The subject of this thesis is the development of a nodal discretization of the low-order quasi-diffusion (QDLO) equations for global reactor core calculations. The advantage of quasi-diffusion (QD) is that it is able to capture transport effects at the surface between unlike fuel assemblies better than the diffusion approximation. We...
Benchmark calculations are performed for neutron transport in a two material
(binary) stochastic multiplying medium. Spatial, angular, and energy dependence
are included. The problem considered is based on a fuel assembly of a common
pressurized water nuclear reactor. The mean chord length through the assembly is
determined and used as...
Through a joint effort by the Swiss Federal
Institute for Reactor Research and Oregon State
University, the fuels modeling code SPECKLE is being
developed to model sphere-pac mixed carbide nuclear fuel.
Major parameters, such as fission gas release, fuel
restructuring phenomena, and the temperature and porosity
distributions in the fuel...
There exists a variety of methods to solve the radiation transport equation in stochastic materials, including the Levermore-Pomraning method and the atomic mix method, each of which is designed to replicate the results given by benchmarks with materials rearranged in a randomized fashion. While the atomic mix method is very...
Theories predict that making a dilute magnetic semiconductor strongly p -type would allow it to remain ferromagnetic at room temperature. This is of intrest as a ferromagnetic semiconductor would allow for a great many applications in the field of spintronics. Neutron scattering experiments were undertaken to better understand the antiferromagnetic...
An important improvement in the area of reactor core neutronic modeling is the development and use of the methods based on "quasi-diffusion" (QD) low-order equations. This family of methods takes into account the transport exactly using "functionals" computed by solving transport equations, and is amenable to solution with a variety...
Real-time, high efficiency neutron spectroscopy has, historically, been a persistent challenge in the field of radiation detection and, for the most part, has gone unsolved. The most promising method to resolve this challenge, is the boron-capture technique using an organic scintillation system (BC-523a). Detectors that utilize this method possess an...
Several computer codes based on one and two-group
diffusion theory models were developed for SHUFFLE. The
programs were developed to calculate power distributions in
a two-dimensional quarter core geometry of a pressurized power
reactor. The various coarse-mesh numerical computations for
the power calculations yield the following:
the Borresen's scheme applied...
The solution of coupled neutronic/thermal hydraulic nuclear reactor calculations
requires the treatment of the nonlinear feedback induced by the thermal hydraulic
dependence of the neutron cross sections. As a result of these nonlinearities, current
solution techniques often diverge during the iteration process. These instabilities arise
due to the low level...