ML19316A051

Describes Interim Measures to Be Taken Re Postulated Feedwater Line Break in Turbine Bldg & Penetration Room Until Accident Analysis Complete or Design Mods Implemented, as Discussed in 730118 Meeting W/Aec

ML19316A051
Person / Time
Site:	Oconee
Issue date:	02/05/1973
From:	Thies A DUKE POWER CO.
To:	Giambusso A US ATOMIC ENERGY COMMISSION (AEC)
References
NUDOCS 7911210618
Download: ML19316A051 (3)

Text

I AEC DIR"lIEUTION FOR PART 50 DOCKET !W"IAL ~

(TEMPORAM FOR 1) CONTROL NO: 980 FIII FROM: DATE OF DOC: DATE REC'D LTR MEMO RPI OTHEd buke Power Company Char.lotte, North Carolina 28201 , 2-5-73 2-9-73 x A. C. Th'es TO: ', ORIG CC OIHER SENT AEC PDa X A. Cicmbusso 1 signed EI'I'T I,0CAI, PDR X CIASS: , h i^*P INFO IliPUT NO CYS REC'D DOCKET IiO:

1 50-269 DESCRIPTION: ENCLOSURES:

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PnopucTnON AND TRANSM6SSION

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February 5, 1973 Q Ry l3! ymt SECTION 3

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Mr. Angelo Giambusso k '7 Deputy Director for Reactor Projects 'q P g g *. /5,

• Directorate of Licensing U. S. Atomic Energy Commission W

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Re: Oconee Nuclear Station 4 #

Unit 1 Docket No. 50-269

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Dear Mr. Giambusso:

Please refer to my letter of January 26, 1973. In that letter, you were informed that as a result of our continuing analysis on the postulated failure of lines containing high energy fluids we would propose appropriate modifications to meet the interpretation of Criterion IV of the Commission's general design criteria. We also informed you that we would implement interim measures which could reduce the consequence of postulated high energy line ruptures, reduce the probability of occurrence, or assure that equipment needed to mitigate the accident is available.

On January 18, 1973, we met with members of your staff to present the results of our analysis to date and advised them that Oconee Unit 1 could be shut down safely in the event that a hypothetical riccident identified by your criteria did occur. In that accident analysis, we identified two instances where the single failure criteria may not have been met. Consequently, interim measures will be taken until the

analysis is complete or design modifications can be implemented.

j For postulated f-riwater line break in the turbine building, we will tcke I the following mc. tres:

1. Dril2 openings in the piping insulation near high stress locations on feedwater piping identified to you in our discussions on January

18. These areas will be visually observed once per shift to detect any leak.

2. The auxiliary service water pump will be tested for a minimum time of one hour each week to assure operability.

984

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Mr. Angelo Giambusso

, Page 2 February 5, 1973

3. A redundant cable will be pulled from the 4160 auxiliary service water switchgear to the high pressure injection pumps. This cable will be available for quick manual connection to any of the high pressure injectiot, pumps should it be needed.

For the feedwater break in the penetration room, the following measures will be taken:

1. The reactor building isolation valve in the high pressure injection line B (HP 27) will be lef t open to reduce the probability of a single failure occurrence.

2. Insulation on the feedv2ter lines in the penetration room will be drilled near the terminal ends and visually observed once per shift to detect any leakage.

3. An additional temperature detector will be installed in the penetration ro m to give the operator information as to the occurrence and location of a break.

The above-mentioned temperature detector will be installed prior to March 15, 1973. In addition to the above measures, emergency procedures are being developed for the following situations: Loss of feedwater to the stnam generators with the emergency feedwater system operable and loss of feedwater to the steam generators with the emergency feedwater system ,

inoperable. Also, the emergency procedare covering steam line break will 1 be revised as required to include information resulting from our analysis.

We are also developing procedures for a surveillance program to inspect the areas of postulated ruptures. Procedures for making visual exami-nations of the metal surfaces of the higher stress locations are also being developed. More information on this program will be forwarded ta you within 10 days following initial criticality.

l Very truly yours, i sb.h* fan" , 1 A. C. Thies ACT:vr )

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