**1. NAME AND TITLE**

MORSE-EMP: General Purpose Monte Carlo Multigroup Neutron and Gamma- Ray Transport Code System with Array Geometry Capability. We recommend C00474/ALLCP/02 MORSE-CGA.

This package is a personal computer implementation of CCC-474C/MORSE-CGA, Version 1, originally released by ORNL in 1985. Experimental and Mathematical Physics Consultants converted the codes and support CCC-588/MORSE-EMP.

**AUXILIARY ROUTINES**

PICTURE: Geometry Input Diagnostic Code.

JUNEBUG-II: Three-dimensional Geometry Plotting Code.

**2. CONTRIBUTORS**

Experimental and Mathematical Physics Consultants, Gaithersburg, Maryland.

Oak Ridge National Laboratory, Oak Ridge, Tennessee.

**3. CODING LANGUAGE AND COMPUTER**

FORTRAN 77, Assembler language; IBM PC, PC 386.

**4. NATURE OF PROBLEM SOLVED**

MORSE-CGA was developed to add the capability of modelling rectangular lattices for nuclear reactor cores or for multipartitioned structures. It thus enhances the capability of the MORSE code system. The MORSE code is a multipurpose neutron and gamma-ray transport Monte Carlo code. It has been designed as a tool for solving most shielding problems. Through the use of multigroup cross sections, the solution of neutron, gamma-ray, or coupled neutron-gamma-ray problems may be obtained in either the forward or adjoint mode. Time dependence for both shielding and criticality problems is provided. General three-dimensional geometry may be used with an albedo option available at any material surface. Isotropic or anisotropic scattering up to a P16 expansion of the angular distribution is allowed.

**5. METHOD OF SOLUTION**

Monte Carlo methods are used to solve the forward and the adjoint transport equations. Quantities of interest are then obtained by summing the contributions over all collisions, and frequently over most of phase space.

Standard multigroup cross sections, such as those used in discrete ordinates codes, may be used as input; either CCC-254/ANISN, CCC-42/DTF-IV, or CCC-89/DOT cross section formats are acceptable. Both fixed and free format are acceptable. Anisotropic scattering is treated for each group-to-group transfer by utilizing a generalized Gaussian quadrature technique.

The MORSE code is organized into functional modules with simplified interfaces such that new modules may be incorporated with reasonable ease. The modules are (1) random walk, (2) cross section, (3) geometry, (4) analysis, and (5) diagnostic.

**6. RESTRICTIONS OR LIMITATIONS**

Flexible dimensioning techniques require the use of a large container array in blank COMMON.

**7. TYPICAL RUNNING TIME**

On a PC 386 running at 25 megahertz under MS DOS4.01, the following times were noted: problem 1 took about 4 minutes; problem 4 took 11 minutes; problem 5 took 6 minutes; the collision density problem using the MORSECD.EXE for a PC 386 took about 7 minutes; the MORSEXR program took only a few seconds.

**8. COMPUTER HARDWARE REQUIREMENTS**

The executable programs which were compiled with Microsoft FORTRAN Version 5.0 using overlays will run on any PC with 640 K of memory. The programs compiled with the Lahey F77-EM/32 compiler will run only on a PC 386 with a 80387 math coprocessor and at least 4 MB of memory. A graphics monitor is required for the JUNEBUG program.

**9. COMPUTER SOFTWARE REQUIREMENTS**

The Microsoft FORTRAN Version 5.0 and Microsoft Macro Assembler were used for compilation and linking for the IBM PC version. For the PC 386, the Lahey F77-EM/32 compiler was used.

**10. REFERENCES**

T. M. Jordan, "Informal Notes" (September 18, 1990).

M. B. Emmett, *MORSE-CGA, A Monte Carlo Radiation Transport Code with Array
Geometry Capability*, ORNL-6174 (April 1985).

M. B. Emmett, *The MORSE Monte Carlo Radiation Transport Code System*,
ORNL-4972 (February 1975); ORNL-4972/R1 (February 1983); ORNL 4972/R2 (July
1984).

J. T. West and M. B. Emmett, "MARS -- A Multiple Array System Using Combinatorial
Geometry," (December 1984). This is Volume 3, Section M9 of NUREG/CR-0200, *SCALE
-- A Modular Code System for Performing Standardized Computer Analysis for Licensing
Evaluation*, NUREG/CR-0200 (ORNL/NUREG/CSD-2), Revision 2.

M. B. Emmett, "PICTURE, A Printer Plot Package for Making 2-D Pictures of MARS
Geometry," (December 1984). This is Volume 3, Section M13 of NUREG/CR-0200, *SCALE
-- A Modular Code System for Performing Standardized Computer Analysis for Licensing
Evaluation*, NUREG/CR-0200 (ORNL/NUREG/CSD-2), Revision 2.

M. B. Emmett, L. M. Petrie, and J. T. West, "JUNEBUG-II -- A Three-Dimensional
Geometry Plotting Code," (December 1984). This is Volume 2, Section F12 of
NUREG/CR-0200, *SCALE -- A Modular Code System for Performing Standardized
Computer Analysis for Licensing Evaluation*, NUREG/CR-0200 (ORNL/NUREG/CSD-2),
Revision 2.

S. N. Cramer, *Applications Guide to the MORSE Monte Carlo Code*, ORNL/TM-9355
(August 1985).

**11. CONTENTS OF CODE PACKAGE**

Included are the referenced documents and 9 DS/HD 5.25-inch diskettes (1.2 MB).

**12. DATE OF ABSTRACT**

May 1991.

**KEYWORDS: ** MONTE CARLO; NEUTRON; GAMMA-RAY; MULTIGROUP; COM
PLEX GEOMETRY; COMBINATORIAL GEOMETRY; ADJOINT;
ARRAY GEOMETRY; MICROCOMPUTER