PNO-III-85-058, on 850702,reactor Brought to Criticality W/O Shift Supervisor Realizing Incident.Caused by Reactor Operator Failing to Follow Proper Procedures for Moving Control Rods in Full Out Position.Incident Being Reviewed
| ML20129J041 | |
| Person / Time | |
|---|---|
| Site: | Fermi  |
| Issue date: | 07/15/1985 |
| From: | Chrissotimos N, Greenman E NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION III) |
| To: | |
| References | |
| PNO-III-85-058, PNO-III-85-58, NUDOCS 8507220166 | |
| Download: ML20129J041 (1) | |
PRELIMINARY NOTIFICATION OF EVENT OR UNUSUAL OCCURRENCE--PNO-III-85-58 Date July 15, 1985 This preliminary notification constitutes EARLY notice of events of POSSIBLE safety or public interest significance. The information is as initially received without veri-
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fication or evaluation, and is basically all that is known by the staff an this date.
Facility: Detroit Edison Company Licensee Emergency Classification:
Fermi 2 Nuclear Plant Notification of an Unusual Event Newport, MI 48166 -
Alert Site Area Emergency Docket no: 50-341 General Emergency XX Not Applicable Subj:ct: INADVERTENT CRITICALITY On July 15, 1985, the licensee reported to the Senior Resident Inspector that an engineering analysis of reactor startup activities on July 2,1985, had determined that the reactor had been brought critical at that time without the shift supervisor realizing that criticality had been achieved. (Fermi 2 had its initial criticality on June 21, 1985.)
During the reactor startup on July 2, a reactor operator moved 11 control rods in Group 3 to the full out position. The operator failed to follow licensee procedures in moving the r rods--they were moved to the full out position, instead of being moved in steps, in accordance with the procedure. The reactor operator noticed the power level increasing faster than he anticipated, and he promptly returned the 11 rods to the fully inserted position.
The shift supervisor then reviewed the operator's actions, and determined that the reactor bad not gone critical. Startup activities then resumed using the step-by-step procedure, and criticality was achieved consistent with the expected estimated critical position.
Five days after the incident, a reactor engineer concluded that the reactor had in fact gone critical during the initial Group 3 rod movements.
Region III (Chicago) was notified of the inadvertent criticality at 1:30 p.m.,
(CDT), July 15, 1985. The licensee has initiated an investigation of the criticality incident. An NRC technical specialist has been dispatched to review the circumstances of the incident. The Office of Nuclear Reactor Regulation has be:n informed. Region III is also reviewing the time lapse between the event, the dstermination of criticality, and its being reported to the NRC.
The plant is currently operating at 2 per cent power.
The State of Michigan will be informed.
This information is cur ent as of 7 a.m., July 16, 1985.
8507220166 850715 CONTACT: .dhrssotimos E. reenman Q_g{[-85-058 PDR -
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