ML19351A011
| ML19351A011 | |
| Person / Time | |
|---|---|
| Site: | Farley  |
| Issue date: | 06/15/1981 |
| From: | Office of Nuclear Reactor Regulation |
| To: | |
| Shared Package | |
| ML19351A010 | List: |
| References | |
| NUDOCS 8106240328 | |
| Download: ML19351A011 (4) | |
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JUN 15 lag; SAFETY EVALUATION REPORT JOSEPH M. FARLEY NUCLEAR PLK.1T, UNITS 1 & 2 7-s
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DIESEL GENERATOR TECHNICAL SPECIFICATION CHANGE Introduction The primary purpose of the 2C diesel generator at the Farley Plant is to start the five river water pumps of the river water systen's Train B.
The attached table shows that emergency bus 1J of Unit 1 is energized 10 seconds followirg receipt of signal and river water pumps 4 and 5 are started at five second interval.e.
Since diesel 2C is relatively small at 2850kw output, care is taken to prevent two river water pumps from starting simultaneously so that the diesel will not trip. A time delay was designed into the system so that emergency bus 2J of Unit 2 is not energized until approximately 21 seconds following receipt of signal. As shown in tNa attached table, the number 1, 2 and 3 river water pumps are started in sequence after the bus is energized.
Farley, Unit 2 utilizos the Standard Technical Specifications.
One of the requirements is that each diesel generator shall start and energize its emergency buses within 10 seconds following receipt of signal. Although a time delay was attached to emergency bus 2J by design, diesel 2C does not meet this requirement.
By letter dated May 5,1981, the licensee requested a Technical 3pecification change to allow diesel generator 2C 24 seconds to energize its emergency buses.
All of the remaining diesels will meet the 10 second requirenent.
Evaluation The proposed Technical Specification change does not involve a safety consideration. The safety analysis involving the river water pumps has previously included the time delay.
The purpose of the river water pumps is to maintain the service water pond. Pond water flows to the common service water suction pit, flows to the two units and then it is normally discharged directly to the river. Under transient conditions, the service water can be pumped directly back to either the pond or the service water suction pit thus reducing or eliminating any immediate need of the river water pumps.
If, however, the seismically designed dam failed causing loss of the service water pond, the river water pumps would be relied upon to discharge directly into the service water suction pit.
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- JUN 151981 If diesel generator 2C energized both emergency buses 1J and 2J ten seconds following receipt of signal, the automatic sequencing would attempt to start two river water pumps simultaneously.
In order to avoid any potential of tripping the diesel, the liensee has the following time delay for bus 2J:
1 second for intermediate relay actuation and breaker tip 1 second for closing of the output breaker 20 second time delay for relay actuation
+ 2 ' seconds tolerance for relay actuation ZT seconds total time to energize bus 2J All river water pumps from Train B are therefore postuldted to be in operation 36 seconds following the initiating event.
The river water pumps on the redundant Train A (whose emergency buses are all energized within 10 seconds) are all postulated to be in operation 32 seconds following the initiating event.
The proposed Technical Specification change has been made to accomodate the system desigr..
There are no deficiencies in either the equipment or its design to prompt this change. There are no safety considerations involved because the plant's analysis has previously included the time delay.
Due to the above considerations, we find the proposed change to the plant's Technical Specifications to be acceptable.
Environmental Consideration We have determined that the amendment does not authorize a change in effluent types or total amcunts nor an increase in power level and will not result in any significant environmental impact.
Having made this determination, we have further concluded that the amendment involves an action which is insignificant from the standpoint of environmental impact and, pursuant to 10 CFR 551.5(d)(4), that an environmental impact statement or negative declaration and environmental impact appraisal need not be prepared in connection with the issuance of this amendment.
Conclusion We have concluded, _ based on the considerations discussed above, that: (1) because the amendment does not involve a significant increase in the probability or consequences of accidents previously considered and does not involve a significant decrease in a safety margin, the amendment does not involve a significant hazards consideration, (2) there is reasonable assurance that the health and safety of the public will not be endangered n
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3-JUN 151981 by operation in the proposed manner, and (3) such activities will be conducted in compliance with the Cortnistion's regulations and the issuance of this amendrent will not be inimical to the common defense and security or to the health and safety of the public.
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JUN 151981 Diesel Generator 2C Loss of Offsite Power (LOSP)
I Typical Sequence of Events Time Event 0
LOSP (Signal to start diesel 2C and trip breaker DG-13) 1 SEC Bus 1J and 2J load shed and starts 20 second timer for Bus 2J 10 SEC 2C D/G energized Bus 1J and its permanent loads 15 SEC RW 4 starts 20 SEC RW 5 starts
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21 SEC 2C D/G energiz::s Bus 2J and its permanent-loads 26 SEC RW 1 starts 31 SEC RW 2 starts 36 SEC RW 3 starts 4
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