ML20091Q925
| ML20091Q925 | |
| Person / Time | |
|---|---|
| Site: | University of Missouri-Columbia |
| Issue date: | 06/08/1984 |
| From: | Alger D, Mckibben J MISSOURI, UNIV. OF, COLUMBIA, MO |
| To: | Thomas C Office of Nuclear Reactor Regulation |
| References | |
| NUDOCS 8406140197 | |
| Download: ML20091Q925 (2) | |
Text
.
Research Reactor Facility UNIVERSITY OF MISSOURI Research Park Columbia, Missouri 65211 Telephone (314) 882-4211 June 8, 1984 Director of Nuclear Reactor Regulation U. S. Nuclear Regulatory Commission Washington, D. C.
20555 Attention: Mr. Cecil 0. Thomas, Chief Standardization & Special Projects Branch
Reference:
Docket 50-186 University of Missouri License R-103
Subject:
Report as required by Technical Specification 6.1.h(2)
Description On May 11,1984 at 1053, with the reactor operating at 10 MW, the personnel airlock doors operated out of sequence, allowing both inner and outer doors to open at the same time. The reactor was immediately shutdown by manual rod run in. The outer airlock door gasket had been pulled partly from its seat, due to the door driving with the gasket inflated. The gasket was replaced in its seat, the airlock door alignment and electrical control circuit operation were checked and the airlock doors were cycled several times to ensure they would sequence normally. The airlock doors were back in operation at 1100.
The reactor was operated for a period of seven minutes out of com-pliance with Technical Specification 3.5.a(1) which states that " containment integrity shall be maintained at all times except when:
(1) the reactor is secured, and irradiated fuel with a decay time less than sixty days is not being handled".
For reactor containment integrity to exist one of the persennel airlock doors rnust be closed with the gasket inflated.
6gQ7Mh0 S
6 COLUMBIA L
an equal opportunity institution
n s
Director of Nuclear Reactor Regulation June 8, 1984-Page 2.
Analysis The' basis for: Technical Specification 3.5.a is to assure that the Lcontainment building can be isolated at all times except when the plant conditions _are such that the probability of release of radioactivity is negligible. When the airlock doors malfunctioned deviating from the limiting conditions for operation, a reactor shutdown was immediately commenced to make the already extremely low probability of release of radioactivity even more negligible. The cause of the out of sequence air-lock door operation could not be reproduced.
' Corrective Action A reactor shutdown was immediately commenced on failure of the door sequence..The outer airlock door gasket was reinserted and the doors were
- tested for proper cperation. The University of Missouri Reactor manage-
' ment will evaluate the_ need to change the Technical Specifications regard-ing a failure of a system or component required as a limiting condition for
. operation. The change would pursue allowing MURR to take credit for a timely reactor shutdown as an action statement for failure or loss of the required component or system. This would alleviate the generation of a Licensee Event Report for conditions which did not pose a safety question for either the general public or the MURR staff _ due to timely corrective actions.
Sincere (b
J. C. McKibben Reactor Manager i
En'dorsement:
g(-
l Ami Reviewed and Approved Don M. Alger Associate Director cc:
U.S. Nuclear Regulatory-Commission
!c/o Document Management Branch James Keppler, Regional Administrator Region Operations - Region III Reactor Advisory Committee Reactor Safety Subcomaittee John H.- Tolan, Radiation Safety Officer i
f b.: