ML20247M161

Offsite Radiation Dose Assessment for Jan-Dec 1988

ML20247M161
Person / Time
Site:	Prairie Island, Crystal River
Issue date:	12/31/1988
From:	NORTHERN STATES POWER CO.
To:
Shared Package
ML20235Y334	List: ML20235Y330 ML20236B207 ML20236B217 ML20247M161 ML20247M169
References
NUDOCS 8904060001
Download: ML20247M161 (4)

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NORTHERN STATES POWER COMPANY

-PRAIRIE ISLAND NUCLEAR GENERATING PLANT OFF-SITE' RADIATION DOSE ASSESSMENT FOR January 1- December 31, 1988 An-assessment of radiation dose due to release from the Prairie Island Nuclear Generating Plant during 1988 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 two Effluent and Waste Disposal Semiannual Reports prepared for NRC review during the year of 1988.

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

Of f-site Doses from Licruid Release Computed doses due to liquid releases are reported in Table 1.

Receptor information is reported in Table 2. Both who?e body. dose and organ dose are a small percentage of Appendix I Guidelines.

poses 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 throlgh 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 main plant buildings (ESE at 0.2 miles). Whole body and inhalation organ doses were calculated for this location and occupuncy time. These doses were reported in Table 1.

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l Doses to Most Exposed Member of the General Public from Reactor i Releases and Other Uranium Fuel Cycle Bources There are no other uranium fuel facilities in the vicinity of the Prairie Island site. The only other artificial source of exposure to the general public in addition to the plant effluent releases is from direct radiation of the reactors. This direct radiation from pressurized water reactors has been shown to be negligible.

An array-of TLD monitoring stations around the perimeter of the site boundary has consistently indicated that plant operation in ,

the past years has no effect on ambient gamma radiation. [

Therefore, the most exposed member of the general public will not receive an annual radiation dose from reactor effluent releases and all other fuel cycle activities in excess of the sum of the liquid and gaseous whole body and organ doses reported in Table 1 for the site boundary and critical receptor, respectively. These doses are well below 40 CFR Part 190 standards of 25 mrem to the whole body, 75 mrem to the thyroid, and 25 mrem to any other organ.

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TABLE 1 OFF-SITE RADIATION DOSE ASSESSNENT - PRAIRIE ISLAND PERIOD: J ANUARY 1 throuch___ DECEMBER 31, 1988 10 CFR Part 50 Appendix I' Guidelines per 2-units site per year g_aseous Releases Maximum Site Boundary Gamma Air-Dose-(mrad) 0.000041 20 Maximum Site Boundary Beta Air Dose (mrad) 0.0011 40 Maximum Off-site Dose to Any Organ (nrem)*

Total 0.3157 30 offshore Location (mren, 7 days / year)

Whole Body 0.015 10 Organ 0.015 30 Liquid Releases Maximum Off-site Dose Whole Body (mrem) 0.0012 6 Maximum Off-site Dose organ, Total 0.0049 20

• Long-lived Particulate, I-131, and H-3

l TABLE 2 OFF-SITE RADIATION DOSE ASSESSMENT - PRAIRIE ISLAND SUPPLEMENTAL INFORMATION ,

1 PERIOD: JANUARY 1 throuch DECEMBER 31, 1988 Gaseous Releases j Maximum Site Boundary Dose Location (from Building vents)

Sector WNW Distance (miles) 0.36 Offshore Location Within Site Boundary ,

i Sector ESE Distance (miles) 0.2 Maximum Off-site Dose Location Sector SSE Distance (miles) 0.6 Pathways Ground, Inhalation, Vegetables Age Group Child Organ Thyroid Licuid Releases Maximum Off-site Dose 1 Location Downstream Pathways Fish Age Group Adult Organ Thyroid L _ -_ _ _ _