ML20235Y428

Offsite Radiation Dose Assessment for 1988

ML20235Y428
Person / Time
Site:	Monticello
Issue date:	12/31/1988
From:	NORTHERN STATES POWER CO.
To:
Shared Package
ML20235Y412	List: ML20235Y411 ML20235Y419 ML20235Y428 ML20235Y432
References
NUDOCS 8903140125
Download: ML20235Y428 (4)

Text

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NORTHERN STATES POWER COMPANY 140NTICELLO NUCLEAR GENERATING PLANT OFF-SITE RADIATION DOSE ASSEBBMENT FOR January 1- December 31, 198.8 An assessment of radiation dose due to release from the Monticello 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 1 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.

1 Off-site poses 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.

Off-site Doses from Licuid Release There were no liquid releases made from the Monticello Plant during the 3988 calendar year.

Doses to Individuals Due to Activities Inside the Site Boundary occasionally sportsmen enter the Monticello site for recreational activities. In addition, an Environmental Protection Agency Field Station is located at the Monticello site (see Figure 3.8.1 of 3.8.2 of the Monticello Technical Specifications) . Workers at this Field Station, spending an average of 40 hours4.62963e-4 days <br />0.0111 hours <br />6.613757e-5 weeks <br />1.522e-5 months <br /> / week, are the most .

exposed individuals. Whole body doses to these individuals have been computed using stack and vent X/Q values for the Field Station location. Annual computed doses were reduced by the factor of 40/168 to account for the limited occupancy for workers at this location. Organ doses to workers at the EPA Field Station due to gaseous releases have been computed for inhalation pathway (no other pathway exists). Doses at this location 'were reported in ,

Table 1.

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Doses to Most Exposed Member of the General Public from ReactpI' Eminar,et..and other Uranium Fuel Cycle Sources.

There are no;other.urant.a fuel. facilities in th2 vicinity'of the '

Monticello sit'e. The only other artificial source of exposure to the general ~public in addition to the plant effluent releases is from direct radiation of the reactor.. Calculations performed in the past have . shown this source to be negligible. . An array of . TLD 1 .

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.

4 Therefore, the most exposed n' ember 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 anc' 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, g-75 mrem to the thyroid,<and 25 mrem to any other organ.-

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> I TABLE 1 I OFF-SITE RADIATION > DOSE ASSESSMENT - MONTICELLO PERIODt'JAF0ARY 1 throuch_pECEMBER 312 1988 1

10 CFR Part,50 Appendix I Guidelines per unit per year Gaseous Releases Maximum Site Boundary Gamma Air Dose (mrad) 2.23 10 Maximum Site Boundary Beta Air Dose (mrad) 2.48 20 Maximum Off-site Dose to Any Organ (mrem)*

Total 0.90 15-EPA Field Station (mrem, 40 hours4.62963e-4 days <br />0.0111 hours <br />6.613757e-5 weeks <br />1.522e-5 months <br /> / week)

Whole Body 1.835 5 Organ 0.288 15 Liguld Releases Maximum Off-site Dose Whole Body (mrem) 0.0 3 Maximum Off-site Dose Organ, Total 0.0 10

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

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l'Y .* OFF-SITE RADIATICN DOSE ASSESSWENT - MONTICELLO' )

SUPPLEMENTAL'INFORMATION x; s,..,

PERIOD: JANUARY 1 throuch DECEMBER __J1,'1988 g,aseous Relpasos

, Maximum' Site Boundary

-7' Dose' Location (from building vents) 3 Sector SSE Distance (miles) 0.43 EPA Field Station Sector .ESE Distance ~(miles) 0.31 Maximum Off-site Dose Location' Sector ESE Distance (mile's) 2.3 Pathways Ground, .f Inhalation, Goat Milk Age Group Infant Organ Thyroid Lisuid Releases Maximum Off-site Dose Location' Downstream Pathways Drinking Water Drinking Water Fish

> Age Group. Infant Adult Organ Whole Body GI-LLI Dilution Factor 7.1 7.1 (drinking water) .

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