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| Entered date | Site | Region | Reactor type | Event description | |
|---|---|---|---|---|---|
| ENS 55359 | 19 July 2021 13:47:00 | Purdue University | NRC Region 0 | On February 28, 2021, (at approximately 1500 EST), following recalibration of the reactor power in accordance with PUR-1 Technical Specifications, the reactor operator operated the reactor at 8.5 kW (85% of nominal power) and noticed that the rate of temperature change of the coolant was greater than expected. Noting that this presents the possibility of the power being in excess of expectations, PUR-1 was shut down and has remained shut down to date. PUR-1 staff immediately notified the Committee on Reactor Operations (CORO) and developed a plan to perform an in-depth investigation. Since then, multiple independent assessments on the reactor power have been performed, which include: Hand calculations, Monte Carlo N-Particle code (MCNP) simulations, analysis on activity measurements of irradiated materials, a thermal-hydraulic analysis using a Computational Fluid Dynamic (CFD) model of PUR-1, and a more physical assessment using resistance heaters as heat sources to determine the coolant temperature change rate as a function of power and pool temperature, which has just been completed. These five independent evaluation methods performed to determine the core power during the experiment on February 28, 2021, suggest that the reactor may have been operated for about 4 hours at a power in the range between 118.3 percent to 129.2 percent of our 12 kW maximum allowable power (per TS 2.2). While the reactor was not operated outside the bounds of the Safety Analysis Report (SAR), this represents a potential need for reporting under TS 6.7.b.1.c.vi, 'An observed inadequacy in the implementation of procedural controls...'. Staff are currently evaluating several potential corrective actions including adjustment of the current power calibration constant, which relates the activity of the gold foil to the core power, by the most conservative factor suggested by these five analyses. There was no impact to the safety of the public or PUR-1 staff and the Safety Limit was not exceeded at any point. A formal report will be subsequently issued. | |
| ENS 54958 | 20 October 2020 15:20:00 | Purdue University | NRC Region 0 | During the course of operations, a potential error in the power calibration of the PUR-1, License Number R-87, was discovered. This calibration error would result in a special report requirement as specified in ((Technical Specification)) TS 6.7.b.1.c.vi, which is that an observed inadequacy in the implementation of a procedural control such that this inadequacy could have caused the development of an unsafe condition with regards to reactor operations. By extension the miscalibration caused a true reactor power higher than the measured reactor power. As such, this likely resulted in the operation in violation of the limiting condition for operation as established in TS Section 3 Table I and operation with an actual safety system setting for a required system less conservative than the limiting safety system settings specified in the Technical Specifications. These reporting requirements are Part i. and ii. of TS 6.7.b.1.c. The calibration error implicates a violation of the maximum licensed power level of 12 kW. The Safety Limit was not exceeded at any point. | |
| ENS 53321 | 9 April 2018 14:48:00 | Purdue University | NRC Region 0 | On April 6, 2018 at approximately 1500 EDT, it was determined there was a potential Reportable Occurrence at the PUR-1 facility. There were no unsafe conditions at any time. The PUR-1 Technical Specification 6.7.b.1.c.vi reads, 'An observed inadequacy in the implementation of administrative or procedural controls such that the inadequacy causes or could have caused the existence or development of an unsafe condition with regard to reactor operations.' A visual inspection of the fuel is required annually with no interval to exceed 15 months. While the reactor has not operated and has remained in shutdown condition since June 5, 2017, this surveillance had not occurred for 20 months as of March, 2018. This surveillance was performed on March 27, 2018 but the administrative control which should have prevented the extended interval was not observed by facility staff. There was no existence of unsafe conditions and no (reactor) operations at any time during the period in question. |