LGS Unit 1 Renewed Facility Operating License, NPF- 39, and
LGS Unit 2 Renewed Facility Operating License, NPF- 85, License Condition 2.C.(3) requires , in part, that Exelon Generation Company shall implement and maintain all provisions of the approved
Fire Protection Program as described in the
UFSAR.
LGS Unit 1 and Unit 2
UFSAR Chapter 9A requires compliance with Branch Technical Position, Chemical Engineering Branch 9.5- 1, guideline C.5.b(1), to limit fire damage so that one train of systems necessary to achieve and maintain cold shutdown conditions from either the control room or emergency control station can be repaired within
72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br />. Contrary to the above, from July 2014 to December 2016, an
unanalyzed condition existed in which an abnormal
ESW system alignment placed two Fire Areas in noncompliance with the FSSD analysis described in the
UFSAR. Specifically, in July 2014,
ESW to
RHRSW flow return valve,
HV -011 -015A was de- energized and tagged closed following
ESW system testing. With on ly one
RHRSW return path available to the A
ESW loop, a postulated fire in Fire Area 12 or Fire Area 18 could cause a single spurious valve operation of either
spray pond bypass valves
HV -012- 031A or
HV -012 -031C, when the
ESW system is aligned in the
spray pond winter bypass mode. This condition would result in no return flow path for the A loop of
ESW, which would in turn result in loss of cooling water to
EDGs aligned to the A
ESW cooling loop. The affected
EDGs would be
inoperable until the
ESW system could be realigned to provide cooling water flow. This condition coupled with a loss of offsite power assumed in FSSD analysis would result in a loss of power to
SRVs needed to transition both
LGS units from hot shutdown conditions to cold shutdown conditions. Following the depletion of station batteries after
4 hours4.62963e-5 days <br />0.00111 hours <br />6.613757e-6 weeks <br />1.522e-6 months <br />, until offsite power is assumed to be restored after
72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br />, direct current power would be lost to
SRVs that are necessary to reduce plant pressure low enough to place the
shutdown cooling system into service and establish cold shutdown plant temperatures. The failure to have a cold shutdown repair that could be implemented within
72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> in accordance with the FSSD analysis described in the
UFSAR, was a performance deficiency. 24 The performance deficiency was more than minor because it was associated with the protection against external factors (fire) attribute of the
mitigating systems cornerstone and it adversely affected the cornerstone objective of ensuring the availability, reliability, and capability of systems that respond to
initiating events to prevent undesirable consequences. The inspectors determined that the finding was of very low safety significance (Green ), based on
IMC 0609, Appendix F, Fire Protection
Significance Determination Process , Attachment 1, Part 1: Fire Protection
Significance Determination Process Phase 1 Worksheet, dated September 2013. The finding screened to Green based upon task 1.3.1 screening question A, since the inspectors determined that for conditions evaluated by Appendix F the reactors were able to reach and maintain hot shutdown. Specifically,
LGS Units 1 and 2 would have been able to achieve and maintain hot shutdown during the period the
unanalyzed condition existed. This would have been accomplished by using
HPCI and
SRVs for pressure and level control. Both units would have been capable of maintaining hot shutdown conditions with postulated fire damage until offsite power could be restored. Because this issue was of very low safety significance (Green) and Exelon entered the issue into the corrective action program as
IR 3955705, this finding is being treated as a licensee identified
NCV , consistent with Section 2.3.2.a of the
Enforcement Policy.
