IR 05000338/2005007
| ML051300173 | |
| Person / Time | |
|---|---|
| Site: | North Anna  |
| Issue date: | 05/10/2005 |
| From: | Ogle C NRC/RGN-II/DRS/EB |
| To: | Christian D Virginia Electric & Power Co (VEPCO) |
| References | |
| IR-05-007 | |
| Download: ML051300173 (39) | |
Text
SUBJECT:
NORTH ANNA POWER STATION - NRC SAFETY SYSTEM DESIGN AND PERFORMANCE CAPABILITY INSPECTION REPORT NOS.
05000338/2005007 AND 05000339/2005007
Dear Mr. Christian:
On April 15, 2005, the U.S. Nuclear Regulatory Commission (NRC) completed a safety system design and performance capability team inspection at your North Anna Power Station. The enclosed report documents the inspection findings which were discussed on April 15, 2005, with Mr. J. Davis and other members of your staff.
The inspection examined activities conducted under your licenses as they relate to safety and compliance with the Commissions rules and regulations and with the conditions of your licenses. The inspection team reviewed selected procedures and records, observed activities, and interviewed personnel.
Based on the results of the inspection, no findings of significance were identified.
In accordance with 10 CFR 2.390 of the NRC's "Rules of Practice," a copy of this letter and its enclosure will be available electronically for public inspection in the NRC Public Document Room or from the Publicly Available Records (PARS) component of NRC's document 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\\
Charles R. Ogle, Chief Engineering Branch 1 Division of Reactor Safety
VEPCO 2 Docket Nos.: 50-338, 50-339 License Nos.: NPF-4, NPF-7
Enclosure:
NRC Inspection Report 05000338/2005007 and 05000339/2005007 w/Attachment: Supplemental Information
REGION II==
Docket Nos.: 50-338, 50-339 License Nos.: NPF-4, NPF-7 Report Nos.: 05000338/2005007 and 05000339/2005007 Licensee: Virginia Electric and Power Company (VEPCO)
Facility: North Anna Power Station, Units 1 & 2 Location: 1022 Haley Drive Mineral, Virginia 23117 Dates: March 21 - 25, 2005 and April 11-15, 2005 Inspectors: R. Moore, Senior Reactor Inspector (Team Lead)
L. Miller, Senior Reactor Inspector D. Mas-Penaranda, Reactor Inspector N. Staples, Reactor Inspector H. Anderson, Contractor Approved by: Charles R. Ogle, Chief Engineering Branch 1 Division of Reactor Safety
SUMMARY OF FINDINGS
IR 05000338/2005-007, 05000339/2005-007; 3/21-25/2005 and 04/11-15/2005; North Anna
Power Station, Units 1 and 2; Safety System Design and Performance Capability Inspection.
This inspection was conducted by a team of inspectors from the NRCs Region II office. No findings of significance 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 3, dated July 2000.
NRC-Identified and Self-Revealing Findings
No findings of significance were identified.
Licensee-Identified Violations
None.
REPORT DETAILS
REACTOR SAFETY
Cornerstones: Initiating Events and Mitigating Systems
1R21 Safety System Design and Performance Capability
The team evaluated the capability of installed plant equipment to detect and respond to a loss of coolant accident (LOCA) which includes small break LOCA, inter-system LOCA, and large break LOCA. Procedures which direct the mitigating actions for this event were also evaluated.
.1 System Needs
.11 Process Medium
a. Inspection Scope
The team reviewed the availability and reliability of water sources required for the LOCA events. These water sources included the reactor water storage tank (RWST), the containment recirculation sump, and casing cooling tank. The review included design documentation; drawings; Updated Final Safety Analysis Report (UFSAR); Technical Specifications (TS); corrective actions history; volumetric and water depth calculations for the RWST, the containment recirculation sump, the containment floor, and casing cooling tank; calculations of system capacity; and calculations of net positive suction head (NPSH) available and required for the high head safety injection (HHSI) pumps, low head safety injection (LHSI) pumps, outside recirculation spray (ORS) pumps, inside recirculation spray (IRS) pumps, and casing cooling pumps. Also included was a review of minimum flow protection for the HHSI and the LHSI pumps.
The team reviewed water depth calculations, system flow rate and suction approach velocity calculations, as well as suction piping configuration drawings to verify that vortexing had been evaluated in the containment recirculation sump suction configuration for the LHSI, ORS and IRS systems. The team also reviewed the flow passage opening sizes in the most restrictive portions of the HHSI, LHSI, ORS, and IRS systems to verify that the flow passage opening sizes in the containment recirculation sump suction strainers were sized accordingly. A list of documents reviewed is included in the Attachment to this report.
b. Findings
No findings of significance were identified.
.12 Energy Sources
a. Inspection Scope
The team reviewed appropriate test and design documents to verify that the 4160 volt alternating current (VAC) and 480VAC power sources, as well as 125 volt direct current (VDC) power sources, were adequate to meet minimum voltage specifications for electrical equipment during and following a LOCA event. This included a review of design torque values for selective rising stem and quarter turn motor-operated valves (MOVs) to verify that the safety functions (open/closed) were adequately tested assuming minimum voltage. A specific list of components and documents reviewed is included in the Attachment to this report.
b. Findings
No findings of significance were identified.
.13 Instrumentation and Controls (I&C)
a. Inspection Scope
The team reviewed the instrumentation that is used by operators for detection and mitigation of a LOCA event. The team reviewed appropriate design basis documents, TS, system flow diagrams, instrument uncertainty calculations, calibration procedures, and calibration test records to verify that selected level, flow, and pressure process instrumentation had the proper range and accuracy needed to perform their safety function. The setpoints for the RWST level alarms and equipment actuation relays were reviewed to verify that they were established in accordance with setpoint guideline procedures and design output documents. Maintenance and calibration records were reviewed to verify that the current performance capability of the selected process instrumentation was consistent with design basis documents. The team conducted field inspections of the accessible instrument installations to verify that the instrument tubing, sensors, and supports were in good material condition and that heat tracing was installed when required. A list of documents and components reviewed is included in the Attachment to this report.
b. Findings
No findings of significance were identified
.14 Operator Actions
a. Inspection Scope
The team reviewed plant operating instructions, including emergency procedures (EPs),abnormal procedures (APs), and alarm response procedures (ARs) that would be used during the identification and mitigation of a LOCA event. The team focused on installed equipment and operator actions that could be used to mitigate the event. The review was done to verify that the instructions were consistent with the UFSAR description of LOCA events and within the Owners Group Emergency Procedure Guidelines (EPGs),any step deviations were justified and reasonable, and the instructions were written clearly and followed the EOP writers guide. The team held discussions with licensed operators and training instructors, reviewed job performance measures and training lesson plans pertaining to use of procedures and equipment used during a LOCA event to confirm that training was consistent with the applicable operating instructions.
In addition, the team observed simulation of large break LOCA event on the plant simulator and walked down portions of applicable instructions to verify that operator training, procedure guidance, and instrumentation were adequate to identify a LOCA event and implement post-LOCA mitigation strategies. The manual operator action times for performance of LOCA mitigation activities were reviewed for consistency with accident analyses, EPGs, and operator training. Procedures reviewed are included in the Attachment to this report.
b. Findings
No findings of significance were identified
.15 Heat Removal
a. Inspection Scope
The team reviewed the calculation of the required minimum exhaust air flow rate from each HHSI (charging pump) cubicle for normal and post-accident operation at the maximum air supply temperature. The team also reviewed completed periodic tests for Train A and Train B of the emergency core cooling system (ECCS) pump room exhaust air cleanup system (PREACS) to verify that the exhaust air flow rate from each HHSI (charging pump) cubicle was demonstrated to be greater than the minimum required exhaust flow rate.
The team reviewed the acceptance criteria basis for minimum service water flow to each recirculation spray heat exchanger (RSHX). This basis incorporated hydraulically limiting service water system configurations and a revised containment analysis. The team reviewed periodic test results to verify that the service water system was capable of supplying the required minimum service water flow rates to each RSHX under limiting configurations. Additionally, the team reviewed evaluations of RSHX heat transfer UA values to verify consistency with related inputs to the current containment analysis and to confirm controls on the implementation of analyzed limitations on the number of heat exchanger tubes in each RSHX which potentially could be plugged in future maintenance activities. A list of documents reviewed is included in the Attachment to this report.
b. Findings
No findings of significance were identified.
.2 System Condition and Capability
.21 Installed Configuration
a. Inspection Scope
The team performed field walkdowns of accessible LOCA mitigation equipment and 480 VAC electrical power supplies to observe the existing conditions and configurations.
Equipment examined included accessible HHSI, LHSI, quench spray, casing cooling, and ORS pumps, system valves, piping, and related components. During this walkdown the team compared valve positions with the configurations on the approved drawings and operating procedures The team reviewed periodic test documentation to verify independent verification was performed and that blank pancake flanges were removed (and spool pieces installed) in returning the recirculation spray system to the pre-test condition after performance of the most recent recirculation spray system header air test. Also, the team walked down portions of the 125VDC and 4160VAC systems to verify that the installed configuration was consistent with design basis information and to assess the material condition. A specific list of documents and components reviewed is included in the Attachment to this report.
b. Findings
No findings of significance were identified.
.22 Operation
a. Inspection Scope
The team walked down selected portions of the LOCA response procedures with operators to check for human factors in the instructions and in the plant; including clarity, accuracy, labeling, lighting, noise, communications, and accessibility. The team also checked HHSI and LHSI system alignments to verify consistency with design and licensing basis assumptions and the TS.
b. Findings
No findings of significance were identified
.23 Design
a. Inspection Scope
Mechanical Design Review The team reviewed design calculations, specifications, the UFSAR, testing, maintenance, and modification documentation to verify that system and equipment design functions were appropriately maintained. Periodic test procedures and equipment monitoring activities were reviewed to verify that design criteria were appropriately translated into the acceptance criteria in the tests for the HHSI, LHSI, ORS, IRS, casing cooling, and quench spray pumps, selected motor operated valves, and check valves. The team reviewed DBDs, selected piping, TS, Plant Issues (PIs),and testing, corrective maintenance, and modification documentation for LOCA mitigation equipment to assess the implementation and maintenance of the systems design basis.
The team reviewed calculations and system configuration to assess the adequacy of the NPSH available for the HHSI, LHSI, ORS, IRS, and casing cooling pumps. System design, testing, and as-maintained configuration were reviewed to assure pump minimum flow requirements and run out protection were provided for the LHSI and HHSI pumps. The team reviewed a sample of replacement parts to verify the parts were appropriately evaluated and qualified for use in safety related applications to assure the design function of the equipment was maintained. A list of documents and components reviewed is included in the Attachment to this report.
Electrical, Instrumentation and Controls Design Review The team reviewed system flow diagrams, I&C drawings, electrical elementary and schematic diagrams, instrument setpoint calculations, as well as calibration procedures and calibration test records to verify that the instrumentation and controls for the HHSI, LHSI, and QS were in accordance with design basis documents. The team reviewed control schematics and electrical drawings to verify design features were incorporated in control circuits for selected LOCA mitigation pumps and valves. Also reviewed were setpoint calculations for selected process instruments including containment pressure, containment sump level, and RWST level to verify that the calculations included appropriate instrument uncertainties. The last two completed calibration test records were reviewed to confirm that instrument setpoints were consistent with setpoint calculations. For the instruments selected, the team reviewed documentation of completed surveillance tests and calibrations to verify that equipment performance was appropriately monitored and maintained consistent with the design and licensing basis.
The team reviewed the EP related setpoints for RCS subcooling to verify that values used were in accordance with design basis documents.
The team reviewed voltage drop calculations to verify that adequate power would be available to meet design basis scenarios. Particular attention was paid to voltage at key motor operated valves, and that voltage calculations were coordinated with torque and thrust calculations. In addition, MOVATS test results were reviewed to check that valve motor inrush currents were consistent with those used in the calculations. Selected samples within the calculation for sizing of thermal overloads were reviewed, and the methodology was compared to industry standards. In addition, the team reviewed over-current protective relays data set point calculation and curves to verify that adequate margin existed between the valve motor start current and the time and instantaneous relay to allow motor start without inadvertent trip. Also, the team reviewed the battery sizing calculation for the class 1E 125VDC electrical distribution system to assess the adequacy of the batteries to provide power for selected components required to mitigate a LOCA event. A list of documents and components reviewed is included in the to this report.
b. Findings
No findings of significance were identified.
.24 Testing and Inspection
a. Inspection Scope
The team reviewed performance and post-maintenance testing of HHSI, LHSI, ORS, IRS, and casing cooling systems pumps and valves to verify that the tests and inspections were appropriately verifying that the assumptions of the licensing and design bases were being maintained and that performance degradation would be identified.
This included operability stroke time testing, thrust and torque testing, and corrective maintenance records for selected HHSI, LHSI, and service water (SW) system risk-significant MOVs. The team also reviewed selected risk-significant check valve periodic tests to verify the check valves were demonstrated to function to the appropriate open /
check positions to support system operation. Test records were reviewed to verify that permissives and interlocks not normally tested during pump testing were verified during periodic surveillance testing The team reviewed electrical equipment service and performance testing and preventive maintenance procedures for the 125VDC, 4160VAC, and 480VAC power system. The review was performed in order to verify that specified acceptance criteria were met and that the equipment operation was consistent with the plants licensing and design bases.
This included the 125VDC batteries 1-I surveillance test records to verify that the batteries are capable of meeting design basis load requirements. The team also reviewed calibrations for the over-current protective relays to support proper operation of 4160VAC safety buses 1H and 1J. Additionally, the team reviewed the inservice test performance data for the pump motors for the HHSI, LHSI, casing cooling and recirculation spray inside and outside systems to verify that the load current and vibrations exhibited by the motors under full load conditions were consistent with the manufacturers guidelines The team reviewed a sample of process and indication instruments, such as containment sump level, temperature, and pressure, that provided input signals to the LOCA or containment depressurization activation (CDA) logic. The last two completed instrument calibration records were reviewed for the selected instruments to verify that they had been calibrated in accordance with the setpoint documents and calibration procedures. The calibration records were also reviewed to verify test deficiencies such as out of tolerance conditions, were being entered into the corrective action program for evaluation and disposition. A specific list of documents and components reviewed is included in the Attachment to this report.
b. Findings
No findings of significance were identified.
.3 Selected Components
.31 Component Degradation
a. Inspection Scope
The team reviewed maintenance and testing documentation, modifications, performance trending, equipment history documented in work orders, PIs, and system health reports to assess the licensees actions to verify and maintain the safety function, reliability and availability of selected components. Equipment reviewed included LOCA mitigation pumps, breakers, and valves. The team also reviewed the potential for common cause failure mechanisms in maintenance. Additionally, the team reviewed in-service trending data for selected components, including the HHSI, LHSI, ORS, IRS, and casing cooling pumps flow profiles to verify that the components were continuing to perform within the limits specified by the test and design basis.
The team reviewed documentation of oil analysis results for 1-CH-P-1A charging pump common reservoir (inboard and outboard pump bearings) and motor inboard and outboard bearings to verify the analysis results indicate normal, anticipated oil conditions. Additionally, the team reviewed documentation of completed performance as well as the frequency of oil changes for the 1-CH-P-1A pump common reservoir and speed increaser gear case (3-year frequency) and motor inboard and outboard bearings (1-year frequency). A specific list of equipment and documents reviewed is included in the Attachment to this report.
b. Findings
No findings of significance were identified
.32 Equipment/Environmental Qualification
a. Inspection Scope
The team conducted in-plant walkdowns to verify that the observable portions of selected mechanical and electrical components were suitable for the environment expected under all conditions, including high energy line breaks (HELBs) and flooding.
The team reviewed qualification test data associated with the environmental testing of the IRS pump motor to verify that the components were qualified for the worst case postulated accident environments where they are installed A list of documents reviewed is included in the Attachment to this report.
b. Findings
No findings of significance were identified
.33 Equipment Protection
a. Inspection Scope
The team walked down the spaces containing 250VDC equipment and the emergency switchgear rooms and reviewed temperature switches qualifications to verify the equipment was adequately protected against external events such as flood, missiles, and HELB. The team observed the exterior of the removable wall blocks to each HHSI (charging pump) cubicle to verify a cured sealant was in place to seal the joints between the wall blocks to a height of at least 44 inches above the floor elevation for flood protection from potential water sources external to the individual cubicles. Additionally, the team verified that cold weather protection provisions remained in place at the time of the walkdown around the RWST level transmitters, located adjacent to the exterior of the RWST
b. Findings
No findings of significance were identified.
.34 Component Inputs/Outputs
c. Inspection Scope
The team reviewed selected MOV operator requirements calculations and evaluated the capability of the MOVs to perform their design function under degraded voltage conditions. The specific MOVs reviewed are those referenced in Section 1R21.21a.
The team reviewed functional, logic, and elementary drawings for a sample of pump control circuits in LHSI and quench spray (QS) start circuits. The team also reviewed control circuits for critical MOV and pump actuation on LOCA. Additionally, the team reviewed the logic and functional diagrams to verify that power was available and adequate for selected critical valves during the design basis duty cycle for HHSI, LHSI, SW, and QS. The team reviewed samples of surveillance test procedures for LOCA and CDA logic functional testing to confirm that the logic paths, including permissives and interlocks, were being tested in a manner to adequately demonstrate that the equipment would perform in accordance with design basis documents. The specific documents and components reviewed are included in the Attachment to this report.
b. Findings
No findings of significance were identified.
.35 Operating Experience (OE)
a. Inspection Scope
The team reviewed the licensees applicability evaluations, extent of condition reviews, and corrective actions for industry and station operating experience issues related to HHSI, LHSI, ORS and IRS equipment problems, use of non-conservative acceptance criteria in safety related pump surveillance tests, line starter relay failures, safety related pump shaft damage, plugging of SI pump oil coolers, gas voids in SI pump suction lines, and check valve problems to verify that plant specific issues were appropriately identified and addressed. Work orders, procedures, field observations and discussions with engineering staff were used to verify if OE related corrective actions were accomplished. The team reviewed a report summarizing the results of the licensees evaluation of safety related logic system testing in response to NRC Generic Letter 96-01. Specifically, the section of the report dealing with HHSI, IRS, and ORS logic system testing was reviewed to verify that logic test deficiencies were properly evaluated The specific industry experience issues and documents reviewed are listed in the Attachment to this report.
b. Findings
No findings of significance were identified.
.4 Identification and Resolution of Problems
a. Inspection Scope
The team reviewed selected system health reports, maintenance records, surveillance test records, and PIs to verify that design and performance problems were identified and entered into the corrective action program. The team assessed the scope of the licensees extent-of-condition reviews and the adequacy of the corrective actions. The team reviewed calibration test records to verify that out of tolerance conditions were properly entered into the corrective action program for evaluation and disposition. A sample of corrective maintenance work orders on the HHSI, LHSI, ORS and IRS pumps and selected valves were reviewed. Additionally, the team reviewed documentation of individual PIs which were originated as a result of the teams inspection activities, including documentation of the status of each initial PI evaluation as it existed at the conclusion of the onsite inspection activities. A list of documents reviewed is included in the Attachment to this report.
b. Findings
No findings of significance were identified.
OTHER ACTIVITIES
4OA6 Meetings, Including Exit
The lead inspector presented the inspection results on April 15, 2005, to Mr. J. Davis and other members of the licensee staff. The licensee acknowledged the findings presented.
Proprietary information is not included in this inspection report.
SUPPLEMENTAL INFORMATION
KEY POINTS OF CONTACT
Licensee
- J. Davis, Site Vice President
- S. Hughes, Manager, Operations
- J. Leberstien, Technical Advisor - Licensing
- J. Martin, Systems Manager - Engineering
- J. McHale, Design Engineer
- A. Royal, Manager, Training
- D. Stuckmeyer, Corporate Engineer
- M. Walker, Manger , Nuclear Oversight
NRC (attended exit meeting)
- G. Wilson, Resident Inspector
LIST OF ITEMS
OPENED, CLOSED AND DISCUSSED
None
LIST OF DOCUMENTS
AND EQUIPMENT REVIEWED