ML20206T253

Off-Site Radiation Dose Assessment for NSP for Jan-Dec 1998

ML20206T253
Person / Time
Site:	Prairie Island
Issue date:	12/31/1998
From:	NORTHERN STATES POWER CO.
To:
Shared Package
ML20206T249	List: ML20206T246 ML20206T253 ML20206T258 ML20206T274
References
NUDOCS 9905240103
Download: ML20206T253 (4)

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PRAIRIE ISLAND NUCLEAR GENERATING PLANT NORTHERN STATES POWER COMPANY OFF-SITE RADIATION DOSE ASSESSMENT FOR NORTHERN STATES POWER COMPANY January through December 1998 9905240103 990517 PDR ADOCK 05000282 R

PDR

NORTHERN STATES POWER COMPANY PRAIRIE ISLAND NUCLEAR GENERATING PIANT OFF-SITE RADIATION DOSE ASSESSMENT FOR January through December 1998 An Assessment of the radiation dose due to releases from Prairie Island Nuclear Generating Plant during 1998 was performed in accordance with the Technical Specifications.

Computed doses were well below the 40 CFR Part 190 Standards and 10 CFR Part 50 Appendix I Guidelines.

Off-site dose calculation formulas and meteorological data from the Off-site Dose Calculation Manual were used in making this assessment.

Source terms were obtained from the Annual Radioactive Effluent and Waste Disposal Report prepared for NRC review for the year of 1998.

Off-site Dores from Gaseous Release Computed doses due to gaseous releases are reported in Table 1.

Critical receptor location and pathways for organ doses are reported in Table 2.

Doses are a small percentage of Appendix I Guidelines.

Off-site Doses from Liquid Release Computed doses due to liquid releases are reported in Table 1.

Critical receptor information is reported in Table 2.

Doses, both whole body and, organ, are a small percentage of Appendix I Guidelines.

Doses to Individuals Due to Activities Inside the Site Boundary occasionally sportsmen enter the Prairie Island site for recreational activities.

These individuals are not expected to spend more than a few hours per year within the site boundary.

Commercial and recreational river traffic exists through this area.

For purposes of estimating the dose due to recreational and river water transportation activities within the site boundary, it is assumed that the limiting dose within the site boundary would be received by an individual who spends a total of seven days per year on the river just off shore from the plant buildings (ESE at 0.2 miles).

The gamma dose from noble gas releases and the whole body and organ doses from the inhalation pathway due to Iodine

131, Iodine-133, tritium and long lived particulates were calculated for this location and occupancy time.

These doses were reported in Table 1.

Doses to Individuals Due to Effluent Releases from the ISFSI No additional fuel casks were loaded or placed in the storage facility during the 1998 calendar year.

The total number of casks in the ISFSI remained at 7.

There has been no release of radioactive effluents from the ISFSI.

Radiation Effluent Monitoring Sampling Deviations There were no sampling deviations during the reporting period.

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Table 1 OFF-SITE RADIATION DOSE ASSESSMENT - PRAIRIE ISLAND j

PERIOD:

JANUARY through DECEMBER 1998 i

10 CFR Part 50 Appendix I Guidelines for a 2-unit site per year Gaseous Releases Maximum Site Boundry Gamma Air Dose (mrad) 1.80E-05 20 Maximum Site Boundry Beta Air Dose (mrad) 1.80E-03 40 Maximum Off-site Dose to any organ (mrem)*

5.30E-02 30 Offshore Location Gamma Dose (mrad) 9.25E-07 Total Body (mrem)*

2.04E-03 Organ (mrad)*

2.05E-03 30 Liquid Releases Maximum Off-site Dose Total Body (mrem) 3.66E-03 6

Maximum Off-site Dose Organ - LIVER (mrem) 4.79E-03 20 Limiting Organ Dose Organ - TOTAL BODY (mrem) 3.66E-03 6

Long-Lived Particulate, I-131, I-133 and Tritium

Table 2 OFF-SITE RADIATION DOSE ASSESSMENT'- PRAIRIE ISLAND SUPPLEMENTAL INFORMATION PERIOD: JANUARY through DECEMBER 1998 Gaseous Releases Maximum Site Boundary Dose Location (from Building Vents)

Sector WNW Distance (miles) 0.4 Offshore Location Within Site Boundary Sector ESE Distance (miles) 0.2 Pathway Inhalation Maximum Off-site Sector SSE Distance (mil'es) 0.6 Pathways

Plume,

Ground, Inhalation, Vegetables Age Group Child j

l Liquid Releases Maximum Off-site Dose Location Downstream Pathway Fish