I hope this source is ok I just found it quickly on google:
http://www.neonnettle.com/news/3763-top-uranium-one-executive-killed-in-russian-plane-crash
‘Ivanov Vyacheslav, the top CFO of Rosatom/RuaniumOne, amongst the dead.’
‘Sergei Millian, a Belarus-born businessman who worked with the Trump Organization, was allegedly the key source in the dossier which claimed ties between Donald Trump and Russia.
Really? The only person I could find with that name is this guy who died in October 2017 and I couldn’t find his name connected or associated with Uranium One or “Rosatom/RuaniumOne”.
https://en.wikipedia.org/wiki/Vyacheslav_Ivanov_(philologist)
http://www.rosatom.ru/en/about-us/governance/management-board/