A finding of very low safety significance and an associated
NCV of
Technical Specification (TS) 5.4.1 was self-revealed when a configuration control error during a local leak rate test (
LLRT) resulted in the inadvertent draining of the spent fuel pool (
SFP). The licensee entered this issue into their
CAP as
IR 1506862,
SFP Level Reduced. Licensee corrective actions included isolating the leak and restoring
SFP level to normal. The inspectors determined that the performance deficiency was more than minor because it was associated with the Human Performance attribute of the
Barrier Integrity Cornerstone and adversely impacted the cornerstone objective of providing reasonable assurance that physical design barriers (
fuel cladding,
reactor coolant system, and containment) protect the public from radionuclide releases caused by accident or events. The finding was screened in accordance with
IMC 0609, Attachment 4, Phase 1 Initial Screening and Characterization of Findings, and was determined to be of very low safety significance since the finding was not associated with the loss of cooling to the
SFP that would have precluded restoration prior to boiling, a fuel handling error, or loss of
SFP inventory below the minimum analyzed level limit specified in the site-specific licensing basis. This finding had a cross-cutting aspect in the Work Practices component of the Human Performance cross-cutting area because operators did not use human error prevention techniques commensurate with the risk of the assigned task nor did personnel stop work in the face of uncertainty.
