The proposed work will investigate possible interactions between boric acid and tellurium under conditions representing the primary circuit break in a pressurized water reactor. Boric acid used as a chemical shim to reduce the number of free neutrons available in the reactor. Furthermore, if the reactor is using boron carbide as the control rod material, then boric acid may also be formed in accident scenarios through its reaction with water at high temperatures.
Tellurium is a fission product and present as several radioactive isotopes. They decay through iodine, which is a highly volatile element and thus presents a radiohazard. Chemically, Tellurium is a volatile element with a rich chemistry, and several NKS- projects have been undertaken the last few years to deepen the understanding of its behavior during severe accidents. Its interaction with boric acid, however, is still unknown. Furthermore, as Tellurium decays into iodine and the interaction between tellurium and iodine in these conditions likewise is unknown. Another set of experiments will be conducted to investigate this aspect of severe accident chemistry, also involving Cesium, which is another volatile fission product.
Previous NKS-R projects have been conducted regarding Tellurium. Examples of such projects are TETRA and ORTEF, both of which involved a partnership between VTT Technical Research Center of Finland Ltd and Chalmers University of Technology. Together these institutions possess a proven technical and theoretical expertise to investigate the behaviour of Tellurium in this context.