**1. NAME AND TITLE**

ORPHEE VI: Kernel Integration Code System Attenuation of Fast Neutrons in Cylindrical
Layers of Water and Dense Material.

This code package represents early work of the French (CEA) Shielding Laboratory, now
located at the CEA/CEN/Saclay. It is retained for reference.

**2. CONTRIBUTOR**

CEA/CEN Fontenay-aux-Roses Nuclear Research Center, France.

**3. CODING LANGUAGE AND COMPUTER**

FORTRAN IV and some Assembly Language; IBM 360.

**4. NATURE OF PROBLEM SOLVED**

The attenuation of fast neutrons is calculated by an empirical kernel. The geometry is a
succession of heavy media separated by thin layers of water in a cylindrical geometry. The
description of the source by bundles renders it particularly suited to light water power reactors. The
fast neutron flux is given for each group of cores and for each height of rods.

**5. METHOD OF SOLUTION**

The coefficients of the empirical kernel, including a buildup factor and removal cross sections,
are determined from either Monte Carlo or discrete ordinates calculations. The kernel is integrated
over a power distribution given by the product of radial and vertical distributions S(x,y) f(z) where
f(z) is a cosine function.

**6. RESTRICTIONS OR LIMITATIONS**

The limits on input parameters are documented.

**7. TYPICAL RUNNING TIME**

No study has been made by RSIC of typical running times for ORPHEE VI. The author
indicates that ORPHEE VI considers the given radial distribution, element by element, and the
actual axial distribution in about 1 minute per point on the IBM 360/50.

**8. COMPUTER HARDWARE REQUIREMENTS**

The code was designed for the IBM 360/50. The packaged version is operable on the IBM
360/50/75/91 computer configurations.

**9. COMPUTER SOFTWARE REQUIREMENTS**

The IBM 360 FORTRAN IV compilers may be used. A few routines are written in assembly
language.

**10. REFERENCE**

M. Simon, "ORPHEE VI Program, Attenuation of Fast Neutrons in a Structure Consisting of
Layers of Water and Dense Material," CEA-N-1244 (ORNL-tr-2357) (January 1970).

**11. CONTENTS OF CODE PACKAGE**

Included are the referenced document and one (1.2MB) DOS diskette which contains the source
codes and sample problem input and output.

**12. DATE OF ABSTRACT**

June 1972; reviewed December 1984.

**KEYWORDS: ** KERNEL; NEUTRON; ONE-DIMENSION