Environmental Engineering Reference
In-Depth Information
are often more stringent than the standard suggested in 1990 by the International Commission
on Radiation Protection by a factor of twenty, and more stringent by a factor of ten than the
standard proposed by the U.S. Environmental Protection Agency for Yucca Mountain for the
first 10,000 years after closure. Moreover, the EPA's proposed standard for greater than 10,000
years is 250 times more permissive than the European limit (Vandenbosch and Vandenbosch
2007, 248).
In the struggle to determine where a high-level radioactive waste dump should be, a basic question
has been lost: Is the disposal policy conceptually sound?
Disposal Is Legal Fiction
The Nuclear Waste Policy Act of 1982 endorsed the fictitious notion that disposal of high-
level radioactive waste is possible. Disposal implies that if waste is thrown away it will stay
away; if it is put deep in the ground it will stay there. But according to DOE guidelines, dis-
posal means placement of highly radioactive materials in excavated holes 350 to 800 meters
(1,000 to 2,620 feet) deep, where it will presumably remain isolated from the atmosphere,
nearby land and surface waters, and surrounding rock “situated more than ten kilometers
in a horizontal direction from the outer boundary of the original location of the waste” (10
Code of Federal Regulations, Part 960, 49 Federal Register 47757-47760). However, sites
with groundwater travel time of more than 1,000 years from the original location of waste to
the human environment are considered potentially acceptable (10 Code of Federal Regula-
tions 960.4-2-1[d], 49 Federal Register 47767), even if the waste products have half-lives
far longer than that.
In other words, disposal sounds like forever, but, according to DOE regulations, disposal is
not really forever. DOE guidelines do not require complete or perpetual isolation of radioac-
tive waste from the human environment. They only require the waste to be buried where we
can predict that radionuclides with half-lives of 20,000 to 200,000 years will not show up for
at least 300 years after permanent closure of the facility (49 Federal Register 47767), and then
only in amounts considered acceptable under regulations of the Nuclear Regulatory Commis-
sion and the Environmental Protection Agency (10 Code of Federal Regulations, Part 60; 40
Code of Federal Regulations 191). Backfilling of waste disposal rooms and sealing of shafts
is contemplated, but DOE guidelines contain no requirement for postclosure on-site or off-site
monitoring of radiation or consideration of site suitability for placement of monitoring equip-
ment during site selection.
Historical attempts to seal small-bore wells for oil, natural gas, and water are notorious for
their failures. At the time the Nuclear Waste Policy Act of 1982 was enacted, the future status of
borehole plugging and shaft sealing was uncertain, at best:
There presently is not uniform agreement about the best material(s) to use in sealing penetrations
associated with a nuclear waste repository. One important property of the seal is durability. The use
of natural earth materials (clays) or melted salt circumvents the durability requirement. However,
fractures in the surrounding host rock (which may have resulted during drilling operations) may
not be filled by compacted clays. The thermal shock to the host rock resulting from introducing
molten earth materials to the penetration may likewise cause microfractures, the healing time
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