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NOED-03-3-004 - LaSalle 1 (Exelon Generation Company)April 14, 2003 Mr. John L. Skolds, President
Dear Mr. Skolds: By letter dated April 11, 2003, you requested that the NRC exercise discretion not to enforce compliance with the actions required in Technical Specifications (TS) 3.8.4, "DC Sources- Operating" and 3.8.7, "Distribution Systems - Operating." This Notice of Enforcement Discretion (NOED) request was made because the Unit 1 Division 2 125 Vdc Battery Charger was experiencing voltage and amperage fluctuations. Your letter documented information previously discussed with the NRC in telephone conferences that occurred on April 8 and 9, 2003. At the time of these telephone conferences, both LaSalle Units were operating in Mode 1 at 100 percent power and stable. The principal NRC staff members who participated in the telephone conference included: Steven Reynolds, Deputy Director, Division of Reactor Projects (DRP), RIII; Bruce Burgess, Branch Chief, Reactor Projects Branch 2, DRP, RIII; Ronald Gardner, Chief, Electrical Engineering Branch, Division of Reactor Safety (DRS), RIII; Michael Parker, Senior Reactor Analyst, DRS, RIII; Daniel Kimble, Senior Resident Inspector, LaSalle; Doug Eskins, Resident Inspector, LaSalle; Lakshminaras Raghavan, Acting Director, Project Directorate-III, Division of Licensing Project Management (DLPM), Office of Nuclear Reactor Regulation (NRR); Bill Macon, Project Manager, DLPM, NRR; Mike Franovich, Probabilistic Risk Assessment Branch, Division of Systems, Safety, and Analysis, NRR; and Saba Saba, Electrical Engineering Branch, Division of Engineering, NRR. Your staff requested enforcement discretion to preclude entry into the shutdown action statement requiring that Unit 1 be in hot shutdown within 12 hours after the expiration of the allowable outage time (all times discussed in this letter refer to Central (CDT) time). Your staff requested that the 2-hour allowed outage times for TS 3.8.4 and TS 3.8.7 be extended by 12 hours based on your evaluation indicating no increase in risk for continued operation versus a plant shutdown. With this extended allowed outage time, Unit 1 would be required to enter the shutdown action statement immediately following expiration of the 12 hour action statement extension or when repair activities were determined to be unsuccessful and the Unit 1 Division 2 125 Vdc Battery Charger was determined to remain inoperable. Upon entry into the shutdown action statement, you were required to immediately commence a controlled, orderly shutdown and be in hot shutdown within 12 hours, as specified by the LaSalle Unit 1 TS. LaSalle Unit 1 TS 3.8.4. allows the Division 1 or 2 125 Vdc electrical power subsystem to be inoperable for 2 hours. If operability cannot be restored, the Required Action E.1 requires that the unit be in Mode 3 (hot shutdown) in 12 hours and Required Action E.2 requires the Unit to be in Mode 4 (cold shutdown) in the following 36 hours. LaSalle Unit 1 TS 3.8.7, Condition B allows Division 1 or 2 125 Vdc electrical power subsystem to be inoperable for 2 hours. If operability cannot be restored, the Required Action D.1 requires Unit 1 to be in Mode 3 in 12 hours and Required Action D.2 require Unit 1 to be in Mode 4 in 36 hours. During plant operation, it was identified that the Unit 1 Division 2 125 Vdc battery charger ampere output and voltage were fluctuating. To perform repairs on the battery charger, it was necessary to render the battery charger and associated battery inoperable. At approximately 12:25 p.m. on April 9, 2003, your staff requested enforcement discretion to preclude a required entry into the shutdown action statement requiring Unit 1 to be in Mode 3 (hot shutdown) within 12 hours required by the TS. Specifically, you requested that the 2-hour allowed outage time for TS 3.8.4 and 3.8.7 for Unit 1 be extended by 12 hours. The 12-hour extension was based on the estimated time that would be needed to repair and test 3 circuit cards suspected to be the cause of the voltage and amperage fluctuations occurring on the Unit 1 Division 2 battery charger. At 5:42 p.m. on April 9, 2003, the licensee entered TS 3.8.4 and TS 3.8.7 to perform planned repairs to the Unit 1 Division 2 125 Vdc battery charger. At this time, it was necessary to receive an NOED from the 2 hour action statement to allow for replacement and testing of three solid state cards within the Unit 1 Division 2 battery charger. Your staff requested this NOED after consideration of the safety significance and potential consequences of such an action. Your staff performed a risk evaluation and compared the risk of plant operation with the risk associated with a Unit 1 shutdown and cycling the plant through a thermal transient. The results of the evaluation indicated that there was no net increase in risk associated with extending the allowed outage times for TS 3.8.4 and 3.8.7 by 12 hours. As for compensatory measures, during the time that the Unit 1 Division 2 battery charger was inoperable, your staff committed to the following: (1) operating crews on-shift during the period of this discretion will be briefed on the current conditions and the provisions of this request; (2) the Unit 1, Division 2 DC system voltage will be monitored hourly via a special log; (3) the Unit 1, Division 2 battery will maintain a full charge greater than or equal to 128 Vdc; (4) work schedules were reviewed and adjusted to ensure no other safety related equipment will be removed from service for planned maintenance or surveillance testing unless required by Technical Specifications; additionally, the Primary Containment Hydrogen Recombiners, Standby Gas Treatment, and Control Room Area Filtration and Ventilation Air Conditioning Systems will not be removed from service or planned maintenance or surveillance testing unless required by the TS during the period of this NOED; (5) should the temporary charger fail, another temporary charger is available to be promptly installed to maintain the Unit 1 Division 2 battery at a full charge greater than or equal to 128 Vdc; (6) the Division 1 and opposite unit Division 2 DC electrical power distribution system will be protected by posting, shift briefings, discussed at the Plan of the Day meetings, and walkdowns twice per shift of the protected areas by non-licensed operators and field supervisors; (7) the Unit 1 Division 1 AC electrical power distribution system will be protected by postings, shift briefings, discussed at the Plant of the Day meeting, and walkdowns twice per shift of the protected areas by non-licensed operation and field supervisors; (8) appropriate operators and electrical maintenance personnel will be briefed on clearance orders and procedures necessary to crosstie Unit 1 Division 2 125 Vdc as a contingency should a loss of offsite power occur on Unit 1; (9) activities will be restricted in the electrical switchyard to minimize the possibility of an induced loss of offsite power. The licensee verified that there are no abnormal weather patterns or conditions expected during the period of this NOED that would adversely impact the electrical switchyard or Commonwealth Edison electrical power grid; and (10) Nuclear Oversight independently validated the compensatory actions. The NRC's basis for this discretion considered: (1) the availability of the other power supplies to the Unit 1 Division 2 battery, including temporary battery chargers connected to non-class 1E and class IE power supplies; (2) the repair plan for the Unit 1 Division 2 battery charger including contingency actions if the repair activities were unsuccessful; (3) the compensatory measures to reduce the probability of a plant transient while ensuring the availability of other safety-related equipment; (4) the risk attributed to the loss of the Unit 1 Division 2 battery charger; and (5) the risk assessment of the condition indicated that the risk of continued operation while extending the allowed outage time by 12 hours was less than the risk associated with performing a plant shutdown. Based on the above considerations, the NRC staff concluded that Criterion B.2.1.1.a and the applicable criteria in Section C.4 to NRC Manual Chapter 9900, "Technical Guidance, Operations - Notices of Enforcement Discretion" were met. Criterion B.2.1.1.a states that for an operating plant, the NOED is intended to avoid unnecessary transients as a result of compliance with the license condition and, thus, minimize potential safety consequences and operational risks. On the basis of the NRC staff's evaluation of your request, we have concluded that issuance of this NOED is consistent with the Enforcement Policy and staff guidance, and had no adverse impact on public health and safety. Therefore, we verbally approved the exercise of discretion at 2:00 p.m. on April 9, 2003, not to enforce compliance with Unit 1 TS 3.8.4 and TS 3.8.7 and instead extended the action statement for both TS from 2 hours to 12 hours or when repair activities were determined to be unsuccessful and the Unit 1 Division 2 125 Vdc Battery Charger was determined to remain inoperable. As stated above, the verbal approval was granted contingent upon declaration of the Unit 1 Division 2 battery charger inoperable and a commencement of repair activities. At 5:42 p.m. on April 9, 2003, the Unit 1 Division 2 battery charger was declared inoperable and the NOED extended outage clock began. We understand that on April 10, 2003, at 3:20 a.m., post maintenance testing of the Unit 1 Division 2 battery charger was completed. At that time, the conditions of the NOED were fulfilled and the NOED was no longer in effect. At 4:07 p.m. on April 10, 2003, you declared the Unit 1, Division 2 125 Vdc battery charger operable. At that time, Unit 2 exited TS 3.8.4 and 3.8.7. As stated in the Enforcement Policy, action may be taken, to the extent that violations were involved, for the root cause that led to the noncompliance for which this NOED was necessary.
Docket Nos. 50-373 cc: |
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