Browse wiki
Jump to navigation
Jump to search
On May 16, 2011, at 2013 Eastern Daylight … 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.</br>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.</br>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.</br>TVA also determined that the TDAFWP was inoperable for a period of 123 hours and 17 minutes while the plant was in Mode 3, which exceeded the 96 hours allowed for an inoperable train of AFW in LCO 3.7.5. (72 hours to restore, 6 hours to be in MODE 3, and 18 hours 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.</br>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).</br>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.</br>The NRC Resident (Inspector) has been notified.RC Resident (Inspector) has been notified.
18:28:00, 14 May 2011 +
46,885 +
14:41:00, 25 May 2011 +
18:28:00, 14 May 2011 +
On May 16, 2011, at 2013 Eastern Daylight … 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.</br>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.</br>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.</br>TVA also determined that the TDAFWP was inoperable for a period of 123 hours and 17 minutes while the plant was in Mode 3, which exceeded the 96 hours allowed for an inoperable train of AFW in LCO 3.7.5. (72 hours to restore, 6 hours to be in MODE 3, and 18 hours 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.</br>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).</br>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.</br>The NRC Resident (Inspector) has been notified.RC Resident (Inspector) has been notified.
Has query"Has query" is a predefined property that represents meta information (in form of a <a rel="nofollow" class="external text" href="https://www.semantic-mediawiki.org/wiki/Subobject">subobject</a>) about individual queries and is provided by <a rel="nofollow" class="external text" href="https://www.semantic-mediawiki.org/wiki/Help:Special_properties">Semantic MediaWiki</a>.
0.00142 d (0.0342 hours, 2.03373e-4 weeks, 4.68015e-5 months) +, 0.00111 d (0.0267 hours, 1.587302e-4 weeks, 3.6528e-5 months) +, 8.333333e-4 d (0.02 hours, 1.190476e-4 weeks, 2.7396e-5 months) +, 6.944444e-5 d (0.00167 hours, 9.920635e-6 weeks, 2.283e-6 months) + and 2.083333e-4 d (0.005 hours, 2.97619e-5 weeks, 6.849e-6 months) +
00:00:00, 25 May 2011 +
Modification date"Modification date" is a predefined property that corresponds to the date of the last modification of a subject and is provided by <a rel="nofollow" class="external text" href="https://www.semantic-mediawiki.org/wiki/Help:Special_properties">Semantic MediaWiki</a>.
02:07:05, 2 March 2018 +
14:41:00, 25 May 2011 +
false +
false +
10.843 d (260.22 hours, 1.549 weeks, 0.356 months) +
18:28:00, 14 May 2011 +
URL"URL" is a <a href="/Special:Types/URL" title="Special:Types/URL">type</a> and predefined property provided by <a rel="nofollow" class="external text" href="https://www.semantic-mediawiki.org/wiki/Help:Special_properties">Semantic MediaWiki</a> to represent URI/URL values.