Hanford workers suit up before entering radioactive areas to protect them from breathing and contacting airborne particles of radiation.
RADIATION IS INESCAPABLE, useful and dangerous, and understanding its
benefits and risks is a necessary part of living in the atomic age.
While the word "radiation" is a broad term that includes sunlight
and heat, it is most commonly used to refer to ionizing radiation, which is caused
by the decay of atoms that releases energetic particles capable of damaging living
cells. Humans have been aware of this kind of radiation for only a century.
We are exposed all the time to low levels of natural ionizing radiation.
Our bodies are mildly radioactive, our bones having absorbed radioactive elements
such as potassium-40 from food we eat. This, on average, contributes 11 percent of
our annual background dose, or 39 millirems. We get cosmic radiation from outer
space and radiation from the naturally occurring uranium, thorium, radium, radon
and potassium atoms in the earth.
Flying in an airplane slightly increases cosmic radiation by lessening the
amount of atmospheric shielding from cosmic rays. Airline crews on the New
York-Tokyo route get an amount estimated to be about three times normal
Similarly, mile-high Denver residents get twice as much radiation from
cosmic rays as Seattleites. Living in Spokane exposes residents to about five
times the natural background radiation as here because of higher levels of radon
in the Spokane area.
Medical X-rays and diagnostic tests add to our exposure. There is even a
tiny amount of fallout left from atmospheric nuclear testing.
Our bodies repair some radiation damage. Healthy cells fix themselves all
the time. But massive doses of radiation can destroy cells, killing quickly, and
milder doses can occasionally overcome the body's repairs and cause DNA damage
that can trigger cancer or other diseases.
This damage and repair cycle makes assessing the risk from nuclear waste,
nuclear-power plants and fallout from nuclear testing extremely difficult.
Scientists can predict with some accuracy that exposing many people to radiation
will result in some percentage of them being harmed. They can't say whether
low-level exposure will trigger cancer or other diseases in any individual.
For example, millions of Americans benefit each year from medical X-rays.
In a tiny handful, the procedure triggers cancer. Most people believe the benefits
of X-ray diagnosis outweighs the extremely remote risk of getting sick from
Even large radiation doses harm some people and not others. Studies of
Hiroshima and Nagasaki victims showed elevated levels of several kinds of cancer,
such as 3.5 times the risk of breast cancer and 1.8 times the risk of lung cancer.
But many survivors have not contracted any cancer.
One worker at the Hanford nuclear reservation in Eastern Washington
received such a strong exposure after an explosive accident that he was dubbed
"The Atomic Man" and could set off Geiger counters at 50 feet. But he
lived 10 more years and died of heart disease.
Still, numerous occupational and disease studies have resulted in
scientists steadily increasing their estimate of radiation's risk and reducing the
recommended maximum dose.
Since 1968, nuclear-industry workers have been limited by the federal
government to no more than 5,000 millirems per year, and usually by their
employers to no more than 2,000 millirems.
By comparison, the standard was 30,000 millirems per year in 1934.
Natural background radiation averages about 360 millirems per year, or one
I wore radiation-monitoring devices at Hanford while visiting spent-fuel
basins, plutonium-storage vaults and an open reactor being refueled. The
accumulated recorded exposure from all this was about 1 millirem. I likely picked
up about 2 millirems at the Trinity bomb test site in New Mexico. At the Nevada
Test Site, radiation badges for visitors were dispensed with in January because of
low remaining levels from most early bomb tests.
Assessing radiation risk is further complicated because not all radiation
For example, alpha radiation is blocked by human skin, but gamma rays and
neutrons are extremely penetrating.
Some radioactive isotopes are extremely dangerous in the short term but
decay quickly and pose no long-term waste problem. The dangerous isotope of
iodine, which may have caused thyroid disease among people living downwind from
Hanford in the 1940s and 1950s, has a half-life of eight days and thus decays
almost entirely in a few weeks.
Other isotopes persist a long time but give off weaker radiation.
Plutonium, for example, has a half-life of 24,000 years but emits only alpha
radiation. It is possible, though not advised, to hold a "button" of
purified plutonium in one's hand without harm; one scientist compared its warm
feel to that of a live bunny.
Plutonium is also unlikely to harm if it is swallowed. The body typically
flushes it out of the digestive system before its weak radiation can have an
effect. Plutonium is extremely dangerous if particles are breathed, however: They
can lodge in the lungs and steadily give off radiation that could eventually
During World War II, the U.S. government allowed plutonium workers to
inhale up to a millionth of a gram of plutonium but by 1950 had concluded there
was no permissible lower limit.
The differences in isotopes makes dealing with nuclear waste complex and,
to the public, confusing. There are four primary kinds:
- High-level defense. The process used to extract bomb-making material from
nuclear-fuel rods produced a soupy mix of chemicals and radioactivity that would
fill 10,000 tanker trucks and is stored in 243 underground tanks around the
nation, including 67 at Hanford that are believed to have leaked. This stew is so
radioactive it quickly destroyed the first cameras lowered into the tanks. But it
is decaying so rapidly that up to 90 percent of its radioactivity will have
dissipated within a hundred years.
Scientists warned as early as 1948 that the single-shell tanks storing this
kind of waste were inadequate, but the tanks were left anyway until they leaked.
Now the government hopes to lock this dangerous waste into glass and store it
permanently underground, but progress so far has been slow.
- Spent fuel from nuclear reactors is highly radioactive and hot. These long
metal tubes are presently stored in water-filled pools next to nuclear-power
plants, the water shielding the environment from the radiation. The tentative plan
is to eventually package the fuel in dry casks and bury it underground, but the
proposed depository at Yucca Mountain in Nevada may be abandoned by Congress.
- Transuranic waste is less radioactive waste that comes chiefly from fuel
reprocessing or weapons production and has a half-life of 20 years or more. There
are half a million drums of this stored in warehouses and dirt pads around the
United States. An underground salt mine in Carlsbad, N.M., called the Waste
Isolation Pilot Plant has been prepared to accept this waste but has not yet been
approved for operation. New Mexico opposes its opening.
- Low-level waste differs from transuranic waste in that it has a shorter
half-life. It comes from power plants, hospitals, laboratories, factories and so
on. It is typically sealed in boxes or drums and buried at special landfills,
including one at Hanford.
There are about 8,700 radioactively and chemically contaminated sites in
the United States that the Department of Energy is responsible for cleaning up.
The agency also hopes to clean and then demolish 20,000 buildings on its 2.3
million acres no longer needed for bomb manufacturing.
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