MCNP5 Method

Requirements

Use of the MCNP5 option requires:

  1. That the user be proficient in MCNP, specifically the coding of MCNP geometries. For those users who are unfamiliar with MCNP, we recommend the introductory primer written by J.K. Shultis and R.E. Faw:

  2. That the MCNP5 software package be installed on the user’s computer, or that the user have access to a network on which it is installed. The package can be obtained free of charge from the Radiation Safety Information Computational Center (RSICC) website.

  3. That the following files be stored in the directory from which MCNP will be run:

    MCNP cutout input file associated with the ATR-3 region being analyzed. This file is named in accordance with the following pattern: the name of the region, followed by the word “mini”, followed by an extension ”.i”. For example, for the region I-6, the MCNP cutout input file is named “I6mini.i”. It can be downloaded on the package website (as yet unspecified).

    xrssa file. This file contains the surface source that will be read into MCNP. When downloaded from the package website (as yet unspecified), it will be named in accordance with the following pattern: the name of the region, followed by ”.w”. For example, the rssa file for region I6 will be named “I6.w”. The user needs to download that file into the working MCNP directory, and then rename it to “rssa”.

Directions

  1. Add the necessary cell and surface definitions in the appropriate sections of the MCNP cutout input file (e.g., I6mini.i) so as to incorporate the desired experiment geometry. Note: this step requires basic proficiency in the language MCNP. Unfamiliar users should consult the MCNP Primer linked above.
  2. Add the experiment materials to the material section of the MCNP cutout input file so as to define any materials that are used in the above cell definitions.
  3. Add tallies to the data section of the MCNP cutout input file to get out the information of interest. A generic mesh tally is included in the MCNP cutout input file for reference.
  4. Run the MCNP cutout input file in MCNP. To do this, open up a command prompt, navigate to the working directory, and type in mcnp5 i=nameofMCNPcutoutfile(eg, I6mini.i) o=nameofoutputfile(youdecide).

Surface source files can be found here.