Reactor Theory (Nuclear Parameters)
DOE-HDBK-1019/2-93
NEUTRON LIFE CYCLE
NEUTRON LIFE CYCLE
Some number of the fast neutrons produced by fission in one generation will
eventually cause fission in the next generation. The series of steps that fission
neutrons go through as they slow to thermal energies and are absorbed in the
reactor is referred to as the neutron life cycle. The neutron life cycle is markedly
different between fast reactors and thermal reactors. This chapter presents the
neutron life cycle for thermal reactors.
EO 1.1
DEFINE the following terms:
a.
Infinite multiplication factor, k
d.
Critical
b.
Effective multiplication factor, keff
e.
Supercritical
c.
Subcritical
EO 1.2
DEFINE each term in the six factor formula using the ratio of
the number of neutrons present at different points in the
neutron life cycle.
EO 1.3
Given the macroscopic cross sections for various materials,
CALCULATE the thermal utilization factor.
EO 1.4
Given microscopic cross sections for absorption and fission,
atom density, and
n
, CALCULATE the reproduction factor.
EO 1.5
Given the numbers of neutrons present at the start of a generation
and values for each factor in the six factor formula, CALCULATE the
number of neutrons that will be present at any point in the life
cycle.
EO 1.6
LIST physical changes in the reactor core that will have an effect
on the thermal utilization factor, reproduction factor, or
resonance escape probability.
EO 1.7
EXPLAIN the effect that temperature changes will have on the
following factors:
a.
Thermal utilization factor
b.
Resonance escape probability
c.
Fast non-leakage probability
d.
Thermal non-leakage probability
Rev. 0
NP-03
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