.. _sec-scale.radiation_shielding:

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Radiation Shielding 
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**Introduction by D. E. Peplow and B. T. Rearden**

The Monaco
with Automated Variance Reduction using Importance Calculations (MAVRIC)
fixed-source radiation transport sequence is designed to apply the multigroup
and continuous energy fixed-source Monte Carlo code Monaco to solve problems too
challenging for standard, unbiased Monte Carlo methods.i The intention of the
sequence is to calculate fluxes and dose rates with low uncertainties in
reasonable times even for deep penetration problems. MAVRIC is based on the
Consistent Adjoint Driven Importance Sampling (CADIS) methodology, which uses an
importance map and biased source that are derived to work together. MAVRIC
generates problem-dependent cross section data and then automatically performs a
coarse mesh 3D discrete ordinates transport calculation using Denovo to
determine the adjoint flux as a function of position and energy. MAVRIC then
applies the information to optimize the shielding calculation in Monaco. In the
Forward-Weighted CADIS (FW-CADIS) methodology, an additional Denovo calculation
is performed to further optimize the Monaco model to obtain uniform
uncertainties for multiple tally locations. Sources can be input using many
spatial and energy distributions, or they can be imported from a previously
generated mesh file. Responses can be generated from cross section reaction
rates, flux-to-dose conversion factors, or user-defined functions; responses are
tallied on geometry regions, Cartesian or cylindrical grids, or as point
detectors. 

MAVRIC enables users to import spent fuel isotopics from ORIGEN
binary concentrations files such as those generated with ORIGAMI and to import
gamma emission spectral data directly from the ORIGEN nuclear data files to
streamline analysis and reduce the opportunity for human error. 

Several utility modules are also provided for data introspection and conversion.  

.. toctree::

   MAVRIC
   MAVRIC-appendix-a
   MAVRIC-appendix-b
   MAVRIC-appendix-c