Radiation, particles transport.

http://www.fluka.org/fluka.php

http://www-rsicc.ornl.gov/rsiccnew/CodesAvailableElsewhere.htm

http://www.nea.fr/html/dbprog/peneloperef.html //not available for using

CUDA zone

http://www.nvidia.ru/object/cuda_what_is_ru.html