IR 05000336/2017007
| ML17256A586 | |
| Person / Time | |
|---|---|
| Site: | Millstone  |
| Issue date: | 09/13/2017 |
| From: | Glenn Dentel Engineering Region 1 Branch 2 |
| To: | Stoddard D Dominion Energy |
| Dentel G | |
| References | |
| IR 2017007 | |
| Download: ML17256A586 (19) | |
Text
ber 13, 2017
SUBJECT:
MILLSTONE POWER STATION - DESIGN BASES ASSURANCE (ENVIRONMENTAL QUALIFICATION PROGRAM) INSPECTION REPORT 05000336/2017007 AND 05000423/2017007
Dear Mr. Stoddard:
On August 17, 2017, the U.S. Nuclear Regulatory Commission (NRC) completed an inspection at Millstone Power Station (Millstone), Units 2 and 3. On August 31, 2017, the NRC inspectors discussed the results of this inspection with Mr. John Daugherty, Site Vice President, and other members of your staff. The results of this inspection are documented in the enclosed report.
The NRC inspectors documented one finding of very low safety significance (Green) in this report. This finding involved a violation of NRC requirements. The NRC is treating this violation as a non-cited violation, consistent with Section 2.3.2.a of the Enforcement Policy.
If you contest the violation or the significance of the non-cited violation, you should provide a response within 30 days of the date of this inspection report, with the basis of your denial, to the U.S. Nuclear Regulatory Commission, ATTN: Document Control Desk, Washington DC, 20555-0001; with copies to the Regional Administrator, Region I; the Director, Office of Enforcement; and the NRC Resident Inspector at Millstone. This letter, its enclosure, and your response (if any) will be made available for public inspection and copying at http://www.nrc.gov/reading-rm/adams.html and at the NRC Public Document Room in accordance with 10 CFR 2.390, Public Inspections, Exemptions, Requests for Withholding.
Sincerely,
/RA/
Glenn T. Dentel, Chief Engineering Branch 2 Division of Reactor Safety Docket Nos. 50-336 and 50-423 License Nos. DPR-65 and NPF-49
Enclosure:
Inspection Report 05000336/2017007 and 05000423/2017007 w/Attachment:
Supplementary Information
REGION I==
Docket Nos. 50-336 and 50-423 License Nos. DPR-65 and NPF-49 Report Nos. 05000336/2017007 and 05000423/2017007 Licensee: Dominion Energy Nuclear Connecticut, Inc. (Dominion)
Facility: Millstone Power Station, Units 2 and 3 Location: P.O. Box 128, Waterford, CT 06385 Dates: July 31, 2017 through August 17, 2017 Inspectors: C. Bickett, Senior Reactor Inspector, Division of Reactor Safety (DRS),
Team Leader J. Brand, Reactor Inspector, DRS D. Werkheiser, Senior Reactor Inspector, DRS Approved By: Glenn T. Dentel, Chief Engineering Branch 2 Division of Reactor Safety Enclosure
SUMMARY
IR 05000336/2017007 and 05000423/2017007; 07/31/2017 - 08/17/2017; Millstone Power
Station; Design Bases Assurance Inspection (Programs).
This report covers the Design Bases Assurance Inspection - Programs, conducted by a team of three U.S. Nuclear Regulatory Commission (NRC) inspectors. The inspection team identified one non-cited violation, which was of very low safety significance (Green). The significance of most inspection 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 November 1, 2016. The NRCs program for overseeing the safe operation of commercial nuclear power reactors is described in NUREG-1649, Reactor Oversight Process, Revision 6.
Cornerstone: Mitigating Systems
- Green.
The inspection team identified a Green non-cited violation of Technical Specification 6.8.1.a, Procedures, because Dominion did not implement procedures as required by Regulatory Guide 1.33, Revision 2, Appendix A.9, Procedures for Performing Maintenance, to properly maintain the environmental qualification of safety-related auxiliary feedwater solenoid valves 2-FW-43AS and 2-FW-43BS. Specifically, Dominion failed to implement the recurring work event task and associated work order to ensure that these auxiliary feedwater solenoid valves were replaced prior to exceeding the qualified life of the solenoid coil and elastomer components. Dominion entered this issue into their corrective action program as condition report 1076005, planned replacement of the solenoid valves, and calculated an alternate ambient temperature for use in determining the qualified life of the solenoid valves. Dominion re-performed the qualified life calculation using this revised ambient temperature and extended the qualified life to support operability.
The inspection team determined that this issue was more than minor because it adversely impacted the equipment performance attribute of the Mitigating Systems cornerstone objective to ensure the availability, reliability, and capability of systems that respond to initiating events to prevent undesirable consequences. This issue is also similar to more-than-minor examples 3.j and 3.k presented in IMC 0612, Appendix E, Examples of Minor Issues. Specifically, this performance deficiency resulted in a condition where there was reasonable doubt as to the operability and reliability of the solenoid valves for both auxiliary feedwater regulating valves, and thus, both trains of auxiliary feedwater. As such, Dominion needed to conduct additional engineering evaluation to extend the service life of the solenoid valves, thus justifying that the valves would continue to perform their safety function. The inspection team determined the finding to be of very low safety significance (Green) because the finding was a deficiency affecting the reliability of a mitigating structure, system, or component, and the structure, system, or component maintained its operability or functionality. The inspection team determined that no cross-cutting aspect was applicable because the finding was not indicative of current performance. (Section 1R21.2.b)
REPORT DETAILS
REACTOR SAFETY
Cornerstones: Initiating Events, Mitigating Systems, and Barrier Integrity
1R21 Design Bases Assurance Inspection (Programs)
.1 Inspection Sample Selection Process
The inspection team assessed the implementation of Dominions Environmental Qualification program, established to meet the requirements of Title 10 of the Code of Federal Regulations (10 CFR) 50.49, Environmental Qualification of Electrical Equipment Important to Safety for Nuclear Power Plants. The inspection team performed this inspection as outlined in NRC Inspection Procedure 71111.21N, 1, Environmental Qualification under 10 CFR 50.49 Programs, Processes, and Procedures. The inspection team reviewed safety-related equipment relied upon to remain functional during and following design basis events, non-safety-related components whose failure could prevent safety-related equipment from performing design functions, and certain post-accident monitoring equipment. The inspection team then determined which components environment would be adversely affected by postulated post-accident environmental conditions (temperature, pressure, radiation level, or flood level) and reviewed information contained in Millstones Probabilistic Risk Assessment and the NRCs Standardized Plant Analysis Risk model for Millstone to determine risk significant components that were also required to meet environmental qualification requirements. Additionally, the inspection team interviewed plant staff, reviewed design records, and discussed the environmental qualification program with the resident inspectors to assist in the selection of components. Finally, the inspection team ensured that different types of components were selected, including pump motors, motor-operated valves, solenoid valves, limit switches, and flow/level transmitters that were located both inside and outside of primary containment. Based on these reviews, the inspection team selected nine environmentally-qualified components and associated subcomponents (e.g., seals, cables, connectors, and lubricants) for inspection.
.2 Results of Detailed Reviews
a. Inspection Scope
The inspection team assessed Dominions implementation of the environmental qualification program required by 10 CFR 50.49. The inspection team reviewed environmental qualification program-related procedures, component files, test records, equipment maintenance and operating history, maintenance and operating procedures, vendor documents, design documents, previously identified deficiencies, and design calculations. The inspection team also interviewed plant staff knowledgeable of the design, maintenance, and operation of the selected components. The review and associated interviews were performed to evaluate whether Dominions staff properly maintained the equipment qualifications for electrical equipment important to safety through plant life (repair, replacement, modification, and plant life extension); established and maintained required environmental qualification documentation records; and implemented an effective corrective action program to identify and correct environmental qualification-related deficiencies and evaluate environmental qualification-related industry operating experience. The inspection team also performed walkdowns (where accessible) of selected components to verify whether equipment was installed as described in Millstones environmental qualification component documentation files, the environmental conditions were consistent with those assumed in the evaluations, equipment surrounding environmentally qualified component could fail in a manner that would prevent the components safety function from being performed, and whether the components were installed in their tested configuration. The inspection team reviewed the following components and associated subcomponents:
Unit 2 B Containment Sump Outlet Header Isolation Motor Operated Valve (M22-CS-16.1B)
Actuator, terminal block, cables, limit switches Pressurizer Pressure Transmitter to C Reactor Protection System/Engineered Safeguards Actuation System (M2PT-102C)
Pressure transmitter, cables, splices, and penetration assembly A Containment Air Recirculation Cooling Unit Fan Motor (M2F14AM)
Fan motor, lubricant, and penetration assembly Building Filtration System Fan Motor (M2-F25BM)
Fan motor, splice, and cables
- 1 Steam Generator Auxiliary Feedwater Regulating Solenoid (M22-FW-43AS)
Solenoid valve, cables Unit 3 Power Operated Relief Valve (M33RCS*PCV455A)
Solenoid, connector, conductor seal, gasket, cables Reactor Coolant System Resistance Temperature Detector to Loop 3 Delta-Temperature/Average Temperature Alarm, Indication, and Control Element (M33RCS*TE431A)
Temperature detector, instrument cable, splice, and penetration assembly Charging and Reactor Plant Closed Cooling Water Area Electric Unit Heaters (M33HVR*UHE3A)
Heater assembly, contactors, transformer, temperature control cutout, thermostat Main Steam Relief Valve 3MSS*RV23C Flow Element (M33SVV-FE29C)
Flow element, qualified connecting cable, connector, and cable In addition to the inspection of the selected components, the inspection team performed general plant walkdowns to determine whether components located in areas susceptible to a high energy line break were properly evaluated for operation in a harsh environment. The inspection team also reviewed procurement records and inspected a sample of replacement parts stored in the warehouse to verify environmentally qualified parts approved for installation in the plant were properly identified and controlled; and that storage time and environmental conditions did not adversely affect the components qualified life or service life. Finally, the inspection team reviewed a sample of components that had been removed from the environmental qualification program to determine if Dominion had correctly determined that the components no longer were required to meet 10 CFR 50.49. Documents reviewed for this inspection are listed in the
.
b. Findings
Introduction.
The inspection team identified a Green non-cited violation of Technical Specification 6.8.1.a, Procedures, because Dominion did not implement procedures as required by Regulatory Guide 1.33, Revision 2, Appendix A.9, Procedures for Performing Maintenance, to properly maintain the environmental qualification of safety-related auxiliary feedwater solenoid valves 2-FW-43AS and 2-FW-43BS.
Description.
The auxiliary feedwater system is designed to provide feedwater to the steam generators following a loss of main feedwater, and to isolate the affected steam generator on a main steam line break or a high energy line break in the turbine building.
Each normally closed, air-operated auxiliary feedwater regulating valve (2-FW-43A and 2-FW-43B) is provided with a normally energized ASCO solenoid valve (2-FW-43AS and 2-FW-43BS). This solenoid valve is required to de-energize to vent air from its regulating valve, allowing spring force to open the auxiliary feedwater regulating valve to perform its function. These solenoid valves are located in the turbine building, and as such, in a harsh environment in which they are expected to perform their post-accident function. These solenoid valves and associated subcomponents are therefore included in the scope of Millstones environmental qualification program, and are subject to its requirements in accordance with 10 CFR 50.49.
In order to qualify the solenoid valves and associated subcomponents to the requirements of 10 CFR 50.49, ASCO tested the solenoid valves to provide assurance that they would perform their post-accident function when subjected to their most limiting harsh environment. Qualification of the valves was documented in qualification test report AQR-67368, Qualification of ASCO NP-1 Solenoid Operated Valves for Safety Related Applications in Nuclear Power Stations. Dominion incorporated this information into their environmental qualification program as Equipment Qualification Record 114-01. Attachment B of Equipment Qualification Record 114-01 stated that the ASCO solenoid valves and coils must be replaced at intervals not to exceed the qualified life, and that the subcomponents with the most limiting service lives were the solenoid coil at 20.7 years, and the elastomer (ethylene propylene diene monomer) components at 21.4 years. The inspection team requested evidence that documented that Dominion had replaced these subcomponents within their qualified life period. Dominion was unable to provide this documentation, and their review of the work management program indicated that the solenoid valves in question (2-FW-43AS and 2-FW-43BS) were last replaced on October 30, 1992, and October 21, 1992, respectively. The inspection team determined that the solenoid coils and elastomer subcomponents for both valves had exceeded their qualified life, representing a non-conforming condition and reasonable doubt as to the ability of these solenoid valves to perform their function in their credited harsh environment.
Dominion entered this issue into their corrective action program as condition report 1076005 and evaluated the impact of the solenoid valves not being replaced within their required environmental qualification replacement period. The original qualified life of the solenoid valves was based on an ambient temperature of 100°F year-round, as documented in calculation EQQLACSO-0582-E2. Based on an engineering review of this information, as well as calibrated ambient temperature monitoring data taken in the associated environmental qualification zone in the 1999 - 2000 timeframe, Dominion calculated an alternate ambient temperature of 91.4°F for use in determining the qualified life of the solenoid valve components. Using this revised ambient temperature, Dominion extended the qualified life of the solenoid coil and the elastomer subcomponents to 26 years and 32.6 years, respectively, which extended the replacement dates to October 2018 for the solenoid coil and October 2024 for the elastomer subcomponents. Dominion revised station documentation to reflect that the installed auxiliary feedwater solenoid valves (2-FW-43AS and 2-FW-43BS) were within their qualified service life. Dominion also concluded that the operability of the auxiliary feedwater valves was not impacted and that solenoid valves 2-FW-43AS and 2-FW-43BS would have been able to perform their safety function during a postulated accident or event. The inspection team reviewed this information and determined that Dominions revised environmental qualification service life values to support operability were reasonable.
Dominion also initiated an apparent cause evaluation to evaluate the cause and develop associated corrective actions. Dominion procedure ER-AA-102, Preventive Maintenance Program, establishes requirements and guidelines for development, implementation, and maintenance of the preventive maintenance program at Millstone to ensure plant equipment is maintained at a quality level to perform its intended function.
Preventive maintenance activities are included in the recurring work event database maintained by the stations work management program. The inspection team noted that Millstones work management program included a recurring work event to ensure that the solenoid valve (2-FW-43AS and 2-FW-43BS) replacements were planned to occur prior to the end of qualified life. However, it was not clear why the solenoid valve replacements did not occur. The inspection team did note that in 2006, there were two open work orders associated with the recurring work event to perform solenoid replacement. On October 11, 2006, one of the work orders (53M20608835) was closed to the second work order (M2-05-00183). However, the second work order was inadvertently closed a few months later, without the task ever being performed.
Analysis.
The inspection team determined that the failure to replace safety-related solenoid valves 2-FW-43AS and 2-FW-43BS within the required environmental qualification frequency, as designated by the preventive maintenance recurring work event for the solenoid valves, was a performance deficiency. The inspection team determined that this issue was more than minor because it adversely impacted the equipment performance attribute of the Mitigating Systems cornerstone objective to ensure the availability, reliability, and capability of systems that respond to initiating events to prevent undesirable consequences. This issue is also similar to more-than-minor examples 3.j and 3.k presented in IMC 0612, Appendix E, Examples of Minor Issues. Specifically, this performance deficiency resulted in a condition where there was reasonable doubt as to the operability and reliability of the solenoid valves for both auxiliary feedwater regulating valves, and thus, both trains of auxiliary feedwater. As such, Dominion needed to conduct additional engineering evaluation to extend the service life of the solenoid valves, thus justifying that the valves would continue to perform their safety function.
The inspection team evaluated this finding using IMC 0609, Attachment 4, Initial Characterization of Findings, for the Mitigating Systems cornerstone, and IMC 0609, Appendix A, The Significance Determination Process for Findings At-Power. The inspection team determined the finding to be of very low safety significance (Green)because the finding was a deficiency affecting the reliability of a mitigating structure, system, or component, and the structure, system, or component maintained its operability or functionality. Specifically, the safety function of the auxiliary feedwater system was not lost based upon an engineering review which extended the qualified life of the solenoid coil and the elastomer subcomponents to 26 years and 32.6 years, respectively. This extended the replacement dates to October 2018 for the solenoid coil and October 2024 for the elastomer subcomponents. The inspection team determined that no cross-cutting aspect was applicable because the finding was not indicative of current performance.
Enforcement.
Technical Specification 6.8.1, Procedures, requires that written procedures be established, implemented, and maintained for activities described in Appendix A of Regulatory Guide 1.33, Quality Assurance Program Requirements.
Section 9 of Regulatory Guide 1.33, Appendix A includes procedures for performing maintenance, including replacement of parts that have a specific lifetime. Dominion procedure ER-AA-102, Preventive Maintenance Program, Section 3.5, requires that the station perform all recurring work event tasks in accordance with the work management program, as well as monitor and track scheduled preventive maintenance tasks until completion. Contrary to the above, from May 2013 to August 17, 2017, Dominion failed to implement the recurring work event task and associated work order to ensure that auxiliary feedwater solenoid valves 2-FW-43AS and 2-FW-43BS were replaced within their qualified life. Specifically, auxiliary feedwater solenoid valves 2-FW-43AS and 2-FW-43BS were installed in October 1992, and should have been replaced or reevaluated prior to exceeding the qualified life of the solenoid coil and elastomer components. Because this issue was determined to be of very low safety significance (Green) and Dominion has taken corrective actions and entered this issue into their corrective action program as condition report 1076005, this finding is being treated as a non-cited violation, consistent with Section 2.3.2.a of the Enforcement Policy. (NCV 05000336/2017007-01, Failure to Replace Auxiliary Feedwater Solenoid Valves within the Required Frequency)
OTHER ACTIVITIES
4OA2 Identification and Resolution of Problems
a. Inspection Scope
The inspection team reviewed a sample of problems that Dominion had previously identified and entered into the corrective action program. The inspection team reviewed a sample of these issues to verify an appropriate threshold for identifying issues and to evaluate the effectiveness of corrective actions. Additionally, the inspection team evaluated whether deficiencies identified during the inspection were properly documented and evaluated in the corrective action program.
b. Findings
No findings were identified.
4OA6 Meetings, including Exit
On August 31, 2017, the team presented the inspection results to Mr. John Daugherty, Site Vice President, and other members of the Dominion staff. The inspection team verified that no proprietary information was retained or documented in this report.
ATTACHMENT:
SUPPLEMENTARY INFORMATION
KEY POINTS OF CONTACT
Dominion Personnel
- J. Daugherty, Site Vice President
- P. Anastas, Backup Environmental Qualification Program Coordinator
- J. Armstrong, Fire Protection and FLEX Engineer
- D. Bajumpaa, Engineer - Nuclear Safety Analysis
- C. Baker, Stock Handler
- B. Clezynski, Engineer - Instrumentation and Controls
- J. Craffey, Principal Engineer
- C. Cramer, Plant Equipment Operator
- M. Farrell, Supervisor of Procurement Engineering Services
- G. Filippides, Electrical Engineering Consultant
- W. Gorman, Instrumentation and Controls Supervisor
- B. Hayes, Contractor
- T. Hendy, Manager - License Renewal Programs
- N. Jaycox, Environmental Qualification Program Owner
- L. Kelly, Manager - Engineering Programs
- S. Larrea, Special Projects Engineer
- M. Long, Warehouse Supervisor
- D. Milhalko, Engineering Intern
- J. Patel, Building System Engineer
- R. Patel, Electrical Engineer
- J. Rigatti, Engineering Program Manager
- E. Stanistreet, Engineer
NRC Personnel
- L. McKown, Resident Inspector - Millstone
LIST OF ITEMS OPENED, CLOSED, DISCUSSED, AND UPDATED
Opened/Closed
- 05000336/2017007-01 NCV Failure to Replace Auxiliary Feedwater Solenoid Valves within the Required Frequency (Section 1R21.2.b)