ML19282D002

Responds to 790425 Ltr Re Safety Concerns.Proposes Upgrading Emergency Feedwater Sys & Completing Sufficient Small Break LOCA Analyses to Develop & Implement Necessary Operator Instructions in Emergency Procedures

ML19282D002
Person / Time
Site:	Arkansas Nuclear
Issue date:	05/03/1979
From:	Cavanaugh W ARKANSAS POWER & LIGHT CO.
To:	Harold Denton Office of Nuclear Reactor Regulation
References
1-059-1, 1-59-1, NUDOCS 7905070483
Download: ML19282D002 (5)

Text

APPENDIX E ARKANSAS POWER & LIGHT COMPANY POST CFFICE BOX 551 UTTLE RCCK ARKANSAS 72203 (501) 371-4422 May 3, 1979 WILLIAM CAVANAUGH 111 Vce Pnesident Genersoon & Consm.cson

.' 1-059-1 Dr. Harold R. Denton Direc;or, Nuclear Reactor Regulation 1717 H Street North West Washington, D. C. 20555

Subject:

Arkansas Nuclear One - Unit 1 Docket No. 50-313 License No. DPR-51 (File: 1510)

Dear Mr. Denton:

In response to the staff safety concerns identified as items a. through

e. on pages 1-7 of ONRR Status Report to the Commission of April 25, 1979, Arkansas Power and Light proposes the following actions:

(a) Upgrade of the timeliness and reliability of the Emergency Feedwater (EFW system by performing the items specified in Enclosure 1.

(b) Develop and implement operating / emergency procedures for initiating and controlling EFW independent of Integrated

- Control System (ICS) control.

(c) Implement a hard-wired control-grade reactor trip on loss of main feedwater or on turbine trip.

D (d) Complete sufficient small break LOCA analyses to develop and implement necessary operator instructions in the emergency procedures.

(e) At least one Licensed Operator who has had TMI-2 training on the B&W simulator will be assigned to the control room (one each shift).

Arkansas Nuclear One - Unit 1 (ANO-1) is currently shutdown and will not be restarted until the items a. through e. above are completed.

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Mr. H. R. Denton May 3, 1979 1-059-1 To provide an increased margin of safety the following "Long-term" items will be implemented:

1) The items in Enclosure 2 will be implemented during our next outage (following completion of the design change engineering) to cold shutdown conditions which is of sufficient length to accommodate the change but no later than the next refueling outage. Further we will provide ,

a schedule for implementing any other modifications iden- .

tified as necessary as a result of our reviews shown on Enclosure 1.

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2) The failure modes and effects analysis (FMEA) of the ICS is underway with high priority and will be submitted as soon as practicable.

3) The hard-wired trips addressed in Item c. above will be upgraded to safety grade.

4) Complete the ECCS small breaks analyses as outlined in Enclosure 3.

5) We will continue operator training and drilling of response procedures as a part of our ongoing program to assure the high state of readiness and safe operation at ANO-1.

AP&L is confident that these steps will resolve the Staff concerns and provide an additional degree of assurance of public safety.

Ver,y truly y 6 )

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William II,I WC:JTE:vb Enclosures

ENCLOSURE (1)

EMERGENCY FEEDWATER SYSTEM UPGRADE

1. Review procedures, revise as necessary and conduct training to ensure timely and proper starting of motor driven emergency feedwater (EP4) pump from an engineered safeguards bus upon loss of offsite power.

. 2. To assure that EFW will be aligned in a timely manner to in-ject on all EFW demand events when in the surveillance test mode, procedures will be implemented and training conducted to provide an operator at the necessary valves in communica-tion with the control room during the surveillance mode to carry out the valve alignment changes upon EFW demand events.

3. Write and implement procedures for the manual initiation and control of the EFW System following failure of the Integrated Control System.

4. The EFW pumps will be verified operable in accordance with the ANO-1 Technical Specifications and Surveillance Procedures.

5. Review and revise, as necessary, the procedures and conduct training for providing alternate sources of water to the suc-tion of the EFW pumps.

6. In the event emergency feedwater is necessary and offsite power is available, an auto start signal will be provided to the motor driven emergency feedwater pump.

7. Procedures will be developed and implemented and training conducted to provide guidance for timely operator verifi-cation of any automatic initiation of EFW.

8. Verification that Technical Specificatien requirements for EPd capacity are in accordance with the accident analysis will be conducted.

9. Modifications will be made to provide verification in the control room of EFW flow.

ENCLOSURE (2)

EMERGENCY FEEDWATER SYSTEM UPGRADE

1. Connect the motor driven Emerrency Feedwater (EFW) pump to a vital AC power supply.

2. Modify the suction piping to improve system separation. -

3. Modifications will be made to provide verification in the control rcom of EFW flow to each steam generator. ..

4. Provide control room annunciation for all auto start conditions of the EFW system.

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ENCLOSURE (3) May 3, 1979 GUIDELINES FOR THE DEVELOPMENT OF OPERATIONAL PROCEDURES FOR SAFE MANAGEMENT OF SMALL BREAKS IN THE REACTOR COOLANT SYSTEM PRESSURE BOUNDARY Operational guid-lines will be prepared for the safe handling of small breaks as an extension of and addition to previously issued guidelines and IE Bulletin 79-05A. These guidelines will include provisions for

, operator recognition of small breaks and discrimination of other acci-dents which might produce similar symptoms.

The guidelines will include expected system response insofar as required

, to assure effective operator understanding and action. The guidelines will include necessary precautions and will describe those actions which the operator must take to assure safe management and mitigation of small break events, including natural circulation cooring where it is predicted to occur in the course of the accident.

These guidelines will specifically cover cases in which RCS stabiliza-tion will occur with a partially filled reactor coolant system for both the case with the reactor coolant pumps on and the reactor coolant pumos off. Delay in the initiation of auxiliary feedwater up to 20 minutes will be considered. System conditions covered will assume availability of ECCS systems at full design ficw in the event that auxiliary feed-water is not available or with single failure in the ECCS systems in the event that auxiliary feedwater is available.

The guidelines will be based on existing analyses and by specific addition-al computer calculations. These calculations will be performed to define system response to restart of reactor coolant pumps in a partially filled system and response of the partially filled system to restart of auxiliary feedwater.

These guidelines will be developed by B&W and reviewed Dy the NRC staff

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in time for implementation of the corresponding procedures by Arkansas Power & Light on or before May 15, 1979.

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