ML20084J470

Ro:On 730116,noise & Relatively High Frequency Vibration Heard in Vicinity of Pressure Suppression Chamber & Persisted Between Recirculation Pump Speeds from 84-87%. Noise Traced to Recirculation Loop Piping B

ML20084J470
Person / Time
Site:	Quad Cities
Issue date:	02/16/1973
From:	Stephenson B COMMONWEALTH EDISON CO.
To:	Giambusso A US ATOMIC ENERGY COMMISSION (AEC)
Shared Package
ML20084J473	List: ML20084J470
References
BBS-73-23, NUDOCS 8305120647
Download: ML20084J470 (2)

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Commoeaiin Edisco Guad-Citie NecMar Po Aer Station O

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Feb ruary 16, 1973

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[I Deputy Director for Reactor Projects I Direetorate of Licensing Z ]J '

U.S. Atomic Energy Commission

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Washington, D.C. 205115 bl - E

SUBJECT:

Quad -Cities Nuclear Power Staticn j '

> License DPR-29, Docket No. 50-2514, i V'J ,

Section 6.6.C 3 j Q f-  ?

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Dear Mr. Giambusso:

TE' The purpose of this letter is to inform you of a condition relating to the operation of the station which took place Q at ""' on January 16,_1973. On that date Unit 1 was being brought g[ts* n s v up in nouer' uith recirculation flow for 100 per cent test-ing purposes. With the unit at a core thermal power level

) of 2300 MUt and generator output of 770 MWe, a noise and

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^ relatively high frequency vibration were heard in the Unit 1 reactor building in the vicinity of the pressure supprcasion L- ch amb e r . 'ihese vibrations persisted between recirculation pump speeds from 811 per cent to 87 per cent.

, V An effort was made to pinpoint the vibration, and it was determined that the vibration was greatest at the point k w -, '+ where the "B" LPCI pipe penetrates the drywell. On January 17,

• following a One-Recirculation Pump trip test, the unit was

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'_.,s brought up in power to duplicate the plant conditions of the

'_ previous clay . A drywell entry was made and excessive vib-

, %' <, rations were noticed on the "B" recirculation loop piping.

Tne " A" recirculation loop piping and the "B" recirculat, ion s pump motor did not appear to have any abnormal vibration.

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• Af ter the Two-Recirculation Pump trip test on January 18, reactor power was decreased and the unit was placed in the hot-standby condition. A thorough inspection of the Unit 1

. Drywell was conducted by Quad-Cities, General Electric, and Sargent & Lundy personnel. No evidence of anage or

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O Mr. A. Giambunno Feb ruary 16, 1973 abnormal conditions una detected on the recirculation or Rl!RS piping. The recirculation pumps, pump motors, and piping supporto were also examined and no defective con-ditions were observed.

A vibration detector with a recorder uns installed on LPCI valve 1-1001-29B over the pressure nupprension chamber for the purpo:se of monitoring vibration during power increases.

On January 20., the unit was placed in the RUll modo and load van increased at the rate of 10 IOle/hr. On January 21, when the power level and pump speed conditions were ae;ain duplicated, no abnormal vibrations or noine occurred.

Recirculation pump speed tests were run between 60 and 90 per cent, and the vibration recorder on valve 1001-29B chowed no abnormalities , iienctor pressure was alno varied with no e f fe ct . Following a load decrease to 70 per cent, vibrations were again monitored in the 80 -90% pump speed range on January 22. Ilo excessive vibrations were obnerved.

Further vibration monitoring has been discontinued for the present time . The Commonwealth Edinon Company Mechanical

• and Structural Engineering Department has been consulted on thic problem and han been requented to design and install a permanent monitoring nyctem. Thin installation will in-clude a permanent vibration detector with indication in the control room, and accociated annunciator. Any information obtained in the future on this subject will be reported to you.

Very truly youra, COMMotlWE ALTil EDISON COMPAllY QUAD-CITIES IJUCl, EAR POWER STATION

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