ML20077A366
| ML20077A366 | |
| Person / Time | |
|---|---|
| Site: | Comanche Peak  |
| Issue date: | 11/11/1994 |
| From: | Terry C TEXAS UTILITIES ELECTRIC CO. (TU ELECTRIC) |
| To: | Russell W Office of Nuclear Reactor Regulation |
| References | |
| TXX-94293, NUDOCS 9411230040 | |
| Download: ML20077A366 (5) | |
Text
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llllllllllll"'llllllllllll Log # TXX-94293 File # 10010 November 11, 1994 C. I,ance Terry Group Vis e President William T. Russell, Director U. S. Nuclear Regulatory Commission Office of Nuclear Reactor Regulation One White Flint North: 11555 Rockville Pike Rockville, MD 20852
SUBJECT:
COMANCHE PEAK STEAM ELECTRIC STATION (CPSES)
DOCKET N05. 50 445 AND 50 446 PREVENTIVE MAINTENANCE AT POWER OPERATION REF:
- 1) NRC letter from Mr. Bill Russell to j
Mr. Joe F. Colvin. NEI, dated October 6, 1994 2
- 2) NRC letter from Mr. Taylor to Mr. Pate, INPO, dated October 6, 1994
- 3) NRC letter from Mr. Taylor to Mr. Nye, TV Electric.
dated October 19, 1994
Dear Bill:
)
I appreciate your taking the time to visit Comanche Peak Steam Electric Station (CPSES) on September 12, 1994. Your visit was beneficial to our 1
continuing efforts to improve our operation at CPSES.
Visits of this nature enhance the dialogue between the regulator and our facility.
By allowing our staff to interface directly with NRC Senior Management at the highest i
levels, our staff will better understand NRC Senior Management views and concerns.
Since your visit to CPSES, the NRC has relayed (via References 1. 2 and 3) concerns about trends toward doing more preventive maintenance during power operation, and requested follow-up discussions on these concerns. The 4
examples identified in the above letters were collected during various NRC plant visits including your visit to CPSES. The following discussion i
provides some clarifying information about the CPSES scheduled preventive maintenance activities that you discussed during your visit.
During our discussion, we may not have made you fully aware of the conservative scheduling and control measures that we practice to minimize risk.
TU Electric agrees with your statement that " configuration control and system / train unavailability must be effectively managed to minimize risk during maintenance activities." We adopted the concept of work windows several years ago to help control train and system unavailability and to j
assure compliance with our Technical Specifications. We carefully control I
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,Page 2 of 3 voluntary entries into Limiting Conditions for Operation (LCO) action statements. Comanche Peak's safety performance indicators three year average (which reflect time equipment or systems are out of service) meet industry goals, and system / component reliability are consistent with that assumed for the Individual' Plant Examination (IPE) Study. To further enhance that reliability, we are implementing a risk matrix based on IPE insights to assist in work planning along with a risk based review of the weekly schedule to assure that planned maintenance activities are conducted with full consideration for plant safety.
During your visit to Comanche Peak in early September, you reviewed a weekly work schedule that included a number of work activities associated with the work window in effect. Although work was planned on several major systems, the work as scheduled and performed ensured that only one safety system of one train was not capable of performing its safety function at a time. The work scheduled was in full compliance with the Technical Specifications with the goal to optimize equipment / system reliability and availability.
A summary of the schedule that was in effect for Unit 2 on September 12 is attached (Attachment 1) as is a summary of the final schedule in effect on September 13 (Attachment 2) for which the work was completed. As a result of discussions during your visit the schedule was revised slightly, but not significantly.
For Unit 1. no conci'rrent disabling work on safety systems was scheduled.
For Unit 2, Auxiliary Feed Water Pump (AFWP 2 02) maintenance was scheduled to be completed, with the pump in its operability run, prior to placing the Safety Injection Pump (SIP 2-02) in an inoperable status.
Even assuming that both were inoperable concurrently, a qualitative assessment of the IPE has concluded that the increased risk would have been insignificant.
In the final schedule, these activities did not overlap.
Your suggestion to hard tie these activities in the schedule to ensure that there is no overlap work, when it would make safety systems inoperable, would help the operators to better control the schedule and has been implemented.
Although the scheduled work on the Residual Heat Removal (RHR 2 02) system and the Station Service Water (SSW) systems required us to declare the systems inoperable by Technical Specification definition, the safety functions of the systems were still available for both systems. Both systems were available to perform their safety functions in an emergency situation. Work on the RHR system was limited to a channel calibration of a flow control valve.
The valve was intact and was available to stroke open (which is its safety function) if needed. Work on the SSW system was limited to the visual inspection of a valve actuator.
The scheduled work on Battery Chargers (BC 2ED2-1, BC 2ED2-2, BC 2ED4 1 and BC 2ED4-2) was on only one battery charger at a time. Each Emergency Diesel Generator (EDG) has two redundant battery chargers available in the CPSES plant specific design. The batteries were confirmed charged, and the redundant battery charger for the associated EDG was confirmed operable before performing the maintenance.
s TXX-9.4293
.,Page 3 of 3 As can be seen from the above explanation, the scheduled work was carefully planned with the objective that multiple systems within the work train would not be rendered incapable of performing their safety function concurrently.
We also assured compliance with Comanche Peak Technical Specifications.
During the accomplishment of the work, the maintenance was controlled to ensure that the objective on the functionality of systems was maintained as originally planned. The plant was maintained in fully analyzed conditions and the work was planned with the goal of optimizing equipment / system reliability and availability.
I hope this clarification has been helpful. Thank you for visiting CPSES and sharing your views with us.
Sincerely, i
)'; ' LL C. L. Terr j
\\J TAH:tg 4'TACHMENTS c-Mr. L. J. Callan, Region IV j
Mr. D. D. Chamberlain, Region IV Resident Inspectors (2)
Mr. T. J. Polich, NRR Document Control Desk Mr. E. A. Nye, TV Electric Mr. W. M. Taylor, TV Electric to TXX-94293 9
WEEK 9/l1194 -9/17/94 SCllEDULE AS OF 0700 9/12/94 MOf1 DAY TUESDAY WEDf1ESDAY TilVRSDAY FRIDAY SATURDAY l
0400 osco 1000 OIL SAMPLE MOTOR BREAKER PM AFWP 2 02 OPT-2088 osoo i4oo 2400 OIL SAMPLE / CHANGE i
i i
MOTOR BREAKER PM SIP 2 02 !OPT-204B l
l 0700 1100 ON FLOW CONTROL VALVE 2-HZ-0607
"^
"^
^
nita Cll AtJf1EL CAL 0800 1400 DiSilvtv 2-HV-4237 MOV ACTUATOR INSPECTION i
SSw ACT selsP SYSTEM WAS NOT TAKEN OUT OF SERVICE l
0700 1300 SAFETY CHILL WATER CONDENSATE PRESSURE SWITCH CllS CllAf1f1EL CAL 0500 1700 BC 2ED21 1700 0500 l
l l BC 2ED2-2 l 0500 1700 BATTERY CHARGER BREAKER PM BC 2ED4-1 l 0500 1700 BC 2ED4 2 to TXr-94293 c.
Page 1 of 1 WEEK 9/11/94-9/17/94 SCHEDULE AS OF 0700 9/13/94 MONDAY TUESDAY WEDNESDAY THURSDAY FRIDAY SATURDAY 0400 0500 1000 OIL SAMPLE
\\
MOTOR BREAKER PM AFWP 2-02 OPT-2068 3100 3800 6
OIL SAMPLE /QIANGE l SIP 2-02
!OPT-2040 0700 1100 ON FLOW CONTROL VALVE I
2-11Z-0607, RHR B llEAT HHR l 1100 1700 EXQlANGER OUTLET VALVE CHANNEL CAL 2-HV-4237 MOV ACTUATOR INSPECTION DISH vtv (NO CLEARANCE IIUNG)
SYSTEM WAS NOT TAKEN OUT OF SERVICE SSW ACT INSP 0700 1300 CHS CHANNEL CAL 0500 i700 SAFETY GIILL UATER CONDENSATE PRESSURE SWITOI BC 2ED21 1700 0500 BC 2ED2-2 0500 1700 BATTERY CIIARGER I
i BREAKER PM l BC 2ED41 l 0500 1700 BC 2ED4-2 i
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