Reactor Theory (Nuclear Parameters)
Xenon-135 has a tremendous impact on the operation of a nuclear reactor. It is
important to understand the mechanisms that produce and remove xenon from the
reactor to predict how the reactor will respond following changes in power level.
LIST two methods of production and two methods of removal
for xenon-135 during reactor operation.
STATE the equation for equilibrium xenon-135 concentration.
DESCRIBE how equilibrium xenon-135 concentration varies
with reactor power level.
DESCRIBE the causes and effects of a xenon oscillation.
DESCRIBE how xenon-135 concentration changes following a
reactor shutdown from steady-state conditions.
EXPLAIN the effect that pre-shutdown power levels have on
the xenon-135 concentration after shutdown.
STATE the approximate time following a reactor shutdown at
which the reactor can be considered "xenon free."
EXPLAIN what is meant by the following terms:
Xenon precluded startup
Xenon dead time
DESCRIBE how xenon-135 concentration changes following an
increase or a decrease in the power level of a reactor.
Fission Product Poisons
Fission fragments generated at the time of fission decay to produce a variety of fission products.
Fission products are of concern in reactors primarily because they become parasitic absorbers of
neutrons and result in long term sources of heat. Although several fission products have
significant neutron absorption cross sections, xenon-135 and samarium-149 have the most
substantial impact on reactor design and operation. Because these two fission product poisons
remove neutrons from the reactor, they will have an impact on the thermal utilization factor and
thus keff and reactivity.