THERMODYNAMICS OF ZINC CHEMISTRY IN PWRS - EFFECTS AND ALTERNATIVES TO ZINC

lit this paper the favourable effect of zinc on radiation field contro l in pressurized water reactors is evaluated in terms of the propertie s of spinels, which are a function of the incorporated elements. In ad dition, the identification of an alternative element to Zinc is descri bed. Thermochemical calculations show that chromites have a higher sta bility than ferrites. Zinc has a high affinity for the relevant spinel s. Cobalt and other elements should therefore be displaced from existi ng oxide layers. For the identification of art alternative element to zinc, the following selection criteria were used: activation behaviour valency and ion radius of candidate elements; affinity for Spinel for mation and occupational health and safety aspects. Based on these crit eria, magnesium was identified as a possible alternative to zinc.