RSICC CODE PACKAGE CCC-694

1. NAME AND TITLE

NMTC-JAERI97: Monte Carlo Nucleon-Meson Transport Code System.

2. CONTRIBUTORS

Center for Neutron Science, Japan Atomic Energy Research Institute, Tokai-mura, Naka-gun, JAPAN through the OECD NEA Data Bank, Issy-les-Moulineaux, France.

3. CODING LANGUAGE AND COMPUTER

Fortran 77; SUN (C00694/SUN05/00).

4. NATURE OF PROBLEM SOLVED

NMTC/JAERI97 is an upgraded version of the code system NMTC/JAERI, which was developed in 1982 at JAERI and is based on the CCC-161/NMTC code system. NMTC/JAERI97 simulates high energy nuclear reactions and nucleon-meson transport processes.

5. METHOD OF SOLUTION

High energy nuclear reactions induced by incident high energy protons, neutrons and pions are simulated with the Monte Carlo method by the intra-nuclear nucleon-nucleon reaction probabilities based on the BERTINI model followed by particle evaporation including high energy fission process. The ISOBAR code is employed as an alternative option for the intranuclear cascade calculation. The pre-equilibrium process is calculated by an exciton model in which proton, neutron, deuteron, triton, helium-3 and -particles are taken into account. Inter-nuclear transport processes of the incident and secondary nucleons in macroscopic material regions are simulated with the Monte Carlo method based on the O5R algorithm and a continuous slowing down model for charged particles. The nucleon-nucleus cross sections are revised to those derived by the systematics of Pearlstein.

A new geometry package on the Combinatorial Geometry with multiple-array system (MARS) is used for defining the geometry model of a problem. The importance sampling technique is implemented in the code to simulate the particle transport process effectively. Tally function is also employed for obtaining such physical quantities as neutron energy spectra, heat disposition and nuclide yield without editing a history file. The array size required for geometry model and tally is adjustable by changing the parameter size in an include file.

6. RESTRICTIONS OR LIMITATIONS

The mass number A of nuclides which can be included in a target is restricted to A=1 and 6<= A <= 250. Energy range of incident particles should be between the cut-off energy and 3.5 GeV for proton and neutron. But for pions the upper the upper boundary is 2.5 GeV. When the ISOBAR code is selected for intranuclear cascade calculation, the upper energy is limited to 1 GeV. Occasionally, abnormal termination occurs when ISOBAR option is selected for intranuclear cascade calculation. The boundary cross estimation tally is available only to the surface crossing the z-axis of r-z two dimensional geometry. Updating work is in progress.

The transport of neutrons with energies below cut-off energy (20 MeV) has to be calculated independently by the neutron-photon transport code such as MCNP4A using a cross section library processed from evaluated nuclear data.

7. TYPICAL RUNNING TIME

Running time depends on the target size and the incident beam energy. In the case of the sample problem of 800 MeV protons on 20 cm diameter by 60 cm long Pb target, it takes about 33.5 minutes for 50,000 proton incidence, or about 0.04 seconds s/history, on the SUN SuperSPARCII 75 MHz (OS: Solaris 2.4), SPECint92:125.8, SPECfp92: 121.2.

8. COMPUTER HARDWARE REQUIREMENTS

NMTC/JAERI97 was developed on Sun workstations and has been executed on Dec Alpha and HP workstations. About 20 mega-bytes memory at minimum is required. Several hundreds of mega-bytes to giga-bytes storage for cut-off neutron history storage. The memory and storage capacity is determined depending upon the parameter values and target size of problems.

9. COMPUTER SOFTWARE REQUIREMENTS

SUN SuperSPARCII 75 MHz (OS: Solaris 2.4), SPECint92:125.8, SPECfp92: 121.2. The program is also executable on the DEC-Alpha with Digital UNIX ver. 4 by modifying some functions.

10. REFERENCES

a) included in documentation:

H. Takade, N. Yoshizawa, N., K. Kosako, K. and Ishibashi, "An Upgraded Version of the

Nucleon Meson Transport Code, NMTC/JAERI97," JAERI-Data/Code 98-005 (February 1998).

M. Teshigawara, et al. "Neutronics Studies of Bare Targets for JAERI 5 MW Pulsed

Spallation Neutron Source," JAERI-Research 99-010 (February 1999).

b) background information:

Y. Nakahara and T. Tsutsui, "NMTC/JAERI: A Simulation Code System for High Energy Nuclear Reactions and Nucleon-Meson Transport Processes," JAERI-M 82-198 (December 2,1982; in Japanese) NEA-0974/02.

T. W. Armstrong and K. C. Chandler, "Analysis Subroutines for the Nucleon-Meson Transport NMTC," ORNL-4736 (November 1971).

R. R. Coveyou, J. G. Sullivan, H. P. Carter, D. C. Irving, R. M. Freestone, Jr., and F. B. K. Kam, "O5R, A General-Purpose Monte Carlo Neutron Transport Code," ORNL-3622 (February 1965).

J. T. West and M. B. Emmett, "MARS A Multiple Array System Using Combinatorial Geometry," Vol. 3, Section M9 of NUREG/CR-200 (1984).

11. CONTENTS OF CODE PACKAGE

Included are the referenced documents in (10.a) and one diskette which includes a GNU compressed tar file containing Fortran source files and test cases. No executable is included with the package.

12. DATE OF ABSTRACT

November 2000.

KEYWORDS: NUCLEON; MESON; MONTE CARLO; COMPLEX GEOMETRY; PROTON; NEUTRON; SPALLATION