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The inspectors documented a self-revealed … The inspectors documented a self-revealed finding of very low safety significance and an associated non-cited violation (NCV) of Title 10 of the Code of Federal Regulations (CFR) Part 50, Appendix B, Criterion XVI, Corrective Action, for the licensees failure to take corrective actions to preclude repetition of a significant condition adverse to quality. After identifying intergranular stress corrosion cracking (IGSCC) on main steam flex hoses as the root cause of reactor coolant system (RCS) pressure boundary leakage in 2007 and concluding the leakage constituted a significant condition adverse to quality, the licensees corrective action to prevent recurrence failed to prevent pressure boundary leakage at the same location in 2016. The licensee entered this issue into their corrective action program as action request (AR) 02670593. The affected hoses were replaced. The remaining hoses will be replaced in the next maintenance outage. The licensee is also developing a design change to address at least one of the three factors that contributes to IGSCC to ensure pressure boundary leakage does not occur at the main steam flex hoses. The inspectors determined that the licensees failure to take corrective actions to preclude repetition for a significant condition adverse to quality was a performance deficiency. Specifically, the licensees corrective action in 2007 to replace main steam flex hoses at 16 year intervals failed to preclude pressure boundary leakage due to IGSCC on the main steam flex hoses in 2016. The performance deficiency was determined to be more than minor in accordance with IMC 0612, Power Reactor Inspection Reports, Appendix B, Issue Screening, dated September 7, 2012, because it was associated with the equipment performance attribute of the Initiating Events cornerstone and adversely affected the cornerstone objective of limiting the likelihood of events that upset plant stability and challenge critical safety functions during shutdown as well as power operations. Using IMC 0609, Attachment 4, Initial Characterization of Findings, and Appendix A, The Significance Determination Process for Findings at Power, issued June 19, 2012, the finding was screened against the Initiating Events cornerstone and determined to be of very low safety significance because the finding did not result in exceeding the RCS leak rate for a small loss of coolant accident (LOCA) and did not affect other systems used to mitigate a LOCA resulting in a total loss of their function. No cross cutting aspect was assigned because the performance deficiency was not indicative of current plant performance.t indicative of current plant performance.

Discovered date

23:59:59, 30 September 2016 +

Docket

05000461 +

Event date

23:59:59, 30 September 2016 +

Finding integer

4 +

Finding type

Non-cited violation +

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Identified by

Self-revealing +

Inspection Manual Chapter

NRC Inspection Manual 0609 + and NRC Inspection Manual 0612, Power Reactor Inspection Reports +

Inspection procedure

IP 71153, Event Followup +

Inspection report

IR 05000461/2016003 +

Inspector

J Wojewoda +, S Mischke +, Gregory Roach +, Karla Stoedter +, William Schaup +, Charles Phillips +, John Bozga +, Nicole Fields + and Geoffrey Edwards +

Modification date"Modification date" is a predefined property that corresponds to the date of the last modification of a subject and is provided by <a rel="nofollow" class="external text" href="https://www.semantic-mediawiki.org/wiki/Help:Special_properties">Semantic MediaWiki</a>.

12:56:08, 25 September 2017 +

Person