Liquid lead has historically been used in SMRs onboard submarines. The main inhibitor to more long-term use of liquid lead is that it may corrode and erode stainless steel structures. However, Blykalla has developed a patented, aluminum alloyed steel exhibiting perfect corrosion resistance. This will be used to protect the SMR’s fuel capsules against corrosion.
Lead as a coolant has a number of intrinsic advantages: it is radiation shielding, and cools the system while simultaneously ensuring that radioactive elements are retained. It has a boiling temperature of 1700°C, which enables a low pressure system and makes it possible to achieve passive safety in its most compact form.