Environmental Impact Statement - radioactive monticello

Description of Site and Environment
typically within MPCA limits. Discharges from the Monticello sanitary sewer system to the City
of Monticello sanitary sewer system is covered under a separate permit with the City of
Monticello.
NMC applies biocides at the service water and circulating water pump bays located in the intake
structure to control biofouling in the circulating water system and service water systems. NMC
applies a non-oxidizing biocide at the service water header to control biofouling in several
service water systems that are only operated intermittently (residual heat removal service water,
emergency diesel generator service water, and fire water protection). NMC also applies
anti-scalant during warm summer months to control scale buildup in the condenser tubes. NMC
uses these approved chemicals in accordance with all the use and discharge requirements of
the NPDES permit.
2.2.4 Air Quality
The climate surrounding the Monticello site has wide seasonal variations in temperature, with
relatively light winter precipitation, and substantial summer rainfall. Representative weather
data was found at the nearby Buffalo, Minnesota, weather station located 10 mi southwest of
the plant. Average total annual precipitation is approximately 30 in. per year, with 54 percent
falling in the months of May through August. For the period of 1948-2004, rainfall ranged from
a monthly average high of 4.25 in. in June, to a monthly average low of 0.89 in. in December.
Average total annual snowfall is approximately 43 in. per year, with 94 percent falling in the
months of November through March. For the period of 1948-2004, the highest average
monthly snowfall was 9.6 in. in the month of January (HPRCC 2004).
Minnesota lies along the north edge of the region of maximum tornado occurrence in the United
States. Tornadoes have occurred in Minnesota in every month from March through November.
Nearly three quarters of all tornadoes in Minnesota have occurred during the three months of
May (16 percent), June (33 percent), and July (27 percent) (SCO 2004). Between 1950 and
2004, eighteen tornados were reported in Wright County (NMC 2005a). The tornado strike
probability for the Monticello Plant is approximately 6 x 10"4 (Ramsdell 2005).
The strongest winds typically occur in the early spring and the lightest winds in late summer.
The topography of the region is generally flat plains to rolling hills and uplands, with few
obstructions to wind. Wind energy potential is generally rated on a scale of Class 1 through
Class 7. The western part of Minnesota has Class 3 and 4 wind resources at exposed areas.
Areas suitable for wind turbine applications have a rating of 3 or higher. The wind power class
for the Monticello site is Class 2 (Elliot et al. 1987).
Nonradioactive air emissions from the Monticello site are regulated by the Minnesota Pollution
Control Agency. With respect to National Ambient Air Quality Standards (NAAQS), there are
currently no non-attainment areas in the state of Minnesota. In prior years, some areas of the
state have been designated non-attainment, but were later re-designated as attainment based
August 2006 2-17 NUREG-1437, Supplement 26 1