SEALER (Swedish Advanced Lead Reactor) is a passively safe lead-cooled reactor designed for commercial power production in a highly compact format. Its fuel is never replaced during operation, which minimises costs related to fuel management. The integrity of steel surfaces exposed to liquid lead is ensured by use of alumina forming alloys, containing 3-4 wt% aluminium. 

For Arctic applications, the fuel is 2.4 tons of 19.9% enriched uranium oxide, and the rate of electricity production may vary between 3 to 10 MW, leading to a core-life between 10 and 30 years (at 90% availability).

For on-grid applications, the fuel is 21 tons of 12% enriched uranium nitride and the rated power is 55 MWe, leading to an equivalent full power core-life of 25 years.


Passive safety of the reactor is ensured by removal of decay heat from the core by natural convection of the lead coolant. Transport of the residual heat from the primary system is accomplished by activation of dip-coolers that will keep the system temperatures within the normal operating range. If the dip-coolers are not activated as intended, the coolant temperature increases so that residual heat can be transported by radiation from the primary vessel to a guard vessel, which is cooled by natural convection of air. In the event of a core disruptive accident, volatile fission products are retained in the lead coolant and no evacuation of persons residing at the site boundary will be required.


The future cost for purchasing a SEALER-Arctic unit is estimated at CAD 100 M. The owner’s cost of a factory assembled SEALER-55 unit (as part of a multi-unit plant)  is estimated at € 200 M. These values include the cost of the fuel.

Waste management

Five years after end of operational life, a SEALER unit will be transported back to a centralised waste management facility. Two major options are considered for management of the high level waste: Either direct disposal of the entire primary vessel, including fuel assemblies encapsulated in frozen lead, or recycle of plutonium and minor actinides in SEALER reactors designed for waste transmutation. In the latter case, residual high level waste (mainly short lived fission products) will be vitrified and isolated from the biosphere in a geological repository for a period of less than 1000 years.




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