scope:

This supplement applies only to liquid-metal cooled fast reactors in which the primary coolant is sodium or a sodium/potassium alloy, and including a secondary system also using these metals. Heat is transferred from the primary coolant to the steam generating units by a secondary circuit using heat exchangers which are usually arranged in two alternative configurations:

a) loop design, where the exchangers are connected by pipes to the reactor enclosure, and

b) pool design, where the exchangers are contained in the same vessel as the reactor core.

A third indirect system using a single unit multiple walled tube heat exchanger is not included in this supplement.

The fuel is clad in metallic sealed cladding.