The US nuclear weapons program had to do something similar in the 2000's with a material known as Fogbank. This is used in the W76 warhead as an interstage mate

The US nuclear weapons program had to do something similar in the 2000's with a material known as Fogbank. This is used in the W76 warhead as an interstage material, and they needed more of it to keep the weapons in operational state. Unfortunately, they'd forgotten the manufacturing process, decommissioned the plant that made it, and the people that knew how to do it weren't around any more. They figured it out, but it doesn't necessarily look easy to do (nor does the material seem easy at all to make in the first place). https://www.armscontrolwonk.com/archive/201814/fogbank/ https://www.armscontrolwonk.com/archive/201814/fogbank/ p20 here says more: https://www.lanl.gov/science/weapons_journal/wj_pubs/17nwj2_09.pdf https://www.lanl.gov/science/weapons_journal/wj_pubs/17nwj2_... Edit: I somehow missed this other thread in this story, despite a search: https://news.ycombinator.com/item?id=26334367 https://news.ycombinator.com/item?id=26334367