ENS 55359
ENS Event | |
|---|---|
20:00 Feb 28, 2021 | |
| Title | Reactor Operated at Greater than 100 Percent Technical Specification Power Limit |
| Event Description | 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 hours4.62963e-5 days <br />0.00111 hours <br />6.613757e-6 weeks <br />1.522e-6 months <br /> 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. |
| Where | |
|---|---|
| Purdue University Research Reactor West Lafayette, Indiana (NRC Region 0) | |
| License number: | R-87 |
| Reporting | |
| Non | |
| Time - Person (Reporting Time:+3378.78 h140.783 days <br />20.112 weeks <br />4.628 months <br />) | |
| Opened: | True Miller 13:47 Jul 19, 2021 |
| NRC Officer: | Donald Norwood |
| Last Updated: | Jul 19, 2021 |
| 55359 - NRC Website
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Purdue University with Non | |
WEEKMONTHYEARENS 553592021-02-28T20:00:00028 February 2021 20:00:00
[Table view]Non Reactor Operated at Greater than 100 Percent Technical Specification Power Limit ENS 549582020-10-19T04:00:00019 October 2020 04:00:00 Non Maximum Licensed Power Level Exceeded ENS 533212018-03-27T19:00:00027 March 2018 19:00:00 Non Failure to Meet Technical Specification Requirement 2021-02-28T20:00:00 | |