The Central Electricity Generating Board reactor inventory code RICE has been used to calculate the buildup of activity and radioactive emissions for a range of alternative fuel cycles based on a conceptual high-temperature gas-cooled reactor design. The fuels included in this study were a conventional 235U-enriched oxide fuel, a mixed PuO2/UO2 fuel employing pressurized water reactor plutonium, and both low- and high-enrichment mixed 235UO2/ThO2 fuels. The results have been used to quantify the radiological protection implications of these fuel cycles in terms of fuel handling and reprocessing waste management. Some of the thorium fuels investigated have distinct advantages compared with those employing recycled plutonium in terms of both reduced neutron dose rates and long-term alpha decay heating. However, this is at the expense of enhanced gamma dose rates during the fabrication and handling of fresh 233U fuels. These gamma emissions build up with time and require rapid fabrication and return of fuel to the reactor following irradiated fuel reprocessing. The hazards associated with fuel reprocessing wastes are dominated by fission product isotopes over the first few centuries and are similar for U/Pu and thorium fuel cycles. The reduced hazards associated with the actinide component of thorium fuels are only advantageous in waste management schemes involving separate treatment of fission products and actinides.