maintenance practices, have been determined to indicate no intention to harm plant operations.

I Coincidentally, on March 6,1987, the licensee's mar.acement reacted to the report of a hoax  !

explosive device found in an administrative area of the plant. Their response resulted in J the admission by a plant employee that he had made the fake bonb as a prank on another i employee. The employee who rade the device and perscn who reported it were both temporarily suspended, as they both were allegedly participants in the prank.

NRC resident inspectors and region-based safeguards ir.spectors have been following the l licensee's investigation. The Information Assessment Team has been kept informed. The licensee plans to submit its investigation results and conclusions to the Regional office within the rext few weeks.

Beginning cn March 26, 1987 there has been extensive news media interest.

l DISTRIBUTION:

H. St. EDO NRR E/W Willste Mail: ADM:CMB l Chairnan Zech PA IE NMSS DOT:Trans only Com. Roberts ELD OIA RES

! Com. Asselstine AE0D NRC Ops Ctr /8/[

Com Bernthal Com. Carr SP //.~0 6 Regional Offices ACRS >

SECY INP0//.N NSAC //.h/ g (

CA RIII Pesident Office '

PDR Licensee: /// /7 (Corp. Office - Peactor Lic. Only)

Region III B7040$381E e7o327 Rev. November 1986

-IIl_e7-031 PDR

PRELIMINARY NOTIFICATION OF EVENTS OR UNUSUAL OCCURENCE --PNO-III-87-31A Date March 77, 1987

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Th2 State of 1111rois will be notified. l R:gion III (Chicago) received this updated informaticn at 1:00 p.m. (CST), Varch 26, 1987.

This information is current as of 9:30 a.m. (CST), March 27, 1987.

CONTACT: . Cree M

W. Axelson f FTS 388-5743 FTS 388-5612 G

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