University Of
Missouri Research Reactor (
MURR)
Technical Specification (TS) 6.6.c(1) requires notification to the NRC Operations Center that an Abnormal Occurrence, as defined by
MURR TS 1.1, has occurred.
MURR was not in compliance with one (1) of the TS Limiting Conditions of Operations.
TS 3.2.g states, 'The reactor safety system and the number (N) of associated instrument channels necessary to provide the following
scrams shall be operable whenever the reactor is in operation.' Specifically, the reactor safety
scram function that occurs when the differential pressure across the reactor pool reflector (PT-917) instrument channel decreases below 2.52 psi minimum in Mode 1 operation was not operable as required by
TS 3.2.g.10.
On 11/15/21 while the reactor was shut down, Control Room operators shut down the pool coolant system and noticed that the `Reflector Hi-Low Diff Pressure Scram' annunciator alarm did not initiate as pool coolant flow rate decreased to zero. The Control Room operators contacted reactor management, and an investigation was initiated to prove whether or not the safety scram function from the PT-917 instrument channel actuated correctly. Further testing revealed the safety scram signal from the PT-917 instrument channel did not occur due to a failed alarm-meter unit. The alarm-meter unit was replaced with an exact spare, the PT-917 instrument channel was calibrated, and the reactor safety scram functions of the PT-917 instrument channel were retested satisfactorily.
In accordance with TS 6.6.c(4), the Reactor Facility Director was briefed and gave permission to restart the reactor prior to the reactor returning to operation later on 11/15/21. Currently, MURR is operating at 10 MW. A detailed event report will follow within 14 days as required by MURR TS 6.6.c(3).
The NRC Project manager was notified.