"Spent Fuel Measurements: Passive Neutron Albedo Reactivity (PNAR) and Photon Signatures,"
Ph.D. Dissertation, Nuclear Engineering, Texas A&M University, College Station, TX (2016).
The International Atomic Energy Agency (IAEA) has the objective
of timely detection of diversion of nuclear material from the
peaceful uses of nuclear energy to weapons production. An important
IAEA task towards meeting this objective is the ability to
accurately and reliably measure spent nuclear fuel (SNF) to verify
reactor operating parameters and verify that none of the fuel has
been removed from reactors or SNF storage facilities. This work
looks at two methods to improve the state-of-the-art of nuclear
material safeguards measurements: passive neutron albedo reactivity
(PNAR) and passive spectral photon measurements.
The methodology developed based on PNAR was used for
measurements of SNF in Japan as well as fresh fuel pins at Los
Alamos National Laboratory (LANL). The measured PNAR signal was
shown to trend well with neutron multiplication and nuclear fissile
content of the SNF. The PNAR measurements showed a 73% change in
signal for a fuel burnup range of 7.1 to 19.2 GWd/MTHM of spent
mixed-oxide (MOX) Fugen fuel and a 40% change in signal over a
range of initial 235U enrichment from 0.2% to 3.2% in UO2 fuel.
Photon measurements were performed on a wide range of SNF pins
to determine which photon signatures are visible in different sets
of fuels. These signatures were then investigated and tested using
a sensitivity analysis to determine which spent fuel parameters
each signal is most sensitive to.
Associated Project(s):PNAR Measurements of Fugen Fuel