05000456/LER-2021-001, Train a and B Source Range Neutron Flux Trip Functions Bypassed During Plant Startup
| ML21172A153 | |
| Person / Time | |
|---|---|
| Site: | Braidwood  |
| Issue date: | 06/21/2021 |
| From: | Exelon Generation Co |
| To: | Office of Nuclear Reactor Regulation |
| Shared Package | |
| ML21172A151 | List: |
| References | |
| BW210042 LER 2021-001-00 | |
| Download: ML21172A153 (5) | |
| Event date: | |
|---|---|
| Report date: | |
| Reporting criterion: | 10 CFR 50.73(a)(2)(i)(B), Prohibited by Technical Specifications 10 CFR 50.73(a)(2)(v)(A), Loss of Safety Function - Shutdown the Reactor |
| 4562021001R00 - NRC Website | |
text
Abstract
On April 23, 2021 at 1216 hours0.0141 days <br />0.338 hours <br />0.00201 weeks <br />4.62688e-4 months <br />, with Unit 1 in Mode 2 during reactor startup activities, control room personnel identified that both Train A and Train B source range neutron flux reactor trip functions were bypassed, and immediately restored by taking the bypass switches to normal. The condition existed since April 21, 2021 at 0738 hours0.00854 days <br />0.205 hours <br />0.00122 weeks <br />2.80809e-4 months <br /> with the unit in Mode
- 5. In accordance with Technical Specification (TS) Limiting Condition for Operations (LCO) 3.3.1, Reactor Trip System (RTS) Instrumentation, the source range neutron flux channels are required in Modes 2, 3, 4 and 5 in accordance with TS Table 3.3.1-1. A review determined periods where TS 3.3.1 Conditions were not met, and of mode changes not in accordance with TS LCO 3.0.4.
The cause of the event was failure of the Operations crew to adequately track equipment status in accordance with operating procedures and processes.
This event is being reported as any operation or condition which was prohibited by Technical Specifications in accordance with 10 CFR 50.73(a)(2)(i)(B), and as any event or condition that could have prevented the fulfillment of the safety function needed to shut down the reactor and maintain it in a safe shutdown condition in accordance with 10 CFR 50.73(a)(2)(v)(A).
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(See NUREG-1022, R.3 for instruction and guidance for completing this form http://www.nrc.gov/reading-rm/doc-collections/nuregs/staff/sr1022/r3/)
G. Component Failure Data
Manufacturer Nomenclature Model Mfg. Part Number N/A N/A N/A N/A