ML20217P180
| ML20217P180 | |
| Person / Time | |
|---|---|
| Site: | Seabrook  |
| Issue date: | 04/29/1998 |
| From: | Feigenbaum T NORTH ATLANTIC ENERGY SERVICE CORP. (NAESCO) |
| To: | NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM) |
| Shared Package | |
| ML20217P183 | List: |
| References | |
| NYN-98058, NUDOCS 9805060147 | |
| Download: ML20217P180 (2) | |
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North Atlantic Energy Service Corporation
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(603) 474-9521 The Northeast Utilities Syst3m April 29,1998 Docket No. 50-443 NYN-98058 United States Nuclear Regulatory Con: mission Attention: Document Control Desk Washington, D.C. 20555 Seabrook Station 1997 Annual Environmental Ooerating Renort North Atlantic Energy Service Corporation (North Atlantic) submits the 1997 Annual Environmental i
Operating Report' for Seabrook Station. The enclosed report is a summary of the implementation of the 2
Environmental Protection Plan (EPP) for the period of January 1,1997 to December 31,1997. This report is submitted pursuant to the requirements of Section 5.4 of the Seabrook Station Environmental Protection Plan.
Should you have any questions, please contact Mr. Terry liarpster, Director of Licensing Services, at (603) 773-7765.
Very truly yours, NORTil ATLANTIC ENERGY SERVICE CORP.
l Ted C. Feigenbaum Executive Vice President and Chief Nuclear Officer cc (without enclosures):
H. J. Miller, NRC Regional Administrator
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C. W. Smith, NRC Project Manager, Project Directorate 1-3
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R. K. Lorson, NRC Senior Resident Inspector (O O\\
National Pollutant Discharge EGmination System (NPDES) Permit No. NilC020338.
2 Facility Operating License No. NPF-86 9805060147 900429 PDF:
ADOCK 05000443 R
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EPP Non-Comoliance and Corrective Actions There was one NPDES Permit exceedence reported to the EPA in the monthly Seabrook Station Discharge Monitoring Reports (DMRs) for the 1997 operating period and is described below.
On June 13,1997, during the fifth refueling outage,2,400 gallons of water containing hydrazine, was inadvertently drained from the secondary side of one steam generator. This resulted in a hydrazine exceedence at Outfall 001. The unplanned drainage occurred during Feedwater System valve testing when a small valve was inadvertently left open. The steam generator water containing hydrazine at a concentration of 107 ppm drained for approximately 22 minutes to the feedwater pipe chase building sump md was discharged via sump pumps to the storm drainage system and Outfall 001. At the time of the unplanned draindown, one Service Water Pump was in operation which provided a dilution flow rate of approximately 8,500 gpm. A conservative calculation was performed to ascertain the hydrazine concentration at Outfall 001. The resultant estimate for the hydrazine concentration at Outfall 001 was 2.48 ppm. The NPDES Permit limit for hydrazine is 0.5 ppm. The short duration of this hydrazine discharge and the calculated exceedence value is based on the following conservative assumptions which support the conclusion that this discharge had a minimal environmental impact:
Both feedwater pipe chase sump pumps were assumed to be running simultaneously providing e
maximum possible discharge, as a worst case condition.
The discharge flowed into the storm drain system which contained some water. This water volume and its d%' ion capability was not included in calculating the hydrazine exceedence value.
The discharge also flowed into the Circulating Water System Pumphouse forebay which contains e
more than four million gallons of water. This water volume and its dilution capability was not included in calculating the hydrazine exceedence value.
The rapid dispersion of the ocean discharge by the offshore diffuser nozzles (dilution ratio of more than 10:1 in less than one minute) was not accounted for.
Training activities are being implemented to address the conditions which contributed to this event in order to preclade recurrence.
The New 11ampshire Department of Environmental Services issued its report on the 1997 NPDES Permit Compliance Evaluation Inspection on July 1,1997. The inspection report gave North Atlantic a facility evaluation rating of four (on a scale one to five, with five being the highest).
Chanoes in Station Desien or Oncration. Tests and Exneriments Involving a Potentially Unreviewed EnsironmentaLQuntion None.
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