CCC-0700 MCNP-4C.

1. NAME OR DESIGNATION OF PROGRAM:  MCNP-4C.

3. DESCRIPTION OF PROGRAM OR FUNCTION

MCNP is a general-purpose, continuous-energy, generalized geometry, time-dependent, coupled neutron-photon-electron Monte Carlo transport code system.
MCNP4C is the first major release of MCNP since version 4B (February 4, 1997). The major new features of MCNP4C include:

* Unresolved resonance range probability tables;
* Perturbation enhancements;
* Superimposed mesh weight window generator;
* Alpha eigenvalues;
* Macrobodies;
* ENDF/B-VI improvements;
* PC Enhancements;
* Electron Physics Enhancements;
* Parallelization enhancements;
* Delayed Neutrons.

In addition, there are 30 minor features/enhancements and 65 corrections. See the MCNP home page more information
http://www-xdiv.lanl.gov/XCI/PROJECTS/MCNP. See the Electronic Notebook at http://www-rsicc.ornl.gov/rsic.html for information on user experiences with MCNP.

4. METHODS

MCNP treats an arbitrary three-dimensional configuration of materials in geometric cells bounded by first- and second-degree surfaces and some special fourth-degree surfaces. Pointwise continuous-energy cross section data are used, although multigroup data may also be used. Fixed-source adjoint calculations may be made with the multigroup data option. For neutrons, all reactions in a particular cross-section evaluation are accounted for. Both free gas and S(alpha, beta) thermal treatments are used. Criticality sources as well as fixed and surface sources are available. For photons, the code takes account of incoherent and coherent scattering with and without electron binding effects, the possibility of fluorescent emission following photoelectric absorption, and absorption in pair production with local emission of annihilation radiation. A very general source and tally structure is available. The tallies have extensive statistical analysis of convergence. Rapid convergence is enabled by a wide variety of variance reduction methods. Energy ranges are 0-60 MeV for neutrons (data generally only available up to 20 MeV) and 1 keV - 1 GeV for photons and electrons.

5. RESTRICTIONS ON THE COMPLEXITY OF THE PROBLEM:  None noted.

6. TYPICAL RUNNING TIME

The 29 test cases ran in approx. 3 minutes on a Pentium III 550 MHz in a DOS window of WindowsNT and in approx. 5 minutes on a Pentium II 300MHz in a DOS windows of Windows98.

8. RELATED OR AUXILIARY PROGRAMS

PRPR: Pre-processor for Extracting the Various Hardware Versions of MCNP and other codes.
MAKXSF: Preparer of MCNP Cross-Section Libraries.

RELATED DATA LIBRARY

MCNP4C includes a test library of cross sections for running the sample problems. The DLC-200/MCNPDATA code package includes data for use with MCNP and is distributed with the code package for the convenience of users.

Expanding the code system (50 MB) and binary cross section libraries (360MB) under Windows requires ~410 MB of hard disk space. Unix users need more because the ASCII cross sections require 880 MB of hard disk space.

A list of cross-section libraries is given in
http://www.nea.fr/html/dbprog/mcnp-lib.html

10. REFERENCES

D. J. Whalen, D. A. Cardon, J. L. Uhle, J. S. Hendricks, "MCNP: Neutron Benchmark Problems," LA-12212 (November 1993).

C. D. Harmon, II, R. D. Busch, J. F. Briesmeister, R. A. Forster, "Criticality Calculations with MCNP: A Primer," LA-12827-M (August 1994).

R. C. Little and R. E. Seamon, "Dosimetry/Activation Cross Sections for MCNP," LANL Memo (March 13, 1984).

11. HARDWARE REQUIREMENTS

MCNP is operable on Cray computers under UNICOS, workstations or PC's running Unix or Linux, Windows-based PC's, and VAX computers under VMS. Executable files for Windows-based PC's are provided for running Pentium computers.

13. SOFTWARE REQUIREMENTS

Compilation of MCNP requires both FORTRAN77 and ANSI C standard compilers. MCNP can be compiled with g77 on PC's running Red Hat Linux. PVM is required for multiprocessing on a cluster of workstations and can be downloaded from www.netlib.org. Scripts are provided for installation on both PC and Unix systems. The PC distribution includes MCNP, PRPR and MAKXSF executables which were built in a DOS window of Windows NT using the Digital Visual Fortran 6.0A and Lahey/Fujitsu Fortran 95 Release 5.50d compilers. The Lahey-compiled MCNP executables were built with MDAS=4,000,000; 8,000,000; and 32,000,000. The DVF-compiled executable was created with dynamically allocated storage. RSICC tested this release on the following systems:

AIX 4.3.3 (IBM 43P-260) with XL C/C++ 4.4; XL Fortran 6.1

Redhat Linux Version 6.1 on 450 MHz Pentium III (9 nodes) with g77

Sun Solaris 2.6 on UltraSparc 60 using F77 Version 5.0 and C/C++ Version 5.0

HP B1000 (PA-8500) under HP-UX 10.20 with FORTRAN 77 V0.20 and HP C V10.32.00

DEC 500 AU under Digital Unix 4.0D with DEC Fortran 5.1-8 and DEC C 5.6-075

SGI MIPS R10000 (225MHz) under IRIX 6.5.5 with MIPS Fortran 77 Version 7.3

Pentium II 300MHz in a DOS window of Windows 98 with Digital Visual Fortran Professional Edition 6.0A Fortran 90 compiler with QuickWin plots

Pentium II 300MHz in a DOS window of Windows 98 with Lahey/Fujitsu Fortran 95 -- LF95 Version 5.50 Fortran 90 compiler with Winteracter Starter Kit

15. NAME AND ESTABLISHMENT OF AUTHORS

Contributed by:
                Radiation Safety Information Computational Center
                Oak Ridge National Laboratory
                Oak Ridge, Tennessee, U. S. A.

Developed by:   Diagnostics Applications Group,
                Los Alamos National Laboratory,
                Los Alamos, New Mexico, U.S.A.