ML19242D739

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Responds to IE Bulletin 79-13,Item 5 Re Cracking in Feedwater Sys Piping.Procedures Dealing W/Feedwater Line Break Accident Were Determined to Be Adequate During Insp Completed 790708
ML19242D739
Person / Time
Site: Beaver Valley
Issue date: 07/16/1979
From: Dunn C
DUQUESNE LIGHT CO.
To: Grier B
NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION I)
References
TAC-11766, NUDOCS 7908170355
Download: ML19242D739 (3)


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435 S.nm Avenue P'ttsburgh. Pt 15219 July 16, 1979 United States Nuclear Regulatory Commission Attention: Boyce H. Grier, Director Region 1 631 Park Avenue King of Prussia, Pennsylvania 19406

Reference:

Beaver Valley Power Station, Unit No. 2 Docket No. 50-334 License No. DPR-66 Response To IE Bulletin 79-13

Dear Mr. Grier:

We have reviewed IE Bulletin 79-13 which reports cracking in feedwater system piping.

Attached is a report addressing the information . requested in Item 5 of the subject Bulletin. We will continue to keep you informed of the actions being taken regarding this problem.

If you have any questions regarding this response, please contact my office.

Very truly yours, t

C . N . j'Dunnd ..

Vice President, Operations Attachment cc: United States Nuclear Regulatory Commission Off!ce of Inspection and Enforcement Divicion of Reactor Operations Inspection Washin;;cua, D. C. 20555 Mr. D. L. Wigginton, BVPS Licensing Project Manager United States Nuclear Regulatory Commission Operating Reactors Branch #4 Washington, 9. C. 20555 97 3 ' LL 4 7 9 0817 0 3 5'J q;

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4 DUQUESNE LIGHT COMPANY Beaver Valley Power Station Unit No. 1 RESPONSE TO IE BULLETIN No. 79-13 Letter Dated June 25, 1979 Item 5 Response

a. The inspection program as required in Item 1 has been performed.

The examination of all feedwater pipe weld areas inside containment and of welds connecting auxiliary feedwater piping to the main feedwater line outside containment required in Item 2 heve also been performed.

The inspection program as required at this time was completed July 8, 1979.

During the next refueling outage, a volumetric examination of the feedwater nozzle-to-pipe weld area for the "C" Steam Generator will again be performed. The re-examination of the feedwater nozzle-to-pipe weld area for all three steam generators will be performed at the second refueling outage as previously discussed in a meeting with the NRR on July 9, 1979.

b. We have reviewed the BVPS operating and emergency procedures and determined that procedures that aadress a feedwater line break accident are adequate. If such a break were to occur, the operator would place the plant in a safe condition with residual heat of the core being dissipated in a controlled manner by means of other intact lines and the line with the leak being isolated. The procedures accomplish this in the following manner:
1) Verification of reactor trip and steam dump actuation for temperature control of the Reactor Coolant System.
2) Verification of the delivery of flow from the auxiliary feedwater system to provide a heat sink for the Reactor Coulant System.
3) Isolation of the main feedwater lines by neans of the ccntainment isolation valves and tripping of the main feedwater pumps to terminate the leak if it is upstream of the containment isolation valves.
4) Monitoring auxiliary feedwater flows, steam generator levels, and steam generator pressures to determine if the leak is downstream of the containment isolation valves. If that is the case, auxiliary feedwater flow will be isolated to the faulted steam generator so that the leak itself is totally isolated.
5) Commencing a plant cooldown using the intact lines if required to repair the break. A faulted line will not restrict the capability to cool the plant down in a controlled manner.

S 9 7 - 2 (G 5

Beaver Valley Power Station, Unit No. 1 Response To IE Bulletin No. 79-13 Page 2

c. The containment at BVPS is the subatmospheric type. The subatmospheric containment is very sensitive to changes in moisture and vacuum. A leak from a feedwater line in containment will readily be detected by increasing moisture and pressure in containment. As a backup, containment temperatures and sump level indications will detect the addition of large quantities of high energy fluids into the containment itself.

59 7- z"