SHIELDING ASSESSMENT OF A VARIETY OF TRANSPORT FLASKS CARRYING MIXED OXIDE FUEL OR VITRIFIED RESIDUE ON BOARD THE PACIFIC HERON SHIP

A shielding and dose rate assessment has been conducted for a variety of transport flasks carrying Mixed Oxide fuels or Vitrified Residues on board a newly designed PNTL ship, Pacific Heron that will transport such flasks from Europe to Japan. The permanent shielding on board the ship was determined such that dose rates met Japanese Transport Regulations in terms of dose rate and dose uptake. The MCBEND Monte-Carlo computer code has been used to optimise the shielding to be installed and to determine total neutron, primary and secondary gamma dose rates in key areas on board the ship with the final shielding layout. Furthermore, the work has been done using a high-performance ‘Beowulf’ cluster computer system for efficient distribution of multiple cases of the same input, thus when combined at job completion result in lower standard deviations (< 10%) in reasonable timescales (?