a
nuclear reactor an apparatus in which an
atomic fission chain reaction can be
initiated, sustained and controlled, for generating
heat or
producing useful
radiation. The
term cross-pile comes from the
fact that the first reactors were constructed of
uranium and graphite bricks arranged in layers that crossed each other.
n. a possible
reference to a
nuclear reactor or "pile," an
assembly of
materials and
equipment used to
initiate, sustain and
control atomic fission and thus
create energy. The
term pile came from the
fact that the first
reactor ever built consisted of
uranium and graphite blocks stacked into a large "pile." It was found that when pieces of
uranium of a certain size were brought together, a
fission reaction took
place which created a large amount of
energy. However, if the
fission was not controlled, the
uranium would explode. In the original pile, the graphite blocks served to slow down the reaction between the blocks of
uranium (by absorbing some of the particles
released through
fission) and thus kept them from exploding.
reference to the construction of early
nuclear reactors (devices in which an
atomic fission chain reaction can be
initiated, sustained and controlled), which consisted of
uranium and graphite bricks arranged in layers that crossed each other.