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The inspectors reviewed a self-revealing G … The inspectors reviewed a self-revealing Green non-cited violation of 10 CFR Part 50, Appendix B, Criterion III, Design Control, for the licensees failure to adequately review the suitability of materials of the diesel fuel oil cooler. Specifically, the Unit 2 A diesel generator fuel oil cooler design allowed for the interface of two dissimilar metals which promoted galvanic corrosion. This corrosion ultimately affected the structural integrity of the cooler and rendered the A Essential Spray Pond inoperable. In response to this, the licensee has replaced all six of the fuel oil cooler covers and initiated a design change to remove the fuel oil cooler from service. The licensee has entered the issue into the corrective action program as Condition Report Disposition Request 4543394. The failure to verify the adequacy of the design of the diesel fuel oil cooler was a performance deficiency. The performance deficiency is more than minor because it affected the equipment performance attribute of the Mitigating Systems cornerstone to ensure the availability, reliability, capability of systems that respond to initiating events to prevent undesirable consequences. Specifically the Unit 2 A diesel fuel oil cooler design allowed for the interface of two dissimilar metals which promoted galvanic corrosion. The corrosion ultimately affected the structural integrity of the cooler and rendered the Unit 2 A spray pond inoperable. In accordance with NRC Inspection Manual 0609, Appendix A, Exhibit 2, Mitigating Systems Screening Questions. The finding screened to a detailed risk evaluation because it involved a potential loss of one train of safety related equipment for longer than the outage time allowed by technical specifications. By performing a detailed risk evaluation, a Region IV senior reactor analyst determined that the associated change to the core damage frequency was 1.5E- 7/year (Green). The dominant core damage sequences included loss of offsite power events that lead to station blackout conditions. The gas turbine generators and the auxiliary feedwater system helped to minimize the risk. This finding has no cross-cutting aspect because it is not indicative of current performance. is not indicative of current performance.

Discovered date

23:59:59, 31 December 2014 +

Docket

05000528 +, 05000529 + and 05000530 +

Event date

23:59:59, 31 December 2014 +

Finding integer

1 +

Finding type

Non-cited violation +

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IR 05000528/2014005 +

Inspector

James Drake +, M Hayes +, G Guerra +, M Hay +, Louis Carson +, Chris Steely +, Natasha Greene +, Peter Jayroe +, Dustin Reinert +, Benjamin Parks + and David You +

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>.

12:57:23, 25 September 2017 +

Person