ENS 52727: Difference between revisions
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| event date = 04/30/2017 18:18 EDT | | event date = 04/30/2017 18:18 EDT | ||
| last update date = 05/03/2017 | | last update date = 05/03/2017 | ||
| title = Open Bypass Valve Causes Loss | | title = Open Bypass Valve Causes Loss of Safety Function | ||
| event text = On April 30, 2017, at 1818 [EDT], the main turbine steam bypass valve #1 partially opened. Power was incrementally lowered. While lowering power the bypass valve would shut and then reopen and power would again be lowered. When power was lowered to approximately 74 percent the bypass valve remained closed. During the transient the reactor protection system (RPS) Turbine Stop Valve Closure and Control Valve Fast Closure trip functions were declared inoperable due to the opening of the bypass valve which affects the bypass setpoint for those RPS trip functions. With the loss of these RPS trip functions a loss of safety function existed intermittently for approximately 37 minutes. The manual reactor trip function and other RPS functions remained operable. | | event text = On April 30, 2017, at 1818 [EDT], the main turbine steam bypass valve #1 partially opened. Power was incrementally lowered. While lowering power the bypass valve would shut and then reopen and power would again be lowered. When power was lowered to approximately 74 percent the bypass valve remained closed. During the transient the reactor protection system (RPS) Turbine Stop Valve Closure and Control Valve Fast Closure trip functions were declared inoperable due to the opening of the bypass valve which affects the bypass setpoint for those RPS trip functions. With the loss of these RPS trip functions a loss of safety function existed intermittently for approximately 37 minutes. The manual reactor trip function and other RPS functions remained operable. | ||
Both channels of the rod withdrawal limiter (RWL) and the end of cycle reactor recirculation pump trip (EOC-RPT) function were also declared inoperable. These functions are credited in accident analysis, this also resulted in a loss of safety function. | Both channels of the rod withdrawal limiter (RWL) and the end of cycle reactor recirculation pump trip (EOC-RPT) function were also declared inoperable. These functions are credited in accident analysis, this also resulted in a loss of safety function. | ||
Latest revision as of 20:42, 1 March 2018
| Where | |
|---|---|
Perry  Ohio (NRC Region 3) | |
| Reporting | |
| 10 CFR 50.72(b)(3)(v)(A), Loss of Safety Function - Shutdown the Reactor 10 CFR 50.72(b)(3)(v)(D), Loss of Safety Function - Mitigate the Consequences of an Accident | |
| LER: | 05000440/LER-1917-002 Regarding Loss of Safety Function Due to Main Turbine Bypass Valve Opening |
| Time - Person (Reporting Time:+62.68 h2.612 days <br />0.373 weeks <br />0.0859 months <br />) | |
| Opened: | Dave Duesing 12:59 May 3, 2017 |
| NRC Officer: | Steven Vitto |
| Last Updated: | May 3, 2017 |
| 52727 - NRC Website
| |
Perry with 10 CFR 50.72(b)(3)(v)(A), Loss of Safety Function - Shutdown the Reactor, 10 CFR 50.72(b)(3)(v)(D), Loss of Safety Function - Mitigate the Consequences of an Accident | |