Numeric Determination and Validation of Neutron-Induced Radioactive Nuclide Inventories for Decommissioning and Dismantling of Light Water Reactors

Updated Recommendations Related to Spent Fuel Transport and Dry Storage Shielding Analyses

“…Furthermore, the density of activation products is expected to vary as a function of depth within reactor vessel and structural materials. High-fidelity, detailed reactor analyses [85] showed that the 60 Co and 55 Fe activity densities were much higher in the pressure vessel liner than deeper within the pressure vessel wall. These activity densities further decreased with increasing depth within the pressure vessel up to a certain depth and then slightly increased near the outer surface because of the neutron streaming in the annulus region between the pressure vessel and the biological shielding.…”

Best Practices for Shielding Analyses of Activated Metals and Spent Resins from Reactor Operation

“…High-fidelity, detailed reactor analyses [38] determined that 99.9% of the activity inventory at 3 years after shutdown was in the activated internal structural materials and the remainder was equally distributed between the pressure vessel and the biological shield. The study by P-W Phlippen et al (2018) [38] has shown that the specific activities of activation products 60 Co and 55 Fe were much higher in the pressure vessel liner than within the pressure vessel. These specific activities further decreased with increasing depth within the pressure vessel up to a certain depth and then slightly increased near the outer surface because of neutron streaming in the annulus region between the pressure vessel and the biological shielding.…”