ML20059J294
| ML20059J294 | |
| Person / Time | |
|---|---|
| Site: | Catawba  |
| Issue date: | 01/20/1994 |
| From: | Rehn D DUKE POWER CO. |
| To: | NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM) |
| References | |
| NUDOCS 9401310425 | |
| Download: ML20059J294 (5) | |
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- . Duke Twer Company D. L Ruts Catawba Nuclear Generanon Depanment Mce President -
4%JO ConcordRoad (803)83I3205 Omce York, SC29745 (803)M13426 Fax DUKEPOWER January 20.1994 j
U. S. Nuclear Regulatory Commission ATTN: Document Control Desk Washington, D.C. 20555 i
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Subject:
Catawba Nuclear Station Dockets Nos. 50-413 and 50-414 Systematic Assessment of Licensee Perfonnance (NRC Inspection Report No. 50-413/93-20 and 50-414/93-20) l 1
In the subject report and during the November 29,1993 SALP Resiew Meeting, you provided us i
with your assessment of the Catawba facility. This report states that overall performance at Catawba has improved, while noting two areas of continuing weakness that indicate the need for l
additional management focus. We concur with your overall assessment and have taken steps to
- improve in the areas mentioned in the report. In the SALP Review meeting, you also mentioned that the Engineering area is the most difficult to evaluate. As a follow-up to the SALP Report, we would like to provide the following additional information. - 11 is our desire that this communication will provide insight that will be helpful for future. evaluations of the Catawba engineering functional area.
Teamwork is the key to solving problems at Catawba Nuclear Station. Our system engineering teams serve as a focal point for this effort. Each system engineering team is made up of-representatives from within engineering (component, modification, and system enginects) and from.
across station organizations such as Operations, I&E, Mechanical Maintenance, Chemistry, and Radiation Protection. The system teams provide a forum for cross functional participation in identifying and resolving problems. Emphasis is placed on resiewing all possible : solutions including plant modifications and non-modi 0 cation alternatives. As a result of this multi-discipline
. process, the quality of problem resolutions is optimized.
4 Catawba's modification selection process is structured to activate and implement the modifications most important to the station. The system engineering teams set priorities for the proposed major modifications and make recommendations to a management steering team for approval. The-steering team consists of all the key managers within engineering and the station organization. For minor modifications, the system engineering teams' work directly with the station groups to solve =
l problems. Examples of minor mods include substitution of components when an exact replacement is not available or minor configuration changes to enhance system operations.
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L We feel that the system engineering teams have been very successful in identifying, solving, and fixing problems associated with the operation and maintenance of the facility. We have observed positive results in the level of safety and reliability of Catawba during the recent SALP period.
Some examples include:
continued improving trend for safety system unavailability
- continued improving trend for component failures
- implementation 109 major modifications implementation of 612 minor modifict.tions e
see attachment Several modifications were completed to the Diesel Generator Annunciator Panel to climinate nuisance alarms. Alarms improved were:
low temperature alanus for cooling water and lube oil e
high difTerential pressure across the fuel oil strainer e
high differential pressure across the tube oil strainer Additionally, modifications were completed that replaced all diesel generator non-safety pneumstic trips with electrical trips. This is a significant reliability improvement.
Modifications to the Regulatory Guide 1.47 Bypass Panel have been completed, at the request of the Operations group, to effect a " Dark Board" This improves the man-machine interface between the operators and safety systems status indication and has removed many inaccurate illuminated annunciators in the Control Room. Presently, there are no illuminated annunciators on the control boards of either unit.
A major modification to the Moisture Separator Reheaters (MSR's) replacing the tube bundles, was completed. This modification was installed to eliminate the tube corrosion problem (copper-nickel) resulting in carry over and deposition of corrosion products in the steam generators (S/Gs).
This phenomena, which hastens S/G tube degradation, has now been climinated.
In the area of Shutdown Risk Management (defined per NUMARC 91-06), we continue to optimize our outage safety. This gives us greater confidence in avoiding " Loss of Decay Heat Removal" transients. This has been possible through engineering and analytical support of -
operation and maintenance and by employing techniques such as:
nitrogen drain down techniques to drain S/G tubes smoothly 3 inch reactor vessel head vent (old Upper licad injection nozzle) utilized to drain upper head by relieving vacuum, accelerating drain down time and improving level accuracy and reliability.
vacuum refill technique in lieu of typical reactor coolant pump jog-vent operation (saves time, improves chemistry. utilizes ultrasonic reactor coolant system level detection, and reduces wear on the reactor coolant pump scals.
Detailed knowledge of the techniques referenced above, along with Catawba specific requirements to fulfill NUMARC 91-06 guidelines, recently enabled Catawba Engineering to respond quickly and provide support to the following industry issues:
In VIL # W 93-07, Westinghouse reported an erroneous LTOP setpoint which failed to.
i account for the pressure drop across the core (approt 50 psid). Catawba Engineering.
placed restrictions on reactor coolant pump operation; limiting operation to a specified number of pumps at low temperature depending on cooldown/heatup modes. This compensates for the original design error.
Reactor Vessel Flange Vent Path Issue ** Catawba Engineering evaluated and rejected l
use of the reactor vessel head as a vent path with the reactor coolant pressure boundary intact (a method currently in use by other nuclear utihties) in favor of procedures which require the S/G hot leg as a vent path. It was concluded that the dynamic pressure effects associated with sudden depressurization might exceed nozzle' dam capacity. Rejection of this technique is a time penalty for coordinating S/G and vessel head work; houtver shutdown risks are reduced by this approach.
INPO Nuclear Professional Article dated Spring 1993 Catawba Engineering is involved significantly in the planning, coordination and implementation of major activities important to safety (for example, Nuclear Service Water (RN) valve replacement, use of temporary diesel generator, containment ventilation unit piping replacement ).
Detailed engineering evaluations were perfonned to assure the plant would be able to respond as designed to any design basis accident or design event. These evaluations were driven by the efforts of the q
associated 10CFR50.59 analyses performed in accordance with the requirements of NSAC-125, as
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they relate to implementation. Particular attention was given to seismic interactions, shared system -
dependencies for this two unit site, system interactions, and electrical separation and isolation.
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- l Specific pre-conditions and compensatory actions were stipulated as required for the above 1
activities to preserve the design basis of the plant throughout these evolutions. For example, related to the noted RN valve implementation, the following were specified:
Spool pieces were available and criteria were defined to tenninate potential leaks that could result from failure of non-qualified flooding barriers involved with the implementation A hydro-test was performed using the Fire Protection (RF) System to pressurize the RN System. Compensatory actions were provided to the Control room to respond to various challenges that might occur during the test without degrading the capability of either the RF System or RN System. Considerations included fires. carthquakes, floods, and any other possible design basis accident or design event.
I The Catawba Design Basis Documentation (DHD) program is in its fourth year of a six year schedule. A total of 57 out of 92. DBDs have been completed. The DBDs have become an important tool for Operations personnel and Smem; engineers for making operability detenninations and performing engineering analyses including 10CFR50.59 cvaluations.
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- L GL.89-10 Program Progress
- . Valve testing required by the-89-10 program has progressed l
significantly.' Most notably, during the recent (12/93) Unit 1 outage, 31 Group 1 (safety.
- significant) valves were successfully tested with respect to differentic! pressure (AP).- Followini; i
the upcoming Unit 2 outage (Spring 1994), all Group 1 valves that are capable of being tested at greater than 80% design AP will be completed This represents a significant effort in that the 89-10 program at Catawba contains an average of 250 valves per unit. This is a very large number of valves compared to the number of valves in the 89-10 programs at other utilities.
Catawba's engineering organization.was involved in the success of each.: m cited above. This contributed to a successful year for both units at Catawba, as exemplified by a station capacity-factor of over 79% for 1993. Engineering continues to proside an in-depth understanding of Catauba's capabilities and limitations and the proper application of each. We are fully committed to provide high quality and responsive engineering services to support the safe and reliable operation of Catawba Nuclear Station.
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- We appreciate the opportunity to provide this additional information.
]r Very truly y ours, J
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D. L. Rehn sc:
S.D. Ebneter Regional Administrator, Region 11 R.E. Martin, NRR R.1 Freudenberger i
Senior Resident inspector
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ki SAFETY SYSTEM UNAVAILABILITY SYSTEM 1991 UNAVAILABILITY 1992 UNAVAILABILITY 1993 UNAVAILABIL!TY UNIT 1 UNIT 2 UNIT 1 UNIT 2 UNIT 1 UNIT 2 j
AUX. FEEDWATER 2.43 %
3.94 %
0.91 %
0.42%
0.145 %
0.34 %
(CA) i ECCS 2.57 %
4.19 %
0.70 %
0.97 %
0.28 %
0.14 %
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DIESEL GENERATOR 4.10%
8.60 %
1.22 %
1.69 %
0.31 %
0.38%
l (D/G)
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E, COMPONENT FAILURE ANALYSIS REPORT h
CATAWBA NUCLEAR STATION CFAR i
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- OF FAILURES THAT 33 EXCEED SIGNIFICANCE y
l CRITERIA 0
l Sm W 90 FAR 90 SM % 91 FAR 91 Sm% W FAR W SN W 93 l.
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