05000353/FIN-2017002-01
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Finding | |
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| Title | Inadequate Design Control of the Drywell Unit Cooler Condensate Flow Rate Monitoring System |
| Description | Green . A self -revealing Green NCV of 10 Code of Federal Regulations (CFR) Part 50, Appendix B, Criterion III, Design Control, occurred when Exelon failed to verify or check the adequacy of design of a new Unit 2 drywell unit cooler condensate flow rate monitoring system. Specifically, the design did not identify that the low conductivity of the drain fluid affected the ability of the flow elements to accurately detect drain flow. In addition to this, LGS staff did not assure adequate post modification acceptance test ing in accordance with CC- AA- 107- 1001, Post Modification A cceptance Testing. This inadequately designed and tested modification also resulted in a violation of technical specification (TS) 3.4.3.1, Leakage Detection Systems , because the system was inoperable and unavailable to perform its function following t he Unit 2 April 2015 refueling outage, and the TS 3.4.3.1 action statement was not met until the system was decl ared inoperable on December10, 2015. In response to this issue, Exelon initiated a condition report, IR 2598308, performed an apparent cause investigation, and replaced the Rosemount drywell unit cooler condensate flow rate monitoring system with a modified ver sion of the previously used system. The inspectors determined that the failure to verify the adequacy of the newly installed Rosemount dr ywell unit cooler condensate flow rate monitoring was within Exelons ability to foresee and correct and should have been prevented and therefore w as a performance deficiency . This issue is more than minor because it adversely affected the design control attribute of the barrier integrity cornerstone to provide reasonable assurance that physical design barriers protect the public from radionuclide releases caused by accidents or events. Specifically, the Unit 2 drywell unit cooler condensate flow rate monitoring system was inoperable and unavailable to perform its function as part of the reactor coolant leakage detection system following the Unit 2 April 2015 refueling outage . This issue was evaluated in accordance with IMC 0609, Appendix A, "Significance Determination Process for Findings At-Power, using Exhibit 3, Barrier Integrity Screening Questions, Section B, Reactor Containment . The finding was determined to be of very low safety significance (Green) because the finding did not represent an actual open pathway in the physical integrity of the reactor containment and did not involve an actual reduction in function of hydrogen ig niters in the reactor containment. The inspectors determined that this finding has a cross -cutting aspect in the area of Human Performance, Conservative Bias , because LGS staff ma de inappropriate decisions based on informal vendor input and a successful implementation of the modification at another facility . [H.1 4] |
| Site: | Limerick  |
|---|---|
| Report | IR 05000353/2017002 Section 4OA3 |
| Date counted | Jun 30, 2017 (2017Q2) |
| Type: | NCV: Green |
| cornerstone | Barrier Integrity |
| Identified by: | Self-revealing |
| Inspection Procedure: | IP 71153 |
| Inspectors (proximate) | S Rutenkroger M Fannon H. Anagnostopoulus J Cherubini D Hardage A Turilin D Schroeder |
| Violation of: | Technical Specification |
| CCA | H.14, Conservative Bias |
| INPO aspect | DM.2 |
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Finding - Limerick - IR 05000353/2017002 | ||||||||||||||||||||||||||||||||||||||||||||||||
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Finding List (Limerick) @ 2017Q2
Self-Identified List (Limerick)
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