ML20082N431

Describes Discovery & Corrective Actions Concerning Discharge of Cooling Tower Water Through Stormwater Outfall, Reported to Ft Lawn Ofc on 950321

ML20082N431
Person / Time
Site:	Catawba
Issue date:	04/19/1995
From:	Cook T DUKE POWER CO.
To:	Robinson L SOUTH CAROLINA, STATE OF
References
NUDOCS 9504250231
Download: ML20082N431 (2)

Text

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Duke P6utt Company (803)831-3000 Catawba Nuclear Station 600 Concord Road York, SC 2976 DUKEPOWEC April 19,1995 Mr. Lanny Robinson '

South Carolina Dept. of Health and Enviromnental Control P.O. Box 100, Ft. Lawn, SC 29741 ,

Subject:

Catawba Nuclear Site Stonnwater Permit Unauthorized Discharge '

File No.: CN- 702.20-2 i

Dear Mr. Robinson:

Per your request this letter will describe the discovery and corrective actions concerning the discharge of Cooling Tower water through a stormwater outfall, as reported to the Ft.

Lawn ofIice on Merch 21,1995.

On March 13, Catawba Site Environmental personnel discovered a steady flow ofwater from Stormwater Outfall #15 while performing an annual"non-stormwater discharge" assessment. Due to recent rain, it was unclear to the observers whether the origin of the water was stormwater, or some other source. On March 20, Stormwater Outfall #15 was revisited. The amount of flow was the same, although there had been no significant rain in the interim. Flowrate was measured to be 15 gpm. The morning of March 21, chlorine was -

added to the Unit 2 Cooling Towers. By afternoon, chlorine was detectable at Stormwater Outfall #15. The Unit 2 Cooling Tower blowdown line was isolated, and flow ceased at Stormwater Outfall #15. Environmental Management personnel notified the -

SCDHEC Ft. Lawn office that afternoon.

Excavation ensued to find and repair the cause of the leak. The root cause of the leak at Stonnwater Outfall #15 was discovered to be a through-hole in the Unit 2 Cooling Tower blowdown line. The assumption is that it was caused by drilling through with a  :

"Geoprobe" groundwater monitor. (Geoprobe drilling was performed in this area on 12/15/94). Since the cooling tower blowdown line crosses over the stormwater line in the-vicinity of the hole, it is assumed that the cooling tower water then " migrated" down the stormwater line ditch to the outfall. An additional" minor" leak was found at a vent pipe flange, as well as some "weepage" through the fiberglass pipe during pressure testing.

. By April 6, all leaks were repaired and the blowdown line was retumed to service. ,

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7 There is no evidence that the leakage of the cooling tower water caused any a'dverse <

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nvironmental impact. Samples taken the afternoon ofMarch 21, downstream of

'tormwater Outfall #15, as the water entered Lake Wylie, indicated no detectable i chlorine. This was after the Unit 2 Cooling Tower water had been chlorinated that morning.

As a final note, while the problem at Stormwater Outfall #15 was being investigaked, leakage was also discovered at Stormwater Oufalls #17 and #18. We showed these to you  ;

during your visit on March 22. The source of this leakage is still being investigated.

However, while we investigate, the water is being collected and returned to the waste treatment system. Sampling is also continuing on a daily basis. Catawba Site Environmental Management personnel will continue to keep SCDHEC informed of the

' progress of this investigation. . .

Ifyou should have any additional questions or concerns regarding this matter, please contact me at (803) 831-3189, or Cheryl Peed at (803) 831-3361.

Sincerely,

/ nw ,'

Thomas E. Cook, Engineer

. CNS Enviromnental Management a; t

cc: Al Williams, SCDHEC - Catawba District NRC - Document Control Desk Docket No: 50-414 .

NRC - S.D. Ebneter NRC - R.E. Martin NRC - R. J. Freudenberger i B. J. Horsley - ECl2T ELL - EC050 NCMPA-1 SREC PMPA NCEM i  ;

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