ENS 48650
ENS Event | |
|---|---|
06:00 Dec 29, 2012 | |
| Title | Part 21 - Anti-Rotation Pin Failure in 10-Inch Anchor Darling (Flowserve) Double Disc Gate Valve |
| Event Description | The following is a summary of the information received from TVA - Browns Ferry via facsimile:
On December 29, 2012 it was determined that sufficient data existed to determine a defect existed in a 10-inch Anchor Darling double disc gate valve installed in Browns Ferry Unit 1. In November, 2012 during a scheduled refueling, the High Pressure Coolant Injection valve, 1-FCV-073-0002 failed its local leak rate test with gross leakage identified on the upstream (reactor side) disc. The downstream side of the discs showed acceptable leakage. When maintenance was performed on the valve, the disc retainer bolt was found sheared. Further investigation revealed that the anti-rotation pin had failed. A review of work order history determined that this valve was installed during the Unit 1 recovery in 2007. The cause of the anti-rotation pin failure was determined to be that the stem was not adequately torqued to the upper wedge at the manufacturing plant. This cause was confirmed by internal inspections of the valve that were performed at Browns Ferry. Flowserve Corporation is also conducting an investigation. The licensee identified 15 other applications of this particular 10-inch valve in all three Browns Ferry units. For all those valves except 2-FCV-073-0002, documentation exists demonstrating that the stem to upper wedge was torqued to manufacturer requirements, determined through MOVATS [Motor-Operated Valve Analysis and Test System] testing that the anti-rotation pin is not sheared, or determined through visual inspection that the anti-rotation pin remains intact. 2-FCV-073-0002 is considered to be non-conforming and will be inspected during the next scheduled Unit 2 refueling. The licensee has notified the NRC Resident Inspector of this notification. |
| Where | |
|---|---|
Browns Ferry  Alabama (NRC Region 2) | |
| Reporting | |
| 10 CFR 21.21(d)(3)(i), Failure to Comply or Defect | |
| Time - Person (Reporting Time:+151.33 h6.305 days <br />0.901 weeks <br />0.207 months <br />) | |
| Opened: | Paul Hermann 13:20 Jan 4, 2013 |
| NRC Officer: | Howie Crouch |
| Last Updated: | Jan 4, 2013 |
| 48650 - NRC Website
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Unit 1 | |
|---|---|
| Reactor critical | Critical |
| Scram | No |
| Before | Power Operation (100 %) |
| After | Power Operation (100 %) |
WEEKMONTHYEARENS 572452024-07-23T18:00:00023 July 2024 18:00:00
[Table view]10 CFR 21.21(d)(3)(i), Failure to Comply or Defect Part 21 - HPCI Rupture Disc Not within Technical Requirements ENS 486502012-12-29T06:00:00029 December 2012 06:00:00 10 CFR 21.21(d)(3)(i), Failure to Comply or Defect Part 21 - Anti-Rotation Pin Failure in 10-Inch Anchor Darling (Flowserve) Double Disc Gate Valve 2024-07-23T18:00:00 | |