Rabble: A Program for Computation of Resonance Absorption in Multiregion Reactor Cells.

Abstract

A method· of computing resonance absorption in either slab or circularized reactor cells is developed and used to write a FORTRAN program, RABBLE, for the CDC-3600. Since the method uses space-and lethargydependent slowing-down sources, the ·program is well suited for the computation of resonance absorption when the effects of overlapping between resonances is significant. The cell is divided into regions, and the energy range of interest is divided into extremely narrow groups. Regional reaction rates are obtained from the slowing-down sources, first-flight transmission and escape probabilities, and interface currents. These regional reaction rates are accumulated over specified.numbers of groups to yield effective cross sections.

Advanced resonance self-shielding method for gray resonance treatment in lattice physics code GALAXY

“…So, the direct formulation of the spatially dependent effective crosssections for each ring region within the cylindrical fuel lump is a difficult task. For generation of the detailed effective cross-section data within the pellet, the more accurate resonance self-shielding methods such as subgroup method [5] or ultra-fine-group calculation method [4] are applied in general. These methods consider the detailed information of the spatial and energetic resonance self-shielding effects within each energy group, so it can directly treat the neutron balance within the pellet.…”

“…In general, the resonance calculation method is classified into three categories [3], i.e. ultra-fine-group method [4], subgroup method [5] and Dancoff method [6] with equivalence theory [7]. The ultra-fine-group method gives an accurate effective cross-section, but has a limitation for the practical design applications of large and complicated geometries in the fuel assembly level because of the long computation time.…”

Elastic Removal Self-Shielding Factors for Light and Medium Nuclides with Strong-Resonance Scattering

“…( 8 ) are inserted into Eq. ( 7 ) and upon truncation after the first two terms, i. e., by making the P, approximation, it is found that +zjl(u')pcj} #(u')du' * (10) Hereafter, the suffix concerning nuclear species will be suppressed for convenience.…”

Rabid: An Integral Transport-Theory Code for Neutron Slowing Down in Slab Cells.

“…Using the property that Pg = e"^uPg_ 1 , we can obtain the following recursion relation: Equation 33 is written for a single material in a given region. Generalization to many materials and regions requires that Eq.…”