Safety assessment of spent fuel transportation through urban regions

A full scale test subjecting a 25.45 metric ton stainless steel/lead cask containing surrogate spent fuel to a reference high explosive device was performed to provide data for developing improved estimates of the radiological consequences resulting from the sabotage of spent fuel transports in urban regions. A total UO2 fuel mass of 5.460 kg was removed from the 201.053 kg UO2 fuel assembly as a result of the test. A total respirable UO2 aerosol mass of 2.94 g was released from the cask as a result of the explosive attack. A total of 540 g of UO2 particles were deposited on the chamber surfaces. Less than 5 mg of the surface deposited UO2 particles were smaller than 10 m aerodynamic diameter. These results are in good agreement with the time-integrated aluminum planchet samples which showed trace amounts of mechanical fractured uranium particles deposited on the chamber surfaces. Analyses of the time-resolving RPS indicated that no uranium particles and/or vapor were explosively deposited on the chamber surfaces. The results of this full-scale test indicate that approximately 6 x 10-4% of the total solid heavy metal inventory (0.5 t) could be released as a respirable radioactive aerosol as a result of an explosive attack on a single-PWR fuel assembly truck cask. The expected health consequences were calculated using the derived release fraction of 6 x 10-4% as the primary input to the consequence reactor safety model called CRAC. The release conditions such as population distribution and weather conditions were assumed to be equivalent to those of the Manhattan borough of New York City. The results of this consequence analysis indicate that one peak latent cancer fatality and no early fatalities or early morbidities could occur as a result of a radioactive release from a single PWR spent fuel truck cask in downtown New York City