On the 14th June 1958 the first nuclear reactor in Poland Was launched. EWA (Experimental, Water, Atomic) begun its work in the Institute for Nuclear Research, created three years prior (predecessor of NCBJ). The reactor Was bought from USSR and its construction assumed thermal power of 2 MW and thermal neutrons’ flux density of 2*10¹³ neutrons/s*cm². The core of the reactor Was placed in an aluminum container filled with cooling water. On full capacity it could contain nearly 800 fuel rods, each one enriched to 10% U-235. In the core there were also 9 control and emergency rods and surrounding the core were 8 vertical channels used for production of radioactive isotopes. The reactor shielding Was fitted with 10 horizontal channels used for physics research. In the later years EWA Was renovated. It has now been shut down for over 20 years and its installations are being partially decommissioned. Nowadays the reactor building complex houses Radioactive Waste Management Plant.