February 17, 2021

Uniper and LeadCold are starting a collaboration with the intent to develop the reactor technology of the future. To this end, Uniper and LeadCold are forming a joint venture, whose first mission is to ensure funding for the construction of an electrically heated prototype of LeadCold’s SEALER concept. This prototype is planned to be built on the premises of OKG at Simpevarp in Oskarshamn, commencing operation in 2024. The collaboration is extended to KTH and its academic partners in the SSF-funded SUNRISE project, which aims at designing a lead-cooled research reactor to be built in Oskarshamn by 2030. Eventually, the goal of the collaboration is to enable the commercialisation of new reactors in Sweden in the 2030’s. Through this initiative, Sweden takes a major step towards developing the next-generation passively safe nuclear power technology, know-how and competence.
The most important advantage of using liquid lead as coolant for a nuclear reactor is that it allows designing the reactor in a highly compact format, with an outstanding set of safety features, including:
No violent exothermic reaction with water
A very high boiling temperature, reducing the risk for loss of coolant
An excellent potential for decay heat removal by natural convection
Chemical retention of iodine and caesium, should a fuel failure occur
Inherent shielding of gamma radiation from fission products
Moreover, the use of lead as coolant results in a so called “fast” neutron spectrum, which facilitates production of fissile fuel from U-238 with a conversion ratio larger than unity. Hence, fuel resources increase by two orders of magnitude, making nuclear power sustainable for thousands of years. Moreover, the fast neutron spectrum makes it possible to efficiently transmute the long-lived waste, such as americium and curium, into stable or short-lived fission products, with a minimum of negative side-effects on the safety of reactor and fuel-cycle facilities.
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 3-6 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.
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.
LeadCold is a spin-off from KTH Royal Institute of Technology in Stockholm, where J. Wallenius carried out research on design and safety analysis on lead-cooled reactor systems since 1996. The company was founded in 2013 by J. Wallenius, P. Szakalos and J. Ejenstam as a joint stock company, with its basis in Stockholm.
(Source and image: LeadCold)