IR 05000220/2015009
ML15288A254 | |
Person / Time | |
---|---|
Site: | Nine Mile Point ![]() |
Issue date: | 10/15/2015 |
From: | Daniel Schroeder Reactor Projects Branch 1 |
To: | Orphanos P Exelon Generation Co, Nine Mile Point |
Schroeder D | |
References | |
IR 2015009 | |
Download: ML15288A254 (26) | |
Text
October 15, 2015
SUBJECT:
NINE MILE POINT NUCLEAR STATION - PROBLEM IDENTIFICATION AND RESOLUTION INSPECTION REPORT 05000220/2015009 AND 05000410/2015009
Dear Mr. Orphanos:
On August 27, 2015, the U.S. Nuclear Regulatory Commission (NRC) completed an inspection at your Nine Mile Point Nuclear Station, LLC (NMPNS), Units 1 and 2. The enclosed report documents the inspection results, which were discussed on August 27, 2015, with Mr. W. Trafton, Plant Manager, and other members of your staff. In-office review continued after the conclusion of the onsite inspection, and a telephone exit was conducted on September 15, 2015, with Mr. D. Moore, Manager of Regulatory Affairs, and other members of your staff.
This inspection examined activities conducted under your license as they relate to identification and resolution of problems and compliance with the Commissions rules and regulations and conditions of your license. Within these areas, the inspection involved examination of selected procedures and representative records, observations of activities, and interviews with personnel.
Based on the samples selected for review, the inspection team concluded that Exelon Generating Company, LLC (Exelon) was generally effective in identifying, evaluating, and resolving problems. Exelon personnel identified problems and entered them into the corrective action program at a low threshold. Exelon prioritized and evaluated issues commensurate with the safety significance of the problems and corrective actions were generally implemented in a timely manner.
This report documents two NRC-identified findings of very low safety significance (Green). The inspectors determined that each of these findings also involved violations of NRC requirements.
However, because of the very low safety significance and because they were entered into your corrective action program, the NRC is treating these findings as non-cited violations, consistent with Section 2.3.2.a of the NRC Enforcement Policy. If you contest these non-cited violations, you should provide a response within 30 days of the date of this inspection report, with the basis for your denial, to the Nuclear Regulatory Commission, ATTN: Document Control Desk, Washington, DC 20555-0001, with copies to the Regional Administrator, Region I; the Director, Office of Enforcement, United States Nuclear Regulatory Commission, Washington, DC 20555-0001; and the NRC Resident Inspector at the NMPNS. In addition, if you disagree with the cross-cutting aspect assigned to any finding in this report, you should provide a response, within 30 days of the date of this inspection report, with the basis for your disagreement, to the Regional Administrator, Region I, and the NRC Resident Inspector at NMPNS.
In accordance with Title 10 of the Code of Federal Regulations (10 CFR) 2.390 of the NRCs Rules of Practice, a copy of this letter, its enclosure, and your response (if any) will be available electronically for public inspection in the NRC Public Document Room or from the Publicly Available Records component of the NRCs Agencywide Documents Access and Management System (ADAMS). ADAMS is accessible from the NRC website at http://www.nrc.gov/reading-rm/adams.html (the Public Electronic Reading Room).
Sincerely,
/RA/
Daniel L. Schroeder, Chief Reactor Projects Branch 1 Division of Reactor Projects
Docket Nos.
50-220 and 50-410 License Nos. DPR-63 and NPF-69
Enclosure:
Inspection Report 05000220/2015009 and 05000410/2015009 w/Attachment: Supplementary Information
REGION I==
Docket Nos.
50-220 and 50-410
License Nos.
Report Nos.
05000220/2015009 and 05000410/2015009
Licensee:
Exelon Generation Company, LLC
Facility:
Nine Mile Point Nuclear Station, LLC
Unit 1 and Unit 2
Location:
Oswego, New York
Dates:
August 10, 2015, through August 27, 2015
Team Leader:
E. DiPaolo, Senior Project Engineer
Inspectors:
E. Miller, Resident Inspector
B. Pinson, Project Engineer
A. Siwy, Project Engineer
Approved by:
Daniel L. Schroeder, Chief Reactor Projects Branch 1 Division of Reactor Projects
SUMMARY
Inspection Report 05000220/2015009 and 05000410/2015009; 08/10/2015 - 08/27/2015;
Nine Mile Point Nuclear Station (NMPNS), Units 1 and 2; Biennial Baseline Inspection of Problem Identification and Resolution. The inspectors identified two findings in the area of corrective action evaluation.
This U.S. Nuclear Regulatory Commission (NRC) team inspection was performed by three regional inspectors and one resident inspector. The inspectors identified two findings of very low safety significance (Green) during this inspection and classified these findings as non-cited violations (NCVs). The significance of most findings is indicated by their color (i.e., greater than Green, or Green, White, Yellow, Red) and determined using Inspection Manual Chapter (IMC)0609, Significance Determination Process, dated April 29, 2015. Cross-cutting aspects are determined using IMC 0310, Aspects Within the Cross-Cutting Areas, dated December 4, 2014. All violations of NRC requirements are dispositioned in accordance with the NRCs Enforcement Policy, dated February 4, 2015. The NRCs program for overseeing the safe operation of commercial nuclear power reactors is described in NUREG-1649, Reactor Oversight Process, Revision 5.
Problem Identification and Resolution
The inspectors concluded that Exelon Generating Company, LLC (Exelon) was generally effective in identifying, evaluating, and resolving problems. Exelon personnel identified problems, entered them into the corrective action program at a low threshold, and prioritized issues commensurate with their safety significance. Exelon appropriately screened issues for operability and reportability, and performed causal analyses that appropriately considered extent of condition, generic issues, and previous occurrences. The inspectors also determined that Exelon typically implemented corrective actions to address the problems identified in the corrective action program in a timely manner. However, the inspectors identified two violations of NRC requirements in the area of evaluation of problems.
The inspectors concluded that, in general, Exelon adequately identified, reviewed, and applied relevant industry operating experience to NMPNS operations. In addition, based on those items selected for review, the inspectors determined that Exelons self-assessments and audits were thorough.
Based on the interviews the inspectors conducted over the course of the inspection, observations of plant activities, and reviews of individual corrective action program and employee concerns program issues, the inspectors did not identify any indications that site personnel were unwilling to raise safety issues nor did they identify any conditions that could have had a negative impact on the sites safety conscious work environment.
Cornerstone: Barrier Integrity
- Green.
The inspectors identified a Green NCV of Title 10 of the Code of Federal Regulations (10 CFR) 50, Appendix B, Criterion XVI, Corrective Actions, because between 2007 and 2015,
Exelon staff did not promptly identify and correct a deficiency associated with Unit 2 reactor building service water pipe penetration W-3177-C. Specifically, on August 20, 2015, during Exelon staffs investigation of an inspector concern associated with the service water pipe penetration into secondary containment, a leakage path into secondary containment was discovered and was not previously identified and evaluated for impact on operability of Unit 2 secondary containment. Exelon generated issue report (IR) 2544831 to document the newly identified condition. The assessment included a review of previously identified leakage paths that were being tracked in accordance with procedure, previously performed secondary containment drawdown leakage testing, and a comparison to the maximum allowable flow rate leakage area. The assessment concluded that based on the gap that was identified at secondary containment penetration W-3177-C, there was a new total of 1.783 square inches of surface area allowing leakage into the Unit 2 secondary containment. Exelon determined this to be acceptable because calculations for secondary containment drawdown testing allows for up to 33.6 square inches of surface area causing in-leakage into secondary containment. Given 1.783 square inches of total identified leakage being less than the allowable 33.6 square inches, there was reasonable assurance that standby gas treatment system will be able to perform its drawdown function and maintain secondary containment vacuum 0.25 inches of vacuum water gauge in accordance with Technical Specification (TS) 3.6.4.1, Secondary Containment.
This performance deficiency was more than minor because it impacted the design control attribute of the Barrier Integrity cornerstone objective to provide reasonable assurance that physical design barriers protect the public from radionuclide releases caused by accidents or events. Specifically, Exelons staff failed to identify the degraded penetration seal that impacted the reasonable assurance of Unit 2 secondary containment operability. In accordance with IMC 0609.04, Initial Characterization of Findings, and Exhibit 3 of IMC 0609, Appendix A, The Significance Determination Process for Findings At-Power, issued June 19, 2012, the inspectors determined this finding was of very low safety significance (Green) because the finding only represented a degradation of the radiological barrier function provided for the control room, or auxiliary, spent fuel pool, or standby gas treatment system (i.e., secondary containment). This finding had a cross-cutting aspect in the area of Problem Identification and Resolution, Evaluation, because Exelon staff failed to properly evaluate the condition identified in multiple IRs to determine the extent of condition associated with secondary containment water in-leakage. Specifically, between 2007 and 2015, three IRs were generated and a 2012 structural monitoring review documented the service water penetration water in-leakage and the issue was not appropriately evaluated for the potential for a service water pipe through-wall leak or the potential impact on secondary containment. [P.2] (4OA2.1.c(1))
Cornerstone: Mitigating Systems
- Green.
The inspectors identified a Green NCV of 10 CFR 50.65, Requirements for Monitoring the Effectiveness of Maintenance at Nuclear Power Plants, under section (a)(1) and (a)(2) for failing to properly monitor the 600 volt alternating current (VAC) system at Unit 1 in accordance with established maintenance rule reliability criteria to assure that breakers were capable of performing their intended function. Specifically, the inspectors identified four events that were not evaluated against the established (a)(2) reliability criteria. This resulted in a failure to evaluate the 600 VAC system for potential corrective actions in accordance with (a)(1) and did not ensure effective control through preventative maintenance to show the system was capable of performing its intended function in accordance with (a)(2). Exelons immediate corrective actions included evaluations of the failures and planning for a maintenance rule expert panel for consideration of placing the system into (a)(1) where corrective actions could be developed to return the system to (a)(2) monitoring. Exelon also noted that IR 2416790 documented the challenge associated with overcurrent trip device drift and subsequent pump failures. This IR was open at the time of the inspection with actions to determine if a replacement is possible and to present any potential options to Plant Health Committee in October 2015.
This performance deficiency is more than minor because it is associated with the equipment performance attribute of the Mitigating Systems cornerstone and affected the cornerstone objective to ensure the availability, reliability, and capability of systems that respond to initiating events to prevent undesirable consequences. Specifically, the overcurrent trip devices associated with Unit 1 600 VAC General Electric (GE)-AK breakers were unreliable and resulted in the trip of five safety-related pumps between April 2013 and February 2014. Only one of the five functions was evaluated by Exelon. This impacted the ability of these pumps to be able to perform their function to provide cooling to their respective systems. In accordance with IMC 0609.04, Initial Characterization of Findings, and IMC 0609, Appendix A, The Significance Determination Process for Findings At-Power, issued June 19, 2012, the inspectors determined this finding was of very low safety significance (Green) because this finding did not represent an actual loss of system safety function, did not represent an actual loss of function of at least a single train for greater than its TS allowed outage time, and did not represent an actual loss of function of one or more non-TS trains of equipment designated as high safety-significant in accordance with Exelons maintenance rule program for greater than 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br />. This finding has a cross-cutting aspect in the area of Problem Identification and Resolution, Evaluation, because Exelon failed to thoroughly evaluate the failures against the monitoring criteria specified for the Unit 1 600 VAC breaker super system. Specifically, between April 2013 and February 2014, four breaker failures were identified by the inspectors that were not evaluated against the Unit 1 600 VAC breaker super system, which prevented compliance with 10 CFR 50.65 (a)(1) to ensure corrective actions are established to return the system to (a)(2) monitoring. [P.2]
(4OA2.1.c(2))
REPORT DETAILS
OTHER ACTIVITIES (OA)
4OA2 Problem Identification and Resolution
This inspection constitutes one biennial sample of problem identification and resolution as defined by Inspection Procedure 71152. All documents reviewed during this inspection are listed in the Attachment to this report.
.1 Assessment of Corrective Action Program Effectiveness
a. Inspection Scope
The inspectors reviewed the procedures that described the corrective action program at NMPNS. Since the last NRC biennial Problem Identification and Resolution inspection completed in August 2013, NMPNS management transitioned from Constellation Energy Nuclear Group, LLC (Constellation) to Exelon. The transition, which occurred on April 1, 2014, resulted in the review of program effectiveness under two separate sets of program procedures and program processes. To assess the effectiveness of the corrective action program, the inspectors reviewed performance in three primary areas:
problem identification, prioritization and evaluation of issues, and corrective action implementation. The inspectors compared performance in these areas to the requirements and standards contained in 10 CFR 50, Appendix B, Criterion XVI, Corrective Action; Exelon procedure PI-AA-125, Corrective Action Program; and Constellation procedure CNG-CA-1.01-1000, Corrective Action Program.
For each of these areas, the inspectors considered risk insights from the stations risk analysis and reviewed condition reports (CRs) (Constellation) and IRs (Exelon) selected across the seven cornerstones of safety in the NRCs Reactor Oversight Process.
Additionally, the inspectors attended multiple Station Ownership Committee and Management Review Committee meetings. The inspectors selected items from the following functional areas for review: engineering, operations, maintenance, emergency preparedness, radiation protection, chemistry, physical security, nuclear oversight, and the corrective action program.
- (1) Effectiveness of Problem Identification
In addition to the items described above, the inspectors reviewed system health reports, a sample of completed corrective and preventative maintenance work orders, completed surveillance test procedures, operator logs, and periodic trend reports. The inspectors also completed field walkdowns of various systems on site, such as the Units 1 and 2 instrument air systems, the Unit 1 emergency service water system, the Unit 2 service water system, the fire protection system, and the Units 1 and 2 emergency diesel generators (EDGs). Additionally, the inspectors reviewed a sample of CRs and IRs written to document issues identified through internal self-assessments, audits, emergency preparedness drills, and the operating experience program. The inspectors completed this review to verify that Exelon staff entered conditions adverse to quality into their corrective action program as appropriate.
- (2) Effectiveness of Prioritization and Evaluation of Issues
The inspectors reviewed the evaluation and prioritization of a sample of CRs and IRs issued since the last NRC biennial Problem Identification and Resolution inspection completed in August 2013. The inspectors also reviewed CRs and IRs that were assigned lower levels of significance that did not include formal cause evaluations to ensure that they were properly classified. The inspectors review included the appropriateness of the assigned significance, the scope and depth of the causal analysis, and the timeliness of resolution. The inspectors assessed whether the evaluations identified likely causes for the issues and developed appropriate corrective actions to address the identified causes. Further, the inspectors reviewed equipment operability determinations, reportability assessments, and extent-of-condition reviews for selected problems to verify these processes adequately addressed equipment operability, reporting of issues to the NRC, and the extent of the issues.
- (3) Effectiveness of Corrective Actions
The inspectors reviewed completed corrective actions through documentation review and, in some cases, field walkdowns to determine whether the actions addressed the identified causes of the problems. The inspectors also reviewed CRs and IRs for adverse trends and repetitive problems to determine whether corrective actions were effective in addressing the broader issues. The inspectors reviewed Exelons timeliness in implementing corrective actions and effectiveness in precluding recurrence for significant conditions adverse to quality. The inspectors also reviewed a sample of CRs and IRs associated with selected NCVs and findings to verify that Exelon personnel properly evaluated and resolved these issues. In addition, the inspectors expanded the corrective action review to five years to evaluate the Exelons actions related to deficiencies associated with the Units 1 and 2 instrument air systems and the Units 1 and 2 neutron monitoring system.
b.
Assessment
- (1) Effectiveness of Problem Identification
Based on the selected samples, plant walkdowns, and interviews of site personnel in multiple functional areas, the inspectors determined that Exelon identified problems and entered them into the corrective action program at a low threshold. Exelon staff at NMPNS initiated approximately 22,000 CRs and IRs between September 2013 and June 2015. The inspectors observed supervisors at the Plan-of-the-Day, Station Ownership Committee, and Management Review Committee meetings appropriately questioning and challenging CRs to ensure clarification of the issues. Based on the samples reviewed, the inspectors determined that Exelon trended equipment and programmatic issues, and appropriately identified problems in CRs. The inspectors verified that conditions adverse to quality identified through this review were entered into the corrective action program as appropriate. Additionally, inspectors concluded that personnel were identifying trends at low levels. In general, inspectors did not identify any issues or concerns that had not been appropriately entered into the corrective action program for evaluation and resolution. In response to several questions and minor equipment observations identified by the inspectors during plant walkdowns, Exelon personnel promptly initiated CRs and/or took immediate action to address the issues.
- (2) Effectiveness of Prioritization and Evaluation of Issues
The inspectors determined that, in general, Exelon appropriately prioritized and evaluated issues commensurate with the safety significance of the identified problem.
Exelon screened CRs for operability and reportability, categorized the CRs by significance, and assigned actions to the appropriate department for evaluation and resolution. The CR screening process considered human performance issues, radiological safety concerns, repetitiveness, adverse trends, and potential impact on the safety conscious work environment.
Based on the sample of CRs reviewed, the inspectors noted that the guidance provided by Exelon corrective action program implementing procedures appeared sufficient to ensure consistency in categorization of issues. Operability and reportability determinations were generally performed when conditions warranted and in most cases, the evaluations supported the conclusion. Causal analyses appropriately considered the extent of condition or problem, generic issues, and previous occurrences of the issue.
However, the inspectors did identify two examples of more than minor significance where Exelon personnel were not effective in evaluating and implementing effective corrective actions. These findings are documented in Section 4OA2.1.c. Additionally, the inspectors noted some observations in Exelons prioritization and evaluation of issues (described below).
Operability Determination Considerations
During an operability run of the Unit 2 Division I EDG on August 12, 2015, Exelon staff detected an increase in noise from one of the engines cylinder heads (8R). Operators shut down the engine and declared the EDG inoperable. Operators later determined the EDG was operable based on supporting data provided by Engineering. The condition was caused by the lock nut on the lifter adjusting screw becoming loose and the adjusting screw backing out. Operators documented the condition and the operability determination as IR 2540902. Exelon staff also previously identified on December 19, 2014, that one of the cylinders exhaust valve lifter needed adjustment (IR 2427663).
The team reviewed the operability determination and identified that several important key aspects to support operability were not addressed. Specifically, the operability evaluation for the degraded condition did not address, or factor in the following: 1) the conditions effect on the mission time of the EDG; 2) potential effect of foreign material if the adjusting screw completely backed out; 3) the effect of the valve rocker arm coming into contact with the valve cover and whether an oil leak could develop and become an oil leakage concern or fire hazard; and 4) vendor or other operating experience with loose valve adjusting screws.
Exelon staff acknowledged that the operability discussion in IR 2540902 did not address the factors raised by the team. Exelon revised the operability evaluation to address the factors. The revised operability determination concluded that the EDG remained operable with the loose valve adjusting screw. The inspectors concluded that this issue was minor because the information was available to Engineering and the conclusion that the EDG was operable did not change after properly addressing the factors in the operability determination.
Operability Determination Documentation
Per OP-AA-108-115, Operability Determinations, Revision 16, the results of operability determinations are to be documented in the IR. During the inspection, the team observed four examples discussed below where the operability evaluation documentation in the IR did not contain all of the information that was available to operators or to support their conclusion that the equipment was operable. Although the requirements of OP-AA-108-115 were not fully met for the four examples, these issues were determined to be minor because the information was available to support operability and operators factored the information into their operability determination for the issues:
IR 2545212 was written for Unit 2 control rod 42-03 not being able to be moved during control rod exercise testing. The IR stated the control rod was operable due to being capable of being scrammed with minimal supporting information. More detailed information associated with troubleshooting the control rod (e.g., control drive flow, directional control valve operation, etc.) to support this conclusion was contained in the Control Room Log. This example was identified by the team during the inspection.
IR 5444831 was written to document an inspector-identified finding related to a degraded Unit 2 secondary containment penetration service water seal identified during the inspection (see Section 4OA2.1.c for additional details). Exelon staff performed a detailed evaluation of the degraded seal and documented the results in the Control Room Log. However, the detailed information was not entered into the IR operability discussion. This was identified by the Station Ownership Committee during IR review during the inspection.
IR 2427663 was written in December 2014 due to the identification of an exhaust valve on the Unit 2 Division I EDG needing a valve lifter adjustment. The operability statement in the IR only contained a statement that the condition did not impact operability. The operability statement did not address the effect on long-term reliability of the EDG although engineering personnel were knowledgeable of the effect if the condition worsened. As a result, the operability information was not readily available to the operating crew on August 12, 2015, when the condition (valve lash) worsened (see next example below). This was identified by the team during the inspection. Exelon wrote IR 2546324 to document the condition.
IR 2540902 was written on August 12, 2015, to document the condition of the Unit 2 Division I EDG exhaust valve lifter adjustment worsening. Information initially provided by Engineering to Operations was incorporated into the operability statement in the IR. Based on questions from Operations, Engineering provided supplemental information to support operability. However, Operations did not update the operability statement in IR 2540902 to include the supplemental information.
This was identified by the Management Review Committee during IR review.
Ineffective EAL associated with Unit 1 High Lake Water Level
EPIP-EPP-01, Attachment 1, Emergency Action Level (EAL) Matrix Unit 1, Revision 23, contains criteria for declaring a Notice of Unusual Event (NOUE), HU1.5, for lake water level greater than 248.2 ft. The EAL matrix also contains criteria for declaring an Alert, HA1.5, for lake water level greater than 254 ft. The basis for the high lake water level is established in Unit 2 updated final safety analysis report (UFSAR) Chapter 2, Section 2.4.2.1 and 2.4.5.2, which discusses analyses of storm surge and wind-wave activity at the NMPNS site. The UFSAR documents a maximum design basis value for wave run up as 254 ft. A revetment ditch was designed and built to protect the site against the analyzed value for storm surges on Lake Ontario.
IR 2000009 documents a discrepancy associated with the Unit 1 screenhouse intake level instrument, PI-73-32, reading approximately three feet less than the lake level when circulating water pumps are running. This condition impacts the Unit 1 Emergency Directors (ED) ability to declare an event in accordance with EP-AA-1013, Radiological Emergency Plan Annex for Nine Mile Point Station, Revision 0, and EALs established for an NOUE and Alert during high lake water level. An action item was generated in the corrective action program to confirm that intake level instrument at Unit 1 matched lake water level. This action item was performed on March 25, 2015, during the Unit 1 refuel outage when the circulating water pumps were not in service. The action confirmed that the intake level matched lake water level. The inspectors determined that Exelon staff did not evaluate the concern regarding the instrument discrepancy during circulating water pump operation. The inspectors also identified that no control room alarm or procedure was available to assist the Unit 1 ED in making an EAL declaration for a high lake level condition. Exelon generated IR 2546064 to document the concern and evaluate a resolution. Exelons immediate corrective actions included modifying Unit 1 procedure N1-PM-S1, Operators Rounds Guide, Revision 02800, to include a step to determine lake level using the National Oceanic and Atmospheric Administration (NOAA) website on a daily basis. It also includes a backup step to determine the lake level from a local buoy in Oswego, NY harbor by telephone if the NOAA website is not functioning properly. The team concluded Exelon could have reasonably identified the discrepancies during the evaluation of IR 2000009.
The inspectors determined that the Unit 1 EDs inability to declare an event in accordance with EP-AA-1013 and the EAL matrix for Unit 1 was a performance deficiency that was reasonably within Exelons ability to foresee and correct and therefore should have been prevented. This issue was minor because, although the Unit 1 ED was not able to declare an event in accordance with EP-AA-1013 and the EAL matrix for Unit 1, there was reasonable assurance that the Unit 2 ED would be able to make an event declaration for the site. Interviews with Unit 2 operators confirmed that operators were familiar with procedures for a high lake water level event. Procedure N2-OP-102, Meteorological Monitoring, Revision 1500, Section H.1.2.3, refers operators to procedure N2-OSP-LOG-M001, Monthly Checks Log, Revision 00704, for obtaining Lake Ontario water level. N2-OSP-LOG-M001, Attachment 5, provides a website to obtain Lake Ontario water level from the NOAA website. Also, EP-AA-1013, Radiological Emergency Plan Annex for Nine Mile Point Station, Revision 0, step 2.1.2, Station Responsibility during Off-Normal Working Hours, states in the event of an emergency declaration due to an initiating condition affecting both Unit 1 and Unit 2, both Units Shift Managers (SMs) will confer and determine:
The SM of the Unit with the higher emergency classification will become the Shift Emergency Director.
If emergency classification levels are equal, the SM first notified will become the Shift Emergency Director.
Given the procedural steps listed in EP-AA-1013 and based on interviews with Unit 2 operators that demonstrated knowledge of actions to take and procedures to use for a high level condition, it was reasonable to assume that a site event for high lake level could be declared from Unit 2.
- (3) Effectiveness of Corrective Actions
The inspectors concluded that corrective actions for identified deficiencies were generally timely and adequately implemented. For significant conditions adverse to quality, Exelon identified actions to prevent recurrence. The inspectors concluded that corrective actions to address the sample of NRC NCVs and findings since the last problem identification and resolution inspection were timely and effective.
c. Findings
- (1) Failure to Identify and Correct a Condition Adverse to Quality Associated with Secondary Containment Leakage
Introduction.
The inspectors identified a Green NCV of 10 CFR 50, Appendix B, Criterion XVI, Corrective Actions, because between 2007 and 2015, Exelon staff did not promptly identify and correct a deficiency associated with Unit 2 reactor building service water pipe penetration W-3177-C. Specifically, on August 20, 2015, during Exelon staffs investigation of an inspector concern associated with the service water pipe penetration into secondary containment, a leakage path into secondary containment was discovered and was not previously identified and evaluated for impact on operability of Unit 2 secondary containment.
Description.
The Unit 2 secondary containment, which consists of the reactor building and auxiliary bay structures, is a structure that encloses primary containment and components that may contain reactor coolant system fluid. The structure forms a control volume that serves to hold up and dilute the fission products during a loss of coolant accident or a fuel handling accident. The secondary containment performs no active function in response to each of these events. As described in the Unit 2 TS Bases, its leak tightness is required to ensure that the release of radioactive materials from the primary containment is restricted to those leakage paths and associated leakage rates assumed in accident analyses and that fission products entrapped within the secondary containment structure will be treated by the standby gas treatment system prior to discharge to the environment.
At elevation 240 in the Unit 2 north auxiliary bay of secondary containment, 30 inch service water pipe 2-SWP-030-39-3 penetrates through the bay wall. This service water pipe supplies water to plant equipment for cooling purposes, including residual heat removal heat exchangers and primary component cooling heat exchangers.
During a walkdown on August 14, 2015, the inspectors noted indications of water in-leakage where the service water pipe penetrates into the room. The inspectors questioned if Exelon staff had previously evaluated whether the water source was from service water as a result of a potential through-wall leak. Exelon staff generated IR 2542251 to document the inspectors concern. Exelon staff then generated an assignment to gather a chemistry sample of the water that was leaking from the penetration in order to determine the source.
During engineering assessment of the penetration in response to IR 2542251, Exelon staff determined that the service water pipe insulation needed to be removed in order to collect water contained within the insulation. During removal of the pipe insulation, Exelon staff detected air movement through the penetration seal. Upon further inspection, Exelon staff discovered a 1.25 square inch gap between the bottom of the service water pipe and the penetration silicone foam seal. The identified gap provided a leakage path to secondary containment and represented an immediate operability concern for secondary containment. Exelon generated IR 2544831 to document the newly identified condition. Exelon performed an operability determination and commenced a review of CC-NM-201, Control of Secondary Containment Leakage Paths, Revision 00000. The assessment included a review of previously identified leakage paths that were being tracked in accordance with CC-NM-201, previously performed secondary containment drawdown leakage testing, and a comparison to the maximum allowable flow rate leakage area. The assessment concluded that based on the gap that was identified at secondary containment penetration W-3177-C, there was a new total of 1.783 square inches of surface area allowing leakage into the Unit 2 secondary containment. Exelon determined this to be acceptable because calculations for secondary containment drawdown testing allows for up to 33.6 square inches of surface area causing in-leakage into secondary containment. Given 1.783 square inches of total identified leakage being less than the allowable 33.6 square inches, there was reasonable assurance that standby gas treatment system will be able to perform its drawdown function and maintain secondary containment vacuum 0.25 inches of vacuum water gauge in accordance with TS 3.6.4.1, Secondary Containment.
The water in-leakage from the penetration seal was initially identified on September 6, 2007, as denoted by deficiency tag number ACR-07-04845. No evaluation in the corrective action program system could be identified by Exelon staff. However, review of the corrective action program by the inspector discovered subsequent IRs which did not lead to identification of the gap in the secondary containment penetration. CR-2010-007406 was generated in 2010 during an Exelon staff walkdown which identified water in-leakage through the penetration. Work order C90940663 was generated and executed in October of 2011. The work order resulted in replacement of the service water pipe insulation and cleaning of the wall staining that was caused by the water in-leakage. The penetration seal was not inspected or assessed for the leakage. During an Exelon staff walkdown in 2011, the service water penetration in-leakage was again identified and entered into the corrective action program as CR-2011-003532. Work order C91265639 was generated to assess the penetration and repair as necessary.
During the inspectors review of the work order, it was discovered that the work order remained in initiation status since it was first issued in 2011. Finally, in 2012, the service water penetration water leakage was again identified in a Unit 2 structural monitoring report. The 2011 IR was referenced and noted the open work order to address the degraded penetration.
Between 2007 and 2015, the W-3177-C service water penetration in Unit 2 reactor building north auxiliary bay was not appropriately inspected and evaluated following the identification of water in-leakage through the penetration seal. This resulted in the failure to identify the gap in the penetration which represented a degradation to secondary containment. Based on Exelons assessment of the penetration gap, a breach permit has been assigned to this penetration and was being tracked to ensure repairs will be made to the penetration.
Analysis.
The inspectors determined that not taking timely action in accordance with Exelons corrective action program to identify and correct a condition adverse to quality associated with service water pipe penetration W-3177-C in the Unit 2 reactor building 240 north auxiliary bay, was a performance deficiency and was within Exelons ability to foresee and correct and should have been prevented. The inspectors determined that this performance deficiency was more than minor because it impacted the design control attribute of the Barrier Integrity cornerstone objective to provide reasonable assurance that physical design barriers protect the public from radionuclide releases caused by accidents or events. Specifically, Exelons staff failed to identify the degraded penetration seal that impacted the reasonable assurance of Unit 2 secondary containment operability.
In accordance with IMC 0609.04, Initial Characterization of Findings, and Exhibit 3 of IMC 0609, Appendix A, The Significance Determination Process for Findings At-Power, issued June 19, 2012, the inspectors determined this finding was of very low safety significance (Green) because the finding only represented a degradation of the radiological barrier function provided for the control room, or auxiliary, spent fuel pool, or standby gas treatment system (i.e., secondary containment).
This finding had a cross-cutting aspect in the area of Problem Identification and Resolution, Evaluation, because Exelon staff failed to properly evaluate the condition identified in multiple IRs to determine the extent of condition associated with secondary containment water in-leakage. Specifically, between 2007 and 2015, three IRs were generated and a 2012 structural monitoring review documented the service water penetration water in-leakage and the issue was not appropriately evaluated for the potential for a service water pipe through-wall leak or the potential impact on secondary containment. [P.2]
Enforcement.
10 CFR 50, Appendix B, Criterion XVI states that measures shall be established to assure that conditions adverse to quality, such as failures, malfunctions, deficiencies, deviations, defective material and equipment, and non-conformances are promptly identified and corrected. Contrary to this, between September 6, 2007, and August 20, 2015, Exelons corrective action program did not assure that a condition adverse to quality associated with a Unit 2 secondary containment penetration seal leak, was promptly identified and corrected. Specifically, ACR-07-04845, CR-2010-007406, and CR-2011-003532 were entered into the corrective action program between 2007 and 2015 regarding water leakage into Unit 2 secondary containment through service water pipe penetration (W-3177-C) in reactor building elevation 240 north auxiliary bay and timely action was not taken to inspect or assess the penetration. As a result of the inspectors questioning, Exelon staff discovered that the service water pipe penetration seal was degraded which represented a condition adverse to quality associated with Unit 2 secondary containment on August 20, 2015. Exelon entered the issue into the corrective action program as IR 2542251 and IR 2544831 and immediately assessed the condition for impact on secondary containment operability with satisfactory results.
Because this violation was of very low safety significance (Green), and Exelon has entered this performance deficiency into the corrective action program, this NRC-identified finding is being treated as an NCV in accordance with Section 2.3.2 of the NRC Enforcement Policy. (NCV 05000410/2015009-01, Failure to Identify and Correct a Condition Adverse to Quality Associated with Secondary Containment Leakage)
- (2) Inadequate Maintenance Rule Monitoring of Unit 1 600 VAC Breaker Super System
Introduction.
The inspectors identified a Green NCV of 10 CFR 50.65, Requirements for Monitoring the Effectiveness of Maintenance at Nuclear Power Plants, under section (a)(1) and (a)(2) for failing to properly monitor the 600 VAC system at Unit 1 in accordance with established maintenance rule reliability criteria to assure that breakers were capable of performing their intended function. Specifically, the inspectors identified four events that were not evaluated against the established (a)(2) reliability criteria. This resulted in a failure to evaluate the 600 VAC system for potential corrective actions in accordance with (a)(1) and did not ensure effective control through preventative maintenance to show the system was capable of performing its intended function in accordance with (a)(2).
Description.
The safety-related 600 VAC system consists of powerboards 16B and 17B and their associated breakers that provide power to their associated loads. The 600 VAC powerboards contain GE model AK-2A-25-1 (GE AK) circuit breakers that are used to supply and terminate power to pump motors and other safety-related equipment needed in the event of a design basis loss of offsite power or loss of coolant accident.
Each of the GE AK breakers contain an overcurrent trip device which consists of a magnetic structure, a series current coil, and a pivoted armature. When current flow through the series coil generates a magnetic field strong enough, the armature overcomes the restraining force of a calibration spring attached to it, and closes against the magnet. This feature interrupts power flow to the associated load in the event of current rising above design requirements. The overcurrent trip device can be set to trip based on a time delay and a high instantaneous setting.
Between April 2013 and February 2015, Unit 1 experienced five pump trips when overcurrent trip device settings were subsequently found to be outside of tolerances established during preventative maintenance using procedure N1-EPM-GEN-153, Inspection and Testing of AK-15/25 Breakers and Associated Motors, Revision 00700.
These five cases associated with the pumps failing to start or run included the following:
IR 1995429 -11 Emergency Service Water Pump tripped on overcurrent during surveillance testing on April 17, 2013. The apparent cause was determined to be due to a preventative maintenance procedure deficiency that did not account for differences in current between the three phases when adjusting the setpoint for the overcurrent trip devices.
IR 1997474 - 12 Reactor Building Closed Loop Cooling pump tripped after running for 15 minutes during vibration testing on June 7, 2013. The cause was determined to be due to the instantaneous overcurrent trip device drifting out of calibration.
IR 1998932 - 11 Emergency Service Water pump failed to start during surveillance testing on August 1, 2013. The cause was determined to be due to a degraded instantaneous overcurrent trip device which drifted 11 percent below its setpoint.
IR 2003523 - 11 Spent Fuel Pool Cooling Pump failed during flow testing following both breaker and pump maintenance on February 8, 2014. The cause was determined to be due to a spurious false trip due to binding in the overcurrent trip device.
IR 1700560 - 11 Reactor Building Closed Loop Cooling pump failed to start during surveillance testing on February 14, 2014. The cause was determined to be due to the overcurrent trip device drifting out of calibration by 21 percent below the setpoint.
In addition to reviewing the cause evaluations associated with each of the pump failures, the inspectors also reviewed the associated maintenance rule evaluations. The inspectors identified that only IR 1998932 was evaluated against the maintenance rule reliability criteria for the 600 VAC breaker super system, 1-SS/BRK-F01. IR 1995429, IR 1997474, IR 2003523, and IR 1700560 were not evaluated against the maintenance rule reliability criteria associated with the 600 VAC super system. Exelon generated IR 2555608 for the failure to review these events against the super system. ER-AA-310-1004, Maintenance Rule - Performance Monitoring, Revision 13 establishes guidance for Exelon staff to ensure effective monitoring against maintenance rule reliability criteria.
Exelon established the criteria for the Unit 1 600 VAC super system to include any breaker that supports a load (i.e. motors, valves, etc.) or a powerboard that is included in the maintenance rule.
The reliability scope then defines what constitutes a functional failure. In the case of the 600 VAC super system, a functional failure is counted when a failure or malfunction of a breaker causes a functional failure of the load or powerboard being supported. Exelon established reliability criteria of not more than 4 functional failures within a two year rolling window before a maintenance rule (a)(1) evaluation must be performed in accordance with ER-AA-310-1003, Maintenance Rule - Performance Criteria Selection, Revision 4. Exelons review determined that of the events identified by the inspectors that were not screened against the 600 VAC breaker super system, each resulted in a functional failure against the 600 VAC super system. Exelons immediate corrective actions included evaluations of the failures; and planning for a maintenance rule expert panel for consideration of placing the system into (a)(1) where corrective actions could be developed to return the system to (a)(2) monitoring. Exelon also noted that IR 2416790 documented the challenge associated with overcurrent trip device drift and subsequent pump failures. This IR was open at the time of the inspection with actions to determine if a replacement is possible and to present any potential options to Plant Health Committee in October 2015.
Analysis.
The inspectors determined that Exelons failure to monitor and evaluate performance of the Unit 1 600 VAC breaker system to ensure the equipment could perform its intended safety function in accordance with established goals as required by 10 CFR 50.65 (a)(1) and (a)(2) was a performance deficiency that was reasonably within Exelons ability to foresee and correct and therefore should have been prevented. This performance deficiency is more than minor because it is associated with the equipment performance attribute of the Mitigating Systems cornerstone and affected the cornerstone objective to ensure the availability, reliability, and capability of systems that respond to initiating events to prevent undesirable consequences. Specifically, the overcurrent trip devices associated with Unit 1 600 VAC GE-AK breakers were unreliable and resulted in the trip of five safety-related pumps between April 2013 and February 2014. Only one of the five functional failures was evaluated by Exelon. This impacted the ability of these pumps to be able to perform their function to provide cooling to their respective systems.
In accordance with IMC 0609.04, Initial Characterization of Findings, and IMC 0609, Appendix A, The Significance Determination Process for Findings At-Power, issued June 19, 2012, the inspectors determined this finding was of very low safety significance (Green) because this finding did not represent an actual loss of system safety function, did not represent an actual loss of function of at least a single train for greater than its TS allowed outage time, and did not represent an actual loss of function of one or more non-TS trains of equipment designated as high safety-significant in accordance with Exelons maintenance rule program for greater than 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br />.
This finding has a cross-cutting aspect in the area of Problem Identification and Resolution, Evaluation, because Exelon failed to thoroughly evaluate the failures against the monitoring criteria specified for the Unit 1 600 VAC breaker super system.
Specifically, between April 2013 and February 2014, four breaker failures were identified by the inspectors that were not evaluated against the Unit 1 600 VAC breaker super system, which prevented compliance with 10 CFR 50.65 (a)(1) to ensure corrective actions are established to return the system to (a)(2) monitoring. [P.2]
Enforcement.
10 CFR 50.65, Requirements for Monitoring the Effectiveness of Maintenance at Nuclear Power Plants, requires, in part, that the licensee shall monitor the performance or condition of structures, systems, or components (SSCs) against licensee-established goals in a manner sufficient to provide reasonable assurance that these SSCs are capable of fulfilling their intended functions. These goals shall be established commensurate with safety and where practical, take into account industry-wide operating experience. When the performance or condition of a SSC does not meet established goals, appropriate corrective action shall be taken. Contrary to the above, between April 2013 and February 2014, Exelon failed to properly monitor the Unit 1 600 VAC breaker super system against established maintenance rule reliability criteria to assure that breakers associated with the system were capable of performing their intended function. Specifically, the inspectors identified four events that were not evaluated against the established (a)(2) reliability criteria. This resulted in a failure to evaluate the 600 VAC breaker system for potential corrective actions in accordance with (a)(1) and did not ensure effective control through preventative maintenance to show the system was capable of performing its intended function in accordance with (a)(2).
Exelon entered this condition into their corrective action program as IR 2416790 and is assessing the Unit 1 breaker super system for transition into (a)(1) status. (NCV 05000220/2015009-02, Inadequate Maintenance Rule Monitoring of Unit 1 600 VAC Breaker Super System)
.2 Assessment of the Use of Operating Experience
a. Inspection Scope
The inspectors reviewed a sample of CRs and IRs associated with review of industry operating experience to determine whether the Exelon staff appropriately evaluated the operating experience information for applicability to NMPNS and had taken appropriate actions, when warranted. The inspectors also reviewed evaluations of operating experience documents associated with a sample of NRC generic communications to ensure that Exelon staff adequately considered the underlying problems associated with the issues for resolution via their corrective action program. In addition, the inspectors observed various plant activities to determine if the station considered industry operating experience during the performance of routine and infrequently performed activities.
b.
Assessment
The inspectors determined that Exelon staff appropriately considered industry operating experience information for applicability, and used the information for corrective and preventive actions to identify and prevent similar issues when appropriate. The inspectors determined that operating experience was appropriately applied and lessons learned were communicated and incorporated into plant operations and procedures when applicable. The inspectors also observed that industry operating experience was routinely discussed and considered during the conduct of Plan-of-the-Day meetings and pre-job briefs.
c. Findings
No findings were identified.
.3 Assessment of Self-Assessments and Audits
a. Inspection Scope
The inspectors reviewed a sample of audits, including the most recent audit of the corrective action program, departmental self-assessments, and assessments performed by independent organizations. Inspectors performed these reviews to determine if the Exelon entered problems identified through these assessments into the corrective action program, when appropriate, and whether Exelon staff initiated corrective actions to address identified deficiencies. The inspectors evaluated the effectiveness of the audits and assessments by comparing audit and assessment results against self-revealing and NRC-identified observations made during the inspection.
b.
Assessment
Based on the inspected sample, the inspectors concluded that self-assessments, audits, and other internal Exelon assessments were critical, thorough, and effective in identifying issues. The inspectors observed that Exelon personnel knowledgeable in the subject completed these audits and self-assessments in a methodical manner. The inspectors observed that Nuclear Oversight was critical and identified weaknesses and areas requiring improvement. When progress in improving performance was not being accomplished in a timely manner, Nuclear Oversight effectively escalated the issues.
Exelon completed these audits and self-assessments to a sufficient depth to identify issues which were then entered into the corrective action program for evaluation. In general, the station implemented corrective actions associated with the identified issues commensurate with their safety significance.
c. Findings
No findings were identified.
.4 Assessment of Safety Conscious Work Environment
a. Inspection Scope
During interviews with station personnel, the inspectors assessed the safety conscious work environment at NMPNS. Specifically, the inspectors interviewed personnel to determine whether they were hesitant to raise safety concerns to their management and/or the NRC. The inspectors also interviewed the station Employee Concerns Program coordinators to determine what actions are implemented to ensure employees were aware of the program and its availability with regards to raising safety concerns.
The inspectors reviewed the Employee Concerns Program files to ensure that the Exelon staff entered issues into the corrective action program when appropriate.
b.
Assessment
During interviews, Exelon staff expressed a willingness to use the corrective action program to identify plant issues and deficiencies and stated that they were willing to raise safety issues. The inspectors noted that no one interviewed stated that they personally experienced or were aware of a situation in which an individual had been retaliated against for raising a safety issue. All persons interviewed demonstrated an adequate knowledge of the corrective action program and the Employee Concerns Program. Based on these limited interviews, the inspectors concluded that there was no evidence of an unacceptable safety conscious work environment and no significant challenges to the free flow of information.
c. Findings
No findings were identified.
4OA6 Meetings, Including Exit
On August 27, 2015, the inspectors presented the inspection results to Mr. W. Trafton, Plant Manager, and other members of the Exelon staff. In-office review continued after the conclusion of the onsite inspection, and a telephone exit was conducted on September 15, 2015, with Mr. D. Moore, Manager of Regulatory Affairs, and other members of your staff. The inspectors verified that no proprietary information was retained by the inspectors or documented in this report.
ATTACHMENT:
SUPPLEMENTARY INFORMATION
KEY POINTS OF CONTACT
Licensee Personnel
- P. Orphanos, Site Vice President
- W. Trafton, Plant Manager
- M. Busch, Operations Director
- M. Kunzwiler, Manager, Site Security
- C. Kronich, Manager, Nuclear Oversight
- S. Howe, Manager, Chemistry
- W. Marsh, System Manager
- B. Scaglione, Manager, Engineering
- D. Moore, Manager, Regulatory Assurance
- G. Tufts, Electrical Maintenance Manager
- J. Vaughn, Manager, Plant Engineering Systems
- T. Barlow, Manager Emergency Preparedness
- P. Collins, Senior Engineer
- S. Goodwin, System Engineer
- L. McClernan, Manager, Corrective Action Program
- K. Daniels, Regulatory Engineer
- M. Checola, Fire Protection System Manager
- F. Feito, Component Maintenance Optimization Engineer
- K. Kristensen, Regulatory Principle Engineer
- J. Rolince, Fire Marshall
- B. Varga, Regulator Engineer
- B. Felicita, System Engineer
- J. Griffo, Neutron Monitoring System Manager
- B. Suanderson, Aging Management Coordinator
NRC Personnel
- K. Kolaczyk, Senior Resident Inspector, NMPNS
LIST OF ITEMS OPENED, CLOSED, DISCUSSED, AND UPDATED
Opened and Closed
- 05000410/2015009-01 NCV Failure to Identify and Correct a Condition Adverse to Quality Associated with Secondary Containment Leakage (4OA2.1.c(1))
- 05000220/2015009-02 NCV Inadequate Maintenance Rule Monitoring of Unit 1 600 VAC Breaker Super System (4OA2.1.c(2))