NOED-03-6-001 - Sequoyah 2 (Tennessee Valley Authority)
January 30, 2003
Mr. J. A. Scalice
Chief Nuclear Officer
and Executive Vice President
Tennessee Valley Authority
6A Lookout Place
1101 Market Street
Chattanooga, Tennessee 37402-2801
|SUBJECT:||SEQUOYAH NUCLEAR PLANT, UNIT 2 - NOTICE OF ENFORCEMENT DISCRETION FOR TENNESSEE VALLEY AUTHORITY (TAC NO. MB7334, NOED NO. 03-6-001)|
Dear Mr. Scalice:
By letter dated January 28, 2003, you requested that the U.S. Nuclear Regulatory Commission (NRC) exercise discretion not to enforce compliance with the requirements in the Sequoyah Nuclear Plant (SQN), Unit 2, Technical Specification (TS) Limiting Condition of Operation (LCO) 184.108.40.206.a, Action 18, regarding the automatic switchover to the containment sump. Your letter documented information previously discussed with the NRC staff in a telephone conference held on January 24, 2003, at 11:30 a.m. Eastern Standard Time (EST). The principal NRC staff members who participated in that telephone conference are listed in Enclosure 1. This one-time relief was requested to allow one less than the minimum number of channels that are required to be operable for the refueling water storage tank (RWST) level indication for a duration of 48 hours.
You stated that on Friday, January 24, 2003, at 8:35 a.m. EST with Unit 2 operating at 100 percent power, while performing the per shift surveillance requirements, the unit operator discovered that the wide range RWST level transmitter (LT) channel 2-LT-63-50 failed, indicating a high level and Action 18 of TS 220.127.116.11.a was entered. Subsequently, the unit operator began investigating RWST LT channel 2-LT-63-52, which also indicated a level greater than 100 percent. The wide-range RWST LTs provide part of the logic input for initiation of the automatic switchover from the suction of the RWST inventory to the containment sump. The apparent cause of the failed LT channels was frozen sensing lines due to the loss of the associated instrument box heaters during the freezing weather. As a result, RWST LT channel 2-LT-63-52 was declared inoperable and LCO 3.0.3, was entered at 8:45 a.m. EST due to less than minimum number of required channels being operable. In accordance with LCO 3.0.3, Unit 2 was required to be in HOT SHUTDOWN at 3:45 p.m. EST.
You requested that a Notice of Enforcement Discretion (NOED) be issued pursuant to the NRC's policy regarding exercise of discretion for an operating facility, set out in Section VII.c. of the "General Statement of Policy and Procedures for NRC Enforcement Actions" (Enforcement Policy), NUREG-1600, and be effective for a period of 48 hours to accomplish recovery or replacement of at least one of the Unit 2 RWST level channels to operable status. You proposed the following compensatory measures: (1) temporary heat would be established for the inoperable channels, (2) temporary heat would be established for Unit 2 RWST level transmitters, and the operable Unit 1 RWST LTs, (3) a fire watch would be established to monitor the additional temporary heat, (4) licensed operators on duty during the 48-hour duration would be briefed on the situation and required to review the procedural operation for manual RWST switchover to the containment sump, (5) all work involving the RWST channels for both units would be suspended until the restoration of the inoperable channels, and (6) the monitoring frequency of the Unit 1 RWST would be increased from every 12 hours to every 2 hours.
You determined that the proposed NOED would not be a potential detriment to the public health and safety, and that no significant hazard consideration was involved. This was based on the continued operability of two channels, the addition of a dedicated operator to ensure the switchover, the fact that allowing this discretion would require no physical modification to the plant and should not significantly reduce any margin of safety. The compensatory measures proposed by your staff provided reasonable assurance that the condition would not recur and ensure the continued operability of existing RWST LTs. The addition of a dedicated operator for the switchover as a compensatory measure was made based on discussion with the staff to reduce the possibility of any single failure from preventing initiation of the switchover. You indicated that your request was reviewed and approved by the Plant Operations Review Committee and the Plant Manager. The staff agrees that the measures proposed would not be of potential detriment to the public health and safety or the environment, and poses no significant hazards consideration. In addition, you performed a qualitative risk evaluation, which was reviewed by the staff. The staff concluded from its qualitative assessment that with the addition of a dedicated operator to ensure the RWST switchover, there would be, at most, an insignificant impact on risk, including the likelihood of no net increase at all. We specifically note that NRC Inspection Manual, Part 9900, Section B, Criteria 2.0(1) and 2.1.1.a. are satisfied.
On the basis of the staff's evaluation of your request, we concluded that a NOED was warranted because we were satisfied that the expanded compensatory measures were adequate and this action involved no safety impact, did not result in a net increase in risk, was consistent with the enforcement policy and staff guidance, and posed no adverse impact on public health, safety or the environment. Subsequent to granting the NOED, you informed us that at 1:45 p.m. EST one RWST LT channel was declared operable which allowed you to exit from LCO 3.0.3 before 3:45 p.m. EST on January 24, 2003, therefore, the requested NOED was not utilized and the TS change is no longer required.
As stated in the Enforcement Policy, action will be taken, to the extent that violations were involved, for the root cause that led to the noncompliance for which this NOED was necessary.
|/original signed by K.Jabbour Acting for/
|Herbert N. Berkow, Director
Project Directorate II
Division of Licensing Project Management
Office of Nuclear Reaction Regulation
Docket No: 50-328
Enclosure: List of Conference Call Participants