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05000352/FIN-2018010-0130 September 2018 23:59:59LimerickNRC identifiedMinor ViolationDuring this inspection, the team reviewed the details and status of Exelons corrective actions. Relative to EDG voltage, the TSs specified a lower limit of 4160 Vac; however, Exelons existing analysis determined the lower EDG voltage limit should be 4235 Vac. Exelon determined that this higher voltage value was necessary in order to ensure full EDG operability and qualification when considering a specific criteria (voltage drop during the loading sequence) as per NRC Regulatory Guide 1.9, Application and Testing of Safety-Related Diesel Generators in Nuclear Power Plants. The team determined that there was not an operability concern because Exelon determined that, although the voltage drop during the starting of the largest electrical load was slightly below the Regulatory Guide 1.9 value, all required loads would, in fact, successfully start and run as designed when started at the 4160 Vac level. Further, the EDG voltage regulators are designed and calibrated to operate the EDGs at 4235 Vac. Notwithstanding, the team identified that the associated EDG surveillance procedures did not contain the higher, administrative limit of 4235 Vac as an acceptance criterion (4160 Vac was specified). The team reviewed this issue using Inspection Manual Chapter 0612, Appendix B, Issue Screening, and determined that the use of non-conservative acceptance criterion was a minor procedure violation because the EDGs were controlled and operated to maintain voltage at 4235 Vac (and 4160 Vac does not render the EDGs inoperable), and EDG reliability or availability were not adversely affected. Exelon entered this minor violation in their corrective action program as IR 4164579 to document and correct this deficiency. For EDG frequency, the TSs allowed an acceptance band (58.8 61.2 Hertz), which is a range typical of EDG transient loading conditions. However, as described in WCAP-17308-NP, and as determined by Exelon engineering staff, a more narrow band (59.9 60.2 Hertz) is the appropriate operating range for steady state EDG operation. Exelon has appropriately maintained the narrow band as the acceptance criteria in the associated EDG surveillance procedures (compensatory action until TSs are revised). However, during this inspection, the team identified that in 2016, Exelon had slightly widened the acceptable band a one-tenth hertz to 59.8 60.2 Hertz. Further review by the team identified that this change was not properly evaluated in accordance with Exelons procedure change process. In particular, the procedure change received a less rigorous review than a 10 CFR 50.59 screen would have provided; and the team concluded that this screen should have been performed. In response, Exelon evaluated past surveillance results and analyzed the lower frequency value of 59.8 Hertz, and determined there to be no adverse consequence at 59.8 Hertz. The team reviewed Exelons analysis and similarly concluded that there was no adverse safety impact. The team reviewed this issue using Inspection Manual Chapter 0612, Appendix B, Issue Screening, and determined that the improper procedure change was a minor procedure violation because there were no adverse consequences and EDG reliability or availability were not adversely affected. Exelon entered this minor violation in there corrective action program as IR 4160819 and IR 4161542 to document and correct this deficiency.
05000352/FIN-2018003-0230 September 2018 23:59:59LimerickSelf-revealingFailure to Correct Adverse Environmental Conditions Impacting Low Pressure Coolant Injection Outboard Primary Containment Isolation ValveA self-revealed Green NCV of 10 CFR Part 50, Appendix B, Criterion XVI was identified when Exelon failed to correct adverse environmental conditions affecting the Unit 1 LPCI outboard PCIV actuator that resulted in long term water intrusion, corrosion, and failure of the valve to stroke closed.
05000352/FIN-2018003-0130 September 2018 23:59:59LimerickNRC identifiedFailure to Assess and Manage Risk Associated with Fuel Oil Storage Tank MaintenanceAn NRC-identified Green NCV of 10 CFR 50.65(a)(4) was identified when Exelon failed to assess and manage risk associated with fuel oil storage tank maintenance by not properly evaluating and establishing compensatory actions for maintaining availability of associated EDGs
05000352/FIN-2018002-0230 June 2018 23:59:59LimerickNRC identifiedUnit 1 Core Spray Pump Failed to Start Resulting in Condition Prohibited by Technical SpecificationsThe inspectors identified a Severity Level IV NCV of Unit 1 Technical Specification 3.5.1 because one core spray subsystem was inoperable from July 17, 2017, until October 5, 2017. Specifically, the Unit 1 C core spray pump did not start upon demand during testing and was declared inoperable because the pumps associated circuit breaker closing charging springs were not charged.
05000352/FIN-2018002-0130 June 2018 23:59:59LimerickSelf-revealingFailure to Conduct Adequate Radiation Surveys and Evaluate Potential Radiological HazardsA self-revealing Green finding and associated NCV of 10 CFR 20.1501, Surveys and Monitoring: General, was identified when Exelon failed to perform adequate loose surface contamination surveys of the Unit 1 RWCU isolation valve room prior to authorizing work to hang shadow shielding near the HV-051-1F017A valve, and also during the conduct of the work itself. Exelon also did not identify very high levels of loose surface contamination on overhead piping and structures which surrounded the work area. This failure resulted in unplanned internal radiation exposures to three personnel, including an RPT who was assigned to monitor the radiological aspects of the work.
05000353/FIN-2018001-0131 March 2018 23:59:59LimerickSelf-revealingFailure of Emergency Diesel Generator Lube Oil Pipe Nipple FittingA self-revealed Green non-cited violation (NCV) of 10 CFR 50, Appendix B, Criterion XVI, Corrective Action, and LGS Unit 2 technical specification (TS) 3.8.1.1 was identified when Exelon failed to correct a degraded lube oil pipe nipple fitting on the D22 emergency diesel generator (EDG) when maintenance was performed to address leakage which caused inoperability of the EDG for greater than its TS allowed outage time.
05000352/FIN-2018001-0231 March 2018 23:59:59LimerickSelf-revealingEmergency Diesel Generator Combustion Air OverheatingA self-revealed Green NCV of LGS Unit 1 TS 6.8.1 and TS 3.8.1.1 was identified when Exelon failed to properly maintain an operating procedure to maintain a fail-safe design feature for the EDGs which led to the D12 EDG combustion air overheating and caused the EDG to be inoperable for greater than its TS allowed outage time.
05000352/FIN-2017007-0131 December 2017 23:59:59LimerickNRC identifiedFailure to Document Technical Basis for Service Temperature Changes for Limitorque Motor Operated Valve Limit SwitchesThe inspection team identified a Green non- cited violation of Title 10 of the Code of Federal Regulations (10 CFR) 50, Appendix B, Criterion III, Design Control, because Exelons design control measures did not provide for verifying or checking the adequacy of design of the inboard high pressure coolant injection ( HPCI ) steam supply primary containment isolation valve from environmental effects. Specifically, as part of extending component life for license renewal, Exelon changed the normal service temperature of the valve limit switches from 145F to 135F without suff icient technical justification. Exelon documented this issue in their corrective action program as issue report 4076939, and changed the qualified life of the limit switches back to 41 years. Exelon also plans to evaluate the impacts of process fluid tem perature on the qualified life of the limit switches. The inspection team determined that the performance deficiency was more than minor because it was associated with the design control attribute of the Barrier Integrity Cornerstone and adversely affected the cornerstone objective of ensuring that physical design barriers (containment) protect the public from radionuclide releases caused by accidents or events. Specifically, using incorrect service temperatures resulted in inappropriately extending qualified service life of the HPCI inboard containment isolation valve limit switches . The inspection team evaluated this finding in accordance with IMC 0609, Appendix A, The Significance Determination Process for Findings at Power, Exhibit 3, Barrier Integrity Screening Questions. The inspection team determined the finding was of very low safety significance (Green) because it was a design deficiency confirmed not to result in an actual open pathway in the physical integrity of reactor containment and did not involve an actual reduction in function of hydrogen igniters in the reactor containment. The finding had a cross -cutting aspect in the area of Human Performance, Design Margins, because Exelon did not evaluate issues to ensure that margins are carefully guarded and changed only through a systematic and rigorous process. Specifically, Exelon c hanged the service temperature for the Limitorque motor operated valves inside containment in 2014 that extended the qualified service life of the most limiting component beyond 60 years. (H.6)
05000353/FIN-2017004-0131 December 2017 23:59:59LimerickNRC identifiedUnplanned HPCI Inoperability Due to Isolating All Suction Sources During Post-Maintenance Te s t i n gThe inspectors identified a self-revealing Green non-cited violation (NCV) of 10 Code of Federal Regulations (CFR) 50, Appendix B, Criterion V, Instructions, Procedures, and Drawings, for Exelons failure to adequately establish post-maintenance testing instructions for a relay replacement for the Unit 2 high pressure coolant injection (HPCI) system. Specifically, implementing the instructions caused a loss of all suction sources and unplanned inoperability of the Unit 2 HPCI system. Exelon initiated a condition report (issue report (IR) 4036417) and conducted a technical human performance (THU) workshop with the maintenance planning department to increase awareness of THU tools and added THU behavior discussion topics to weekly maintenance planning department all hands meetings.This finding is more than minor because it adversely affected the configuration control attribute of the mitigating systems cornerstone to ensure the availability of systems that respond to initiating events to prevent undesirable consequences (i.e. core damage). Specifically, HPCI was made inoperable when it was planned to remain operable. Using IMC 0609, Appendix A, Exhibit 2, the inspectors determined that this finding required a detailed risk assessment because it represented a loss of the single train systems function. The Regional Senior Reactor Analyst performed a detailed risk evaluation using the Limerick Generating Station (LGS) Unit 2 Standardized Plant Analysis Risk Model. The issue was modeled with a HPCI failure to start due to the suction valves being closed. The change in core damage frequency per year was determined to be in the low E-9 range due to the very short duration that both suction sources were isolated. Therefore the issue was determined to be of very low safety significance (Green). The inspectors determined that this finding has a cross-cutting aspect in the area of Human Performance, Work Management, because the work process did not ensure individuals were aware of plant status and the changes in the plan of work were not effectively implemented. (H.5)
05000352/FIN-2017003-0230 September 2017 23:59:59LimerickLicensee-identifiedLicensee-Identified ViolationLGS Unit 1 Renewed Facility Operating License, NPF- 39, and LGS Unit 2 Renewed Facility Operating License, NPF- 85, License Condition 2.C.(3) requires , in part, that Exelon Generation Company shall implement and maintain all provisions of the approved Fire Protection Program as described in the UFSAR. LGS Unit 1 and Unit 2 UFSAR Chapter 9A requires compliance with Branch Technical Position, Chemical Engineering Branch 9.5- 1, guideline C.5.b(1), to limit fire damage so that one train of systems necessary to achieve and maintain cold shutdown conditions from either the control room or emergency control station can be repaired within 72 hours. Contrary to the above, from July 2014 to December 2016, an unanalyzed condition existed in which an abnormal ESW system alignment placed two Fire Areas in noncompliance with the FSSD analysis described in the UFSAR. Specifically, in July 2014, ESW to RHRSW flow return valve, HV -011 -015A was de- energized and tagged closed following ESW system testing. With on ly one RHRSW return path available to the A ESW loop, a postulated fire in Fire Area 12 or Fire Area 18 could cause a single spurious valve operation of either spray pond bypass valves HV -012- 031A or HV -012 -031C, when the ESW system is aligned in the spray pond winter bypass mode. This condition would result in no return flow path for the A loop of ESW, which would in turn result in loss of cooling water to EDGs aligned to the A ESW cooling loop. The affected EDGs would be inoperable until the ESW system could be realigned to provide cooling water flow. This condition coupled with a loss of offsite power assumed in FSSD analysis would result in a loss of power to SRVs needed to transition both LGS units from hot shutdown conditions to cold shutdown conditions. Following the depletion of station batteries after 4 hours, until offsite power is assumed to be restored after 72 hours, direct current power would be lost to SRVs that are necessary to reduce plant pressure low enough to place the shutdown cooling system into service and establish cold shutdown plant temperatures. The failure to have a cold shutdown repair that could be implemented within 72 hours in accordance with the FSSD analysis described in the UFSAR, was a performance deficiency. 24 The performance deficiency was more than minor because it was associated with the protection against external factors (fire) attribute of the mitigating systems cornerstone and it adversely affected the cornerstone objective of ensuring the availability, reliability, and capability of systems that respond to initiating events to prevent undesirable consequences. The inspectors determined that the finding was of very low safety significance (Green ), based on IMC 0609, Appendix F, Fire Protection Significance Determination Process , Attachment 1, Part 1: Fire Protection Significance Determination Process Phase 1 Worksheet, dated September 2013. The finding screened to Green based upon task 1.3.1 screening question A, since the inspectors determined that for conditions evaluated by Appendix F the reactors were able to reach and maintain hot shutdown. Specifically, LGS Units 1 and 2 would have been able to achieve and maintain hot shutdown during the period the unanalyzed condition existed. This would have been accomplished by using HPCI and SRVs for pressure and level control. Both units would have been capable of maintaining hot shutdown conditions with postulated fire damage until offsite power could be restored. Because this issue was of very low safety significance (Green) and Exelon entered the issue into the corrective action program as IR 3955705, this finding is being treated as a licensee identified NCV , consistent with Section 2.3.2.a of the Enforcement Policy.
05000353/FIN-2017003-0130 September 2017 23:59:59LimerickNRC identifiedOperational Condition Mode Change from Startup to Run was Made with RCIC InoperableThe inspectors identified a Green NCV of Unit 2 technical specification (TS) 3.0.4, when Exelon changed the operating condition of Unit 2 from mode 2 (startup) to mode 1 (run) with reactor core isolation cooling ( RCIC ) inoperable for surveillance testing. Specifically, the TS 3.7.3 limiting condition for operation (LCO) for RCIC was not met, a mode change from startup to run was made, and none of the allowances, TS 3.0.4.a, TS 3.0.4.b, or TS 3.0.4.c, were met to allow the mode change in that condition. Exelon entered this issue into the corrective action program with issue report (IR) 4057128. The inspectors determined that the change in operating condition of LGS Unit 2 from startup to run with RCIC inoperable was reasonably within Exelons ability to foresee and correct and should have been prevented and therefore was a performance deficiency. This finding is more than minor because it adversely affected the configuration control attribute of the mitigating systems cornerstone to ensure the availability of systems that respond to initiating events to prevent undesirable consequences (i.e. core damage). Specifically, RCIC was inoperable during the time it was required to be operable, i.e. the mode change from startup to run. Additionally, this finding was similar to example 2.g of IMC 0612, Appendix E, in that a mode change was made without all required equipment being operable. Using IMC 0609, Appendix A, Exhibit 2, the inspectors determined that this finding was of very low safety significance (Green). Specifically, the finding did not represent a loss of function and did not represent the loss of a single train for greater than technical specification allowed outage times or greater than 24 hours. The inspectors determined that this finding has a cross - cutting aspect in the area of Human Performance, Documentation, because with respect to TS 3/4.7.3 Exelon did not create and maintain complete and accurate documentation of the correct usage of TS 3.0.4 that was more fully explained in the applicable safety evaluation. (H.7)
05000352/FIN-2017003-0030 June 2017 23:59:59LimerickLicensee-identifiedLicensee-Identified ViolationLER 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 hour, determine the position of the control rod by using an alternate method, or otherwise, be in at least hot shutdown within the next 12 hours. 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 hours 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.
05000352/FIN-2017002-0230 June 2017 23:59:59LimerickNRC identifiedFollow -Up of Events and Notices of Enforcement DiscretionInspection Scope On March 20, 2016, Limerick Unit 1 was performing a planned shutdown to support a refueling outage. The drywell leak inspection team identified a 0.5 gallons per minute reactor coolant system (RCS) pressure boundary leak on the shutdown cooling equalizing line. The apparent cause evaluation determined that the 34 inch A RHR shutdown cooling return check valve equalizing line developed a crack at the toe of the weld due to high cyclic fatigue induced by vibration from the reactor recirculation system. This check valve was previously replaced in 2006, and the equalizing line came pre - fabricated to the valve body. The affected section of the piping was replaced with a new socket weld with a 2x1 overlay to improve the pipe stability and minimize stresses. The Unit 1 B RHR shutdown cooling return check valve equalizing line weld was also reworked using the 2x1 weld method during the Unit 1 refueling out age in April 2016. The similar Unit 2 welds on the equalizing lines were examined and reinforced during the May 2017 refueling outage. The LER and associated evaluations and follow -up actions were reviewed for accuracy, the appropriateness of corrective actions, violations of requirements, and potential generic issues. This LER is closed. b. Findings Description. On March 20, 2016, Limerick Unit 1 was performing a planned shutdown to support a refueling outage. The drywell leak inspection team identified a 0.5 gallons per minute RCS pressure boundary leak on the shutdown cooling equalizing line. Additionally, Exelon determined that this leakage constituted a violation of the Unit 1, TS 3.4.3.2. Operational Leakage that requires the RCS leakage to be limited to no pressure boundary leakage. The condition was reported in event notification 51809 as required by 10 CFR 50.72(b)(3)(ii)(A ) because it represented a degradation of a principal safety barrier. Exelon evaluated the flaw and determined the cause of the RCS pressure boundary leakage was that the 34 inch A RHR shutdown cooling return check valve equalizing line developed a crack at the toe of the weld due to high cyclic fatigue induced by vibration from the reactor recirculation system. The inspectors reviewed the LER and Exelons apparent cause evaluation of the event. The inspectors reviewed the event information and leakage data over the previous cycle and concluded that reactor pressure boundary leakage reasonably began on an unknown date that was more than 36 hours before March 20, 2016. However, the inspectors determined that the existence of R CS pressure boundary leakage was not within Exelons ability to foresee and correct and therefore was not a performance deficiency. In particular, the RHR shutdown cooling return check valve was replaced on the recommended periodicity, and the equalizing line that developed the crack came pre- fabricated to the valve body when replaced in 2006. For information, the inspectors screened the significance of the condition using IMC 0609, Appendix A, The Significance Determination Process For Findings At -Power , and determined that the condition represented very low safety significance (Green) because it would not result in exceeding the RCS leak rate for a small LOCA and would not have likely affected other systems used to mitigate a LOCA. 19 Enforcement. TS 3.4.3.2 requires, in part, that RCS operational leakage shall be limited to no pressure boundary leakage. If pressure boundary leakage exists, the TS 3.4.3.2 limiting condition for operation action statement requires Unit 1 to be in at least hot shutdown within 12 hours and in cold shutdown within the next 24 hours. Contrary to the above, for a period that began on an unknown date that was very likely more than 36 hours before March 20, 2016, and ending on March 20, 2016, RCS pressure boundary leakage existed, and Exelon did not place Unit 1 in at least hot shutdown within 12 hours and in cold shutdown within the next 24 hours. This issue is considered within the traditional enforcement process because there was no performance deficiency associated with the violation of NRC requirements. Inspection Manual Chapter 0612, Power Reactor Inspection Reports, Section 03.22 states, in part, that traditional enforcement is used to disposition violations receiving enforcement discretion or violations without a performance deficiency. The NRC Enforcement Policy, Section 2.2.1 states, in part, that, whenever possible, the NRC uses risk information in assessing the safety significance of violations. Accordingly, after considering that the condition represented very low safety significance, the inspectors concluded that the violation would be best characterized as Severity Level IV under the traditional enforcement process. However, the NRC is exercising enforcement discretion (EA- 17- 076) in accordance with Section 3.10 of the NRC Enforcement Policy which states that the NRC may exercise discretion for violations of NRC requirements by reactor licensees for which there are no associated performance deficiencies. In reaching this decision, the NRC determined that the issue was not within the licensees ability to foresee and correct; the licensees actions did not contribute to the degraded condition; and the actions taken were reasonable to identify and address the condition. Furthermore, because the licensees actions did not contribute to this violation, it will not be considered in the assessment process or the NRCs Action Matrix.
05000352/FIN-2017002-0330 June 2017 23:59:59LimerickLicensee-identifiedLicensee-Identified ViolationLER 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 hour, determine the position of the control rod by using an alternate method, or otherwise, be in at least hot shutdown within the next 12 hours. 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 hours 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 finding 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 other 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.
05000353/FIN-2017002-0130 June 2017 23:59:59LimerickSelf-revealingInadequate Design Control of the Drywell Unit Cooler Condensate Flow Rate Monitoring SystemGreen . 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)
05000352/FIN-2017403-0130 June 2017 23:59:59LimerickLicensee-identifiedLicensee-Identified Violation
05000352/FIN-2017001-0231 March 2017 23:59:59LimerickSelf-revealingFailure to Implement Human Performance Tools Results in Draining of Emergency Diesel Generator Jacket Water SystemGreen. The inspectors identified a Green self-revealing finding for the failure of Exelon personnel to follow procedures related to human performance tools which resulted in the inadvertent opening of a valve on the D13 emergency diesel generator (EDG). Specifically, Exelon personnel did not correctly identify and maintain a distance barrier from the diesel generator jacket water drain valve during a maintenance activity which resulted in the draining of the jacket water system and unplanned inoperability and unavailability of the D13 EDG. Exelon refilled the jacket water system, restored D13 EDG to an operable condition, and entered the issue into the corrective action program as IR 3986305. This finding is more than minor because it adversely affected the configuration control attribute of the mitigating systems cornerstone to ensure the availability of systems that respond to initiating events to prevent undesirable consequences (i.e. core damage). Specifically, the valve mispositioning caused the D13 EDG to be inoperable and unavailable. Using IMC 0609, Appendix A, Exhibit 2, the inspectors determined that this finding was of very low safety significance (Green). Specifically, the finding did not represent a loss of system or function and did not represent the loss of a single train for greater than technical specification allowed outage times or greater than 24 hours. The inspectors determined that this finding has a cross-cutting aspect in the area of Human Performance, Avoid Complacency, because Exelon personnel did not properly implement error reduction tools. (H.12)
05000353/FIN-2017001-0131 March 2017 23:59:59LimerickNRC identifiedInadequate Work Instructions for Staging of Equipment and Routing of Temporary Power CablesGreen. The inspectors identified a Green NCV of 10 Code of Federal Regulations (CFR) 50, Appendix B, Criterion V, Instructions, Procedures, and Drawings, for Exelons failure to establish instructions appropriate to the circumstances to properly stage equipment and route temporary power cables. Specifically, during cell replacement of the Class 1E 2A2 125/250 volts direct current (Vdc) safeguards battery, a portable battery charger was staged adjacent to operable 2A1 battery cells and not restrained to prevent potential tipping and shorting of exposed battery cell terminals and a non-safety related extension cord was routed in near contact with exposed safety related cables in an open cable tray. Exelon moved the portable battery charger, removed and rerouted extension cords, and entered the issues into the corrective action program as issue report (IR) 3980217; IR 3980203; and IR 3983203. This finding is more than minor because it adversely affected the configuration control attribute of the mitigating systems cornerstone to ensure the availability and reliability of systems that respond to initiating events to prevent undesirable consequences (i.e. core damage). Specifically, the portable battery charger was adjacent to the 2A1 battery rack and oriented such that it was susceptible to tipping over and causing electrical shorting, and a non-safety related temporary power cable connected to a non-safety related power source was routed in near contact with safety related cables in an open cable tray which introduced a potential to damage and disable safety related equipment. Using IMC 0609, Appendix A, Exhibit 2, the inspectors determined that this finding was of very low safety significance (Green). Specifically, the finding did not represent a loss of system or function and did not represent the loss of a single train for greater than technical specification allowed outage times or greater than 24 hours. The inspectors determined that this finding has a cross-cutting aspect in the area of Human Performance, Training, because Exelon did not provide sufficient training to maintain a knowledgeable workforce and instill nuclear safety values associated with the staging of material and equipment. (H.9)
05000352/FIN-2016004-0131 December 2016 23:59:59LimerickNRC identifiedFailure to Demonstrate Effective Preventive Maintenance Under 50.65(a)(2) for the Instrument Air SystemGreen. The inspectors identified a Green NCV of 10 Code of Federal Regulations (CFR) 50.65, Requirements for Monitoring the Effectiveness of Maintenance at Nuclear Power Plants," because Exelon did not demonstrate that the performance of the Unit 1 instrument air system had been effectively controlled through the performance of appropriate preventive maintenance and did not monitor against licensee-established goals in accordance with 10 CFR 50.65(a)(1). Specifically, the inspectors identified that the instrument air system reliability performance monitoring did not properly account for instrument air compressor failures such that the system exceeded the performance criteria established by Exelons procedures. Exelon entered the issue into the corrective action program (CAP) as IR 3961244. This issue is more than minor because it adversely affected the equipment performance attribute of the mitigating systems cornerstone to ensure the availability and reliability of systems that respond to initiating events to prevent undesirable consequences (i.e. core damage). Specifically, the instrument air system reliability performance monitoring did not accurately account for multiple functional failures that resulted in the system exceeding the performance criteria established by Exelons procedures. Additionally, this finding was similar to example 7.d of IMC 0612, Appendix E, in that appropriate preventive maintenance under 10 CFR 50.65 (a)(2) was not demonstrated. Using IMC 0609, Appendix A, Exhibit 2, the inspectors determined that this finding was of very low safety significance (Green). Specifically, the finding did not represent a loss of system or function and did not represent the loss of a single train for greater than technical specification allowed outage times or greater than 24 hours. The inspectors determined that the finding has a cross-cutting aspect in the area of Human Performance, Procedure Adherence, because Exelons staff did not adequately implement the procedures for reliability performance criteria evaluation. Specifically, Exelon did not verify that the established performance criteria for train reliability accurately monitored the scope of the function and demonstrated the effectiveness of maintenance when performing functional failure determinations and the periodic 10 CFR 50.65(a)(3) assessment. (H.8)
05000352/FIN-2016004-0231 December 2016 23:59:59LimerickSelf-revealingControl Structure Chiller Unit Trip Caused by Failure to Properly Implement ProceduresGreen. A self-revealing Green NCV of LGS Units 1 and 2 technical specification 6.8.1 was identified when Exelon did not properly implement a surveillance procedure. Specifically, operators secured cooling water to the operating A control structure chilled water system (CSCWS) chiller unit which resulted in the unit automatically tripping to prevent damage. Operators subsequently restored cooling water flow in accordance with procedures. Exelon entered the issue into the corrective action program as IR 2720374. This finding is more than minor because it is associated with the human performance attribute of the mitigating systems cornerstone to ensure the availability, reliability, and capability of systems that respond to initiating events to prevent undesirable consequences. Specifically, the loss of cooling water to the A CSCWS chiller unit resulted in a trip of the unit on high condenser pressure and rendered the chiller unavailable. Using IMC 0609, Appendix A, Exhibit 2, the inspectors determined that this finding was of very low safety significance (Green). Specifically, the finding did not represent a loss of system or function and did not represent the loss of a single train for greater than technical specification allowed outage times or greater than 24 hours. The inspectors determined that this finding has a cross-cutting aspect in the area of Human Performance, Avoid Complacency, because operators did not recognize and plan for the possibility of mistakes and inherent risk and did not use appropriate error reduction tools. (H.12)
05000352/FIN-2016003-0230 September 2016 23:59:59LimerickLicensee-identifiedLicensee-Identified ViolationThe following violation of very low safety significance (Green) was identified by Exelon and is a violation of NRC requirements which meets the criteria of the NRC Enforcement Policy for being dispositioned as a non-cited violation. 10 CFR 50.54(q)(2), Emergency Plans, requires, in part, that a holder of a licensee under this part shall follow and maintain the effectiveness of an emergency plan that meets the requirements in Appendix E to this part, and for nuclear power reactor licensees, the planning standards of 50.47(b). 10 CFR 50.47(b)(4) requires that a standard emergency classification and action level scheme, the bases of which include facility system and effluent parameters, is in use by the nuclear facility licensee. Contrary to the above, from April 25, 2016, until August 3, 2016, the spent fuel pool level emergency action level (EAL) RG2/RS2 threshold of Limericks Emergency Plan for a General Emergency and Site Area Emergency did not meet the requirements of Appendix E and the planning standards of 10 CFR 50.47(b). Specifically, Exelon identified that the spent fuel pool level for RG2/RS2 threshold was 0.08 feet, and the correct threshold value was 0.8 feet. The spent fuel pool EAL threshold values for a lowering water level for an Alert and Unusual Event were correct at 10.20 feet and less than 22 feet, respectively. The normal spent fuel pool water level is over 23 feet. The inspectors evaluated this finding using IMC 0609, Appendix B, Emergency Preparedness Significance Determination Process, Table 5.4-1. This Table indicates, in part, that the following should be assessed as low safety significance (White): an EAL has been rendered ineffective such that any General Emergency would not be declared for a particular off-normal event, but because of other EALs, an appropriate declaration could be made in a degraded manner (e.g. delayed), and, an EAL that has been rendered ineffective such that any Site Area Emergency would not be declared for a particular off-normal event. However, the inspectors confirmed that the spent fuel pool level instrumentation at LGS goes off scale at approximately 0.635 feet, and the Limerick Emergency Plan, in Addendum 3, directs any Emergency Director to assume the EAL threshold has been exceeded if the associated parameter goes off scale. In addition, the NEI recommended and NRC endorsed value for this EAL threshold would have been at nominally 0.0 feet, the level at which the fuel remains covered and actions to implement make-up water addition should no longer be deferred. Although the LGS threshold for declaration at 0.8 feet would have been exceeded, the inspectors concluded that the event would have been classified when the SFP level dropped below 0.635 feet, sufficiently above the NEI recommended level. Because the event would have been declared with margin to the actual water level needed for protection of the public, i.e. the spent fuel would still be fully covered by water at the time of the EAL declaration(s), the inspectors concluded that this performance deficiency was most similar to the Table 5.4-1 branches representing very low safety significance (Green). Exelons corrective actions included revising EP-AA-1008, Addendum 3, with the correct spent fuel pool level EAL RG2/RS2 threshold of 0.8 feet. Because this issue was of very low safety significance (Green) and Exelon entered the issue into the corrective action program (IR 2700440), this finding is being treated as a non-cited violation, consistent with Section 2.3.2.a of the Enforcement Policy.
05000353/FIN-2016003-0130 September 2016 23:59:59LimerickSelf-revealingInadequate Design Control of Plant Processing Computer ModificationA self-revealing finding of very low safety significance (Green) was identified when Exelon did not implement their engineering design control procedures during the plant processing computer (PPC) modification. Specifically, Exelon did not fully address effects of the modification on other plant systems and did not establish a testing boundary that encompassed all components whose operation was altered by the modification. As a result, the PPC modification had a wiring design error that resulted in the trip of both reactor recirculation pumps (RRPs) which required a manual reactor trip of Unit 2. In response to this issue, Exelon initiated IR 2676712, investigated the cause of the trip, fixed the wiring design error, performed a root cause evaluation, and performed an extent of condition review. This issue is more than minor because it adversely affected the design control attribute of the initiating events cornerstone to limit the likelihood of events that upset plant stability and challenge critical safety functions during shutdown as well as power operations. Specifically, the PPC modification process had a wiring design error that resulted in the trip of both RRPs which required a manual reactor trip of Unit 2. The issue was evaluated in accordance with IMC 0609, Appendix A, "Significance Determination Process for Findings At-Power, using Exhibit 1, "Initiating Events Screening Questions, Section B, Transient initiators. The finding was determined to be of very low safety significance (Green) because the finding did not cause a reactor trip and the loss of mitigation equipment relied upon to transition the plant from the onset of the trip to a stable shutdown condition. The inspectors determined that this finding has a cross-cutting aspect in the area of Human Performance, Challenge the Unknown, because LGS staff did not stop when faced with uncertain conditions, and risks were not evaluated and managed before proceeding. Specifically, Exelon did not stop and reevaluate the risks and effects on plant systems when changes were made to the PPC design modification package. (H.11)
05000352/FIN-2016001-0331 March 2016 23:59:59LimerickNRC identifiedInadequate Work Staging and Housekeeping Walkdowns During PreOutage PreparationsThe inspectors identified a Green NCV of technical specification 6.8.1 for Exelons failure to properly control, store, and stage material in accordance with station procedures within Class I buildings during refueling outage preparation. Specifically, Exelon personnel did not secure numerous rolling carts staged in both units, did not secure welding blankets in the common pipe tunnel to prevent blocking floor drains, and did not properly build scaffolds to include engineering approval for scaffold procedure deviations. In addition, Exelons housekeeping and material condition program did not identify and resolve these conditions through the corrective action process during a time of increased activities in the plant. Exelon restrained the carts and other rolling equipment, removed the weld blankets, and removed, reworked, and evaluated scaffolding. This finding is more than minor because it adversely affected the protection against external factors (flood and seismic hazards) attribute of the mitigating systems cornerstone to ensure the availability, reliability, and capability of systems that respond to initiating events to prevent undesirable consequences (i.e. core damage). Specifically, the loose unattended welding blankets would have blocked the pipe tunnel floor drains during an analyzed internal flooding event which would result in structural failures if not identified and corrected by operations personnel; the unrestrained carts would translate and rotate during a seismic event which could potentially impact safety related equipment and challenge the function or barrier; and the scaffold clearance and attachment issues could potentially cause impact with ductwork, cable trays, hangers, and structural supports during a seismic event. In addition, the performance deficiency is similar to the more-than-minor example described in IMC 0612, Appendix E, example 4.A, in that Exelon routinely failed to perform engineering evaluations on similar issues. Using IMC 0609, Appendix A, Exhibit 2, the inspectors determined that this finding was of very low safety significance (Green). Specifically, the finding is a deficiency affecting the design or qualification of mitigating structures, systems, and components, and the actual functions of the structures, systems, and components were maintained. The inspectors determined that this finding has a cross-cutting aspect in the area of Human Performance, Training, because the organization did not provide sufficient training to maintain a knowledgeable workforce with respect to proper material handling and storage, awareness of flood hazards and floor drains, and scaffolding requirements. (H.9)
05000352/FIN-2016001-0131 March 2016 23:59:59LimerickSelf-revealingReactor Enclosure Recirculation System Design Change not EvaluatedA self-revealing Green NCV of Title 10 of the Code of Federal Regulations (10 CFR) Part 50 (10 CFR 50), Appendix B, Criterion III, Design Control, was identified because Exelon did not properly maintain the design of the LGS Unit 1 reactor enclosure recirculation system (RERS). Specifically, Exelon replaced the Unit 1 1A RERS flow straightener assembly using thinner material than was originally qualified and did not evaluate the change in design. Exelon initiated IR 2563872 and implemented a temporary configuration change that removed the flow straightener assembly from the system and restored Unit 1 RERS to operability on October 5, 2015. Exelon also initiated corrective actions to install a new flow straightener assembly with correctly sized honeycomb material. This finding 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 (secondary containment) protect the public from radionuclide releases caused by accidents or events. Specifically, the inadequate 1A RERS flow straightener assembly installed in 2012 resulted in degraded performance and then unplanned unavailability of 1A RERS from October 1 to 5, 2015. Using IMC 0609, Appendix A, Exhibit 3, the inspectors determined that this finding was of very low safety significance (Green). Specifically, the degraded 1A RERS performance and associated unavailability only represented a degradation of the radiological barrier function provided for the standby gas treatment system and screened to Green. The inspectors determined that the finding did not have cross-cutting aspect because the performance deficiency did not occur within the last three years, and the inspectors did not conclude that the primary cause of the performance deficiency represented present Exelon performance.
05000352/FIN-2016001-0431 March 2016 23:59:59LimerickSelf-revealingEntry into a High Radiation Area without Radiological Briefing and Complying with the RWPA self-revealing Green NCV of LGS Unit 1 technical specification 6.12.1 was identified involving improper entry of two workers into the Unit 1 reactor drywell on March 22, 2016. Specifically, the workers entered the drywell, an area controlled as a Locked High Radiation Area, without obtaining the required access radiological conditions briefing. Further, one of the two workers entered under the control of an RWP that did not authorize access into High Radiation Areas. Exelon initiated IR 2644005, restricted the workers from further radiological controlled area access, re-configured the access area, conducted an extent of condition and human performance review, issued a site communication, and performed a staff stand down. This finding is more than minor because it is associated with the programs and process attribute of the Occupational Radiation Safety cornerstone and adversely affected the cornerstone objective to ensure adequate protection of workers from radiation exposure. In addition, this example is similar to example 6.h of IMC 0612, Appendix E. Specifically, the workers did not receive a brief and did not review surveys prior to entering a work area with radiation levels that exceeded 100 mrem/hr at 30 cm. Using IMC 0609, Appendix C, Occupational Radiation Safety Significance Determination Process, the inspectors determined the finding was of very low safety significance (Green) because: 1) it was not an as low as is reasonably achievable (ALARA) finding, 2) there was no overexposure, 3) there was no substantial potential for an overexposure, and 4) the ability to assess dose was not compromised. The inspectors determined that this finding has a cross-cutting aspect in the area of Human Performance, Procedure Adherence, because the individuals failed to follow verbal work instructions. (H.8)
05000352/FIN-2016001-0231 March 2016 23:59:59LimerickNRC identifiedSeismic Qualification of Safety Related Battery not MaintainedThe inspectors identified a Green NCV of 10 CFR 50, Appendix B, Criterion III, Design Control, and technical specification 3.8.2, D.C. Sources, because Exelon failed to ensure the design control measures for field changes impacting the seismic support of station batteries were commensurate with those applied to the original design requirements. Specifically, during cell replacement of the Class 1E 1A1 125/250 volts direct current (Vdc) safeguards battery, removal of adjacent cells and restraint barriers left the battery in a state in which the seismic qualification was not maintained. Exelon initiated IR 2624349, stopped the battery cell replacement work, and performed a technical evaluation to determine the requirements to maintain the seismic qualification during the cell replacement process. This finding is more than minor because it adversely affected the protection against external factors (seismic) attribute of the mitigating systems cornerstone to ensure the availability and reliability of systems that respond to initiating events to prevent undesirable consequences (i.e. core damage). Specifically, during cell replacement of the Class 1E 1A1 125/250 Vdc safeguards battery, removal of adjacent cells and restraint barriers left the battery in a state in which the seismic qualification was not maintained. In accordance with IMC 0609, Appendix A, Exhibit 4, External Event Screening Questions, the inspectors determined that a detailed risk evaluation was required because the loss of this equipment by itself during the seismic event it was intended to mitigate would degrade one or more trains of a system that supports a risk significant function. The Region I Senior Reactor Analyst referenced the Limerick External Events Notebook to assess the potential increase in plant risk associated with this condition. As referenced in the Notebook, the initiating event frequency for the safe shutdown earthquake (SSE) is approximately 5E-4/year. Based upon the inspectors review of operations logs, the five battery replacement activities that occurred over the past 12 months ranged in duration from between one to six days. Assuming the seismic qualification was compromised the entire duration of these maintenance activities, the consequential increase in risk for any single event would be in the low to mid E-9 delta core damage frequency range. The dominant core damage sequences involve an SSE that results in a loss of offsite power and the subsequent failure to remove heat from containment (via the multi-train residual heat removal system and associated service water cooling trains). This estimated small increase in core damage frequency represents a condition of very low safety significance (Green). The inspectors determined that this finding has a cross-cutting aspect in the area of Human Performance, Avoid Complacency, because Exelon did not recognize and plan for the possibility of latent issues associated with the battery replacement process. (H.12)
05000352/FIN-2016001-0731 March 2016 23:59:59LimerickLicensee-identifiedLicensee-Identified ViolationThe following violation of very low safety significance (Green) was identified by Exelon and is a violation of NRC requirements which meets the criteria of the NRC Enforcement Policy for being dispositioned as a NCV. From 2010 to 2014, Exelon made a total of 16 shipments of radioactive material which contained category 2 quantities of radioactive material. Exelon did not implement a transportation security plan for any of these shipments, which is contrary to the requirements of 49 CFR 172, Subpart I, Safety and Security Plans. This performance deficiency adversely affected the Public Radiation Safety cornerstone attribute of Program and Process based on inadequate procedures associated with the transportation of radioactive materials. The finding was determined to be of very low safety significance (Green) because the transportation of radioactive material issue did not involve: (1) a radiation limit that was exceeded; (2) a breach of package during transport; (3) a certificate of compliance issue; (4) a low level burial ground nonconformance; or (5) a failure to make notifications or provide emergency information. This issue was documented in Exelons corrective action program as IR 2490592. Corrective actions included contracting with a vendor to receive regular, prompt notifications of potentially applicable rule changes in the Federal Register.
05000353/FIN-2016001-0531 March 2016 23:59:59LimerickSelf-revealingMain Turbine Digital Electrohydraulic Control System Modification Failed to Revise the Plant Startup ProcedureA self-revealing Green NCV of LGS Unit 2 technical specification 6.8.1 was identified because Exelon failed to maintain a plant startup procedure. Specifically, the implementing procedure for normal plant startup from hot shutdown or cold shutdown to rated power was not maintained when a modification to the Unit 2 turbine electrohydraulic control system was performed and required changes to the plant startup procedure were not identified and implemented. Exelon initiated issue report (IR) 2602637, revised the startup procedure to properly incorporate the software changes made at the factory acceptance test, validated the software changes that were made were technically correct, trained all operators on the new procedural changes, and reviewed operating procedures for extent of condition. This finding is more than minor because it is associated with the procedure quality attribute of the initiating events cornerstone and affected the objective to limit the likelihood of events that upset plant stability during power operations. Specifically, the procedure directed actions intended in the software for rapid reactor depressurization that resulted in a reactor trip. Using IMC 0609, Significance Determination Process, Appendix A, Exhibit 1, Initiating Events Screening Questions, the inspectors determined that this finding was of very low safety significance (Green) because the finding did not cause both a reactor trip and the loss of mitigation equipment relied upon to transition the plant from the onset of the trip to a stable shutdown condition. Specifically, although the finding caused a Level 8 trip of the feedwater pumps followed by a reactor trip, the rate of water injection from the condensate pumps was sufficient when the reactor was tripped to safely shutdown and operators were able to reset the feedwater pumps. The inspectors determined that this finding has a cross-cutting in the area of Human Performance, Change Management, because leaders did not use a systematic process for implementing the modification so that nuclear safety remained the overriding priority.
05000353/FIN-2016001-0631 March 2016 23:59:59LimerickNRC identifiedFailure to Implement Procedures for Control of Potentially Contaminated Clean SystemsThe inspectors identified a Green NCV of technical specification 6.8.1 because Exelon failed to implement procedure CY-AA-170-210, Potentially Contaminated System Control Program, for the evaluation and control of potentially cross-contaminated systems. Specifically, Exelon did not implement CY-AA-170-210 for the evaluation and control of a potentially cross-contaminated system when samples collected from the Unit 2 service air system, a non-contaminated system, indicated the potential presence of contamination on June 16, 2015. Exelon entered this issue into the corrective action program (IR 2556568), restricted use of the service air system, conducted a 10 CFR 50.59 screening and radiological evaluation of the system, conducted bounding radiation dose analyses for both occupational workers and members of the public, conducted an extent of condition review, decontaminated the system, and subsequently modified operation of the service air system to preclude re-contamination. This finding is more-than-minor because it is associated with the program and process attributes of the occupational and public radiation safety cornerstones and adversely affected both cornerstone objectives to ensure adequate protection of worker and public health and safety from exposure to radioactive material. Specifically, during the time the service air system was contaminated but not recognized as such and not restricted in use, the potential existed to inadvertently contaminate workers and release radioactive material to the environment. Using IMC 0609, Appendix C, Occupational Radiation Safety Significance Determination Process, the inspectors determined that this finding was of very low safety significance (Green) because the finding did not involve an as low as is reasonably achievable (ALARA) issue, was not an overexposure, did not result in a substantial potential for an overexposure, and did not compromise the ability to assess dose. In addition, using IMC 0609, Appendix D, Public Radiation Safety Significance Determination Process, the inspectors determined that the issue did not involve a substantial failure to implement the effluent release program and did not result in public doses exceeding 10 CFR 50, Appendix I or 10 CFR 20.1301 (e) and thus was of very low safety significance (Green). The inspectors determined this finding has a cross-cutting aspect in the area of Problem Identification and Resolution, Resolution, because Exelon did not take effective corrective actions when service air system issues were identified.
05000352/FIN-2015004-0131 December 2015 23:59:59LimerickNRC identifiedSeismic Qualification of Safety Related Block Wall Not MaintainedThe inspectors identified a Green non-cited violation (NCV) of 10 CFR 50, Appendix B, Criterion III, Design Control, because Exelon did not properly store circuit breakers and ground trucks in accordance with the established design in order to maintain the seismic qualification of safety-related structures. Specifically, Exelon personnel attached stored circuit breakers and ground trucks to safety-related concrete block walls but did not evaluate the greater weight of circuit breakers, did not maintain the required separation distances, and did not attach all equipment to required attachment points. Exelon initiated issue report (IR) 2592543, removed all stored circuit breakers from the location, rearranged ground trucks to attach them only to designated wall anchors that maintained the required separation distance, and required refresher training of all operators and electrical maintenance personnel on proper spacing and restraint of circuit breakers and ground trucks. This finding is more than minor because it adversely affected the protection against external factors (seismic) attribute of the mitigating systems cornerstone to ensure the availability and reliability of systems that respond to initiating events to prevent undesirable consequences (i.e. core damage). Specifically, the improper storage of the circuit breakers and ground trucks affected the seismic qualification of the concrete block walls separating the switchgear of the emergency diesel generators (EDG) which had potential to damage the block walls during a seismic event. Using IMC 0609, Appendix A, Exhibit 4, the inspectors determined that this finding was of very low safety significance (Green). Specifically, the inspectors determined that the performance deficiency only affected the seismic qualification of the concrete block wall, the loss of the concrete wall by itself would not necessarily cause an initiating event or degradation of the EDG system, and the finding did not involve the total loss of any safety function. Furthermore, the inspectors consulted a Senior Risk Analyst regarding the risk screening and determined that a failure of the walls would not necessarily result in the degradation or failure of the EDG systems. Specifically, for screening purposes, assuming total failure of the concrete masonry walls only introduces a potential of degraded performance since the switchgear are anchored to the concrete floor. As such, Exhibit 4 provides a reasonable basis for screening the finding as Green. The inspectors determined that this finding has a cross-cutting aspect in the area of Human Performance, Procedure Adherence, because equipment operators did not follow the established work instructions (posted signs).
05000352/FIN-2015004-0231 December 2015 23:59:59LimerickLicensee-identifiedLicensee-Identified ViolationTechnical Specification 3.6.5.3, Standby Gas Treatment System Common System, requires with one SGTS subsystem, restore the inoperable subsystem to operable status within 7 days, or be in at least hot shutdown within the next 12 hours and in cold shutdown within the following 24 hours. Contrary to Technical Specification 3.6.5.3, SGTS subsystem B was inoperable for Unit 1 from August 27, 2015, to September 4, 2015, for a time of 8 days 18 hours, and Exelon did not place Unit 1 in hot shutdown or cold shutdown. Exelon entered this issue into the corrective action program as IR 2517538. The inspectors evaluated this finding using IMC 0609.04, Initial Characterization of Findings, and IMC 0609, Appendix A, Exhibit 3, Barrier Integrity Screening Questions. The inspectors determined that the finding was of very low safety significance (Green) because the finding only represented a degradation of the radiological barrier function of the SGTS. In addition, the inoperable condition would have resulted in a flowrate exceeding the analyzed 2500 cfm with a differential pressure greater than the minimum 0.25 inches of vacuum water gauge. However, the condition did not represent a larger pathway through secondary containment and SGTS retained radiological filtering capability.
05000352/FIN-2015201-0230 September 2015 23:59:59LimerickNRC identifiedSecurity
05000353/FIN-2015003-0130 September 2015 23:59:59LimerickSelf-revealingInadequate Procedure for RWCU Backwashing OperationsA self-revealing Green NCV of Technical Specification (TS) 6.8.1.a, Procedures and Programs, occurred because Exelon failed to establish, implement, and maintain an adequate procedure for the control of radioactivity and limiting personnel exposure during operation of a solid radioactive waste system. Specifically, the procedure for the conduct of reactor water cleanup (RWCU) filter media backwashing and collection was inadequate to ensure a sufficient receiving tank volume prior to transferring waste media. On June 28, 2015, this resulted in the overflow of a Unit 2 RWCU collection tank and back up of the reactor building floor drain system, causing high levels of radioactive contamination in accessible portions of the Unit 2 reactor building, and resulting in radioactive contamination of personnel. Exelon controlled access, decontaminated affected areas and personnel, conducted bounding dose assessments, performed extent of condition reviews, and revised affected procedures to address the issue. Exelon placed this issue into the corrective action program as issue report (IR) 2520732. This issue is more-than-minor because if left uncorrected, it had the potential to lead to a more significant safety concern. Specifically, the failure to effectively control and manage radioactive material could result in significant unplanned, unintended occupational radiation exposure of workers. Using IMC 0609, Appendix C, Occupational Radiation Safety Significance Determination Process, the inspectors determined that this finding was of very low safety significance (Green) because the finding did not involve an as low as is reasonable achievable (ALARA) issue, was not an overexposure, did not result in a substantial potential for an overexposure, and did not compromise the ability to assess dose. The inspectors determined this finding has a cross-cutting aspect in the area of Human Performance, Avoiding Complacency, because Exelon did not recognize and plan for the possibility of mistakes, latent issues, and inherent risk, even while expecting successful outcomes, and therefore did not implement appropriate error reduction tools. Specifically, Exelon operated the backwash receiving tank (BWRT) to routinely accept high level alarms with associated potential for system overflow. Consequently, although this mode of operation of the system was longstanding, the issue reflects present performance.
05000352/FIN-2015007-0130 September 2015 23:59:59LimerickNRC identifiedFailure to Verify Adequacy of EDG Voltage to Start Safety-Related MotorsThe team identified a finding of very low safety significance involving a non-cited violation (NCV) of the 10 CFR Part 50, Appendix B, Criterion III, Design Control, in that Exelon did not verify and assure in design basis calculations, that adequate voltage would be available for starting Class 1E accident mitigating motors when the safeguards buses are powered by the emergency diesel generators (EDG). Specifically, in the calculation performed to evaluate voltage available to individual motors when they are powered by the EDGs, Exelon assumed that the generator output voltage would be 4285 Volts, alternating current (Vac), rather than the minimum voltage allowed by station technical specifications (4160 Vac). Additionally, the electrical ratings of loads powered by the EDG were not adjusted for the maximum frequency allowed by station technical specifications (61.2 hertz (Hz)). As a result, the starting voltage for some of the safetyrelated motors would not have been acceptable under EDG generator voltage and frequency limiting conditions. In response, Exelon entered the issue into their corrective action program and performed evaluation that determined that EDG actual test results demonstrated the EDGs to be operable. The team review of the evaluation determined it to be reasonable. This finding was more than minor because it was similar to Example 3.j of NRC IMC 0612, Appendix E, and was associated with the Design Control attribute of the Mitigating Systems Cornerstone and adversely affected the cornerstone objective of ensuring the availability, reliability, and capability of systems that respond to initiating events to prevent undesirable consequences. The team determined the finding was of very low safety significance because it was a design deficiency confirmed not to result in a loss of safety-related motor operability or functionality. The team determined this finding had a cross-cutting aspect in the area of Problem Identification and Resolution (Identification, Aspect P.1), because during a calculation revision in 2014, Exelon did not recognize that the limits of voltage and frequency allowed by the station technical specifications affected the calculation results and, therefore, did not completely and accurately identify the issue and revise the calculation in accordance with the stations corrective action program requirements.
05000352/FIN-2015007-0230 September 2015 23:59:59LimerickNRC identifiedFailure to Verify Adequate Voltage Available for DC EquipmentThe team identified a finding of very low safety significance involving a non-cited violation (NCV) of 10 CFR Part 50, Appendix B, Criterion III, Design Control, in that Exelons design control measures did not verify the adequacy of the design regarding adequate direct current voltage (Vdc). Specifically, Exelon did not ensure that adequate voltage existed to emergency diesel generator (EDG) relays and output breaker spring charging motors. Additionally, the team determined that the overall impact to voltage drop calculations was not adequately assessed when the temporary battery cart is used. Following identification of the issue, Exelon entered it into their corrective action program and evaluated the operability of the batteries, concluding that the affected DC components would function at the current battery capacities. The teams review of the evaluation determined it to be reasonable. The finding was more than minor because it was similar to Example 3.j of NRC IMC 0612, Appendix E, and 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.The team determined the finding was of very low safety significance because it was a design deficiency affecting the safetyrelated batteries that did not result in the loss of operability or functionality. The team determined this finding had a cross-cutting aspect in the area of Human Performance, (Documentation, Aspect H.7) because the battery sizing calculation was revised on March 15, 2014, which provided an opportunity to identify the inaccuracies of the battery calculations.
05000352/FIN-2015201-0130 September 2015 23:59:59LimerickNRC identifiedSecurity
05000353/FIN-2015003-0230 September 2015 23:59:59LimerickSelf-revealingInadequate Preventive Maintenance of the HPCI System Motor Control CenterA self-revealing Green NCV of TS 6.8.1.a, Procedures and Programs, occurred when Exelon inadequately maintained and implemented a preventive maintenance (PM) task for the 2DB-1-14 high pressure coolant injection (HPCI) direct current (DC) motor control center (MCC) cubicle. Specifically, PM procedure M-095-002, 250 VDC Westinghouse MCU Maintenance, Revision 6, was performed on the main compartment but was not performed on the auxiliary compartment of the 2DB-1-14 MCC cubicle. Subsequently, the 1A timetactor failed due to lack of cleaning and inspection, which led to a fire in the HPCI DC MCC. Exelons corrective actions included initiating issue report (IR) 2480166, replacing the affected components, and revising the PM task to perform future preventive maintenance on both the main and auxiliary compartments of the 2DB-1-14 cubicle. Exelon also conducted immediate extent of condition reviews and scheduled further reviews to ensure no similar conditions exist. This issue is more than minor because it was associated with the procedures quality attribute of the Mitigating Systems cornerstone, and adversely affected the cornerstone objective to ensure the reliability of systems that respond to initiating events to prevent undesirable consequences (i.e., core damage). Specifically, PM procedure M-095-002, 250 VDC Westinghouse MCU Maintenance, Revision 6, was not performed on both compartments of the 2DB-1-14 cubicle and caused the fire in the HPCI DC MCC that had the potential to affect HPCI system operation. Using IMC 0609, Significance Determination Process, Appendix A, Exhibit 2, Mitigating Systems Screening Questions, the inspectors determined that this finding was of very low safety significance (Green) because the finding was not a deficiency affecting the design or qualification of the HPCI system and the system maintained operability and functionality. Specifically, the affected portions of the HPCI system were a part of the HPCI vacuum tank condensate pump that is not required to ensure operability or functionality. The inspectors determined that the finding did not have a cross-cutting aspect because the PM task change did not occur within the last three years, and the inspectors did not conclude that the causal factors represented present Exelon performance.
05000352/FIN-2015002-0130 June 2015 23:59:59LimerickSelf-revealingDesign Requirements Not Met for Installed Instrument Gas Tubing FittingA self-revealing Green NCV of 10 CFR 50, Appendix B, Criterion III, Design Control, was identified because Exelon failed to control the proper design configuration of installed plant equipment in Unit 1. Specifically, a fitting used in the safety-related primary containment instrument gas (PCIG) tubing supplying the 1C inboard main steam isolation valve (MSIV) was not installed in accordance with the specified quality standard and this deviation was not controlled. Subsequently, the fitting failed due to high cycle fatigue and caused a reactor trip. Exelons corrective actions included initiating condition report IR 2458005, installing approved tubing and fittings on February 24, 2015, on the 1C inboard MSIV which maintained wall thicknesses greater than original specifications, and verifying that current maintenance practice, training, and knowledge would preclude substitution of a different style fitting without further evaluation. This finding is more than minor because it is associated with the design control attribute of the initiating events cornerstone and affected the objective to limit the likelihood of events that upset plant stability during power operations. Specifically, the inadvertent closure of the 1C inboard MSIV resulted in a reactor trip. Using IMC 0609, Significance Determination Process, Appendix A, Exhibit 1, Initiating Events Screening Questions, the inspectors determined that this finding was of very low safety significance (Green) because the finding did not cause a reactor trip and the loss of mitigation equipment relied upon to transition the plant from the onset of the trip to a stable shutdown condition (e.g. loss of condenser, loss of feedwater). Specifically, the finding caused the loss of one steam line to the main condenser but three steam lines remained available. The inspectors determined that the finding did not have cross-cutting aspect because the installation of the fitting that failed did not occur within the last three years, and the inspectors did not conclude that the causal factors represented present Exelon performance.
05000352/FIN-2015001-0231 March 2015 23:59:59LimerickNRC identifiedStartup Procedure Considered High Pressure Coolant Injection Operable with High Reactor Water Level Trip Actuated Preventing High Drywell Pressure Automatic ActuationThe inspectors identified an NCV of Title 10 of the Code of Federal Regulations (10 CFR), Appendix B, Criterion V, Instructions, Procedures, and Drawings, because Exelon prescribed a procedure affecting quality with instructions which were not appropriate to the circumstances. Specifically, procedure GP-2, Normal Plant Startup, contained a note that stated high pressure coolant injection (HPCI) systems have been determined operable by engineering evaluation with a high level trip setpoint actuated. The inspectors determined that the note was inconsistent with Units 1 and 2 technical specifications (TS) and was not supported by an adequate engineering basis. Exelons corrective actions included briefing staff to ensure HPCI system operability is appropriately assessed when implementing GP-2, initiating condition report IR 2464416, completing a procedure revision to reference an interim evaluation contained in the condition report, and initiating an action to complete an engineering evaluation. This finding is more than minor because it is associated with the procedure quality attribute of the mitigating systems cornerstone and affected the objective to ensure the capability of systems that respond to initiating events to prevent undesirable consequences (i.e., core damage). Specifically, procedure GP-2 stated that the HPCI system was operable with a Level 8 trip present without the ability to automatically actuate upon a high drywell pressure without an engineering evaluation which was inconsistent with the existing safety analysis performed at normal operating reactor pressure and temperature. Using IMC 0609, Significance Determination Process, Appendix A, Exhibit 2, Mitigating Systems Screening Questions, the inspectors determined that this finding was of very low safety significance (Green) because the finding did not represent an actual loss of the HPCI system or function to inject high pressure emergency core cooling water. Specifically, the note in GP-2 allowed considering the HPCI system operable at normal operating reactor pressures with the HPCI system tripped. However, the HPCI system was not tripped at normal operating reactor pressures. The inspectors determined that the finding did not have cross-cutting aspect because the procedure development performance deficiency did not occur within the last three years, and the inspectors did not conclude that the causal factors represented present Exelon performance.
05000352/FIN-2015001-0331 March 2015 23:59:59LimerickNRC identifiedOperability of High Pressure Coolant Injection and Entries into Operational Conditions at Low Reactor Pressures with High Reactor Water Level Trip ActuatedOn February 23, 2015, LGS Unit 1 automatically shut down and remained in the hot shutdown operational condition (i.e. mode 3) for equipment repair and restart. Based on a lit overhead annunciator and indicating light in the main control room, the inspectors noted that the HPCI high reactor water level trip (Level 8, trip setpoint 54 inches) was actuated with normal reactor water level being maintained using the reactor water level narrow range instruments (35 inches). This annunciator provided indication that HPCI was potentially inoperable. The inspectors noted that Exelon had been tracking the HPCI system as operable. The inspectors questioned the ability of the high drywell pressure instruments to fulfill the function required by TS to actuate the HPCI system with the high water level trip actuated. Technical specification 3.3.3 requires that the emergency core cooling system actuation channels shown in Table 3.3.3-1 be operable. Table 3.3.3-1, trip function 3.b, drywell pressure high, requires four operable channels during operating modes 1, 2, and 3 (Power Operation, Startup, and Hot Shutdown) when reactor pressure is greater than 200 psig. With more than one channel inoperable, the HPCI system must be declared inoperable. With a Level 8 trip present, the logic circuitry prevents actuation of the HPCI system by tripping its urbine stop valve closed. In addition, to prevent undue cycling of the HPCI system, when the reactor water level drops below the Level 8 trip signal setpoint, a sealin circuit prevents actuation of the HPCI system until the Level 8 trip relays are reset, either by a manual reset pushbutton or when reactor water level drops to the reactor vessel water level low-low (Level 2, actuation setpoint -38 inches) actuation setpoint. The operators did not declare HPCI inoperable because procedure GP-2, Normal Plant Startup, contained a note that stated HPCI systems have been determined operable by engineering evaluation with a high level trip setpoint actuated. Exelon determined that the note was added to Revision 56 of GP-2, approved on December 18, 1995. However, Exelon was unable to find the referenced engineering evaluation that justified this conclusion. The inspectors determined that at normal operating reactor pressure the TS required the high drywell pressure channels be declared inoperable when the channels were incapable of automatically actuating the HPCI system and the procedural note was not supported by an associated evaluation. Therefore, the lack of an adequate evaluation supporting the procedural note represented a performance deficiency and violation of regulatory requirements. However, in consultation with staff from the Technical Specifications and Reactor Systems Branches in the NRC Office of Nuclear Reactor Regulation, the inspectors determined that Exelons conclusion that the operability and safety function of the HPCI system was maintained at lower reactor pressures with the Level 8 trip actuated required further information in order to determine if that issue of concern was a performance deficiency and violation.
05000352/FIN-2015001-0131 March 2015 23:59:59LimerickNRC identifiedFire Safe Shutdown Diesel Generator Maintenance Program Did Not Account for Cold Temperatures due to Inadequate Specification for Fuel Oil Cloud PointThe inspectors identified an NCV of LGS Units 1 and 2 operating license condition 2.C(3), Fire Protection, because Exelon did not implement and maintain in effect all provisions of the NRC approved fire protection program. Specifically, Exelon did not implement and maintain a maintenance program to ensure the operability of the fire safe shutdown diesel (FSSD) generator by not ensuring a fuel oil supply specified or protected for typical winter cold temperatures. Exelons corrective actions included adding a fuel oil additive (modifiers which inhibit wax crystal growth) to improve low temperature flow and pour characteristics at a time when ambient temperatures were greater than the cloud point and initiating condition report IR 2463216. This finding is more than minor because it adversely affected the protection against external factors (fire) attribute of the mitigating systems cornerstone to ensure the reliability of systems that respond to initiating events to prevent undesirable consequences (i.e., core damage). Specifically, the failure to ensure the cloud point of the diesel fuel oil was below the temperature of the surrounding air would impact the reliable operation of the equipment during low temperature conditions. Using IMC 0609, Appendix F, Fire Protection Significance Determination Process, the inspectors determined that this finding was of very low safety significance (Green) because the finding did not impact the ability of LGS Units 1 and 2 to achieve safe shutdown. Specifically, the cloud point of diesel fuel delivered onsite by the vendor was substantially lower than Exelons specification, unavailability of the FSSD generator would not by itself prevent LGS from reaching and maintaining safe shutdown, and the need for powered ventilation given a loss of normal HVAC during cold weather would be less than during hot weather. The inspectors determined that this finding has a cross-cutting aspect in the area of Human Performance, Resources, because Exelon did not ensure that cold weather preparedness procedures were adequate to support nuclear safety. Specifically, Exelon relied upon the cold weather procedures to establish reliable equipment operation during cold temperatures, but the procedures did not address diesel fuel cloud point for equipment stored and/or operated outdoors.
05000352/FIN-2014008-0131 December 2014 23:59:59LimerickNRC identifiedSecurity
05000352/FIN-2014005-0131 December 2014 23:59:59LimerickSelf-revealingUnplanned Manual Power Reduction to 90% on Unit 1A self-revealing, Green non-cited violation (NCV) of Technical Specification (TS) 6.8.1.b, Administrative Controls, was identified for LGS failure to properly implement station procedure MA-AA-716-100, Maintenance Alterations Process, during troubleshooting and calibration associated with the Unit 1 condensate filter (CF) system. As a result, on September 9, 2014, one of two Instrument Maintenance (IM) technicians inadvertently mispositioned the air supply valve to the 1G CF flow transmitter causing an unplanned plant transient. The inspectors determined that the failure to properly implement station procedure MA-AA-716-100, Maintenance Alterations Process, during troubleshooting of CF system instrumentation, was a performance deficiency. LGS promptly performed an investigation, verified the plant alignment and safely returned the Unit 1 reactor to 100 percent power. LGS entered the issue into their corrective action program (CAP) as issue report (IR) 2116233 This self-revealing finding is more than minor because it affected the human performance attribute of the Initiating Events Cornerstone and affected the cornerstone objective of limiting the likelihood of those events that upset plant stability and challenge critical safety functions. This resulted in elevated main steam line radiation levels which required operators to reduce reactor power in accordance with abnormal operating procedures. The inspectors evaluated the finding using inspection manual chapter (IMC) 0609, Appendix A, The Significance Determination Process for Findings At-Power, to IMC 0609, Significance Determination Process. This finding was determined to be of very low safety significance (Green) because it was associated with a transient initiator, but didnt cause a reactor trip and the loss of mitigation equipment relied upon to transition the plant from the onset of the trip to a stable shutdown condition. The finding has a cross-cutting aspect in the area of Human Performance, because LGS maintenance management did not ensure supervisory and management oversight of work activities (H.2).
05000352/FIN-2014004-0130 September 2014 23:59:59LimerickNRC identifiedInadequate Evacuation Time Estimate SubmittalsThe inspectors identified a Green NCV of Title 10 of the Code of Federal Regulations (CFR) 50.54(q)(2), 10 CFR 50.47(b)(10), and 10 CFR Part 50, Appendix E, Section IV.4, for not maintaining the effectiveness of the LGS, Units 1 and 2, emergency plan as a result of failing to provide the station evacuation time estimate (ETE) to the responsible offsite response organizations (OROs) by the required date. Exelon entered this issue into their corrective action process (CAP) as issue reports (IR) 1525923 and 1578649. Additionally, Exelon re-submitted a new revision of the LGS ETE to the NRC on January 31, 2014. This performance deficiency is more than minor because it is associated with the emergency preparedness cornerstone attribute of procedure quality and adversely affected the cornerstone objective of ensuring that LGS is capable of implementing adequate measures to protect the health and safety of the public in the event of a radiological emergency. The finding was determined to be of very low safety significance (Green) because it was a failure to comply with a non-risk significant portion of 10 CFR 50.47(b)(10). The cause of the finding is related to the cross-cutting element of Human Performance, Documentation, because LGS did not appropriately create and maintain complete, accurate and, up-to-date documentation.
05000352/FIN-2014004-0230 September 2014 23:59:59LimerickLicensee-identifiedLicensee-Identified ViolationThe following violation of very low safety significance (Green) was identified by LGS and is a violation of NRC requirements which met the criteria of the NRC Enforcement Policy for being dispositioned as a NCV. LGS Unit 1 and 2 TS 6.8.1 require that written procedures be established, implemented, and maintained including an ODCM. LGS Procedure CY-LG-170-301, Revision 26, ODCM, requires in Table 3.3-1, that continuous airborne radioactivity samplers be placed in three locations close to the site boundary (in different sectors) of the highest calculated annual average ground level deposition (D/Q). Contrary to the above, there was no sampler close to the site boundary location in the southeast sector with the highest ground level D/Q. That air sampler located in the southeast sector was at a distance of 3 miles beyond the site boundary. This matter was identified by LGS in late 2012 and placed in the CAP. At the time of this inspection, LGS was installing a new air sampling station near the site boundary location in the southeast sector. LGS evaluated the impact of the lack of this station and concluded there was no radiological impact in that: air monitoring stations near the site boundary in adjoining sectors had not detected radioactivity attributable to plant operations; analysis of samples of broadleaf vegetation in the specific sector did not identify any radioactivity attributable to station operations; and routine effluent sampling did not identify any abnormal airborne effluent releases. The issue was determined to be more than minor because it adversely affected the program and process attribute of the Public Radiation Safety cornerstone objective to ensure adequate protection of public health and safety from exposure to radioactive materials released into the public domain. The inspectors determined that the finding was of very low safety significance (Green) because the finding was in the radiological environmental monitoring program and was contrary to TS. Because this finding is of very low safety significance, and the issue was entered into LGS' CAP (IRs 1390579, 1668838), this violation is being treated as a Green NCV consistent with the NRC Enforcement Policy.
05000352/FIN-2014404-0330 June 2014 23:59:59LimerickLicensee-identifiedLicensee-Identified Violation
05000353/FIN-2014003-0130 June 2014 23:59:59LimerickNRC identifiedInadequate Corrective Actions Following Repeat Test Failures of a High Pressure Coolant Injection System Level InstrumentThe inspectors identified a Green NCV of 10 Code of Federal Regulations (CFR) Part 50, Appendix B, Criterion XVI, Corrective Action, for the failure to adequately evaluate and correct repeat calibration test failures in April 2012 and in February 2014 on the Unit 2 high pressure coolant injection (HPCI) system suppression pool level transmitter LT-055- 2N062F. This resulted in LT-055-2N062F, a technical specification (TS) required instrument, being in a degraded and unreliable condition. The inspectors determined that failure to adequately evaluate and correct the condition was reasonably within the ability to foresee and correct, and should have been prevented. LGS personnel promptly replaced the instrumentation and returned the HPCI system to an operable status prior to the Unit 2 startup. LGS also entered the issue into their corrective action program (CAP) for resolution as Issue Reports (IRs) 1646041, 1651480, and 1659171. This NRC-identified finding is more than minor because it affected the Barrier Integrity cornerstone attribute of the reliability and availability of structures, systems, or components to maintain the functionality of containment and affected the cornerstone objective to provide reasonable assurance that physical design barriers (containment) protect the public from radionuclide releases caused by accidents or events. The inspectors evaluated the finding using Appendix A, The Significance Determination Process for Findings At-Power, to IMC 0609, Significance Determination Process. This finding was determined to be of very low safety significance (Green) because it was associated with the functionality of the reactor containment but didnt represent an actual open pathway in the physical integrity of containment, the containment isolation system, and heat removal components and, the finding did not involve an actual reduction in function of hydrogen igniters. In addition, the logic for the HPCI pump suction transfer from the condensate storage tank to the suppression pool on high level in the suppression pool is a one-out-of-two logic. The inspectors determined that this function was available because the other channel which performs the function was not affected by the finding and was available during the time period in question with the exception of during brief testing periods. The finding has a cross-cutting aspect in Problem Identification and Resolution, Evaluation, because LGS personnel did not thoroughly evaluate the issue to ensure that resolutions addressed the causes and extent of conditions commensurate with their safety significance.
05000352/FIN-2014403-0330 June 2014 23:59:59LimerickLicensee-identifiedLicensee-Identified Violation
05000352/FIN-2014404-0130 June 2014 23:59:59LimerickNRC identifiedSecurity
05000352/FIN-2014404-0230 June 2014 23:59:59LimerickLicensee-identifiedLicensee-Identified Violation