ENS 46885
ENS Event | |
|---|---|
18:28 May 14, 2011 | |
| Title | Violation of License Condition |
| Event Description | On May 16, 2011, at 2013 Eastern Daylight Saving Time (EDT), Watts Bar Nuclear Plant Unit 1 (WBN) entered Technical Specification (TS) Limiting Condition for Operation (LCO) 3.7.5, Condition B, because based on performance of Surveillance Requirement (SR) 3.7.5.2, the Turbine Driven Auxiliary Feedwater system was determined to be inoperable. Failure of the surveillance was caused by loss of the ability to control the turbine driven auxiliary feedwater pump (TDAFWP) manually. This was the first operation of the TDAFWP since the turbine had been rebuilt and had a new governor and servo installed during the WBN refueling outage 10 in May 2011. Misalignment of the servo caused the controller to stick, so that the TDAFWP pump could not be controlled in manual. The servo was replaced and the TDAFWP subsequently passed its required surveillance. LCO 3.7.5 was exited at 1745 on May 19, 2011.
Although the TDAFWP was not known to be inoperable until performance of the surveillance, TVA has concluded that the inoperability existed from the time that WBN entered Mode 3. WBN had entered Mode 3 at 1428 EDT, on May 14, 2011. LCO 3.0.4 prohibits MODE changes when an LCO is not met except under certain conditions that were not applicable to this event. Therefore, TVA considers that WBN entered Mode 3 without the required three operable trains of AFW. TVA also determined that the TDAFWP was inoperable for a period of 123 hours0.00142 days <br />0.0342 hours <br />2.03373e-4 weeks <br />4.68015e-5 months <br /> and 17 minutes while the plant was in Mode 3, which exceeded the 96 hours0.00111 days <br />0.0267 hours <br />1.587302e-4 weeks <br />3.6528e-5 months <br /> allowed for an inoperable train of AFW in LCO 3.7.5. (72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> to restore, 6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br /> to be in MODE 3, and 18 hours2.083333e-4 days <br />0.005 hours <br />2.97619e-5 weeks <br />6.849e-6 months <br /> to be in MODE 4). It should be noted that actions were taken and completed within the required time from time of discovery of the condition. Changing MODEs when LCO 3.7.5 was not met, and exceeding the time allowed for an inoperable train of auxiliary feedwater (AFW) were determined to be reportable as a condition prohibited by Technical Specifications in accordance with 10 CFR 50.73(a)(2)(i)(b). Since these conditions are a violation of the requirements contained in Section 2.c of the WBN License (Technical Specifications), this notification is made in accordance with Watts Bar License condition 2.G. The NRC Resident [Inspector] has been notified. |
| Where | |
|---|---|
Watts Bar  Tennessee (NRC Region 2) | |
| Reporting | |
| Other Unspec Reqmnt | |
| Time - Person (Reporting Time:+260.22 h10.843 days <br />1.549 weeks <br />0.356 months <br />) | |
| Opened: | Robert W. Dittmer 14:41 May 25, 2011 |
| NRC Officer: | Dong Park |
| Last Updated: | May 25, 2011 |
| 46885 - NRC Website
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Unit 1 | |
|---|---|
| Reactor critical | Not Critical |
| Scram | No |
| Before | Hot Standby (0 %) |
| After | Hot Standby (0 %) |
WEEKMONTHYEARENS 476092012-01-17T22:46:00017 January 2012 22:46:00
[Table view]Other Unspec Reqmnt 24-Hour Report Per Section 2.G of Unit 1 Operating License ENS 468852011-05-14T18:28:00014 May 2011 18:28:00 Other Unspec Reqmnt Violation of License Condition ENS 468392011-05-09T19:18:0009 May 2011 19:18:00 Other Unspec Reqmnt Potential Valve Mispositioning Led to a Condition Prohibited by Technical Specifications ENS 458272010-04-08T04:00:0008 April 2010 04:00:00 Other Unspec Reqmnt Diesel Generators Wired Incorrectly ENS 453312009-09-08T01:20:0008 September 2009 01:20:00 Other Unspec Reqmnt Discovery of After-The-Fact Emergency Condition Unusual Event ENS 426902006-07-07T18:45:0007 July 2006 18:45:00 Other Unspec Reqmnt Alternative Report for Non-Declared Emergency Condition in Accordance with Nureg-1022 ENS 414822005-03-11T19:29:00011 March 2005 19:29:00 Other Unspec Reqmnt It Was Determineded That Greater than 1% of Inspected S/G Tubes Must Be Repaired. ENS 402002003-09-26T12:50:00026 September 2003 12:50:00 Other Unspec Reqmnt Greater than 1 Percent of Steam Generators 1,2 & 4 Tubes Inspected Indicate That the Inspected Tubes Require Plugging. 2012-01-17T22:46:00 | |