Radiotoxicity wastes, sources

Waste Products and Recycling No chemotoxic or radiotoxic effects on microorganisms or plants are known from exposure to environmental radioactivity from natural and industrial sources of uranium, thorium and their decay products. 

One of the advantages often cited for the thorium fuel cycle is a significant reduction in the production of long-lived transuranic actinides. It has lower "radiotoxicity" than uranium-based fuels, and so fhe source term in the waste management vault will be lower. 

The neutron absorption of hafnium leads to the formation of hafnium isotopes, themselves absorbers (Fig. 15.7) and then to isotopes of heavier elements Ta, and W (up to a few percent Lu is produced in very small amounts). Among these, Ta is the main source of the radiotoxicity of the material, but with a 115-day period, making it a shortlived waste. 

---