The MCNP code is distributed to its worldwide user community by the Radiation Safety Information Computational Center (RSICC), which is based at the Oak Ridge National Laboratory in Oak Ridge, Tennessee.
Because the MCNP code is export controlled, the distribution through RSICC is governed by US laws and Department of Energy regulations. US citizens may request either the executable-only distribution package or the distribution package that includes source coding. Non-US citizens should generally request the executable-only distribution package to avoid possible delays in approval.
The MCNP6 distribution package from RSICC includes executables for Linux, macOS, and Windows. The package also includes documentation (release notes & user manual), numerous verification and validation problems, a variety of utility programs and scripts, and numerous ACE-formatted nuclear data libraries.
For further information or specific questions regarding obtaining MCNP6 from RSICC, please contact RSICC directly using the RSICC email.
If you are a LANL employee and have access to the internal network, please follow this link to learn about gaining access to, and using, MCNP6 at LANL.
Do not request MCNP6 from RSICC.