ML20085F529

Updated AO AO-24-74 Re Greater than Allowed Ph Difference Between Lake Inlet & Outlet Water.Caused by Cooling Tower Acid Injection Sys Continuing to Operate After Pump Shut Off Due to Incorrect Relocation of Sample Probe

ML20085F529
Person / Time
Site:	Palisades
Issue date:	11/18/1974
From:	Sewell R CONSUMERS ENERGY CO. (FORMERLY CONSUMERS POWER CO.)
To:	US ATOMIC ENERGY COMMISSION (AEC)
Shared Package
ML20085F531	List: ML20085F529 ML20085F532
References
AO-24-74, NUDOCS 8308220402
Download: ML20085F529 (2)

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C General Offices: 212 West Mich. - ovenue. Jackson Michigan 492016 Area Code B17 788-0550 November 18, 197h Directorate of Licensing Re: Docket 50-255, License DPR-20 US Atomic Energy Commission Palisades Plant - A0-2h-74 Washington, DC 205h5 Additional Information Gentlemen:

Abnormal Occurrence Report A0-2h-Th (transmitted to the AEC on October 29, 197h) described an event at the Palisades Plant which involved a greater than allowed pH difference between the lake inlet and outlet water.

Item 7 " Apparent Cause" and Item 9." Corrective Action" are amplified as follows:

Item 7 - Apparent Cause On October 18,19Th at 1930 hours0.0223 days <br />0.536 hours <br />0.00319 weeks <br />7.34365e-4 months <br />, the "A" cooling tower circu-lating pump E30A was shut off. However, the cooling tower acid injection system continued to operate.

The cooling tower acid injection system was initially designed and installed to operate automatically to maintain a preset pH. A problem associated with the sampling probe installation caused the acid injection system to function improperly. On October 17, 197h, one sample probe was relocated in a position which was thought to provide a more representative basin semple. However, we have since determined that this probe, in its new location, does not see a representative sample when the_ cooling tower circulating vater pumps are shut off. When the cooling tower circulating pump E30A vas shut off, the acid injection system continued to run until October 19,19Th, adding excess acid to the mixing basin of the "A" cooling tover.

Item 9 - Corrective Action The following corrective action van taken or vill be taken:

a. About 2500 pounds of line were added to the "A" cooling tower basin to raise the pH. We previously stated that we intended to operate the tovera with only additions of sulphuric acid and chlorine compounds. However, we l believe that the addition of lime in this instance was a reasonable course of action, as it would not bc ,

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I Palisades Plant - A0-24-74 i f Additional Information {

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permissible (by Michigan Water Resources Commission Limits) t to discharge water that was strongly acidic directly to the lake. The li=e addition resulted in the formation of cal-cium sulfate which occurs naturally in the lake.

b. To prevent recurrence, it is proposed that the cooling tower acid injection system be interlocked with the cooling tower circulating water pumps to permit operation of the acid pumps only when the circulating water pumps are in operation.

This action vill be taken after appropriate reviews and approvals have been made.  ;

c. A temporary procedure change has been instituted (until modi- i fications have been completed) to ensure that the acid pump is shut off when a cooling tower is taken out of service.

Yours very truly,

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RBS/ map Ralph B. Sewell Nuclear Licensing Administrator CC: JGKeppler, USAEC I