ML19318C509

Responds to IE Bulletin 80-05, Vacuum Condition Resulting in Damage to Chemical Vol Control Sys (CVCS) Holdup Tanks. Chemical & Vol Control Sys & Components & Gaseous & Liquid Waste Disposal Sys & Components Were Reviewed

ML19318C509
Person / Time
Site:	Prairie Island
Issue date:	06/09/1980
From:	Gilberts D NORTHERN STATES POWER CO.
To:	James Keppler NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION III)
References
IEB-80-05, IEB-80-5, NUDOCS 8007010549
Download: ML19318C509 (2)

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NORTHERN STATES P O W E R-COMPANY M I N N E A PO L.l s. M I N N E S OTA 8 8 401 June 9, 1980 Mr. James G. Keppler Director, Region III Office of Inspection and Enforcement U. S. Nuclear Regulatory Commission 799 Roosevelt Road Glen Ellyn, IL 60137

Dear Mr. Keppler:

PRAIRIE ISLAND NUCLEAR GENERATING PLANT Dockets No. 50-282 and 50-306 This report is in response to IE Bulletin No. 80-05.

The following systems and components were reviewed for protection against tank collapse:

1.

Chemical and Volume Control System (CVCS) n.

Holdup Tanks (HUT) b.

Volume Control Tanks (VCT) c.

Monitor Tanks (MT) d.

Concentrate Holding Tanks (CHT)

Boric Acid Storage Tanks (BAST) e.

The VCT is designed for vacuum conditions. The MT, CHT, and PAST are vented to atmosphere. The HUT is vulnerable to collapse.

2.

Gaseous and Liquid Waste Disposal Systems All tanks in these systems are designed for vacuum conditions or are vented to the atmosphere.

f Partial collapse of Nos. 11 and 121 CVCS HUT occurred at Prairie Island in Sep-tember 1973 during preoperational testing. The incident occurred following tank overflow, vent header flooding and subsequent rapid transfer of water from one HUT to another. Since that incident pumpdown rate of the HUT has been re-stricted by installation of fixed orifices in the HUT recirculation pump and by operating in strict accordance with written operating procedures.

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i Mr._ James G. Keppler Page 2' June 9,1980 In the light of events described in Bulletin No. 80-05, HUT drawdown, which can lead to tank collapse in the absence of adequate venting, will be prevented by installing a low suction pressure trip on the HUT transfer and recirculation pumps. This added protection will be installed by January 1,1981.

Yours truly,

{

D. E. Gilberts Vice' President Power Production ec:

Mr. G. Charnoff NRC Office of Inspection and Enforcement Washington, D. C.

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