 With the mission to "make something with neutrons", the Swedish team, with scientists like Rolf Maximilian Sievert, set out to research the subject and eventually build a nuclear reactor for testing.After a few years of basic research, they started building a 300 kW (later expanded to 1 MW) reactor, named "Reaktor 1" ("R1"), in a reactor hall 25 meters under the surface right underneath KTH.Today this might seem ill-considered, since approximately 40,000 people lived within a 1 km radius.