ENS 41139
ENS Event | |
|---|---|
23:30 Oct 19, 2004 | |
| Title | High Pressure Coolant Injection (Hpci) Inoperable Due to Controller Signal Converter Trouble. |
| Event Description | On October 19, 2004 at approximately 1830 hours0.0212 days <br />0.508 hours <br />0.00303 weeks <br />6.96315e-4 months <br /> CDT, Unit One was performing QCOS 2300-05, Quarterly HPCI Pump Operability Test. This was being performed to prove operability following maintenance work on various valves and the turning motor gear unit. At this time when the HPCI turbine was rolled, the HPCI Signal Converter Trouble alarm was received. The HPCI Flow Controller demand controlled at approximately 7250 gpm instead of controlling at the desired 5600 gpm. HPCI was determined not to be operable and was shutdown per procedure. Due to the unexpected behavior of the HPCI Flow Controller, at this time it is not certain if the HPCI will meet its safety function. Therefore, we are reporting this event under 10 CFR 50.72 (b)(3)(v).
Licensee entered Tech Spec 3.5.1.(f) 14 day Limiting Condition of Operation (LCO) for HPCI. Reactor Core Isolation Cooling (RICI) is operable. All other Emergency Core Cooling Systems (ECCS) and the Emergency Diesel Generators (EDG) are fully operable if needed. The NRC Resident Inspector was notified of this event by the licensee.
The purpose of this report is to retract the ENS report made on October 19, 2004 at 2237 CDT (ENS #41139). The initial report was made following HPCI operability testing in accordance with QCOS 2300-05, Quarterly HPCI Pump Operability Test. When the HPCI turbine was rolled, the HPCI Signal Converter Trouble alarm was received. The HPCI Flow Controller failed to control at the desired 5600 gpm (instead, the system ramped to 7250 gpm). Due to the unexpected behavior, it was not certain at the time if HPCI could have met its design basis requirements. However, a subsequent review of this event has determined that HPCI would have performed its safety function. The Signal Converter failed in a manner that prevented automatic flow control, but did not prevent HPCI from initiating and ramping to full flow (i.e., the turbine high speed stop). In this condition, HPCI would have met corresponding Technical Specifications and Accident Analysis requirements. The circuit board was replaced and the Signal Converter and flow controller feedback loop were re-calibrated. The Unit 1 HPCI turbine's automatic flow control was successfully tested on October 20, 2004. The Licensee notified the NRC Resident Inspector. Notified R3DO (R. Garner) |
| Where | |
|---|---|
Quad Cities  Illinois (NRC Region 3) | |
| Reporting | |
| 10 CFR 50.72(b)(3)(v)(D), Loss of Safety Function - Mitigate the Consequences of an Accident | |
| Time - Person (Reporting Time:+0.12 h0.005 days <br />7.142857e-4 weeks <br />1.64376e-4 months <br />) | |
| Opened: | Ken Hill 23:37 Oct 19, 2004 |
| NRC Officer: | John Knoke |
| Last Updated: | Oct 28, 2004 |
| 41139 - NRC Website
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Unit 1 | |
|---|---|
| Reactor critical | Critical |
| Scram | No |
| Before | Power Operation (85 %) |
| After | Power Operation (85 %) |