**1. NAME AND TITLE**

SLAROM: A Code to Produce Cell Averaged Cross Sections for Fast Critical Assemblies and
Fast Power Reactors

**2. CONTRIBUTOR**

Japan Atomic Energy Research Institute, Tokai-mura, Naka-gun, Ibaraki-ken, Japan.

**3. CODING LANGUAGE AND COMPUTER**

Fortran 77 and Assembler; FACOM M380.

**4. NATURE OF PROBLEM SOLVED**

SLAROM solves the neutron integral transport equations to determine the flux distribution and
spectra in a fast reactor lattice and calculates cell averaged effective cross sections. The code uses
multigroup data of the type in DLC-111/JFS that use Bondarenko factors for resonance effects.

**5. METHOD OF SOLUTION**

SLAROM consists of six blocks: PREP, PATH, PIJF, EDIT, RATE, and EIND. PREP calculates
region dependent effective or homogenized multigroup cross sections, PATH calculates the collision
probability, and PIJF solves the multigroup integral transport equations by the matrix inversion
method. Cell averaged cross sections and diffusion coefficients and calculated using EDIT, in-cell
reaction rate distributions are calculated with RATE, and collapsed cross sections are produced by one-dimensional diffusion calculations with EIND.

**6. RESTRICTIONS OR LIMITATIONS**

Variable dimensioning removes most restrictions on the complexity of the problems that can be
treated.

**7. TYPICAL RUNNING TIME**

An infinite plate geometry problem with 14 regions requires about 30 s on a FACOM M380.

**8. COMPUTER HARDWARE REQUIREMENTS**

FACOM M380 with partitioned data sets to store intermediate cross sections.

**9. COMPUTER SOFTWARE REQUIREMENTS**

Fortran 77, Assembler, FACOM OS IV Operating System.

**10. REFERENCE**

M. Nakagawa and K. Tsuchihashi, "SLAROM - A Code for Cell Homogenization Calculation of
Fast Reactor," JAERI 1294 (September 1984).

**11. CONTENTS OF CODE PACKAGE**

Included are the referenced document and two (1.2MB) DOS diskettes which contain the source
code, sample problem input and output, data library and conversion program.

**12. DATE OF ABSTRACT**

June 1987.

**KEYWORDS: ** NEUTRON CROSS SECTION PROCESSING; REACTOR PHYSICS