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The inspectors opened an Unresolved Item ( … The inspectors opened an Unresolved Item (URI) to further evaluate the capability of the Fermi 2 simulator to model core thermal-hydraulic instabilities, to evaluate the adequacy of licensed operator training using the plant simulator for response to the condition, and to determine whether a noncompliance with the regulatory requirements exists. Description: On March 19, 2015, Fermi 2 received an automatic reactor scram signal generated from the oscillation power range monitor (OPRM) logic of the reactor protection system. As discussed in Section 4OA3.1 of this inspection report, following the transition of the unit to single loop operation due to the loss of a reactor recirculation pump, licensed operators failed to stabilize the plant while operating in a region of core thermal-hydraulic instability on the Power-to-Flow Map due to inadequate procedures. The result was a reactor scram. During review of this event, the inspectors questioned whether licensed operator training and the licensees simulator were adequate to prepare the operators to respond to the condition. Currently, the Fermi 2 plant simulator does not model core thermal-hydraulic instability under the high power and low flow conditions experienced on March 19; however, the training staff is able to artificially introduce the instability in the simulator in certain scenarios. The inspectors questioned whether the modeling of thermal-hydraulic instability falls under the requirements of Title 10 of the Code of Federal Regulations (10 CFR) 55.46(c)(1), which requires the simulator to demonstrate expected plant response to operator input and to normal, transient, and accident conditions. This issue of concern is considered a URI pending additional review by the NRCs operator licensing inspectors (URI 05000341/201500301, Inadequate Simulator Fidelity Regarding the Ability to Model Core Thermal-hydraulic Instabilities).del Core Thermal-hydraulic Instabilities). +
23:59:59, 30 September 2015 +
23:59:59, 30 September 2015 +
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00:53:20, 21 February 2018 +
23:59:59, 30 September 2015 +