Environmental Engineering Reference
In-Depth Information
for at least six months before it can enter interim storage, before
being prepared for fi nal disposal. Simultaneously work begins on
removing other primary hazardous materials from the cooling systems.
Both types of waste must be put in casks and sent for permanent
disposal.
The facility must then be decontaminated, a process in which residual
radioactive and chemical waste is removed from the buildings and equip-
ment by washing, heating, chemical action, and mechanical cleaning.
This creates a cocktail of chemical and radioactive particles that may
evaporate into the atmosphere or leak out into the ground.
The reactor itself is sealed for perhaps 100 years, during which time
the site is policed and monitored. Then the reactor core can be unsealed
and disassembled, although it still contains dangerous radioactive waste.
This intermediate waste must be cut into small pieces to be packed in
containers for fi nal disposal somewhere.
Finally the containment buildings are demolished. The rubble may be
removed or buried on-site. The site is then decommissioned and the land
made available for alternative uses. Decommissioning has not been com-
pletely achieved for any reactor because of the youthfulness of the
nuclear age.
Radioactivity Never Dies; It Just Fades Away—Very Slowly
Radioactive waste is classifi ed for convenience as low level or high
level.
Low-Level Waste
Ninety-nine percent of all radioactive waste is low level, meaning it will
be dangerous for only 300 to 500 years, approximately from the time
King Henry VIII of England married Anne Boleyn until today. About 63
percent of low-level waste (but 94 percent of the radioactivity) originates
in nuclear power plants. The 37 percent not related to nuclear power
plants comes from hospitals, university and industrial laboratories, man-
ufacturing plants, and military facilities. Low-level waste includes con-
taminated items such as clothing, hand tools, and, eventually, the
materials of which the reactor itself is built. Radioactive items include
fabric, metal, plastic, glass, paper, and wood.
Low-level wastes are usually sealed in metal drums, commonly after
being burned in special incinerators to reduce their volume, and they are
either stored above ground in vast holding pens, near the place where
