| |
|
|
Writing MCNP Input Files
The cell and surface blocks are included when writing an MCNP input file. TR cards, superimposed mesh cards, and grid tally mesh cards, if defined, are written to the data block. Data items that were read from an input file and material definitions imported from a material library are written.
Several options on the MCNP Output property page control the style of the written (or previewed) file.
The option for specifying a Fixed number of decimal places is not currently operative.
Cell and Surface comments can be written on a separate line (beginning with `c `) before the definition, or at the end of the First or Last line of the definition following a $ character.
Surface coefficients can be repeated, as comments, in alternate units. The alternate units permit convenient documentation of dimensions taken from plans with lengths given in feet, inches, or feet & inches. The alternate unit can be explicitly specified on the MCNP Output property page, or the unit currently in use for the Surface and other dialogs used.
Surfaces that carry a transformation can be written with or without the transformation applied. The transformed surface is written if the Write Expanded Surfaces box is checked. When checked, the property page presents the option to Show Original (untransformed) Surface as a Comment.
The cells and surfaces can be written in numerical order, or in the order in which they are stored in the program. The latter option preserves the order in which they were read in from a geometry file. The cells can be sorted by material and position; the sorting is performed using the Cell Order dialog.
Macrobodies (and solid bodies for which there is a macrobody equivalent) can be used as a single object or expanded into the constituent surfaces depending on the Expand Macrobodies option on the MCNP Output property page. When expanded, the cell description references the decomposition surfaces that are included in the surface block (the macrobody is not). The decomposition surfaces are given an ordinary number—not using the surface.facet notation. When not expanded, the cell descriptions reference the macrobody and the surface block includes the macrobody definition. The TABSF body is always expanded regardless of the Expand setting.
The Repeat Syntax for Fill setting affects how lattice fill specifications are written. If checked, the MCNP nR repeat syntax is used (e.g., 2 3R instead of 2 2 2 2). Otherwise, each fill entry is written.
The Columns setting is the maximum line length written. The value must be between 36 and 80 (inclusive). In rare cases, some lines may slightly exceed the limit. Line lengths < 80 may be useful if one anticipates making changes to a file with a text editor.
 White Rock Science http://www.whiterockscience.com/wrs.html 505 672 1105 |
| |
|
|