A self-revealing
NCV of
10 CFR 50, Appendix B, Criterion XVI was identified because the surveillance procedure frequency used to flush the
service water (
SW) piping in Mechanical Equipment Room (MER)-3 and MER-4 was changed from two weeks to four weeks without sufficiently considering the effects of river conditions on biological growth and without getting management permission to change the periodicity. As a result of the periodicity change, the B charging (
CH) and main control room (
MCR)
SW header became blocked with biological growth and was declared
inoperable on September 22, 2016, during the performance of 0-OSP-VS-012, High Flow Flush of
SW Strainers and Piping in MER 3 and MER 4. As immediate corrective action, the licensee cleaned the clogged
SW strainer and completed the backflushing of the
SW header. The
SW flushing periodicity was restored to a two week frequency to be seasonally and risk assessed and reduced as heavy fouling season ends. This issue was documented in the licensees corrective action program (
CAP) as CR 1048251. The inspectors reviewed
Inspection Manual Chapter (IMC) 0612, Appendix B, Issue Screening, dated September 7, 2012, and determined the performance deficiency (
PD) was more than minor because it was associated with the equipment performance attribute of the
Mitigating Systems Cornerstone, and it adversely affected the cornerstone objective to ensure the availability, reliability, and capability of systems that respond to
initiating events to prevent undesirable consequences. Using
IMC 0609.04, Initial Characterization of Findings, Table 2, dated June 19, 2012, the finding was determined to affect the
Mitigating Systems Cornerstone. The inspectors screened the finding using
IMC 0609, Appendix A,
Significance Determination Process (
SDP) for Findings at-Power, dated June 19, 2012, and determined that it screened as Green because the deficiency did not affect the design or qualification of the charging pump
service water pump system and it did not represent a loss of system safety function. This finding has a cross-cutting aspect in conservative bias aspect of the human performance area, H.14, because the licensee did not use decision making-practices that emphasize prudent choices over those that are simply allowed.
