Semi-Analytical Nodal Expansion Method
Open Access
- Author:
- Reed, James
- Area of Honors:
- Nuclear Engineering
- Degree:
- Bachelor of Science
- Document Type:
- Thesis
- Thesis Supervisors:
- Kostadin Nikolov Ivanov, Thesis Supervisor
Kostadin Nikolov Ivanov, Thesis Supervisor
Arthur Thompson Motta, Thesis Honors Advisor - Keywords:
- Nodal Expansion Method
neutronics
nuclear - Abstract:
- In current and next generation nuclear power plants, core designs are utilizing mixed oxide fuel (MOX), high burnup loadings, and advanced designs of fuel assemblies which can complicate calculations based on diffusion theory. In order to make core calculations more accurate, the expansion that is used to approximate the neutron flux must be improved. The nodal expansion method code (NEM) currently utilizes a fourth order polynomial expansion to approximate the neutron flux for diffusion calculations. The implementation of semi-analytical terms in this expansion will allow for more accurate calculations to be made on more heterogeneous core designs such as those with MOX fuel. In this thesis, the semi-analytical solution to the multi-group neutron diffusion equation will be derived and the procedure for implementing the necessary code changes in NEM will be described. Unfortunately, the current version of the semi-analytical code is unable to solve the response matrix equation, which gives the partial currents in each node. Work is currently being performed in order to debug the code. The problem is most likely with the LAPACK matrix solving routines. A recommendation for future work is to use a different LAPACK routine to solve the response matrix equation.