PNO-III-93-013, on 930305,while Operators Were Performing Normal Manual Shutdown of 500-kilowatt pool-type Reactor,One Safety Rod Failed to Insert on Manual Scram Signal.Reactor Shutdown & Licensee Investigating to Determine Root Cause
| ML20203G556 | |
| Person / Time | |
|---|---|
| Site: | Ohio State University |
| Issue date: | 03/08/1993 |
| From: | Mccormickbarge, Pederson C NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION III) |
| To: | |
| References | |
| PNO-III-93-013, PNO-III-93-13, NUDOCS 9712180153 | |
| Download: ML20203G556 (1) | |
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CWfWGJ G3 @ ~tGEWSTRW 02 Date March 5, 1993 PRELIMINARY NOTIFICATION CF EVENT OR UNUSUAL OCCURRENC3 PM39313
- This preliminary notification oonstitutes BARIN of possIRLs safety or publio interest significanos. The notice of events gn
, information is as initially received without verification or 1 evaluation,is staff on th date.and is basically all that is knownl- by the Region III
- I Facilitys-Linanmaa Enaraanov Clammification Ohio State University General Emergency '
Research Reactor site Area keergency f /N C/chru Columbus, Ohto ,,_,, ,,A l o r t l -g L Unusual-Event
- Docket No. 50-150/R-75 _X_N/A l Z /$,/ A
, subject FAILURE OF SNIM SAFETY NOD TO INSERT UMING MANUAL SCRAM
' On March 5, 1993, while operators were performi g a normal manual
, shutdown of the-500-kilowatt pool-type reactor, one of three safety rods failed to insert on a manual scram nignal. The reactor had sufficient shutdown margin that the' reactor was shut down and remained suboritical with the two rods inserted. The
- whim rod, which failed to insert initially, was then inserted
. Using the rod drive motor.
The licensee. believes that the failure was caused by corrosion in i a limit switch, causing a short circuit which damaged the circuitry controlling the scram e 3p1 for the safety rod. The
- licensee is in the process of Le cing the switch and the damaged
- oircuits.
f The-1Aconsee is continuing its investigation to determine the root cause of the failure and to identify Jong-term corrective actions.[)N'p Magion III (Chicago)-will conduct a special insplection beginning March s, 1993. The licensee does not intend to{ restart the reactor until Region III has reviewed its corrective actions.
I The state of Ohio will be notified. The information in this preliminary notification han been reviewed with licensee management.
l Region III was notified of this inaldent at 9:30 a.m. on March 8, 1993. This information is current as of 4 p.m.
on March 8, 1993.
s .
CONT CT:
O uXS 8/8//s ames McCormick-Barger Cynthia Pederson ,
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