Management of Commercially Generated Radioactive Waste - U.S. ...

F.11
Also, as illustrated in Figure F.6.1, radiation exposure of man via surface water path-
ways may include that from ingesting radionuclides with drinking water, consumption of
aquatic foods, and direct radiation from surface waters received through shoreline activ-
ities or swimming or boating.
For the milk and home garden pathways, the nearest dwelling is assumed to be a farm-
house adjacent to the site boundary southeast of the main plant where the maximum ground-
level atmospheric dispersion factor (X/Q') is about 3 x 10 -7 sec/m 3 for ground-level
releases and 1.5 x 10-8 sec/m 3 for tall stack releases. A milk cow is assumed to be
kept at this farm and maintained on fresh pasture 7 months of the year. It is assumed that
a garden is kept for vegetables; however, there are no large truck gardens in the area.
For the farm-crop-irrigation pathway, it is assumed that about 82% of land in the
vicinity of the site is farmed. Production is essentially 60% soybeans (0.7 kg wet
weight/m 2 ) 30% corn, oats and other grain (0.35 kg wet weight/m 2 ) and 10% hay (1.5 kg
wet weight/m2). For dose calculation purposes, it is assumed that 10% of the ,erage flow
rate (.12,000 k/sec) of the R River in the vicinity of the plant site is drawn from the
river during June, July and August for irrigation of 250 km 2
For the recreational and aquatic food pathways, it is assumed that in the vicinity of
the plant a "maximum-expos?d individual"(a) may spend 100 hr/yr swimming or boating and
may spend 500 hr/yr obtaining 10 kg of fish and 10 kg of fresh water mollusca. Aquatic
foods are assumed to be consumed within 24 hours of the time they are harvested.
For pathways to the population, it is assumed that 85% of the 2 million residents
within 80 km of the site obtain their drinking water from the R River. Travel time to the
consumer from a point on the river nearest the site is taken to be 48 hours. It is assumed
that on the average each person will spend 5 hr/yr swimming and 10 hr/yr boating or fishing
downstream from the site. The average per capita fish consumption for this area has been
estimated to be 1.1 kg/yr. It is assumed that 10% of this consumption is from fish obtained
downstream from the site.
(a) A "maximum-exposed individual" is an individual whose habits tend to maximize his or her
dose.