**1. NAME AND TITLE**

RHEIN: Reactor Code System for Neutron Physics Calculation.

**2. CONTRIBUTOR**

Zentralinstitut Fur Kernforschung Rossendorf, Dresden, Germany, through NEA Data Bank, Gif-sur-Yvette Cedex, France.

**3. CODING LANGUAGE AND COMPUTER**

FORTRAN IV; IBM 3090, ES-1055.

**4. NATURE OF PROBLEM SOLVED**

RHEIN is a modular reactor code system for neutron physics calculation.

**5. METHOD OF SOLUTION**

The calculation routines can be used for the following problems: calculation of cross section sets for infinite medium; zero-dimensional spectrum calculation in diffusion, P1 or B1 approximation; one-dimensional calculation in diffusion, P1 or collision probability approximation; two-dimensional diffusion calculation; cell calculation; zonewise homogenized group collapsing within zero, one or two-dimensional model.

**6. RESTRICTIONS OR LIMITATIONS**

None noted.

**7. TYPICAL RUNNING TIME**

On the IBM 3090, test case 1 took 7 seconds; test case 2 took 2 seconds; test case 3 took 66 seconds.

**8. COMPUTER HARDWARE REQUIREMENTS**

RHEIN runs on the IBM 3090 and ES-1055 computers.

**9. COMPUTER SOFTWARE REQUIREMENTS**

The code was written in FORTRAN IV. On the IBM 3090, VS FORTRAN 2.1.1 (with the FORTRAN 66 option) was used under the MVS/XA operating system.

**10. REFERENCE**

**a. Included in the documentation:**

C. Reiche, H. Barz, B. Kunzmann, E. Seifert, H. Wand. *Reactor-Code-System RHEIN fur
ESER Computer*, ZfK-668, Zentralinstitut fur Kernforschung, Dresden, Germany, April 1989.
(in German).

**11. CONTENTS OF CODE PACKAGE**

Included are the referenced documents and one DS/HD (1.2 MB) 5.25-inch diskette.

**12. DATE OF ABSTRACT**

March 1991.

**KEYWORDS: ** CELL CALCULATION; CROSS SECTION PROCESSING; CROSS
SECTIONS; DIFFUSION THEORY; NEUTRON; REACTOR PHYSICS;
TWO-DIMENSIONS