IR 05000395/2002007
| ML023160611 | |
| Person / Time | |
|---|---|
| Site: | Summer  |
| Issue date: | 11/08/2002 |
| From: | Ogle C NRC/RGN-II/DRS/EB |
| To: | Byrne S South Carolina Electric & Gas Co |
| References | |
| IR-02-007 | |
| Download: ML023160611 (17) | |
Text
SUBJECT:
VIRGIL C. SUMMER NUCLEAR STATION - NRC INSPECTION REPORT 50-395/02-07
Dear Mr. Byrne:
On October 11, 2002, the Nuclear Regulatory Commission (NRC) completed a safety system design and performance capability inspection at your Summer Nuclear Station. The enclosed report documents the inspection findings which were discussed on October 11, 2002, with you and other members of your staff.
This inspection was an examination of activities conducted under your license as they relate to safety and compliance with the Commissions rules and regulations, and with the conditions of your operating license. Within these areas, the inspection involved selected examination of procedures and representative records, observations of activities, and interviews with personnel.
On the basis of the results of this inspection, no findings of significance were identified.
In accordance with 10 CFR 2.790 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 Publically Available Records (PARS) component of the NRCs 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 Docket No.: 50-395 License No.: NPF-12
Enclosure:
(See page 2)
SCE&G 2 Enclosure: NRC Inspection Report 50-395/02-07 w/Attachment
REGION II==
Docket No.: 50-395 License No.: NPF-12 Report No.: 50-395/02-07 Licensee: South Carolina Electric & Gas (SCE&G) Company Facility: Virgil C. Summer Nuclear Station Location: P. O. Box 88 Jenkinsville, SC 29065 Dates: September 23-27, 2002 (Week 1)
October 7-11, 2002 (Week 2)
Inspectors: F. Jape, Senior Project Manager (Lead Inspector)
M. Thomas, Senior Reactor Inspector R. Moore, Reactor Inspector N. Garrett, Resident Inspector (Hatch)
N. Merriweather, Senior Reactor Inspector (Week 1 only)
C. Smith, Senior Reactor Inspector (Week 2 only)
Approved by: Charles R. Ogle, Chief Engineering Branch 1 Division of Reactor Safety Enclosure
SUMMARY OF FINDINGS
IR 05000395-02-07, South Carolina Electric & Gas Co., on 9/23-10/11/2002, Virgil C. Summer, safety system design and performance capability biennial baseline inspection.
The inspection was conducted by regional inspectors and the Hatch resident inspector. The NRCs program for overseeing the safe operation of commercial nuclear power reactors is described in NUREG-1649, Reactor Oversight Process, Revision 3, dated July 2000.
No findings of significance were identified.
REPORT DETAILS
REACTOR SAFETY
CORNERSTONES: Initiating Events, Mitigating Systems
1R21 Safety System Design and Performance Capability
.1 System Needs
a. Inspection Scope
Instrumentation The team reviewed the design of the instrument channels which would be used by the operators to determine the refueling water storage tank (RWST) level, the containment sump level, and the instrumentation used to initiate automatic switchover to the containment sump during a small break loss of coolant accident (SBLOCA). The team reviewed appropriate design drawings, surveillance test procedures, scaling documents, and calibration procedures to determine if the instrument channels were consistent with the design bases and/or Technical Specifications (TS). Specifically, the team reviewed the RWST instrument level sensor channels, actuation logic, and interlocks for the automatic switchover to the containment sump to verify consistency with design basis documents. The instrument loop uncertainty calculation for the containment sump level channels was reviewed to determine if it adequately addressed instrument uncertainties associated with elevated containment temperatures and pressures postulated during accident conditions.
The team walked down and inspected the heat tracing control panels for the RWST level instruments to verify that they were operable and no alarms were present. Also, the team reviewed design drawings depicting the heat tracing system to verify that the temperature sensors were properly located to detect process temperatures.
The team reviewed design basis documentation that demonstrated the containment sump level instrumentation qualification for submergence post-accident operation as required by 10 CFR 50.49, Environmental Qualification of Electrical Equipment Important to Safety for Nuclear Power Plants.
Controls The team reviewed the design, calibration, and maintenance of residual heat removal system (RHR) controls to verify that RHR system performance and monitoring were consistent with the design basis, Updated Final Safety Analysis Report (UFSAR), and accident analysis assumptions. A review of vendor manuals, set point calculations, calibration procedures, RWST and containment sump drawings was conducted to ensure the accuracy and reliability of controls of water sources for mitigation of the SBLOCA. Additionally, the team reviewed the calibration and surveillance tests of the flow control instrumentation for the RHR pump miniflow valves.
This review was conducted to verify that adequate pump flow was assured, consistent with vendor recommendations.
Process Medium The team reviewed the capability of the RHR system to mitigate the effects of a SBLOCA. The team verified that this capability was consistent with the licensing bases such as the UFSAR, TS, and licensee Safety Evaluation Reports. This review included design documentation; drawings; and calculations of system capacity, RHR pump net positive suction head (NPSH) available and required, and RHR pump minimum flow and runout flow protection. In addition, the system performance documentation was reviewed to assess the reliability, availability, and adequacy of system performance testing and equipment maintenance.
The team also reviewed the RWST licensing and design basis documents to verify that an adequate supply of borated water was available to mitigate the effects of a SBLOCA.
This review included TS Section 3/4.5.4, UFSAR Section 6.3.2.6, drawings, system design basis documents (DBDs), and RWST volume calculations. Also, test results (performed on a 1/4 scale model of the RWST to show the effectiveness of the RWST anti-vortex design) were reviewed to verify that vortexing had been properly considered in RWST volume calculations.
Heat Removal The team reviewed the heat removal equipment for the RHR pump motor and RHR pump room to assess the reliability and availability of this equipment. This review included design documentation, drawings, calculations, vendor manuals, test documentation, surveillance and operating procedures and installed equipment.
The team reviewed the vendor manuals, drawings, RHR system DBD, component cooling water (CCW) heat exchanger heat load calculations, surveillance test documentation, and operating procedures to assess the design and performance of the RHR and component cooling heat exchangers. The team also reviewed CCW heat exchanger calculations, test acceptance criteria, and surveillance test results to verify that CCW heat exchanger tube plugging and fouling were evaluated for impact on heat exchanger performance.
Electrical Power Source The team performed a design review for probable common cause failure of the charging safety injection pump (CSIP) and RHR pump motors to operate because of inadequate equipment utilization voltage. The team reviewed DBDs, calculations, vendor information and approved design output drawings of the 7.2 kilovolt (KV) and 480 volt alternating current (VAC) power distribution system. Minimum motor terminal voltages and overcurrent protective relay application for the charging injection pump and RHR motors were evaluated for compliance with vendor recommendations and industry guides and standards. The team also evaluated selected RHR motor operated valves (MOVs) for their performance capability under degraded voltage conditions against the valve actuator minimum required open/close torque requirements. Additionally, the team reviewed the sizing and application of thermal overloads for the MOVs to verify compliance with vendor information and industry guides and standards.
b. Findings
No findings of significance were identified.
.2 Selected System Conditions and Capability
a. Inspection Scope
Installed Configuration The team performed a field walkdown of accessible equipment related to the CSIP and support systems to assess material condition and verify the equipment alignment was consistent with system drawings and procedures. Specific equipment examined during the walkdown included the CSIPs, CCW pumps, system valves, piping, and related components.
Operations The team reviewed selected system trending data, modifications, and maintenance histories for the CSIPs, RHR heat exchangers, and CCW heat exchangers to identify any degradation in system performance. The team reviewed selected system calculations to ensure that adequate NPSH was available for all operational modes of the CSIPs and adequate injection flow would be available during a SBLOCA scenario.
Design Design and test documentation were reviewed to determine if the design basis assumptions for system capability were maintained. Additionally, system design changes were reviewed to verify the design function of the system was appropriately maintained. This review included design documentation, drawings, calculations, vendor manuals, test documentation, and surveillance and maintenance procedures for installed equipment. The team also performed a review to verify that power uprate modifications had been evaluated for impact on the capability of the CCW and RHR heat exchangers to remove the required heat load during the recirculation phase after a SBLOCA.
Testing The team reviewed selected completed test data to ensure that CSIP system injection flow rates remained within system design calculations. The team reviewed documentation of completed surveillance tests, calibration procedures, and inspections of equipment required for mitigation of a SBLOCA to verify that equipment performance was appropriately monitored and maintained consistent with the design and licensing bases. Additionally, the team verified the accurate translation of setpoint values and acceptance criteria from design documentation into the applicable test procedures.
Component testing reviewed included RHR pumps, containment sump and RWST level instrumentation, RHR and CCW heat exchangers, and selected critical MOVs important for mitigating a SBLOCA.
b. Findings
No findings of significance were identified.
.3 Selected Components
a. Inspection Scope
Component Inspection The team reviewed maintenance and testing documentation, performance trending information, and equipment history to assess the licensees actions to verify the safety function, reliability, and availability of selected components were consistent with the UFSAR, NRC generic letters and industry standards. Additionally, potential common cause failure mechanisms due to flooding and maintenance were reviewed. The selected equipment included the RHR pumps, RHR room heating, ventilation, and air conditioning equipment, RHR and CCW heat exchangers, a risk based selection of important valves (XVG-8706A, - 8811 A&B, -8812 A&B, 0602 A&B) and level instrumentation for the RWST and containment sump.
The team performed selected field inspections of 7.2 KV switchgears and 480 VAC motor control centers. The team assessed the adequacy of the equipment material condition. The team also evaluated the installed equipment configuration for compliance with design output drawings. Additionally, the team conducted a field inspection of the RWST level transmitters to verify that the instrument locations were consistent with the instrument isometric drawings and scaling documents.
The team performed field walkdowns of the accessible equipment required for the mitigation of the SBLOCA, including RHR pumps, important valves and RWST instrumentation to assess material condition and identify degraded conditions.
b. Findings
No findings of significance were identified.
.4 Identification and Resolution of Problems
a. Inspection Scope
The team reviewed equipment problems identified in the licensees corrective action program. This included the licensees review and evaluation for applicability of industry Operating Experience (OE) issues.
Findings b. No findings of significance were identified.
OTHER ACTIVITIES
4OA6 Management Meetings
The lead inspector presented the inspection results to Mr. S. Byrne, and other members of the licensees staff at an exit meeting on October 11, 2002. The licensee acknowledged the findings presented. Proprietary information is not included in this inspection report.
SUPPLEMENTAL INFORMATION
KEY POINTS OF CONTACT
Licensee
- R. Brenner, System Engineer
- S. Byrne, Senior Vice President, Nuclear Operations
- D. Gatlin, Manager, Operations
- G. Halnon, General Manager, Nuclear Plant Operations
- G. Moffatt, Manager, Design Engineering
- A. Monroe, Engineer, Licensing
- B. Stokes, Supervisor, Design Engineering
- R. Sweet, Supervisor, Licensing
- D. Watson, Senior Nuclear Training Supervisor
- S. Zarandi, Manager, Maintenance
NRC
- M. King, Resident Inspector
- J. Moorman, Team Leader
- M. Widmann, Senior Resident Inspector
ITEMS OPENED, CLOSED, AND DISCUSSED
None