ML20148S943
| ML20148S943 | |
| Person / Time | |
|---|---|
| Site: | Sequoyah  |
| Issue date: | 01/26/1988 |
| From: | Gridley R TENNESSEE VALLEY AUTHORITY |
| To: | NRC OFFICE OF ADMINISTRATION & RESOURCES MANAGEMENT (ARM) |
| References | |
| RTR-NUREG-1275 NUDOCS 8802030179 | |
| Download: ML20148S943 (7) | |
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TENNESSEE VALLEY AUTHORITY CHATTANOOGA, TENNESSEE 374ot SN 157B Lookout Place JAN 261988 U.S. Nuclear Regulatory Consission ATTN: Document Control Desk Washington, D.C.
20555 Gentlemen:
In the Matter of
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Docket Nos. 50-327 Tennessee Valley Authority
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50-328 SEQUOYAH NUCLEAR PLANT (SQN) - IMPLICATIONS OF IMPROVEMENT LESSONS OF NUREG-1275, "OPERATING EXPERIENCE FEEDBACK REPORT: NEW PLANTS." TO SQN
Reference:
NRC letter to TVA dated December 3, 1987, "Implications of Improvement Lessons of NUREG-1275, ' Operating Experience Feedback Report:
New Plants' to SQN" Enclosed is TVA's response providing the information requested in the above reference. The enclosure addresses actions taken or planned at SQN with respect to the Improvement Lessons that are marked applicable to operating reactors in NUREG-1275. TVA considers the Improvement Lessons valuable information and has given attention to these kinds of ideas during the development of the Nuclear Performance Plan (NPP). Specific references to sections of the NPP and other programs are provided in the enclosure.
If you have questions, please telephone Kathy S. Whitaker at (615) 870-7748.
Very truly yours.
[
TENNESSEE ALLEY AUTHORITY R. Gridley, irector Nuclear Licensing and Regulatory Affairs Enclosure cc: See page 2 8802030179 880126 PDR ADOCK 05000327 P
$8 D*fl I
An Equal Opportunity Employer
. U.S. Nuclear Regulatory Commission JAN 261988 cc (Enclosure):
Mr. K. P. Barr, Acting Assistant Director for Inspection Programs TVA Projects Division Office of Special Projects U.S. Nuclear Regulatory Commission Region II 101 Marietta Street, NW, Suite 2900 Atlanta, Georgia 30323 Mr. G. G. Zech, Assistant Director for Projects Mall Stop 7E23 TVA Projects Division office of Special Projects U.S. Nuclear Regulatory Commission 7920 Norfolk Ave.
Bethesda, Maryland 20814 Sequoyah Resident Inspector Sequoyah Nuclear Plant 2600 Igou Ferry Road Soddy Daisy, Tennessee 37379 I
)
I j ENCLOSURE SEQUOYAH NUCLEAR PLANT (SQN) ACTIONS OR PLANNED ACTIONS WITH RESPECT TO NUREG-1275 IMPROVEMENT LESSONS The issues addressed in the Improvement Lessons of NUREG-1275 were considered during the development of the Nuclear Performance Plan (NPP).
In this enclosure. TVA references the specific sections of the NPP and other programs that address the Improvement Lessons information. Each section of the Improvement Lessons is paraphrased, and TVA has provided a response addressing the intent of each of these sections.
A.
Management Lecsons
- 1. KRC Lesson Establish an operating plant mentality well before initial criticality.
TVA Response SQN has recently realigned the Operations organization to ensure adequate emphasis is placed on restart requirements.
One layer of l
manag2 ment has been eliminated to allow more direct involvement in the process.
Additionally, as stated in previous correspondence with NRC, SQN's restart functional testing program will serve to focus attention on the operating plant requirements at SQN before nuclear restart.
During this period, TVA will operate, test, and inspect plant equipment to ensure system integrity and functionality. This testing program will provide operations personnel with the opportunity to redirect emphasis to operating plant concerns.
Section II of Volume 2 of the NPP also addresses this lesson.
Procedure adherence is specifically addressed in sections II.2.4 and II.4.0, and SQN plant management is stressing management dedication to procedure adherence.
Systems training continues to be emphasized, and section II.2.3 of the NPP describes this and other training developed to improve plant awareness.
Expedited resolution of problems is addressed in sections II.2.1.4 and II.2.5 of the NPP.
- 2. L@C Lesson Conduct a deliberate, evenly paced, thorough, and well-planned preoperational and startup test program.
TVA Response Section III.ll of Volume 2 of the NPP and the response to lesson A.1 above provide information concerning SQN's restart test program.
- 3. URC Lesson Use the finalized technical specifications to generate and validate surveillance testing procedures as early as possible.
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/ TVA Response TVA developed the Surveillance Instruction Review and Revisien Program to ensure that the technical specification requirements necessary for the startup, operation, and shutdown of the plant are addressed in the surveillance instructions. This program has been completed for SQN unit 2 and is ongoing for unit 1.
- 4. NRC Lesson Improve administrative control of surveillance.
TVA Response TVA has undertaken a comprehensive and disciplined program to review and revise surveillance instructions.
Section II 5.0 of Volume 2 of the NPP addresses SQN's Surveillance Instruction Procedures Program.
Surveillance Testing Activities are presented in Appendix 2 of Volume 2 of the NPP.
- 5. NRC Lesson Give high visibility to the sources of unplanned scrams caused by human error and establish performance goals.
TVA Response Appendix 2 of Volume 2 of the NPP describes SQN's program to reduce reactor trips and engineered safety feature (ESF) actuations.
The program description notes staff attention to the root causes of reactor trips and actuations as a positive management tool for trip and r
actuation reductions. A performance goal of less than three unplanned reactor trips per unit per year has been established.
- 6. NRC Lesson Ensure that operating experience feedback programs:
(a) combine internal events and relevant events from similar plants, (b) communicate them directly to the appropriate first-level supervisors and working-level staff at the plant on a periodic basis including i
before startup, and (c) address preventative measures.
P TVA Response The Nuclear Experience Review Program is described in section II.1.2.7 of Volume 2 of the NPP.
TVA has procedures in place that provide for dissemination of both internal and external operating experience information to operations and other appropriate departments.
- 7. NRC Lesson l
A number of improvement lessons are directed at training, i
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/ TVA Response Training is used extensively to communicate rules and expectations to employees at TVA.
Specific training programs include Operator Training, Systems Training Technical Support Group Training, Maintenance Training, Project Manager Training, and Technical Staff Training for Nuclear Site Personnel. The training programs for SQN are described in sections II.2.3 and II.4.4 of Volume 2 of the NPP.
B.
Equipment Lessons
- 1. NRC Lesson Focus on the balance of plant before operation and early in life appears to provide a high return regarding the reduction of unplanned
-scrams and ESF actuations.
TVA Response Appendix 2 of Volume 2 of the NPP describes SQN's program to reduce reactor trips and ESF actuations. SQN is participating in the Westinghouse Owner's Group - Trip Reduction Assessment Program (WOG-TRAP). TVA sent a licensed reactor operator to a WOC-TRAP expert panel session to investigate feedwater-initiated transients and identify remedial actions.
- 2. NRC Lesson Install test jacks and bypass switches at appropriate points in actuation circuitry.
TVA Response SQN's reactor protection system has test jacks and switches designed into the system configuration.
Bypass functions are available for actuations that have one out of two logic.
These include source and intermediate range high neutron flux trips and containment spray actuation. The reactor trip protection system and ESF actuation testing are more fully detailed in sections 7.2 and 7.3 of SQN's Final Safety Analysis Report.
- 3. NRC Lesson Implement on a priority basis vendor or licensee trip reduction measures.
TVA Response Information is provided concerning SQN's trip reduction program in TVA's response to lessons B.1 and B.7 in this enclosure.
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/ 4. NRC Lesson Pay attention to the design and installation of equipment located in the vicinity of radiation monitors and associated cabling to ensure that adequate grounding of equipment cable shielding, etc.
are provided to prevent the occurrence of electromagnetic interference (EMI), which can trigger this extremely sensitive instrumentation.
TVA Response TVA identified spurious auxiliary building isolations as a major source of unnecessary ESF actuations.
The problems were caused by actuations during fuel movement as a result of high background radiation from the radwaste storage area and by noise interference.
SQN has recently received technical specification setpoint changes to the radiation monitors in the auxiliary building. This change will eliminate the spurious actuations caused by the passage of fuel assemblies near the monitors. The radiation monitors were also modified to include time delays to prevent spurious actuation from noise interference.
A task force has been assembled to study recent ESF actuations involving containment vent isolation at SQN.
EMI is the suspected cause of these events.
Root cause analysis is being performed and recommendations are being developed. The task force's report will document their efforts and findings. This information will be shared with the resident inspector as it becomes available.
- 5. NRC Lesson Thoroughly test new or unique plant features before fuel load to reduce unanticipated f ailures or unexpected erratic behavior.
TVA Response This requirement is directed at unlicensed nuclear plants and is not applicable to SQN restart.
- 6. NRC Lesson For future designs or major plant modifications, preference for proven designs and standardization of design in plant feedwater and turbine systems appears justified.
TVA Response The process used for a current feedwater system modification is an indication of TVA's attention to possible complications as a result of design changes.
A phased approach is being applied to the installation of digital feedwater controllers on the bypass valves at SQN.
Lab testing was completed on the equipment, and a digital controller is currently installed on one loop of unit 1.
The analog controller is
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_5 still in place and functioning, and data from both instruments will be collected and compared. The next phase will use the digital controller as the functioning equipment while continuing to collect data from the analog controller for comparison. Dependent upon operational analyses, digital controllers will be installed in other loops of unit 1 and unit 2.
- 7. NRC Lesson Incorporate scram prevention measures.
TVA Response Appendix 2 of Volume 2 of the NPp describes SQN's program to reduce reactor trips and ESF actuations. As noted previously. TVA is an active participant in WOG-TRAP and has modified setpoints and equipment to reduce ESF actuations. TVA is thoroughly testing the installation of digital feedwater controllers and their capability to reduce reactor trips. Until this equipment is proven acceptable. TVA has analog bypass feedwater controllers, a proven technology, to automatically control feedwater during reactor startup. TVA insists on a consistent, thorough investigation of root causes and implementation of corrective actions to prevent reactor trip and ESF actuation recurrence.
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