05000368/FIN-2015001-01
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Finding | |
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| Title | Failure to Protect Safety Equipment From Potential High Energy Line Breaks |
| Description | The inspectors identified a non-cited violation of 10 CFR Part 50, Appendix B, Criterion Ill, "Design Control," for the licensees failure to assure that applicable regulatory requirements and the design basis were correctly translated into specifications, drawings, procedures, and instructions and that design changes were subject to design control measures commensurate with those applied to the original design. Specifically, the Unit 2 radwaste supply fans, 2VSF-7A and B, plenum doors and turbine building fire door 447 were maintained open, which provided a potential path for steam to enter the auxiliary building and impact both safety-related dc power trains during a high energy line break event in the turbine building. On February 12, 2014, the licensee suspended the modification and corrected the procedure. The licensee documented the concern in Condition Report CR-ANO-2-2014-00345. The licensees failure to maintain separation of safety related systems and high energy piping systems in accordance with design, as stated in the Safety Analysis Report, was a performance deficiency. The performance deficiency was more than minor because it was associated with the design control attribute of the Mitigating Systems Cornerstone and adversely affected the cornerstone objective to ensure the availability, reliability, and capability of systems that respond to initiating events to prevent undesirable consequences. Using Inspection Manual Chapter 0609, Attachment 4, Initial Characterization of Findings, dated July 1, 2012 and Appendix A, The Significance Determination Process (SDP) for Findings At-Power, Exhibit 2, dated July 1, 2012, the inspectors determined that the finding required a detailed risk evaluation because the finding represented a potential loss of system and/or function of the safety-related dc motor control centers, battery chargers and inverters. A senior reactor analyst performed the detailed risk evaluation and determined that the change to the core damage frequency was less than 4.8E-7/year (Green). The dominant core damage sequences included losses of the plants DC electrical systems. The initiating event likelihood of a rupture of the specific section of piping needed to initiate core damage sequences was extremely low. The inspectors determined that there was no cross-cutting aspect associated with this finding because the cause of the performance deficiency occurred more than three years ago, and was not representative of current licensee performance. |
| Site: | Arkansas Nuclear  |
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| Report | IR 05000368/2015001 Section 1R18 |
| Date counted | Mar 31, 2015 (2015Q1) |
| Type: | NCV: Green |
| cornerstone | Mitigating Systems |
| Identified by: | NRC identified |
| Inspection Procedure: | IP 71111.18 |
| Inspectors (proximate) | B Tindell J Melfi M Williams M Young N Greene P Hernandez R Lantz S Garchow W Sifre |
| Violation of: | 10 CFR 50 Appendix B Criterion III, Design Control |
| INPO aspect | |
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Finding - Arkansas Nuclear - IR 05000368/2015001 | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
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Finding List (Arkansas Nuclear) @ 2015Q1
Self-Identified List (Arkansas Nuclear)
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