ML20212Q697
| ML20212Q697 | |
| Person / Time | |
|---|---|
| Site: | Dow Chemical Company |
| Issue date: | 08/26/1986 |
| From: | Kocher C DOW CHEMICAL CO. |
| To: | James Keppler NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION III) |
| References | |
| NUDOCS 8609080001 | |
| Download: ML20212Q697 (2) | |
Text
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DOW CHEMICAL U.S.A. hM August 26, 1986 MICHIGAN DIVISION MIDLAND,. MICHIGAN 48640 Mr. James C. Keppler U.S. Nuclear Regulatory Commission Region III 799 Roosevelt Road Glen Ellyn, IL 60137 DOW TRIGA RESEARCH REACTOR, LICENSE R-108, DOCKET 55-264
Dear Mr. Keppler:
This letter reports an event which is described in section D.(1) of the operating license of the Dow TRIGA Research Reactor.
NUCLEAR SYSTEM:
Source Interlock SAFETY FUNCTION:
Prevent withdrawal of control elements with less than two neutron induced counts per second on the startup channel.
CONDITION:
During pre-startup checkout on Augut 21, 1986 the source interlock operated, given the proper signal, but failed to prevent the movement of the control rods.
The pre-startup checkout was halted while the operation of the interlock was reviewed. The interlock was reset and a signal was again provided which operated the source interlock. At this time the interlock did prevent the movement of the control rods. The interlock system was examined, relays and connections were removed and inspected, the system was returned to working order and was tested three times. At each time the proper interlock was achieved.
The failure was ascribed to a temporary loss of electrical contact in the logic circuits, which use plug-in relays. Subsequent inspection and movement restored the proper electrics.1 contacts and the system, af ter testing, was returned to service, mY
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1 8609080001 860826 PDR ADOCK 05000264 S
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AUG 2 91986 AN OPERATING UNIT of' THE DOW C#4EMICAL COMPANY
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Mr. James C. Keppler U.S. Nuclear Regulatory Commission August 26, 1986 Page 2 A telephone report was made to the duty officer at llegion III on the afternoon of August 21, 1986.
- Yours, G&) /6L C. W. Kocher Reactor Supervisor Analytical Laboratories 1602 Building cc: L. W. Rampy Chairman, Radiation Safety Committee The Dow Chemical Company 1803 Building Midland, MI 48674 D. L. Berry Chairman, Reactor Operations Committee The Dow Chemical Company 1602 Building Midland, MI 48674 i
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