A self-revealing
NCV of
10 CFR Part 50 Appendix B, Criterion V, Instructions, Procedures, and Drawings, was identified because workers did not properly follow the work instructions during a core drilling activity which resulted in a breach of
secondary containment. A maintenance worker missed the containment box designed to maintain
secondary containment integrity during core drilling to support a plant modification. The finding is more than minor because it adversely impacted the Configuration Control Attribute of the
Barrier Integrity Cornerstone. The improper core drill caused
secondary containment to become
inoperable. In accordance with NRC
Inspection Manual Chapter 0609, Significant Determination Process, the inspectors performed a Phase 1 analysis and determined the finding was of very low safety significance (Green) because the finding only affected
secondary containment. The finding has an associated cross-cutting aspect in the area of Human Performance. Specifically, work practices as it relates to use of human error prevention techniques commensurate with the risk of the assigned task. The workers mistakenly measured the drill location from two different reference points above and below the floor (
H.4.a)