WHAT IS RADIOACTIVE
WASTE?

THE NUCLEAR FUEL CYCLE

URANIUM MINES
AND MILLS

CONVERSION
TO UF6

ENRICHING

CONVERSION
TO FUEL

RECOVERED
URANIUM                               RC
PLUTONIUM                      REACTOR
REPROCESSING

WASTE STORAGE

Both commercial and military waste are the result of a process called the fuel cycle. Each
step in the cycle forms some type of radioactive waste, but high-level radioactive waste,
or spent fuel, is produced only when fuel has been irradiated in reactors.

MINING
Mining releases low levels of
radioactivity into the environ-
ment through radon gas and
uranium dust. There are no
uranium mines in Wisconsin,
although prospecting for ura-
nium has been carried out
recently.
MILLING
Uranium ore is crushed,
ground and chemically
processed into a compound
called yellowcake. Milling
leaves behind large quantities
of tailings, which emit low
levels of radioactivity through
radon gas and long-lived
radioisotopes.

CONVERSION
Yellowcake is converted to
uranium hexafluoride. Resi-
dues are chemical and low-
level radioactive wastes.
ENRICHMENT
Uranium hexafluoride is
heated and becomes a gas
which increases the concen-
tration (enrichment) of ura-
nium-235, the uranium isotope
needed for reactor fuel. This
process produces low-level
radioactive gaseous and liq-
uid wastes which are dis-
charged directly into the
environment.

FUEL FABRICATION
A chemical process converts
uranium hexafluoride gas into
solid uranium oxide, which is
formed into ceramic fuel pel-
lets that are placed into long,
thin zircaloy (a metal) fuel
rods. About 200 fuel rods are
then bundled into each fuel as-
sembly, which is placed, with
other assemblies, in the reac-
tor core. Fuel fabrication re-
leases small quantities of tho-
rium and uranium into the
environment through gas and
liquid emissions. The fuel for
commercial and military reac-
tors is very similar.

High-Level Nuclear Waste

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