"On 4/9/20, at 1432 CDT, the University of Missouri-Columbia Research Reactor (MURR) was shut down due to the failure of the geared rotary limit switch assembly to move with corresponding regulating blade drive mechanism movement. This email is a required notification per MURR Technical Specification (TS) 6.6.c(1) to report to the NRC Operations Center that an Abnormal Occurrence, as defined by MURR TS 1.1, had occurred. MURR was not in compliance with one (1) Limiting Conditions of Operations (LCO). TS 3.2.f states, 'The reactor shall not be operated unless the following rod run-in functions are operable.' Specifically, the rod run-in function that occurs when regulating blade position is less than or equal to 10 percent withdrawn was not operable as required by TS 3.2.f.8.
"The regulating blade drive mechanism was repaired, post-maintenance operability testing was conducted satisfactorily, and permission from the Reactor Facility Director was obtained prior to the reactor returning to operation later on 4/9/20. Currently, MURR is at 10 MW. A detailed event report will follow within 14 days as required by MURR TS 6.6.c(3)."