Low Level" Radioactive
Primary Source: Nuclear Information Resource
Service Fact Sheet
is one of the most misleading terms
ever created. In the U.S., it is all nuclear waste that is not legally
high-level waste, some transuranic waste, or mill tailings. It includes:
Reactors: Irradiated Components and Piping:
reactor hardware and pipes that are in continual contact with highly
radioactive water for the 20 to 30 years the reactor operates. The metal
becomes "activated" or radioactive itself from bombardment by
neutrons that are released when energy is produced. Also called Irradiated
Primary System Components.
Control Rods: from the core of
nuclear power plants--rods that regulate and stop the nuclear reactions in
the reactor core.
Poison Curtains: which absorb
neutrons from the water in the reactor core and irradiated fuel (high level
Resins, Sludges, Filters and Evaporator
Bottoms: from cleansing the water that circulates around the irradiated
fuel in the reactor vessel and in the fuel pool, which holds the irradiated
fuel when it is removed from the core.
Entire Nuclear Power Plants if and
when they are dismantled. This includes, for example, from a typical 1,000
megawatt nuclear reactor building floor: over 13,000 tons of contaminated
concrete and over 1,400 tons of contaminated reinforcing steel bar.
Medical and Scientific Research: The highly radioactive and long-lived
reactor wastes are included in the "low-level" waste category
along with the much less concentrated and generally much shorter-lived
wastes from medical treatment and diagnosis and some types of scientific
High-Level Radioactive Waste is the
irradiated fuel from the cores of nuclear reactors, the liquid and sludge
wastes that are left over after irradiated fuel has been reprocessed (a
procedure used to extract uranium and plutonium), the solid that would
result from efforts to solidify that liquid and sludge from reprocessing.
Transuranic Waste is material
contaminated with radioactive elements heavier than uranium, such as
plutonium, neptunium, americium and curium. These elements have extremely
long hazardous lives--hundreds of thousands to millions of years and emit
alpha radiation a type of radiation that is especially dangerous if inhaled
or swallowed. Note: Some transuranic waste is allowed in the
"low-level" radioactive waste category. In 1983, when the
Nuclear Regulatory Commission (NRC) adopted regulations on land disposal of
radioactive waste (lOCFR61), it increased the allowable concentration of
transuranics in "low-level" radioactive waste.
Uranium Mill tailings, resulting
from mining and milling uranium for weapons and commercial reactors, are not
usually included in the "low-level" waste category, but may be
handled with it in some states. The large volumes of these wastes, which
will emit radiation for centuries, pose serious health problems.
RADIOACTIVE CONCENTRATION vs. VOLUME
The nuclear industry and government
commonly describe "low-level" waste in terms of volume although
there can be a tremendous concentration of radioactivity in a small package
and a small concentration in a big package. The amount of radioactivity,
measured in CURIES, indicates how much radioactive energy is being emitted
by the waste. (1 Curie = 37,000,000,000 or 37 Billion disintegrations or
radioactive emissions per second from a radioactive material.)
The medical waste from diagnosis and
treatment shipped in one year from most states usually gives off a fraction
of one curie of radiation. In contrast, each nuclear reactor generates
hundreds and thousands of curies in "low-level" waste every year.
Nuclear reactor waste is concentrated:
Solidified liquid emits about 2 curies per cubic meter; Filter/Demineralizer
sludges emit about 10 curies per cubic meter; Cartridge filters emit about
20 curies per cubic meter; Demineralizer resins emit about 160 curies per
cubic meter. Primary Components average 1000 to 5000 curies per cubic
All of this material is legally considered
HALF-LIFE and HAZARDOUS LIFE
Radioactive elements decay by emitting
energy in the form of radioactive particles and rays. As radiation is given
off, other elements (some radioactive and some stable) are formed.
The Half-Life is the time it takes
for HALF of the radioactive element to decay (give off half of its
radioactivity). Different radioactive elements have different half-lives.
The Hazardous Life of a radioactive
element is about 10 or 20 Half-Lives. (It is best to measure the amount of
radiation after 10 or 20 half-lives before releasing waste from active
Reactor waste remains hazardous for
a very long time. Most medical waste from treatment and
diagnosis is hazardous for a very short time. Research and
industrial waste can contain small amounts of some long-lived radioactive
Among the radioactive elements commonly
found in nuclear reactor "low-level" waste are: Tritium, with a
half-life of 12 years and a hazardous life of 120-240 years; Iodine-131,
half-life of 8 days, hazardous life of 80-160 days; Strontium-90, half life
of 28 years, hazardous life of 280-560 years; Nickel-59, half life of 76,000
years, hazardous life of 760,000-1,520,000 years, and Iodine-129, half-life
of sixteen million years, hazardous life of160-320 million years.
By contrast, common medical waste elements
include Technetium-99m, with a half-life of 6 hours and a hazardous life of
2.5-5 days; Galium-67, half-life of 78 hours and hazardous life of 1-2
months; and Iodine-131, with its half-life of 8 days and hazardous life of
The vast majority of medical waste is
hazardous for less than 8 months. Yet, it is in the same category as reactor
waste that will be hazardous for hundreds of thousands to millions of years.
Clearly, the definition of "low-level
radioactive waste" must be changed. It would make sense to
redefine the more concentrated and/or longer-lived waste as high-level.
Active re-containerization and operational control must be provided for the
entire hazardous life of the waste, yet the NRC requires only 100 years of
passive institutional control. Thus, waste hazardous longer than 100 years
could be forgotten. Retrievability is essential.
LEAKAGE AND "ACCEPTABLE" RISK
Waste containers and forms will not last as
long as some waste remains hazardous. Therefore, waste should be placed in a
manner which will facilitate recontainerization and make continued isolation
from the environment possible in the future. If the waste is "disposed
of" as the NRC currently requires, it will not be isolated from the
environment. "Planned leakage will occur at (what NRC considers) an
"acceptable" leak rate leading to "acceptable" public
radiation exposures and health risks. The allowable leak rates and exposure
levels are determined by federal agencies, not those experiencing the risk.
To avoid leakage, above-ground, engineered
storage at or near the source of generation could allow responsible routine
monitoring and repair.
States have the right and responsibility to
protect their citizens' health. In 1980, Congress gave states the
responsibility for "low-level" radioactive waste. How and whether
states choose to take on that responsibility will be reflected indefinitely
into the future.
Updated March 1992, Diane D'Arrigo
Institute of Energy and
Environmental Research Publication: High Level Dollars,
Low Level Sense
Nuclear Information and Resource Service
Massachusetts Department of
Public Health, Radiation Control Program