ML20031F148

Safety Evaluation Supporting Amend 8 to License NPF-8

ML20031F148
Person / Time
Site:	Farley
Issue date:	10/01/1981
From:	Office of Nuclear Reactor Regulation
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Shared Package
ML20031F144	List: ML20031F143 ML20031F148 ML20031F154
References
NUDOCS 8110190259
Download: ML20031F148 (4)

Text

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UNITED STATES 31 j.([g I. p,,

NUCLEAR REGULATORY COMMISSION

• yn pf WASHINGTON, D. C. 20555

,yv s SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION RELATED TO AMENDMENT NO. 8 TO FACILITY OPERATING LICENSE NO. NPF-8 ALABAMA POWER COMPANY JOSEPH M. FARLEY NUCLEAR PLANT, UNIT 2 DOCKET NO. 50-364 Introduction The two unit Farley plant has five diesel generators (DG). Units 1 and 2 have dedicated DG-1B and DG-28,respectively. The remaining DG-lC, DG-2C and DG l-2A are swing diesels capable of serving either unit.

Unit 1 is currently shutdown due to repairs of the main turbine generator.

Unit 1 is not expected to be ready to resume power operations until January. 1982.

Unit 2 is currently operating at 100% 1wer. Teciinical Specifications (TS) 3.8.1.1.b for Unit 2 state that two separate and independent diesel generator sets must be operable (Set A:DG l-2A and DG-lC, Set B: DG-2B and DG-2C). The associated Action statements require that:

3.8.1.1.b)

With one DG set inoperable, restore both sets to operable status within 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br />.

3.8.1.1.b.2)With Unit 1 in mode 5 or 6, either DG-lC or DG-2C may be inoperable for up to 14 days to perfom scheduled maintenance.

(The primary purpose of these DG is to provide power for the train A and train B river water systems respectively).

3.8.1.1.c) With bcth DG sets inoperable, restore both sets to operable status within 2 hours2.314815e-5 days <br />5.555556e-4 hours <br />3.306878e-6 weeks <br />7.61e-7 months <br />.

If any of the above three Action statements cannot be met, the' Unit 2 facility must be placed in the Hot Standby condition within 6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br />.

On September 27,1981, Unit 2 was in the fifth day of Action statement 3.8.1.1.b.2.

With Unit 1 shutdown in Mode 5, DG-lC was inoperable due to scheduled maintenance. While attempting to perform routine surveillance i

testing on DG-2C, the engine tripped on high crankcase pressure after being successfully started and loaded for thirty minutes. DG-2C was immediately declared inoperable. Preliminary investigations indicated a crack in the liner seal between the jacket water system and the air intake system which allowed water to enter one of the cylinders.

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. Since DG-lC and DG-2C are now both inoperable. Unit 2 entered Action statement 3.8.1.1.e '.which calls for plant shutdown within two hours.

Based on the remaining DG capacity to provide power to at least one safety related train for each unit, including the river water system, under all postulated accident conditions, NRC management gave verbal agreement to extend TS Action statement 3.8.1.1.e for 33 hours3.819444e-4 days <br />0.00917 hours <br />5.456349e-5 weeks <br />1.25565e-5 months <br /> to get through the current weekend and provide the NRC staff one complete working day to further analyze the situation.

On September 28, 1981 the licensee stated that DG-2C needed to be.

disassembled and repaired. Their preliminary investigation indicated a need to replace the liner, o-rings, gaskets, pistons, wrist pins and bushings for all the affected cylinders.

In addition, all the cylinder liners would be evaluated and probably replaced. The licensee has estimated that this work will take approximately 17 days to accomplish.

With Unit 1 shutdown for repairs, the licensee believes there is a critical need for the operation of Unit 2 for the Southern Company Power Pool. Therefore, in order to prevent shutting down Unit 2, the licensee has requested the following, one time only extensions to the Farley TS to allow for the repair of DG-2C:

1) TS 3.8.1.1.b needs to be extended to allow one DG set to remain inoperable up to 17 days (an increase from 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br />).

2) TS 3.8.1.1.e needs to be extended to allow both DG sets to remain inoperable up to eight days (an increase from 2 hours2.314815e-5 days <br />5.555556e-4 hours <br />3.306878e-6 weeks <br />7.61e-7 months <br />).

(On September 28 the licensee was ' dr y 6 of Action statement 3. 8.1.1. b. 2.

By extending this o for eight days, the licensee is assured of having the full 14 days originally allowed for the scheduled maintenance of DG-lC).

3) TS 3.8.1.1 also states that if any of the DG sets or offsite power sources is inoperable, the camaining AC sources must be tested in order to show operability every eight hours. Due to the expected time required to repair DG-2C, over 100 starts would be required from the remaining DG. Since the DG manufacturer recommends against this testing frequency, the licensee proposes to extend the frequency from 8 to 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> in order 'o avoid any potential, accelerated wear.

Discussion and Evaluation Availability of Safety Trains The two DG currently out of service are the smaller (2850 Kw) units.

The remaining three DG have a larger (4075 Kw) capacity. The NRC staff has examined the DG schematic arrangement and has discussed the load sharing capability of the remaining DG with the liwnsee. The licensee has shown that for all combinations of loss of offsite power with and without a coincident LOCA at one of the units, there will be at least

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. one train of safety related equipment available at each. unit.

In addition, the staff has investigated the possibility of each unit experiencing a single failure of a remaining diesel generator (cincident with loss of offsite power to both units and a LOCA occurrintj at one unit. But even under these postulated conditions, the flexibility of the diesels circuitry results in one safety train being available on each unit to supply power to the required loads.

The primary purpose of the two DG out of service is to supply power to the river water pumps. The river water pumps supply water to the pond.

The safety related service water system takes suction from the pond.

The pond has a 30 day capacity according to FSAR analysis. Service water exiting from Unit 2 can either go directly back to the river or be recirculated back to the pond.

The licensee has stated that under worst case conditions (i.e., loss of pond dam coincident with plant LOCA), caly two river water pumps would be necessary per unit. With the three remaining diesel generators, there will be the capability to automatically run six river water pumps.

Operator action will not be necessary to actuate the river water system.

Station Blackout Station blackout is characterized by the loss of both offsite and emergency AC power for an extended period of time. Core melt can occur if the turbine-driven auxiliary feedwater system fails or if the reactor coolant pump seals fail subsequently because of lack of cooling if no corrective actions are taken.

In the staff's evaluation found in License Amendment No. 20 for Unit 1 and No. 2 for Unit 2, an estimate was made of the core melt probabilities assuming that diesel generator 1C would be inoperable for a total of 13 days.

Since the licensee has requested a 17 day outage for diesel generator 2C, the probabilities can be assumed to be nearly identical to that previously reported and found to be acceptably low.

Diesel Testing The reduced testing frequency requested is acceptable provided staggered testing of the four diesels is scheduled within the,72 hour8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> time frame.

The following actions are being taken during recovery from this event:

1.

Plant procedures will assure operators are aware of the staggered diesel test frequency and proper ben loading procedures with diesel 2C out of commission.

2.

Each Senior Reactor Operator will brief each oncoming shift ar.d the Shift Technical Advisor.

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. Summary The licensee has shown that for all combinations of loss of offsite power with and without a coincident LOCA at one of the units, there will always be power available to run at least one of the redundant safety trains at each unit. Staff analyses also showed that the inclusion of single failures of a remaining diesel generator at either or both units would not change this result.

The probability of core melt during the one-time 17 day Technical Specifica+n change is acceptably low. Therefore, the proposed Tech-nical Specification change is acceptable on a one-time only basis.

Currently, the licensee, with a team of engineers and technicians from the DG vendor, is undertaking a tSorough investigation / repair program of DG-2C. DC-lC is nearly ready for operation and it can provide additional margin if needed. We believe that the licensee has taken prompt and appropriate action to correct the DG failure.

Based on our review of the system and discussions with the licensee, we believe that the remaining DG will provide sufficient capacity to automatically operate all necessary safety related equipment following a postulated accident. Therefore, we conclude that the proposed TS change should be acceptable.

Environmental Consideration We have detennined that the amendment does not authorize a change in effluent types'or total amounts nor.an increase in power level and will not result in any significant environmental impacit. Having made this determination, we have further concluded that the amendment involves an action which is ins'gnificant from the standpoint of environmental impact and, pursuant to 10 CFR 551.5(d)(4), that an environmental impact statement, or negative declaration and environ-mental 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 inargin, 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 by operation in the proposed manner, and (3) such activities will be conducted in compliance with the Commission's regulations and the issuance of this amendment will not be inimical to the common defense and security or to the health and safety of the public.

Date:

October 1,1981

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