ML050450343
| ML050450343 | |
| Person / Time | |
|---|---|
| Site: | Braidwood  |
| Issue date: | 02/02/2004 |
| From: | Polson K Exelon Generation Co, Exelon Nuclear |
| To: | Document Control Desk, Office of Nuclear Reactor Regulation |
| References | |
| BW050009 | |
| Download: ML050450343 (5) | |
Text
Exekrnem Exelon Generation Company. LLC Braidwood Station 35100 South Rt 53. Suite 84 Braceville, IL 60407-9619 Tel. 815-417-2000 www.exeloncorp.com Nuclear February 2, 2004 BW050009 U.S. Nuclear Regulatory Commission ATTN: Document Control Desk Washington, DC 20555-0001 Braidwood Station, Units 1 and 2 Facility Operating License Nos. NPF-72 and NPF-77 NRC Docket Nos. STN 50-456 and STN 50-457
Subject:
Regulatory Commitment Change Summary Report Please find enclosed the Regulatory Commitment Change Summary Report for Braidwood Station.
This report contains summary information for regulatory commitment changes from January 1, 2004 through December 31, 2004.
If you have any questions regarding this report, please contact Mr. Dale Ambler, Regulatory Assurance Manager, at (815) 417-2800.
Respectfully, Keith &'olson Site Vice President Braidwood Station Attachment cc:
Regional Administrator-NRC Region IlIl NRC Senior Resident Inspector-Braidwood Station
-OU
Attachment Braidwood Station Regulatory Commitment Change Summary Report Originating Document:
ComEd (currently known as Exelon Generation Company) 180-day response to Nuclear Regulatory Commission (NRC) Generic Letter (GL) 96-05, "Periodic Verification of Design-Basis Capability of Safety-Related Motor-Operated Valves," dated March 15, 1997.
Subject of Change:
Document a one-time frequency extension for diagnostic testing of valve 2WO056A due to the testing exceeding the 1 0-year frequency requirement.
Original Commitment:
In a March 15, 1997 letter Commonwealth Edison (Exelon) provided its 180-day response to NRC Generic Letter 96-05, "Periodic Verification of Design-Basis Capability of Safety-Related Motor-Operated Valves". In this response, ComEd committed to participating in the Joint Owners Group (JOG) Periodic Verification Program for Motor-Operated Valves (MOVs). In the NRC's Safety Evaluation of the JOG Periodic Verification Program dated October 30, 1997, a static diagnostic testing frequency was established based on margin and safety significance for the specific MOV. The maximum frequency for static diagnostic testing of high margin and low risk MOVs is 6 cycles (not to exceed 10 years). This periodic testing criteria has been incorporated into Exelon procedure ER-AA-302 and its associated Training and Reference Material Guide, ER-AA-302-1003, MOV Margin Analysis and Periodic Verification Test Intervals.
Revised Commitment:
Actuator preventative maintenance activities including static diagnostic testing for Motor Operated Valve 2WO056A, Chilled Water Inboard Containment Isolation Valve, was moved from outage A2R10 (November, 2003) to on-line based on concerns for the environmental effects caused by having containment chilled water unavailable during the outage. This work was moved to on-line (March, 2004) without an accurate understanding of the change in radiological dose that workers would receive while performing the work on-line. Current estimates are that the on-line dose would be approximately 5.6 person-rem vs. an estimated 1.3 person-rem to perform the work during an outage. -These estimates follow a detailed review of the scaffolding needed for the job, the area dose rates, and improved worker job time estimates. Based on this information, the MOV preventative maintenance activities were moved to refueling outage A2R1 1 (March, 2005). The MOV was last diagnostically tested on October 28, 1994 and based on the new scheduled test date, the test frequency will exceed 10 years by approximately 6 months. This is a one-time frequency extension for diagnostic testing of valve 2WO056A. The valve will be scheduled for its next test in accordance with the established periodic verification program (currently 6 cycles or A2R17).
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Attachment Braidwood Station Regulatory Commitment Change Summary Report Basis:
MOV 2WO056A is a containment isolation valve with a safety function to close on a containment phase A isolation signal. This valve is considered low risk and high margin in accordance with the periodic verification program. The valve is stroke tested quarterly in accordance with Operating Surveillance Procedure 2BwOSR 3.6.3.5.WO-1, Containment Chilled Water Containment Isolation Valve Stroke Quarterly Surveillance, and the Inservice Testing Program (IST). This testing has indicated acceptable performance of the valve. Other preventative maintenance activities including stem lubrications, actuator lubrication samples and electrical inspections have been performed on their specified frequency with no issues noted. Additionally, similar MOVs including 1(2) WO06ANB, 1 (2)WO020ANB, 1 (2)WO056B and 1WO056A have been tested in accordance with the IST and the MOV periodic verification programs with acceptable results. Based on this, delaying the performance of static diagnostic testing on 2WO056A until A2R11 will not affect continued acceptable performance of this valve.
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Attachment Braidwood Station Regulatory Commitment Change Summary Report Originating Document:
NRC Supplemental Safety Evaluation of Byron Station, Units 1 and 2, and Braidwood Station, Units 1 and 2 (Response to the Station Blackout Rule [TAC Nos. 68522, 68523, 68515 and 68516]), dated March 14,1991.
Subject of Change:
Content of Updated Final Safety Analysis Report (UFSAR) Table 8.3-5 "Loading on 4160-Volt ESF Buses."
Original Commitment:
The licensee re-evaluated the loss of offsite power (LOOP) loads and the station blackout (SBO) loads using equipment design requirements for the loads as opposed to overly conservative motor ratings. Also, actual motor efficiencies rather than assumed efficiencies were used for the larger motor loads. The licensee stated that UFSAR Table 8.3-5 would be revised to reflect these changes and to correct some errors that were identified during the SBO review. Based on the load re-evaluation and the licensee's commitment to revise the UFSAR, the staff now finds that the proposed alternate AC (MC) power source qualifies as an excess capacity MC source consistent with the SBO rule and associated guidance.
The commitment was originally identified in Supplemental Safety Evaluation of Byron Station, Units Nos. 1 and 2 and Braidwood Station, Unit Nos. 1 and 2; Response to the Station Blackout Rule (TAC Nos. 68522, 68523, 68515 and 68516) - dated 3/14/91. A correction to the supplemental safety evaluation was issued on 4/4/91. This correction did not revise the commitment from the 3/14/91 supplemental safety evaluation.
Revised Commitment:
The original commitment is not being revised. However, the changes to the UFSAR originally performed for the commitment are being revised. The changes to Table 8.3-5 originally made, replaced the motor rated horsepower (HP) with motor brake horsepower (BHP) based on design demand conditions. Draft Revision Package (DRP) 9-087 revised Table 8.3-5 to show loads connected to the Emergency Diesel Generator (EDG), but the table will no longer be used as a load tabulation to calculate EDG loading and the BHP data was eliminated. Motor rated HP is listed in the table to provide indication of the relative size of the loads. EDG loading is provided in the table based on the results of the current EDG load flow studies using equipment design requirements and actual motor efficiencies. Load data from both the Loss of Coolant Accident (LOCA) and LOOP conditions defined by the table are provided.
Basis:
During the original review of the Byron and Braidwood Station Blackout submittal, the NRC questioned the capacity of the EDGs to operate as the MC power source. The issue was based on the EDG loading determined from the data presented in Table 8.3-5 of the UFSAR.
At that time, Table 8.3-5 was used as a load tabulation to determine EDG loading. Since Table 8.3-5 at that time contained rated HP for the loads and generic motor data, the EDG loading 3
Attachment Braidwood Station Regulatory Commitment Change Summary Report calculated using.the table was higher than design EDG loading. The changes to Table 8.3-5 discussed in the Safety Evaluation Report (SER) were intended to revise Table 8.3-5 such that the loading provided by the table more accurately reflected EDG loading. However, EDG loading is calculated using analytical software that takes into account BHP, actual motor data (efficiencies and power factors) and system losses. Table 8.3-5 was only revised to list load BHP, but continued to use a generic efficiency and power factor for the motors. In addition, system losses cannot be accounted for using the load tabulation provided in Table 8.3-5.
Therefore, even with the changes originally made to Table 8.3-5, the table still did not accurately reflect EDG design loading.
The actual changes made to Table 8.3-5 from the commitment only replaced the motor rated HP with BHP based on design demand conditions. Further, the BHP values added were only for LOCA conditions, not for LOOP or SBO conditions as indicated in the SER. This data was provided as part of the SBO submittal and not incorporated into the UFSAR. Table 8.3-5 was not revised to reflect actual motor efficiencies even though the SER indicated that we were revising Table 8.3-5 to address efficiencies in addition to horsepower changes. Since the EDG load data included in Table 8.3-5 are from load studies using motor BHP for each applicable design conditions and actual motor efficiencies, the changes to Table 8.3-5 for DRP 9-087 are in accordance with the original commitment, which was to revise Table 8.3-5 to reflect accurate EDG loading based on actual motor horsepower and efficiencies.
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