Little waste and no radiation, enter Helium-3 at $3B per metric ton
https://www.x-mol.com/paper/1261391243220459520
https://www.ph.ed.ac.uk/news/2020/helium-ammonia-compounds-predicted-20-05-14
https://onlinelibrary.wiley.com/doi/abs/10.1002/adts.202000008
https://www.bauer-kompressoren.de/fileadmin/documents/products/industry/Helium-Recovery_EN.pdf