The main inhibitor to long-term use of liquid lead in SMRs is that it can corrode and erode stainless steel structures. Historically, lead-cooled reactors have been used for a short amount of time before they have had to be retired due to corrosion.Blykalla has solved this problem by developing steel alloys that protect the core components from corrosion.

Hence, our key innovations are three aluminium alloyed steels: a aluminium oxide forming steel for protecting cladding tubes, an austenitic steel for protecting reactor vessels, and a martensitic steel suited for lead pump impellers. The new steels exhibits perfect corrosion resistance during exposure to lead, and thereby enables the long-term use of lead as a coolant.

The SEALER only takes up 6x6 meters. It has an output of 55MW and fuel residence time of 25 years. It has no overpressure system (1 atm), no exothermic reaction with structural materials nor water, and passive decay heat is removed by natural convection.

The competitive advantage stems from the reactor’s overall compactness and forecasted production volumes, which results in components that are of a size that are more optimally conducive to scalability and repeatability in production.

Blykalla’s reactors are passively safe, which means that no supply of electricity, other means of power nor human action is required for emergency cooling of residual heat. Moreover, the lower power of SMRs as compared to larger reactors, means that less residual heat needs to be removed to ensure the integrity of the fuel cladding tubes.

The SEALER will initially use industrially fabricatable uranium dioxide (UO2), proven across decades of reactor operation, that builds upon established routes for fabrication, transportation and reprocessing. UO2 is the most widely used reactor fuel in the world, de-risking the supply chain, the irradiation data challenge giving greater regulatory certainty.

Long-term, we aim to leverage uranium nitride due to its superior in-core performance. The 40% higher uranium per unit volume, can lead to longer fuel life while the greater thermal conductivity improves safety margins.

This fuel has traditionally been challenging to fabricate, though UN pellets have been made and irradiated since the 1960s and were tested as part of historic fast reactor and space reactor programmes. Conventional carbothermic and hydride-based routes to synthesize UN are understood and routes to industrial scale form the basis of Blykalla's fabrication planning. Blykalla is exploring innovative routes and holds a patent on the direct conversion of UF6 in streaming NH3, while also exploring further innovations to established methods, including Spark Plasma Sintering, which can produce a high density pellet in minutes at around 1450°C, versus several hours around 1900°C using conventional pressureless sintering.