ENS 46645
ENS Event | |
|---|---|
15:48 Feb 26, 2011 | |
| Title | |
| Event Description | High Pressure Coolant Injection (HPCI) system declared inoperable due to Flow Indicating Controller process value indicating 542 gpm while in standby readiness condition. This condition could impact the system response time in developing flow for events it was credited in mitigating.
HPCI declared inoperable per TS 3.5.1 Condition F which allows 14 days to restore to operable status. Preliminary cause is air intrusion into instrument sensing lines following pre-planned maintenance where system draining was performed. Troubleshooting is in progress. All remaining ECCS and RCIC are operable and available. Grid stability has been verified." The NRC senior resident has been notified.
The purpose of this notification is to retract a previous report made on 2/26/2011 at 1216 (EDT) (EN 46645). Notification of the event to the NRC was initially made as a result of declaring High Pressure Coolant Injection (HPCI) system inoperable due to Flow Indicating Controller process value indicating 542 gpm while in standby readiness condition. This condition could have impacted the system response time in developing flow for events it was credited to mitigate. Subsequent to the initial report, NextEra Energy Duane Arnold (NextEra) has determined that the HPCI system was capable of performing its safety function. NextEra concluded that the erroneous Flow Indicator Controller indication was due to air entrainment in the instrument sensing line. A detailed engineering analysis has concluded that the HPCI system was capable of providing design required flow rates with the flow offset. This event is not considered a Safety System Functional Failure and is not reportable to the NRC as a Licensee Event Report (LER) per 10 CFR 50.73. The NRC Senior Resident Inspector has been notified. Tech spec required flow is 2700 gpm. Calculations show that a margin of 600 gpm exists between the tech spec flow rate, and the HPCI automatic flow setpoint, therefore, with an error of 542 gpm, the required flow is met. Notified the R3DO (Phillips). |
| Where | |
|---|---|
Duane Arnold  Iowa (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:+-3.53 h-0.147 days <br />-0.021 weeks <br />-0.00484 months <br />) | |
| Opened: | Jeff Miell 12:16 Feb 26, 2011 |
| NRC Officer: | Bill Huffman |
| Last Updated: | Apr 21, 2011 |
| 46645 - NRC Website
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Unit 1 | |
|---|---|
| Reactor critical | Critical |
| Scram | No |
| Before | Power Operation (100 %) |
| After | Power Operation (100 %) |
Duane Arnold with 10 CFR 50.72(b)(3)(v)(D), Loss of Safety Function - Mitigate the Consequences of an Accident | |
WEEKMONTHYEARENS 528812017-08-01T14:34:0001 August 2017 14:34:00
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