Complex sentence: Electromagnetic uranium enrichment was abandoned in the post-war period in favor of the more complicated, but more efficient, gaseous diffusion method, but calutrons remained in use to produce isotopically enriched samples of naturally occurring elements for military, scientific and medical purposes.
Split into simpler sentences: Electromagnetic uranium enrichment was abandoned in the post-war period in favor of the more complicated, but more efficient, gaseous diffusion method. Some of the calutrons of the Manhattan Project remained in use after the war to produce isotopically enriched samples of naturally occurring elements for military, scientific and medical purposes.