An Advanced Integrated Diffusion/Transport Method for the Design, Analysis and Optimization of the Very-High-Temperature Reactors

Technical Report · Mon Apr 04 04:00:00 EDT 2011

DOI:https://doi.org/10.2172/1011245· OSTI ID:1011245

Rahnema, Farzad ^[1]; Zhang, Dingkang; Ougouag, Abderrafi; Gleicher, Frederick

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1. Nuclear & Radiological Engineering and Medical Physics Programs

The main objective of this research is to develop an integrated diffusion/transport (IDT) method to substantially improve the accuracy of nodal diffusion methods for the design and analysis of Very High Temperature Reactors (VHTR). Because of the presence of control rods in the reflector regions in the Pebble Bed Reactor (PBR-VHTR), traditional nodal diffusion methods do not accurately model these regions, within which diffusion theory breaks down in the vicinity of high neutron absorption and steep flux gradients. The IDT method uses a local transport solver based on a new incident flux response expansion method in the controlled nodes. Diffusion theory is used in the rest of the core. This approach improves the accuracy of the core solution by generating transport solutions of controlled nodes while maintaining computational efficiency by using diffusion solutions in nodes where such a treatment is sufficient. The transport method is initially developed and coupled to the reformulated 3-D nodal diffusion model in the CYNOD code for PBR core design and fuel cycle analysis. This method is also extended to the prismatic VHTR. The new method accurately captures transport effects in highly heterogeneous regions with steep flux gradients. The calculations of these nodes with transport theory avoid errors associated with spatial homogenization commonly used in diffusion methods in reactor core simulators

• Research Organization: Georgia Institute of Technology
• Sponsoring Organization: USDOE
• DOE Contract Number: FC07-07ID14821
• OSTI ID: 1011245
• Report Number(s): DOE/ID/14821
• Country of Publication: United States
• Language: English

Related Subjects

21 SPECIFIC NUCLEAR REACTORS AND ASSOCIATED PLANTS
ABSORPTION
ACCURACY
CONTROL ELEMENTS
DESIGN
DIFFUSION
EFFICIENCY
FUEL CYCLE
NEUTRONS
OPTIMIZATION
PEBBLE BED REACTORS
REACTOR CORES
SIMULATORS
TRANSPORT
TRANSPORT THEORY