ML20080P740
| ML20080P740 | |
| Person / Time | |
|---|---|
| Site: | Limerick  |
| Issue date: | 02/28/1995 |
| From: | Boyce R PECO ENERGY CO., (FORMERLY PHILADELPHIA ELECTRIC |
| To: | Bauer R PENNSYLVANIA, COMMONWEALTH OF |
| References | |
| NUDOCS 9503080110 | |
| Download: ML20080P740 (3) | |
Text
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PECO ENERGY ecco t <av co a "v is' Umerick Generating Swion PO Box 2300 Sanatoga PA 1946@20 l
M5 3N t200 Ext. 2003 February 28,'1995 Robert Bauer, Jr.
Department of Environmental Resources l
Bureau of Water Quality Management Suite 6010, Lee Park 555 North Lane Conshohocken, PA 19428
SUBJECT:
Limerick Generating Station, Units 1 and 2 Noncompliance of NPDES Permit No. PA-0051926, Outfall 005 Total Zinc Concentration in Excess of the Daily Maximum Limitation
Dear Mr. Bauer:
Description of the Event:
On January 27, 1995, the daily maximum limit of 1.0 mg/l for storm drain outfall 005 zine concentration was exceeded.
The noncompliance was discovered on February 20, 1995, when an offsite analysis result of 6.8 mg/l total zine was reported to the facility.
A description of this noncompliance is as follows:
Approximately five days prior to the noncompliance and in preparation for system drainage via Outfall 005, Chemistry personnel performed increased monitoring of the Unit 2 circulating water system for zine residuals and other parameters.
Chemistry personnel then implemented chemical feedrate adjustments which included shutdown of the zinc inhibitor chemical injection system to ensure NPDES permit compliance.
As a result, the bulk circulating water system zine levels continuously decreased during this 5 day period, and was reduced to 0.14 mg/l prior to the day of the drainage via Outfall 005.
f On January 27, 1995, with the Unit 2 reactor shutdown for its third refueling outage, Operations personnel commenced draining of the Unit 2 circulating water system directly to I
the Possum Hollow Creek via the storm drain Outfall 005.
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.s This wasLthe first time that drainage via Outfall 005 was permissible by the NPDES-permitt and performed by the station.
The discharge limits and sample frequency for Outfall 005 were based on the requirements for Outfall 001 since sample results were expected to be characteristic of that experienced with the discharge of circulating water through Outfall 001 (i.e., samples representing bulk circulating water system zine levels should be approximately the same at the outfall discharge).
Approximately one hour into the drain procedure, samples
-i were taken and sent offsite for laboratory analysis (i.e.,
onsite lab-equipment failed to operate on the day the discharge was initiated).
On February 20, 1995, the zinc analysis results were obtained and Chemistry personnel l
identified that the zine concentration value was 6.8 mg/1.
Cause of the Noncompliance The evaluation of the cause of the 6.8 mg/l total zinc level is ongoing, however, we are investigating three potential contributors to the zinc exceedance:
Mud and silt pre-existing in the storm drain piping l
e system to an unquantifiable degree.
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Mud and silt may have been present in the circulating e
water system drain p/or may have originated from iping between the water box.and the i
isolation valve, and cooling tower basin water seepage from the stop logs.
The circulating water system piping material at Outfall e
005 is constructed of galvanized metal which is coated with zine and tar to prevent corrosion.
This may have caused zine to leach into the NPDES samples from the l
metal surface.
Based on the deliberate control and minimization of bulk water zine concentrations during the entire week preceding this event, we fully expected the Outfall 005 discharge water to be in compliance with the NPDES permit and the possible contributions from any of the above sources were not anticipated.
Actions to Prevent Recurrence
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An interim corrective action has been implemented to temporarily suspend the use of Outfalls 005 and 003 (i.e.,
Outfall 003 is the similar drain path for the Unit 1 circulating water system) for discharge of the circulating i
water system into the Possum Hollow Creek, until the cause I
of the exceedance is further investigated.
Long term
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e corrective actions are pending completion of the
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investigation.
i If you have any questions'please contact Jim Kantner at (610) 718-3400.
Sincerely, l
J s
s DMS:cah l
I cc:
U.S. Nuclear Regulatory Commission
. i Document Control Desk
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Docket Nos. 50-352/353 i
Washington, D.C. 20555 T. T. Martin Administrator, Region I, USNRC Docket Nos. 50-352/353 l
N. S. Perry USNRC Senior Resident Inspector, LGS L
Docket Nos. 50-352/353
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t Program Management Section (3WM52)
Permits Enforcement Branch i
Environmental Protection Agency Water Management Division i
Environmental Protection Agency Water Permits Section Region III 841 Chestnut Building Philadelphia, PA 19107 b
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