Availability: MCNP is distributed within the United States by the Radiation Safety Information Computational Center (RSICC) --- formerly, Radiation Shielding Information Center (RSIC), Oak Ridge, Tennessee. There are versions for virtually all systems asked about (PC, Sun Solaris, etc.). Please contact RSICC directly.

MCNP has been distributed internationally by the Nuclear Energy Agency (OECD/NEA), Paris, France. The distribution is the same package as that from RSICC. Please contact Enrico Sartori.

MCNP 5.1.40 was released. No patch file is provided to update previous versions of MCNP. Users are recommended to obtain the latest version directly from RSICC.

MCNP5 was released to ORNL/RSICC and made available to people within the US in April 2003.  This release is identified as MCNP5_RSICC_1.14.  In December 2003, a patch was released to RSICC and made available.  The patch (which creates MCNP5_RSICC_1.20) is availble here. 

In September 2004, a new patch was made available (MCNP5_RSICC_1.30) it is available here.

Hardware Requirements:
MCNP5 is supported on the following platforms: sgi, alpha, aix, sun, PC Linux and PC Windows. 

A minimum of 70 MB of hard disk space is required along with ANSI standard C and FORTRAN 90 or 95 compilers. Complete installation, including nuclear data libraries, requires a total of 2.3 GB of harddisk space.   Additional hard disk space (MB to GB) is required for mcnp input and output files. 

PC Windows users who use Intel processors are required to have at least a Pentium II CPU.

At least 128 Megabytes of memory is recommend.

Manual:
The MCNP Manual has been updated with the release of MCNP5.  An electronic version (.pdf) is included with the RSICC release.  For LANL users, Appendix A (a summary of MCNP commands), and the MCNP5 Manual, are available.

Future Releases:
Currently under development is an in-house version of MCNP which can automatically generate weights for weight windows, track high-energy protons, run 1x10²⁰ source particles, and use direct magnetic field tracking or COSY maps.  A nuclear data processing code, called DOPPLER, has been added, which enables the user to generate a new nuclear data library at a specific temperature from an existing data library.  Features to be added over the next few months include improved pulse height tallies and the ability to transport additional particles. 

Feedback: Feedback from users running real applications is important to us, for finding/fixing bugs and making general improvements to the codes. If you find bugs, have suggestions, or have difficulties, please send email.