05000454/FIN-2010007-03
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Finding | |
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| Title | |
| Description | The inspectors identified an unresolved item associated with the licensees program that classifies ISFSI components and systems as either important to safety (ITS) or not important to safety (NITS). The inspectors identified that the licensee failed to have a procedure in place to classify ancillary pieces of equipment, not specifically classified in the Holtec FSAR, as ITS or NITS. The Holtec FSAR, Table 8.1.6 classifies ancillary pieces of equipment as ITS or NITS. The Holtec FSAR indicates that the maximum annulus cooling water temperature is 125oF during vacuum drying operations. This temperature can only be achieved through some active means, and at the Byron Station, is achieved through the use of an annulus cooling system. Under medium and high heat loads, failure of this system would result in annulus cooling water exceeding the125oF design basis limit absent some intervention. The system used by the licensee for HI-TRAC annulus cooling consists of a heat exchanger, submersible pump, temperature monitoring device, and chiller. The system is not classified as either ITS or NITS in the Holtec FSAR. The licensee purchased the chiller as commercial grade equipment and since the system was not identified within the Holtec FSAR, characterized the system as NITS. The licensee initiated IR 1116408, NRC Potential URIs from ISFSI Reactive Inspection, to determine whether the system needed to be re-designated as ITS. Subsequent to the completion of the inspection, the licensee utilized input from Holtec to make the ITS or NITS classification. Holtec Standard Procedure 345 is used to implement a graded classification approach, consistent with NUREG/CR-6407. Using the evaluation matrix in Holtec Standard Procedure 345 the licensee classified the cooling system as NITS. In Holtecs response to the licensee regarding its recommendation to classify the annulus cooling system as NITS, Holtec recommended the following: To preclude the possibility of peak cladding temperature exceeding 1058F, administrative measures should be taken by the licensee to monitor the operation of the system and mitigate the likelihood of the annulus water temperature rising above 125F by taking additional actions such as (a) regular monitoring of the device operability, (b) regular monitoring of the annulus bulk water temperature, and (c) procedurally establishing compensatory measures in order to mitigate the possibility of an adverse temperature condition. In the event of failure of the annulus cooling device which cannot be quickly restored (within 6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br />, based on the completion time for the similar condition in LCO 3.1.1 condition B from Amendment 5 of the Technical Specification), the cask should be backfilled with helium to the minimum limits as specified in Table 3-2, Appendix A, Amendment 3 of the Technical Specification (vacuum drying can be continued from that condition once the flushing system is restored). The inspectors reviewed the licensees revised procedures for implementation of the Holtec recommendations. However, this issue will remain unresolved pending further review of the system classification as NITS by the SFST office. (URI 05000454/2010007-03; 05000455/2010007-03; 07200068/2010002-03, Licensee ISFI Annulus System Important to Safety Classification.) |
| Site: | Byron  |
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| Report | IR 05000454/2010007 Section 4OA5 |
| Date counted | Sep 30, 2010 (2010Q3) |
| Type: | URI: |
| cornerstone | Mitigating Systems |
| Identified by: | NRC identified |
| Inspection Procedure: | |
| Inspectors (proximate) | J Mcgee J Robbins M Holmberg M Learn B Metrow C Thompson E Duncan J Cassidyc Lipa E Love J Nicholson J Robbins J Solis M Lear |
| INPO aspect | |
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Finding - Byron - IR 05000454/2010007 | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
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Finding List (Byron) @ 2010Q3
Self-Identified List (Byron)
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