ENS 46415: Difference between revisions

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| event date = 11/12/2010 13:00 CST
| event date = 11/12/2010 13:00 CST
| last update date = 11/12/2010
| last update date = 11/12/2010
| title = Inaccurate Information Provided In License Amendment Request
| title = Inaccurate Information Provided in License Amendment Request
| event text = At 1300, on November 12, 2010, Exelon Generation Company LLC concluded that inaccurate information contained in the PRA technical bases for a 1987 License Amendment Request (LAR) for Byron and Braidwood Stations would have potentially impacted the acceptability of the LAR by the NRC.  The LAR was to extend Allowed Outage Times (AOT) from 72 hours to 7 days for several systems, to include the Component Cooling (CC) and Residual Heat Removal (RH) Systems.
| event text = At 1300, on November 12, 2010, Exelon Generation Company LLC concluded that inaccurate information contained in the PRA technical bases for a 1987 License Amendment Request (LAR) for Byron and Braidwood Stations would have potentially impacted the acceptability of the LAR by the NRC.  The LAR was to extend Allowed Outage Times (AOT) from 72 hours to 7 days for several systems, to include the Component Cooling (CC) and Residual Heat Removal (RH) Systems.
The original design intent of the CC system was that each unit has two independent CC pumps and a fifth pump (U0) CC pump could be used as an operable spare for any of the unit specific pumps.  This is how CC was modeled in the PRA technical justification for the 1987 LAR.  However, a piping configuration design flaw that was recently evaluated in that the U0 CC pump could not be considered an operable spare for either unit's B pumps was not correctly modeled in the PRA.
The original design intent of the CC system was that each unit has two independent CC pumps and a fifth pump (U0) CC pump could be used as an operable spare for any of the unit specific pumps.  This is how CC was modeled in the PRA technical justification for the 1987 LAR.  However, a piping configuration design flaw that was recently evaluated in that the U0 CC pump could not be considered an operable spare for either unit's B pumps was not correctly modeled in the PRA.

Latest revision as of 22:08, 1 March 2018

ENS 46415 +/-
Where
Braidwood Constellation icon.png
Illinois (NRC Region 3)
Reporting
10 CFR 50.72(b)(3)(ii)(B), Unanalyzed Condition
Time - Person (Reporting Time:+-3.27 h-0.136 days <br />-0.0195 weeks <br />-0.00448 months <br />)
Opened: Mike Deboard
15:44 Nov 12, 2010
NRC Officer: Donald Norwood
Last Updated: Nov 12, 2010
46415 - NRC Website
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