- 38 high temperatures needed for fusion,
but in turn,
the high
neutron flux from fusion was used to fission more material.
This is the fission-fusion-fission process and is used in
the largest of current nuclear devices.
The radioisotopes
released to the environment by this process include those
that are created by both fission and fusion.
Because the
hazard per unit of energy released is less for the fusion
process than for the fission process the term "clean device"
or “clean bomb" has become associated with devices or bombs
using the fusion process.
Actually a "clean device” is
one in which the ratio of fission to fusion is at a minimun,
i.e., as little fission as possible in order to keep to a
minimum the hazard from radioisotopes released to the environment.
A third source of radioisotopes in the sea is the
waste disposed from the operation of nuclear reactors or
from research and clinical laboratories.
Little use 1s now
being made of the oceans for disposal of radioactive wastes
and,
although the United States always may dispose of most
of its waste by underground burial,
necessity,
future.
other countries,
by
are expected to make use of the sea in the near
Once the radioisotopes are deposited in the sea