V.C. Summer Operating License condition 2.c(18) states in part that the licensee shall implement and maintain in effect all provisions of the approved
fire protection program that comply with
10 CFR 50.48(c), National Fire Protection Association (
NFPA) 805 of which Chapter 3, Section 3.2.3, Procedures, states, Procedures shall be established for implementation of the
fire protection program. Contrary to this, on September 14, 2016, the licensee failed to implement the requirements of procedure, Fire Protection Procedure,
FPP-025, Fire Containment, Rev. 4, to ensure that fire door and SPB, DRIB/107, did not remain open in excess of
1 hour1.157407e-5 days <br />2.777778e-4 hours <br />1.653439e-6 weeks <br />3.805e-7 months <br />. NRC
IMC 0609.04 and NRC
IMC 0609 Appendix A screening determined that the finding represented a loss of the short term heat removal safety function within the
Mitigating Systems Cornerstone and required a detailed risk evaluation. A bounding analysis was performed by a regional
SRA using the
VC Summer
SPAR model. The finding was modelled as a Steam Line Break Outside Containment (SLBOC) initiating event assessment. A
3 hours3.472222e-5 days <br />8.333333e-4 hours <br />4.960317e-6 weeks <br />1.1415e-6 months <br /> and 22 minutes bounding exposure was utilized. No recovery was assumed. Equipment impacts from potential
HELBs were determined using the results from Gothic Analyses performed to assess the temperature, pressure and relative humidity increases in mild environment spaces in the Intermediate Building due to the various
HELB boundary breaches associated with the finding. For non-Loss of Offsite Power (
LOOP) conditions,
HELB impacts in mild areas were minimal. For
LOOP conditions, the
HELB was assumed to impact the chilled water system such that one train of safety related equipment was assumed failed as a bounding impact. The dominant sequence was a SLBOC initiator with a failure to isolate the break and a failure of high pressure injection impacted by loss of chilled water leading to loss of core heat removal. The risk evaluation determined that the finding represented a risk increase of < 1.0E-6/year, a GREEN finding of very low safety significance. The licensee has documented this problem in their
CAP as CR-16-04703
