Variationally Derived Discontinuity Factors for the Asymptotic Homogenized Diffusion Equation
- Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
- Univ. of Michigan, Ann Arbor, MI (United States). Dept. of Nuclear Engineering and Radiological Sciences
Here in this work, we derive and test variational discontinuity factors (DFs) for the asymptotic homogenized diffusion equation. We begin with a functional for optimally estimating the reactor multiplication factor, then introduce asymptotic expressions for the forward and adjoint angular fluxes, and finally require that all first-order error terms vanish. In this way, the reactor multiplication factor can be calculated with second-order error. The analysis leads to (1) an alternate derivation of the asymptotic homogenized diffusion equation, (2) variational boundary conditions for large periodic systems, and (3) variational DFs to be applied between adjacent periodic regions (e.g., fuel assemblies). Numerical tests show that applying the variational DFs to the asymptotic homogenized diffusion equation yields the most accurate estimates of the reactor multiplication factor compared to other DFs for a wide range of problems. However, the resulting assembly powers are less accurate than those obtained using other DFs for many realistic problems.
- Research Organization:
- Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
- Sponsoring Organization:
- USDOE
- Grant/Contract Number:
- 89233218CNA000001; FG02-97ER25308
- OSTI ID:
- 1494462
- Report Number(s):
- LA-UR-16-20468
- Journal Information:
- Nuclear Science and Engineering, Vol. 185, Issue 1; ISSN 0029-5639
- Publisher:
- American Nuclear Society - Taylor & FrancisCopyright Statement
- Country of Publication:
- United States
- Language:
- English
An Improved Free-Surface Boundary Condition for the P-3 Approximation
|
journal | April 1964 |
Assembly homogenization techniques for light water reactor analysis
|
journal | January 1986 |
Variational boundary conditions for the spherical harmonics approximation to the neutron transport equation
|
journal | April 1964 |
Asymptotic, multigroup flux reconstruction and consistent discontinuity factors
|
journal | April 2015 |
Variational P 1 Approximations of General-Geometry Multigroup Transport Problems
|
journal | December 1995 |
Similar Records
Asymptotic, multigroup flux reconstruction and consistent discontinuity factors
Improved Modelling for the Assembly Discontinuity Factors in the APEC Method