ML20247K222

NPDES Noncompliance Notification:On 890518,cooling Tower Blowdown Manhole Overflowed to Possum Hollow Creek.Estimates of Overflow Rate Vary from 100 Gpm to 250 Gpm.Investigation Focusing on Partially Blocked Diffuser Line

ML20247K222
Person / Time
Site:	Limerick
Issue date:	05/24/1989
From:	Mccormick M PECO ENERGY CO., (FORMERLY PHILADELPHIA ELECTRIC
To:	Bauer R PENNSYLVANIA, COMMONWEALTH OF
References
NUDOCS 8906010245
Download: ML20247K222 (2)

Text

_ . . _ _ _ . _ . _ _ _ _ . _ _ _ _ _ _ _ _ _ _ _ _ _ _ . ,

.,, f

• s g- . g ,

PHILADELPHIA ELECTRIC COMPANY' LIMERICK GENER ATING STATION P. O. DOX A SAN ATOG A, PENNSYLV ANI A 19464 (215) 3271200 rar, 2000

"",$.,""'.*,."'.',"""- May 24, 1989 i...nio......,,........

Mr. Robert Bauer, Jr.

Department of Environmental Resources Bureau of Water Quality. Management 1875 New Hope Street Norristown, PA 19401.*

SUBJECT:

Cooling Tower Blowdown Manhole Overflow to Possum Hollow Creek, Limerick Generating Station, NPDES Permit No. PA-0051926 g

Dear Mr. Bauer:

On May 18, 1989 at 9:15 a.m. Oral Notification was given.to Cindy Steel of the Department of Environmental Resources regarding unpermitted discharge of cooling water.

Unit 1 Cooling Tower was blowing down under routine conditions; simultaneously Unit 2 Cooling Tower was draining at 30% of maximum flow.

At 3:40 a.m. the Unit 2 Tower Drain valve was opened to 50%.

The combined inputs caused 100 to 250 gpm of cooling water to overflow a. vented manhole to Possum Hollow Creek. Site personnel identified the overflow condition while performing rounds at 8:30 a.m.'on 5/17/89 immediately after the drain valve had been adjusted to 60% open. The operator quickly identified the cause of the overflow and returned to the valve pit to close the drain valve. Thinking the 10% he had opened the valve had caused the overflow, the operator returned the valve to the 50% open position. He then went hack to the manhole and found it still overflowing, although ac a reduced rate. He returned to the valve pit and closed the valve an additional 10%. At )

approximately 10 a.m. the operator verified that the manhole was ]

no longer overflowing.

1 L

The duration is estimated at 6 1/3 hours assuming the overflow was the result of the 20% increase in flow which )

f occurred at 3:40 a.m. )

l l

8906010245g{g5bh52 r ,

f ' '

PDR ADOCK PNV ku S ,

1. .r 2 of 2

,. l Estimates of the overflow rate vary from 100 gpm to 250 gpm.

The estimate of the volume discharged, based on flow rates and duration previously mentioned, therefore varies from 38,000 gallons to 95,000 gallons.

The chemical makeup of the water discharged has been j determined by averaging-the chemical residuals from each tower on <

I 5/17/89. Total zinc-was 0.7 ppm and Nalco 1372 was 17.6 ppm..

This indicates.the water was of discharge quality for outfall 001. A sample of Possum Hollow Creek was taken downstream of the discharge. No chemical residual other than background phosphate was identified.

Preliminary investigation is focusing on the possibility of.a-partially blocked diffuser line. The diccharge rate at the time of the incident was only 60% of the design capability. A followup letter will be submitted with May's DMR.

> t

.) 3 67y e e BJ (

MY J. McCormick,.Jr.

Plant Manager RSU/sjm rsu 5/19/89.1 cc: U. S. Nuclear Regulatory _ Commission Document-Control Desk Washington, D.C. 20555 Administrator Region I ,

Office of Inspections and Enforcement U. S. Nuclear Regulatory Commission 475 Allendale Road i King of Prussia, PA 19406 Station Resident NRC Inspector Tora Kenny, M.C. #NRC Program Management Section Permits Enforcement Branch Water Management Division Environmental Protection Agency Water Permits Section l Region III 841 Chestnut Building Philadelphia, PA 19107 i

r .

..