IR 05000482/2015007
| ML15246A568 | |
| Person / Time | |
|---|---|
| Site: | Wolf Creek  |
| Issue date: | 09/03/2015 |
| From: | Thomas Farnholtz Division of Reactor Safety IV |
| To: | Heflin A Wolf Creek |
| J. Braisted | |
| References | |
| IR 2015007 | |
| Download: ML15246A568 (19) | |
Text
ber 3, 2015
SUBJECT:
WOLF CREEK GENERATING STATION - NRC EVALUATIONS OF CHANGES, TESTS, AND EXPERIMENTS AND PERMANENT PLANT MODIFICATIONS BASELINE INSPECTION REPORT 05000482/2015007
Dear Mr. Heflin:
On July 23, 2015, the U.S. Nuclear Regulatory Commission (NRC) completed an inspection at the Wolf Creek Generating Station and discussed the results of this inspection with you and other members of your staff. Inspectors documented the results of this inspection in the enclosed inspection report.
The NRC inspectors did not identify any findings or violations during this inspection.
In accordance with Title 10 of the Code of Federal Regulations 2.390, Public Inspections, Exemptions, Requests for Withholding, 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 NRCs Public Document Room or from the Publicly Available Records (PARS) component of the NRCs Agencywide Documents Access and Management System (ADAMS). ADAMS is accessible from the NRC Web site at http://www.nrc.gov/reading-rm/adams.html (the Public Electronic Reading Room).
Sincerely,
/RA/
Thomas R. Farnholtz, Chief Engineering Branch 1 Division of Reactor Safety Docket No: 05000482 License No: NPF-42 Enclosure: Inspection Report 05000482/2015007 w/Attachment: Supplemental Information
U.S. NUCLEAR REGULATORY COMMISSION
REGION IV
Docket: 50-482 License: NPF-42 Report: 05000482/2015007 Licensee: Wolf Creek Nuclear Operating Corporation Facility: Wolf Creek Generating Station Location: 1550 Oxen Lane NE Burlington, Kansas Dates: July 6, 2015, to July 23, 2015 Inspectors: J. Braisted, Reactor Inspector, Lead N. Okonkwo, Reactor Inspector G. Larkin, Emergency Response Coordinator Approved By: T. Farnholtz, Chief, Engineering Branch 1 Division of Reactor Safety-1- Enclosure
SUMMARY OF FINDINGS
IR 05000482/2015007; Wolf Creek Generating Station; Evaluations of Changes, Tests, and
Experiments and Permanent Plant Modifications.
This report covers a two-week announced baseline inspection on evaluations of changes, tests, and experiments and permanent plant modifications. The inspection was conducted by Region IV based engineering inspectors. No findings were identified. The significance of most findings is indicated by their color (i.e., greater than Green, or Green, White, Yellow, Red) using Inspection Manual Chapter (IMC) 0609, Significance Determination Process (SDP). Cross-cutting aspects were determined using IMC 0310, Aspects Within the Cross-Cutting Areas.
Findings for which the SDP does not apply may be Green or be assigned a severity level after NRC management review. All violations of NRC requirements are dispositioned in accordance with the NRCs Enforcement Policy, dated July 9, 2013. The NRCs program for overseeing the safe operation of commercial nuclear power reactors is described in NUREG-1649, Reactor Oversight Process, Revision 5, dated February 2014.
NRC-Identified Findings
and Self-Revealed Findings No findings were identified.
Licensee-Identified Violations
No findings were identified.
REPORT DETAILS
REACTOR SAFETY
Cornerstones: Initiating Events, Mitigating Systems, Barrier Integrity, and Emergency Preparedness
1R17 Evaluations of Changes, Tests, and Experiments and Permanent Plant
Modifications (71111.17T)
.1 Evaluations of Changes, Tests, and Experiments
a. Inspection Scope
The inspectors reviewed 19 evaluations performed pursuant to Title 10, Code of Federal Regulations (CFR), Part 50, Section 59, to determine whether the evaluations were adequate and that prior NRC approval was obtained as appropriate. The inspectors also reviewed 6 screenings, where licensee personnel had determined that a 10 CFR 50.59 evaluation was not necessary. The inspectors reviewed these documents to determine if:
- the changes, tests, and experiments performed were evaluated in accordance with 10 CFR 50.59 and that sufficient documentation existed to confirm that a license amendment was not required;
- the safety issue requiring the change, tests and experiment was resolved;
- the licensee conclusions for evaluations of changes, tests, and experiments were correct and consistent with 10 CFR 50.59; and
- the design and licensing basis documentation was updated to reflect the change.
The inspectors used, in part, Nuclear Energy Institute (NEI) 96-07, Guidelines for 10 CFR 50.59 Implementation, Revision 1, to determine acceptability of the completed evaluations and screenings. The NEI document was endorsed by the NRC in Regulatory Guide 1.187, Guidance for Implementation of 10 CFR 50.59, Changes, Tests, and Experiments, dated November 2000. The list of evaluations, screenings and/or applicability determinations reviewed by the inspectors is included as an to this report.
This inspection constituted 6 samples of evaluations and 19 samples of screenings and/or applicability determinations as defined in IP 71111.17-04.
b. Findings
No findings were identified.
.2 Permanent Plant Modifications
a. Inspection Scope
The inspectors reviewed 12 permanent plant modifications that had been installed in the plant during the last three years. This review included in-plant walkdowns for portions of the diesel generator, component cooling water, and turbine-driven auxiliary feedwater pump systems. The modifications were selected based upon risk significance, safety significance, and complexity. The inspectors reviewed the modifications selected to determine if:
- the supporting design and licensing basis documentation was updated;
- the changes were in accordance with the specified design requirements;
- the procedures and training plans affected by the modification have been adequately updated;
- the test documentation as required by the applicable test programs has been updated; and
- post-modification testing adequately verified system operability and/or functionality.
The inspectors also used applicable industry standards to evaluate acceptability of the modifications. The list of modifications and other documents reviewed by the inspectors is included as an Attachment to this report.
This inspection constituted 12 permanent plant modification samples as defined in IP 71111.17-04.
.2.1 Main Condenser Vacuum Pump Seal Water Heat Exchangers Replacement
The inspectors reviewed Change Package 012862, implemented to replace the tube bundles of the main condenser vacuum pump seal water heat exchangers ECG01A, ECG01B, and ECG01C, and also to replace the heat exchanger shells. These heat exchangers remove heat from the main condenser vacuum pump seals and the main condenser vacuum pumps remove non-condensable gasses from the main condenser during all modes of plant operation except shutdown. The licensee had identified material loss on the tube bundles and had changed plant secondary side chemistry.
Because of the material loss and the change in chemistry, the licensee decided to replace the tube bundles and shells with new bundles and shells of materials less susceptible to the types of corrosion they had identified. The inspectors did not identify any issues with the change package.
.2.2 Installation of New Component Cooling Water Flow Restriction Device
The inspectors reviewed Change Package 013540, implemented to install a flow restriction device in the component cooling water (CCW) system. The CCW system provides bot nonsafety- and safety-related cooling to various plant heat loads. The NRC inspectors in 2010 raised questions about whether the CCW surge tanks had the capacity to keep up with the maximum blow down rate due to a large break in the nonsafety-related side of the CCW piping prior to isolation of the break. The licensees response to the NRCs questions was the development of this change package. The change package involved the installation of an orifice plate, changes to pipe supports, rerouting or removal of piping, replacement of valves, and rerouting of instrument tubing.
The inspectors did not identify any issues with the change package.
.2.3 Train B Emergency Diesel Generator and Essential Service Water Ventilation Issues
The inspectors reviewed Change Package 013800, implemented to address issues the licensee identified as a result of a post-fire safe shutdown assessment. Specifically, the licensee identified that train B emergency diesel generator (EDG) and train B essential service water (ESW) room ventilation dampers may have control function challenges during extreme weather conditions that are aggravated during a postulated control room fire. The change package evaluated and approved relocation of the controls of the train B EDG and ESW dampers to eliminate the probability of a control room fire affecting the required function of these dampers. The inspectors did not identify any issues with the change package.
.2.4 Spent Fuel Pool Cooling Heat Exchanger Tube Plugging
The inspectors reviewed Configuration Change Package 014494, implemented to stake and plug tubes in the spent fuel pooling cooling (FPC) heat exchangers. The FPC heat exchangers, EEC01A and EEC01B, function to transfer decay heat from the fuel pool cooling system water to the component cooling water system. The licensee had identified a through wall leak in one tube of EEC01A, which the licensee attributed to fatigue failure caused by flow induced vibration. The change package evaluated and approved the tube staking and plugging method implemented in this change since the vendor manual was silent on staking and found the plugging method not workable. The inspectors did not identify any issues with the change package.
.2.5 Elimination of Generator Excitation Volts per Hertz Relay Single Point Vulnerability
The inspectors reviewed Design Change Package 012079, implemented to eliminate a single point vulnerability (SPV) in the main generator excitation and voltage regulation system, which could trip the turbine/generator, as presented by the volts per hertz relays MBMB04STV1 and MBMB04STV2. The volts per hertz relay scheme is designed to protect the generator and unit transformer from excessive heating associated with operating the unit with the alternating current voltage regulator in service at reduced generator speed (offline) or having the direct current voltage regulator in service following a load rejection where turbine/generator speed increases above 1,800 revolutions per minute. To eliminate the SPV and to still maintain volts per hertz protection, this change package added the two-out-of-three redundancy for the volts per hertz relay protection by installing four additional volts per hertz relays (MBMB04STV3, MBMB04STV4, MBMB04STV5, and MBMB04STV6) to the generator protection logic.
The existing volts per hertz relays now have two of the four new relays set with the same ratio and time values for redundancy. The other two relays are calibrated to actuate on slightly different sensed volts per hertz ratios and delay times. The inspectors did not identify any concerns with the change package.
.2.6 Protection of Control Circuit Cables for Motor Operated Valves
The inspectors reviewed Change Package 013614, implemented to reconfigure the control circuits for boron injection tank (BIT) outlet isolation valves EMHV8801A and EMHV8801B. The opening and damaging of the BIT outlet isolation valve EMHV8801A and EMHV8801B are postulated to occur due to a control room fire. Also a spurious start of the centrifugal charging pumps is postulated for the fire that causes valve EMHV8801A and EMHV8801B to open. Spurious opening or damaging of these valves could create a flow path that may produce excessive flow, causing overfill of the pressurizer if not mitigated in a timely manner. This change package reconfigured the control circuits for EMHV8801A and EMHV8801B so that a hot short in the control room due to fire will not bypass the torque and limit switches. Specifically, this was accomplished by reconfiguring control logic for EMHV8801A and EMHV8801B by relocating the circuit conductors for each of the valves torque and limit switches from the line side of the contactor coils to the neutral side of the contactor coils. With this new reconfiguration, each of the valves torque and limit switches will remain capable of breaking control current to the contactor coil, even in the event of a hot short on the line (control room) side of the circuit. The inspectors did not identify any concerns with the change package.
.2.7 Diesel Fire Pump Controller Modifications
The inspectors reviewed Change Package 014501, implemented to eliminate the spurious remote start signal which the diesel fire pump engine experienced in coincident with grounds on PK0. The change package approved the removal of 125 VDC power from the remote start circuit to correct this issue. Diesel fire pump 1FP01PB is a 100 percent capacity pump which provides fire protection water to the power block and out-building water based fire suppression systems and standpipes. This change package also replaced the existing 125 VDC remote start hand switch 1HSFP0003A with a 24 VDC hand switch to drive the 24 VDC indicator lights thus eliminating the voltage dropping resistors (as was originally installed) in the existing switch 125 VDC hand switch. Diesel fire pump controller 1PL0006J provides the 24 VDC output will provide the supply voltage to illuminate the indicator lights. The inspectors did not identify any concerns with the change package.
.2.8 Turbine Driven Auxiliary Feedwater Pump Control Modification
The inspectors reviewed Design Change Package 012958, implemented to replace the original Woodward governor control system for the turbine driven auxiliary feedwater pump (TDAFWP) which was no longer supported by the supplier. Specifically, the manufacturer no longer provided complete repair and refurbishment of components and spare parts are no longer available from the manufacturer. The auxiliary feedwater (AFW) system automatically supplies feedwater to the steam generators to remove decay heat from the reactor coolant system upon the loss of normal feedwater supply.
The AFW pumps normally take suction through a common suction line from the condensate storage tank (CST). Should the CST become unavailable, cooling water is available from the essential service water (ESW) system. In order to ensure reliable operation of the TDAFWP and support maintenance or repair activities, this change package replaced the original analog Woodward governor controls for the turbine driven auxiliary feed water pump controls with new current generation digital TDAFWP control system supplied by Dresser-Rand. The inspectors did not identify any concerns with the change package.
.2.9 Steam Generator Feed Pump Protection and Control Replacement
The inspectors reviewed Change Package 013380, implemented to replace the existing feedwater pump turbine speed control and protection systems for the steam generator feedwater pumps (SGFPs). Operating experience at the site had revealed to the licensee that the system was becoming increasingly unreliable and was leading to more frequent plant problems, including start-up delays, over speed testing issues, unplanned transients and forced outages. The licensee also identified that the manufacturer no longer supports the components and aftermarket components are only available. The function of the SGFP protection and control system is to generate position signals for the high pressure and low pressure control valves, the SGFP recirculation valves, and the condensate pump recirculation valves. Changing the position of the steam valves provides the method of controlling the SGFP turbine speed. This engineering change package replaced the existing system electronic speed governor control systems, turbine protection systems and selected process instrumentation and operator interfaces of SGFP turbine drives KFC01A and KFC01B and their attached feed pumps PAE01A and PAE01B. The inspectors did not identify any concerns with the change package.
.2.10 Replacement of the Residual Heat Removal Room Cooler
The inspectors reviewed Configuration Change Package 11994. Room cooler SGL10B removes heat from the residual heat removal (RHR) train B pump room to prevent overheating of the RHR train B pump motor. Following work on the room cooler, the licensee determined that the cooling coils were installed upside down such that the existing inlet and outlet piping flanges were misaligned with the flanges of the cooler.
The licensee modified portions of the supply and return piping and a pipe support to realign the existing flanges to make proper fit up with the room cooler flanges. The licensee also approved the continued use of the RHR room cooler coil with the modified piping. At the coolers next scheduled outage, the station will inspect the cooling coils to ensure satisfactory installation and use of the cooler. The inspectors did not identify any concerns with the change package.
.2.11 Modification of the Main Steam Feedwater Isolation Signal
The inspectors reviewed Change Package 013361, implemented to modify the control logic needed to open the main feedwater isolation valves (MFIVs) by implementing a pressure open mode. The pressure open mode provides greater capacity to open the MFIVs when a high differential pressure exists across the valve discs. In refueling Outage 17, high differential pressure developed a crossed the valves disc faces, following a separate plant modification that relocated check valves in the main feedwater system, preventing valve opening. The change package is a corrective fix for the failure of MFIVs to open during refueling Outage 17. The modifications open logic is located within the finite state machine of the main steam feedwater isolation signal MFIV controls. The inspectors did not identify any concerns with the change package.
.2.12 RF20 Auxiliary Feedwater Vents
The inspectors reviewed Design Change Package 014485. The modification installed four vent valves in the safety-related auxiliary feedwater system to remove non-condensable air from the suction of the auxiliary feedwater pumps. Following maintenance that had previously drained the suction piping, the piping was subject to incomplete filling. The licensee attributed to pressure fluctuations and turbulence in the pumps suction line to the failure to remove non-condensable air from the suction piping.
The inspectors reviewed the material, mechanical, seismic environmental conditions, structural, operational and welding, and test aspects of the modification to verify that the installed installation meet design requirements of the facility. The inspectors did not identify any concerns with the change package.
b. Findings
No findings were identified.
OTHER ACTIVITIES
4OA2 Problem Identification and Resolution
.1 Review of Corrective Action Program Documents
a. Inspection Scope
The inspectors reviewed 18 corrective action program documents that identified or were related to 10 CFR 50.59 program and permanent plant modifications. The inspectors reviewed these documents to evaluate the effectiveness of corrective actions related to permanent plant modifications and evaluations of changes, tests, and experiments. In addition, corrective action documents written on issues identified during the inspection were reviewed to verify adequate problem identification and incorporation of the problems into the corrective action system. The list of specific corrective action documents that were sampled and reviewed by the inspectors are listed in the to this report.
b. Findings
No findings were identified.
4OA6 Meetings
.1 Exit Meeting Summary
On July 23, 2015, the inspectors presented the preliminary inspection results to Mr. Adam Heflin, President and Chief Executive Officer, and other members of the licensees staff. The licensee acknowledged the results as presented. While some proprietary information was reviewed during this inspection, no proprietary information was included in this report.
4OA7 Licensee-Identified Violation(s)
No findings were identified.
SUPPLEMENTAL INFORMATION
KEY POINTS OF CONTACT
Licensee Personnel
- A. Heflin, President and Chief Executive Officer
- D. Hendel, Corporate Counsel
- R. Clemens, Director, Engineering Projects
- T. Harris, Assistant to Engineering Vice President
- S. Smith, Plant Manager
- D. Dees, Operations Supervisor
- D. Grove, Superintendent, Maintenance Planning
- R. Audano, Superintendent, Mechanical Maintenance
- S. Henry, Manager, Integrated Plant Scheduling
- W. Muilenburg, Supervisor, Licensing
- D. Erbe, Manager, Security
- B. Schafer, Design Engineer
- T. Jamar, Principal Engineer
- G. Curten, Supervisor, Design Engineering
- S. Furfuson, Acting Nuclear Manager
- V. Kanal, Supervisor, Design Engineering
- C. Hafenstine, Supervisor, Engineering Projects
- K. Fredrickson, Licensing Engineer
- L. Stevens, Licensing Engineer
NRC Personnel
Douglas Dodson, Senior Resident Inspector, Wolf Creek Generating Station
Raja Stroble, Resident Inspector, Wolf Creek Generating Station
Fred Lyon, Project Manager, Plant Licensing Branch IV-1
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