IR 05000245/2016007
| ML16355A293 | |
| Person / Time | |
|---|---|
| Site: | Millstone  |
| Issue date: | 12/20/2016 |
| From: | Dentel G T Engineering Region 1 Branch 2 |
| To: | Stoddard D G Dominion Resources |
| Dentel G T | |
| References | |
| IR 2016007 | |
| Download: ML16355A293 (21) | |
Text
December 20, 2016
Mr. Daniel Senior Vice President and Chief Nuclear Officer Innsbrook Technical Center 5000 Dominion Blvd. Glen Allen, VA 23060-6711
SUBJECT: MILLSTONE POWER STATION - EVALUATION OF CHANGES, TESTS, AND EXPERIMENTS AND PERMANENT MODIFICATIONS TEAM INSPECTION REPORT 05000336/2016007 AND 05000423/2016007
Dear Mr. Stoddard:
On November 17, 2016, the U.S. Nuclear Regulatory Commission (NRC) completed an inspection at your Millstone Power Station (Millstone), Units 2 and 3. On November 17, 2016, 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 inspection examined activities conducted under your license as they relate to safety and compliance with the Commission's rules and regulations and with the conditions of your license. In conducting the inspection, the team reviewed selected procedures, calculations, and records; observed activities; and interviewed station personnel.
No NRC-identified or self-revealing findings were identified during this inspection. 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 05000336/2016007 and 05000423/2016007
w/Attachment:
Supplementary Information
cc w/encl: Distribution via ListServ
SUMMARY
IR 05000336/2016007 and 05000423/2016007; 10/31/2016 - 11/17/2016; Millstone Power Station, Units 2 and 3; Engineering Specialist Plant Modifications Inspection.
This report covers a two week inspection of the evaluations of changes, tests, or experiments and permanent plant modifications. The inspection was conducted by four region-based engineering inspectors. No findings were identified. The NRC's program for overseeing the safe operation of commercial nuclear power reactors is described in NUREG-1649, "Reactor Oversight Process," Revision 6, dated July 2016.
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REPORT DETAILS
REACTOR SAFETY
Cornerstones: Initiating Events, Mitigating Systems, and Barrier Integrity 1R17 Evaluations of Changes, Tests, and Experiments and Permanent Plant Modifications (IP 71111.17)
.1 Evaluations of Changes, Tests, and Experiments (36 samples)
a. Inspection Scope
The team reviewed 13 safety evaluations to evaluate whether the changes to the facility or procedures, as described in the Updated Final Safety Analysis Report (UFSAR), had been reviewed and documented in accordance with Title 10 of the Code of Federal Regulations (10 CFR) 50.59 requirements. In addition, the team evaluated whether Dominion had been required to obtain U.S. Nuclear Regulatory Commission (NRC)approval prior to implementing the changes. The team interviewed plant staff and reviewed supporting information including calculations, analyses, design change documentation, procedures, the UFSAR, technical specifications, and plant drawings to assess the adequacy of the safety evaluations. The team compared the safety evaluations and supporting documents to the guidance and methods provided in Nuclear Energy Institute (NEI) 96-07, "Guidelines for 10 CFR 50.59 Evaluations," Revision 1, as endorsed by NRC Regulatory Guide 1.187, "Guidance for Implementation of 10 CFR 50.59, Changes, Tests, and Experiments," to determine the adequacy of the safety evaluations. The team also reviewed 23 samples of 10 CFR 50.59 screenings and applicability determinations for which Dominion had concluded that no safety evaluation was required. These reviews were performed to assess whether Dominion's threshold for performing safety evaluations was consistent with 10 CFR 50.59. The samples included design changes, calculations, procedure changes, and setpoint changes. The screenings and applicability determinations were selected based on the safety significance, risk significance, and complexity of the change to the facility. Finally, the team compared Dominion's administrative procedures used to control the screening, preparation, review, and approval of safety evaluations to the guidance in NEI 96-07 to determine whether those procedures adequately implemented the requirements of 10 CFR 50.59. The documents reviewed for each section of this report are listed in the Attachment.
b. Findings
No findings were identified.
.2 Permanent Plant Modifications (13 samples)
.2.1 MP2-11-01079, Replacement of Pressurizer Spray Manual Isolation Gate Valves 2-RC-252 and 2-RC-253
a. Inspection Scope
The team reviewed modification MP2-11-01079, which installed two Class 1 manual isolation valves, replacing the existing valves. The valves are used to isolate the pressurizer spray nozzles. Dominion replaced two valves and a section of piping to correct bonnet leakage from the installed valves. The new piping and valves were installed on existing pipe supports in the containment. Dominion evaluated the seismic qualifications of the valves to verify adequate structural margin existed for design basis seismic events; and welded the new valves and piping into the system and performed associated post-maintenance testing to verify the integrity of the valves, piping, and associated welds.
The team reviewed the modification to determine if the design bases, licensing bases, or performance capability of the pressurizer spray header had been degraded by the modification. The team interviewed design engineers and reviewed design drawings and calculations to determine if the new piping and valves met applicable specifications and requirements. Additionally, the team reviewed the post-modification test (PMT)results, welding certifications, and associated maintenance work orders to determine if the modification was appropriately implemented.
b. Findings
No findings were identified.
.2.2 MP2-14-01009, Replace the Shutdown Cooling Isolation Valve 2-SI-652 Motor
a. Inspection Scope
The team reviewed modification MP2-14-01009, which replaced the motor for motor-operated valve 2-SI-652 with a new style motor. The motor was replaced to address industry operating experience related to corrosion issues identified with magnesium rotors. Dominion replaced the original motor with a motor of similar electrical and torque characteristics and an aluminum rotor. As part of the modification, Dominion verified the motor's locked rotor amps, full load amps, and torque capability of the motor would meet valve and electrical system design requirements. Dominion also verified that the motor met seismic and environmental qualifications requirements; and motor weight and dimensions did not impact the seismic qualifications of the safety injection system. Following installation of the motor, Dominion performed a PMT to ensure design, licensing, and American Society of Mechanical Engineers (ASME) Code requirements were met.
The team reviewed the modification to determine if the design bases, licensing bases, or performance capability of the motor-operated valve, safety injection system, or electrical system had been degraded by the modification. The team interviewed design engineers and reviewed design drawings, vendor documentation, and calculations to determine if the motor met the applicable specifications and requirements for the shutdown cooling system. Additionally, the team reviewed PMT results and associated maintenance work orders to determine if the changes were appropriately implemented and the valve test results were within the required ASME Code and licensing specifications. Finally, the team reviewed environmental qualification testing results to determine if the testing bounded the design basis post-accident containment atmosphere.
b. Findings
No findings were identified.
.2.3 MP3-14-01187, Reactor Plant Closed Loop Cooling Water Heat Exchanger 3CCP*E1B Replacement
a. Inspection Scope
The team reviewed modification MP3-14-01187, which replaced one of three reactor plant closed loop cooling water (RPCCW) heat exchangers. Dominion replaced the heat exchanger to restore heat removal capacity and provide additional operating flow margin to the RPCCW system. Dominion also upgraded the heat exchanger with a more corrosion/erosion resistant Monel material. As part of the modification, Dominion redesigned the structural supports for the new heat exchanger to ensure the heat exchanger and associated RPCCW piping maintained the required Seismic I capability as required by the licensing basis. Finally, Dominion performed a PMT to assess the cooling capacity, flow velocity though the heat exchanger tubes, and the integrity of the RPCCW system. The team reviewed the modification to determine if the design bases, licensing bases, or performance capability of the RPCCW heat exchanger had been degraded by the modification. The team interviewed design engineers and reviewed design drawings, vendor documentation, and calculations to determine if the heat exchanger met the specifications and requirements for the RPCCW system. Additionally, the team reviewed the PMT results and associated maintenance work orders to determine if the changes were appropriately implemented; the heat removal capability of the heat exchanger met design requirements; and post-modification leakage results were within the required ASME Code and licensing specification. The team performed a walkdown of the heat exchanger to determine if the modification was installed in accordance with the design, and to assess the overall material conditions of the systems following the modification work. Finally, the team reviewed the 10 CFR 50.59 screening associated with this modification as described in Section 1R17.1 of this report.
b. Findings
No findings were identified.
.2.4 MP3-12-01028, Reactor Vessel Head Vent Valve Replacements
a. Inspection Scope
The team reviewed modification MP3-12-01028, which replaced the reactor vessel head vent valves and associated electrical connections. The valves provide the capability to vent non-condensable gasses from the reactor vessel following a design basis event.
Dominion performed the modification to correct degraded performance of the previously installed valves. Dominion performed pre-installation testing on the valves to ensure the valves met ASME Code leak requirements and post-installation testing to verify the integrity of the valve flange connections and the correct operation of the valves.
The team reviewed the modification to determine if the design bases, licensing bases, or performance capability of the valves and associated piping had been degraded by the modification. The team interviewed design engineers and reviewed design drawings, calculations, and vendor specifications to determine if the valves met the applicable specifications and requirements of the reactor head vent system. Additionally, the team reviewed PMT results, associated maintenance work orders, and leakage test results to determine if the changes were appropriately implemented. The team reviewed environmental qualification testing results to determine if the testing bounded the projected design basis post-accident containment atmosphere. Finally, the team reviewed the 10 CFR 50.59 screening associated with this modification as described in Section 1R17.1 of this report.
b. Findings
No findings were identified.
.2.5 MP3-13-01127, Replacement of Service Water Valves 3SWP*AOV39A&B due to Material Change
a. Inspection Scope
The team reviewed modification MP3-13-01127, which replaced service water air-operated butterfly isolation valves. The valves' operation provided service water to the emergency diesel generator (EDG) heat exchangers. Dominion performed the modification to address identified valve degradation due to de-alloying of the cast aluminum-bronze alloy valve material. Dominion installed the same style valves with improved metallurgical properties to minimize this salt water degradation mechanism.
Following installation, Dominion performed testing to verify the valves were properly installed and the ASME Code requirements were met.
The team reviewed the modification to determine if the design bases, licensing bases, or performance capability of the valve and associated service water and/or air systems had been degraded by the modification. The team interviewed design engineers and reviewed design drawings, calculations, and vendor specifications to determine if the valves met the design and licensing requirements of the system. Additionally, the team reviewed PMT results and associated maintenance work orders to determine if the changes were appropriately implemented. Finally, the team performed a walkdown of the valves to determine if the modification was installed in accordance with the design, and to assess the overall material conditions of the systems following the modification work.
b. Findings
No findings were identified.
.2.6 MP3-14-01156, 3HVK CHL 1B Relay Module Replacement
a. Inspection Scope
The team reviewed modification MP3-14-01157, which replaced an existing time delay relay module in the 19FA control building chiller with a time delay relay module conversion kit. The new installed time delay relay module conversion kit was a complete upgrade from the old relay module. However, the automatic chiller re-start feature after a loss of power, which was built-in in the original relay, was not incorporated in the new relay module design. Therefore, in order to maintain this operational feature, Dominion added an additional timing relay to the 19FA control building chiller circuitry.
The team reviewed the modification to verify that the design bases, licensing bases, and performance capability of the control building chiller had not been degraded by the modification and had been adequately implemented. The team reviewed the purchase order and the certification of conformance associated with the relay module kit to verify that quality requirements, including technical, administrative, regulatory, and reporting requirements (e.g., specifications, codes, standards, tests, inspections) were specified in procurement documents. The team interviewed engineering staff to verify that the relay module design would function in accordance with its design requirements. The team also reviewed the associated work order instructions and vendor documentation to ensure that maintenance personnel had implemented the modification as designed. In addition, the team verified that procedures, design documents, and drawings affected by the modification had been adequately updated. The team performed a walkdown to independently assess the performance of the 19FA control building chiller by visually inspecting the local chiller control panel. The team reviewed the associated PMT results and the 3HVK CHL1B chiller operational performance to verify that the system functioned as designed following the modification. Finally, the team reviewed the 10 CFR 50.59 screening associated with this modification as described in Section 1R17.1 of this report.
b. Findings
No findings were identified. 2.7 MP3-14-01148, Replacement of 48/15 Vdc Power Supplies for Solid State Protection System
a. Inspection Scope
The team reviewed modification MP-14-01149, which installed four 48/15 Vdc power supplies for the solid state protection system. There are two 48/15 Vdc power supplies per train, and each power supply provides a 48 Vdc and 15 Vdc output to the solid state protection system logic and output relays. This change was performed due to preventive maintenance that required the existing power supplies to be replaced on a ten-year frequency. The originally installed Basler Electric dual output supply unit was no longer manufactured, therefore, an equivalent power supply module was procured as a replacement.
The team reviewed the modification to verify that the design bases and licensing bases of the power supplies had been adequately implemented. The team reviewed the equivalency change report to ensure that performance capability of the power supplies had not been degraded by the modification. The team reviewed the associated work order instructions and documentation to verify that maintenance personnel had implemented the modification as designed. The team reviewed the associated PMT requirements and results of the new power supplies to confirm that the implementation was properly executed and to verify that the system functioned as designed following the modification. In addition, the team reviewed procedures, design documents, and drawings affected by the changes to verify that these documents had been adequately updated.
b. Findings
No findings were identified.
2.8 10000032204, MP3 Commercial Grade Dedication - Battery Charger Failure Relay
a. Inspection Scope
The team reviewed modification 10000032204, which replaced a relay associated with Millstone Unit 3 battery charger No. 1. This replacement relay was not designed nor manufactured as a basic component. The relay was purchased as a commercial grade item (CGI) and was dedicated by Dominion to be used as a safety-related component.
Dominion characterized this replacement as a like-for-like replacement. The safety function of the relay was to maintain electrical circuit continuity in the battery charger and to change states when energized or de-energized by allowing the relay contacts to pick up or drop out. This change was performed because the original relay failed in service.
The team reviewed the modification to verify that the design bases, licensing bases, and performance capability of the battery charger relay had not been degraded by the modification. The team verified that Dominion's process for dedicating the CGI provided reasonable assurance that the commercial grade relay would perform its intended safety function. Specifically, the team verified that Dominion had established adequate controls for acceptance of the CGI through its receipt inspection requirements. The team verified that Dominion properly identified and verified that all critical characteristics associated with the replacement relay satisfied their respective acceptance criteria. The team reviewed the associated work order instructions and documentation to verify that maintenance personnel had implemented the modification as designed. The team reviewed the associated acceptance criteria and PMT requirements of the new relay to confirm that the implementation was properly executed and to verify that the battery charger would function as designed following the modification. Finally, the team reviewed procedures, design documents, and drawings affected by the changes to verify that these documents had been adequately updated.
b. Findings
No findings were identified.
.2.9 MP2-15-01097, Reactor Protection System Bistable Trip Unit, Auxiliary Trip Units, and Trip Test Cable Assemblies Replacement
a. Inspection Scope
The team reviewed design change package MP2-15-01097 for a planned modification that will replace the reactor protection system (RPS) bistable trip units (BTU), the auxiliary trip units (ATU), and the trip test cable assemblies (TTCA). This design change is required to replace the obsolete BTUs, ATUs, and TTCAs for the Millstone Unit 2 RPS. This design change will replace eight BTUs, two ATUs, and a TTCA in RPS channel 'B' during the next Unit 2 outage (2R24), and the remaining three channels ('A',
'C', and 'D') will be replaced during 2R25.
The team reviewed the design work package to evaluate whether the design bases, licensing bases, and performance capability of the RPS can be degraded by the modification. The team reviewed Dominion's technical evaluation, design specifications, calculations, analysis, drawings, and logic control sheets to verify that design assumptions were valid. The team reviewed the procurement specification to verify that quality requirements, including technical, administrative, regulatory, and reporting requirements (e.g., specifications, codes, standards, tests, inspections) were specified in procurement documents. The team interviewed system engineers and technical staff to evaluate the adequacy of the modification. Additionally, the team reviewed the 10 CFR 50.59 screening associated with this modification as described in Section 1R17.1 of this report.
b. Findings
No findings were identified.
2.10 Calculation 96-067, Auxiliary Feedwater System Comprehensive Flow Analysis, and Modification MP3-14-01107, MP3 TDAFW Pump Overspeed Margin Change
a. Inspection Scope
The team reviewed Millstone Unit 3 Calculation 96-067, which was revised in support of lowering the operating speed (from 4500 to 4400 rpm) of the turbine-driven auxiliary feedwater (TDAFW) pump to gain margin to the relief valve setpoint and to increase pump reliability. This change was implemented due to prior operating experience events at Millstone Unit 3 involving TDAFW pump/turbine overspeed trips and challenging the discharge relief valve. The change involved a reduction in auxiliary feedwater (AFW)flow due to the speed reduction. In the calculation revision, Dominion evaluated the lower AFW flow on postulated events in the safety analysis. The team also reviewed the associated modification, MP3-14-01107, TDAFW Pump Overspeed Margin Change, for which the above calculation supported.
The team reviewed the calculation change to determine if the design bases, licensing bases, or performance capability of the AFW system had been degraded by reduction in TDAFW pump operating speed. The team interviewed design engineers and reviewed the revised calculation and associated design basis events to determine whether the change met design and licensing requirements. Surveillance procedures, including test results, were reviewed by the team to determine whether the results were bounded by the modification and existing analyses. The 10 CFR 50.59 safety evaluation associated with this change was also reviewed as described in Section 1R17.1 of this report.
b. Findings
No findings were identified.
2.11 MP3-14-01070, Replace Emergency Diesel Generator Air Cooler Service Water Relief Valves M33SWP*RV90A/RV90B
a. Inspection Scope
The team reviewed modification MP3-14-01070 that Dominion implemented to replace the service water system thermal protection relief valves to the Unit 3 EDG air coolers. The function of the relief valves is to provide overpressure protection to the service water side of the safety-related EDG combustion air heat exchangers in the event of an unintentional equipment isolation or a thermal transient during component lay-up conditions. The original relief valves were configured with a metal-to-metal seat design that was susceptible to the effects of corrosion and debris, resulting in failure to lift within the specified tolerance of the set pressure. The modification allowed for a soft seat configuration for both of the system relief valves.
The team reviewed the modification to determine if the design and licensing bases, and performance capability of the EDG system had been degraded by any of the associated equipment, process, and/or procedure changes. The team interviewed design engineers, and reviewed evaluations, surveillance results, technical data sheets, and associated maintenance activities to verify that Dominion appropriately implemented the design change in accordance with their design process and assumptions. The team performed walkdowns of accessible portions of the EDG and service water systems to assess configuration control and the material condition of the associated components. The team also reviewed condition reports, completed preventive maintenance activities, and the EDG system operating logs to determine if there were reliability or performance issues that may have resulted from the modification.
b. Findings
No findings were identified.
.2.12 MP3-14-01027, Motor-Driven Auxiliary Feed Pump Lube Oil Pump 3FWL*P6A Replacement
a. Inspection Scope
The team reviewed modification MP3-14-01027 that Dominion implemented to replace the direct drive (shaft-driven) lube oil pump 3FWL*P6A for AFW pump 3FWA*P1A, due to unrepairable minor seal leakage and component obsolescence. The AFW pump's lube oil pump is designed to provide the necessary lubricating oil to the motor-driven AFW pump. The replacement lube oil pump has slightly different suction and discharge piping connections, as well as different orientation, which required some minor piping replacement and rerouting. The replacement lube oil pump was determined to be an acceptable equivalent replacement pump for the existing 3FWL*P6A.
The team reviewed the modification to determine if the design bases, licensing bases, or performance capability of the motor-driven AFW pump had been degraded by the modification. The team interviewed design and system engineers and reviewed installation procedures, surveillance results, and associated maintenance activities to determine if the new lube oil pump, piping, and configuration met design specifications and requirements of the system. The team performed a walkdown of both motor-driven AFW pumps and the TDAFW pump rooms to assess configuration comparisons and material conditions.
b. Findings
No findings were identified.
2.13 MP2-14-01001, Replace Emergency Diesel Generator M-7A Service Water Coolers Supply and Discharge Lines with AL-6XN Material
a. Inspection Scope
The team reviewed modification MP2-14-01001 that replaced 6-inch and 8-inch lined carbon steel flanged pipe spools on the 'A' train service water supply header to the Unit 2 'A' EDG jacket water cooling, lube oil cooling, and air cooler heat exchangers.
The modification also included the replacing previously-installed AL6XN material pipe spools to correct flange alignment issues, replacing check valve 2-SW-13A with an AL6XN pipe spool, and replacing stainless steel flow restricting orifices. The modifications were necessary to eliminate dissimilar metal galvanic interactions and corrosion issues.
The review was performed to determine if the design bases, licensing bases, or performance capability of the 'A' EDG had been degraded by the modifications. Design assumptions were reviewed to evaluate whether they were technically appropriate and consistent with the UFSAR. The team discussed the impact of the modification on the EDG operation with responsible engineers. Additionally, the team reviewed maintenance work orders to confirm that the modifications were appropriately implemented. The team performed walkdowns of the EDG to assess the quality of the modification work and the overall material condition of the equipment. The adequacy of the PMT was verified, and affected design documents and drawings were reviewed to ensure they had been properly updated. Additionally, the equivalent 10 CFR 50.59 screen associated with this modification was reviewed as described in Section 1R17.1 of this report.
b. Findings
No findings were identified.
OTHER ACTIVITIES
4OA2 Identification and Resolution of Problems (IP 71152)
a. Inspection Scope
The team reviewed a sample of problems that Dominion had previously identified and entered into the corrective action program. The team reviewed these issues to verify an appropriate threshold for identifying issues and to evaluate the effectiveness of corrective actions. In addition, the team reviewed corrective action condition reports written on issues identified during the inspection to verify adequate problem identification and incorporation of the problem into the corrective action system.
b. Findings
No findings were identified.
4OA6 Meetings, including Exit
The team presented the inspection results to Mr. John Daugherty, Site Vice President, and other members of Dominion staff at an exit meeting on November 17, 2016. The team returned the proprietary information reviewed during the inspection to Dominion staff and verified that this report does not contain proprietary information.
ATTACHMENT: