Coolant treatment process design

The scope, extent and detail of the safety analysis for low power research reactors may be significantly less than is required for high power research reactors because certain accident scenarios may not apply or may need only a limited analysis. For example, the treatment of loss of coolant accidents may differ significantly, depending on the power and design of the reactor. Paragraphs 6.72-6.78 establish requirements for the scope, factors and process to be considered in the safety analysis. 

Pending the development of materials resistant to lead corrosion at higher temperature, surface treatment, and small quantities of additional elements in the stmctoral matrix and oxygen control are necessary to protect materials immersed in lead from corrosion and also to protect against the formation of solids in the lead coolant from oxidation processes. In the design configuration developed to date, relatively low coolant outlet temperatures serve to reduce the potential impact of this issue. 

A further challenge is due to the environment, as materials have to retain their structure and properties in reactive or corrosive media (reactor coolant, process fluid, reprocessing treatment). In addition, the Generation IV systems are intended to have a license period of 60 years, whereas the maximum design life of current reactor materials is more in the range of 30—40 years. The combination of environment, high-temperature operation, and long duration of service restricts choices to the best available or near commercial materials. Optimization and development of new solutions may also be required. 

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