05000352/FIN-2017003-00
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Finding | |
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Title | Licensee-Identified Violation |
Description | LER 05000352/2017- 003 -00 Condition Prohibited by Technical Specifications Due to an Inoperable Rod Position Indication System . TS 3.1.3.7 requires, in part, with one or more control rod position indicators inoperable, within 1 hour1.157407e-5 days <br />2.777778e-4 hours <br />1.653439e-6 weeks <br />3.805e-7 months <br />, determine the position of the control rod by using an alternate method, or otherwise, be in at least hot shutdown within the next 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br />. Contrary to the above, on March 16, 2017, a power supply for the Unit 1 rod position indication system rendered position indication for 83 control rods inoperable for approximately 19.5 hours5.787037e-5 days <br />0.00139 hours <br />8.267196e-6 weeks <br />1.9025e-6 months <br /> until the power supply was replaced. Exelon incorrectly used the full core display to verify control rod position for 81 of the 83 rods. The power supply failure rendered the full core display incapable of updating in response to a rod position change and was, therefore, not a valid means to determine rod position. Exelon initiated condition report IR 3988302 to document the TS violation. The inspectors evaluated the significance of this findi ng using IMC 0609 Appendix A , Significance Determination Process for Findings at Power, Exhibit 2, Mitigating Systems Screening Questions. The inspectors determined that this finding was of very low safety significance (Green) because the issue did not affect a single reactor protection system trip signal or the function of the ot her redundant trips or diverse methods of reactor shutdown, did not involve addition of positive reactivity, and did not result in mismanagement of reactivity by operators. Because this issue was of very low safety significance (Green) and Exelon entered the issue into the corrective action program (IR 3988302), this finding is being treated as a non- cited violation, consistent with Section 2.3.2 .a of the NRC Enforcement Policy. |
Site: | Limerick |
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Report | IR 05000352/2017003 Section 4OA7 |
Date counted | Jun 30, 2017 (2017Q2) |
Type: | NCV: Green |
cornerstone | Mitigating Systems |
Identified by: | Licensee-identified |
Inspection Procedure: | |
Inspectors (proximate) | S Rutenkroger M Fannon H. Anagnostopoulus J Cherubini D Hardage A Turilin D Schroeder |
Violation of: | Technical Specification |
INPO aspect | |
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Finding - Limerick - IR 05000352/2017003 | ||||||||||||||||||||||||||||||||||||||||||||||||
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Finding List (Limerick) @ 2017Q2
Self-Identified List (Limerick)
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