A New Equivalence Theory Method for Treating Doubly Heterogeneous Fuel - I. Theory
- Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
- Ulsan National Institute of Science and Technology (UNIST), Ulju-gun (South Korea)
A new methodology has been developed to treat resonance self-shielding in doubly heterogeneous very high temperature gas-cooled reactor systems in which the fuel compact region of a reactor lattice consists of small fuel grains dispersed in a graphite matrix. This new method first homogenizes the fuel grain and matrix materials using an analytically derived disadvantage factor from a two-region problem with equivalence theory and intermediate resonance method. This disadvantage factor accounts for spatial self-shielding effects inside each grain within the framework of an infinite array of grains. Then the homogenized fuel compact is self-shielded using a Bondarenko method to account for interactions between the fuel compact regions in the fuel lattice. In the final form of the equations for actual implementations, the double-heterogeneity effects are accounted for by simply using a modified definition of a background cross section, which includes geometry parameters and cross sections for both the grain and fuel compact regions. With the new method, the doubly heterogeneous resonance self-shielding effect can be treated easily even with legacy codes programmed only for a singly heterogeneous system by simple modifications in the background cross section for resonance integral interpolations. This paper presents a detailed derivation of the new method and a sensitivity study of double-heterogeneity parameters introduced during the derivation. The implementation of the method and verification results for various test cases are presented in the companion paper.
- Research Organization:
- Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
- Sponsoring Organization:
- USDOE
- Grant/Contract Number:
- AC05-00OR22725
- OSTI ID:
- 1223634
- Journal Information:
- Nuclear Science and Engineering, Journal Name: Nuclear Science and Engineering Journal Issue: 1 Vol. 180; ISSN 0029-5639
- Publisher:
- American Nuclear Society - Taylor & FrancisCopyright Statement
- Country of Publication:
- United States
- Language:
- English
Similar Records
A new approach for resonance treatment of doubly heterogeneous fuel using the RSE method
Resonance Self-Shielding Using Deterministic Transport Methods with Pointwise Cross Sections (Invited) - Eugene P. Wigner Reactor Physics Award