english: It's between two isotopes of hydrogen, two kinds of hydrogen: deuterium, which is heavy hydrogen, which you can get from seawater, and tritium which is super-heavy hydrogen.
non_english: Ona se odvija između dva izotopa vodonika, dve vrste vodonika, deuterijuma, koji je težak vodonik, koji se dobija iz morske vode, i tritijuma koji je super teški vodonik.