The inspectors identified a severity level (
SL) IV
NCV of
10 CFR 50.59, Changes, Tests, and Experiments for the licensees failure to perform a written evaluation prior to implementing a
temporary modification to compensate for the absence of containment air cooler VHX-4. Specifically the modification adversely impacted the
service water (
SW) system and this was not evaluated in accordance with
10 CFR 50.59. The licensee entered the item into their corrective action process, added structural elements to minimize fouling of the
service water system, evaluated the change in accordance with
10 CFR 50.59, and performed a written evaluation. The revised modification did not require prior NRC approval. The inspectors concluded this finding was more than minor since it impacted the NRCs ability to perform its regulatory function and resulted in a condition which reduced the reliability of the
SW system, a mitigating system. The inspectors concluded the original modification may have required prior NRC approval. The issue screened green in the phase 3 assessment for the equipment degradation and therefore was of very low safety significance, and therefore, SLIV. The finding has a cross-cutting aspect in the area of human performance in that the licensee failed to use conservative assumptions in decision making and failed to identify possible unintended consequences when implementing the augmented cooling for
service water modificatio
