ENS 51440
ENS Event | |
|---|---|
12:25 Oct 2, 2015 | |
| Title | Loose Safety Relief Valve Discharge Flange Bolts |
| Event Description | On October 2nd, at approximately 0825 EDT, maintenance technicians were performing as-found torque checks on the discharge flange of the 'B' Safety Relief Valve (SRV). 12 of the 16 bolts were not adequately torqued. The 'B' Safety Relief Valve is credited for Remote Shutdown. The as-found condition of inadequate torque potentially impacts the seismic qualification of the 'B' SRV.
An investigation and extent of condition review is ongoing. The NRC Resident Inspector has been notified. Before the outage, there were no abnormal indications of leakage as indicated by a rise in drywell temperature or pressure. The SRVs had been cycled under pressure with no abnormal indications. The four bolts that were tight were in a diagonal pattern. The looses bolts were described as "finger tight." The licensee is determining the actions to take regarding the remaining 14 SRVs.
As part of the event investigation and extent of condition review, the as-found torque values of the inlet and outlet Safety Relief Valve (SRV) flange connections were measured and an engineering evaluation of the as-found condition was performed. The evaluation confirmed that all 15 SRVs would have remained operable during a design basis earthquake. Any potential discharge flange connection leakage during SRV operation would be bounded by the design basis Loss of Coolant Accident analysis described in the UFSAR. Subsequent investigation activities of the as-found condition of SRV 'B' determined that the four tight bolts were not oriented in a diagonal pattern across the discharge flange as originally reported. This information is provided only to clarify previously reported information and does not affect the original basis for reporting or the current basis for retraction. The licensee notified the NRC Resident Inspector. Notified R3DO (McCraw). |
| Where | |
|---|---|
Fermi  Michigan (NRC Region 3) | |
| Reporting | |
| 10 CFR 50.72(b)(3)(ii)(B), Unanalyzed Condition 10 CFR 50.72(b)(3)(v)(A), Loss of Safety Function - Shutdown the Reactor | |
| Time - Person (Reporting Time:+2.42 h0.101 days <br />0.0144 weeks <br />0.00331 months <br />) | |
| Opened: | Chris Robinson 14:50 Oct 2, 2015 |
| NRC Officer: | Mark Abramovitz |
| Last Updated: | Nov 20, 2015 |
| 51440 - NRC Website | |
Fermi with 10 CFR 50.72(b)(3)(v)(A), Loss of Safety Function - Shutdown the Reactor, 10 CFR 50.72(b)(3)(ii)(B), Unanalyzed Condition | |
WEEKMONTHYEARENS 564292023-03-23T15:45:00023 March 2023 15:45:00
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