Jared Harris Valery Legasov Actor Stellan Skarsgård Boris Shcherbina Actor Emily Watson Ulana Khomyuk Actor Paul Ritter Anatoly Dyatlov Actor Jessie Buckley Lyudmilla Ignatenko Actor Adrian Rawlins Nikolai Fomin Actor Con O'Neill Viktor Bryukhanov Actor Sam Troughton Akimov Actor Ralph Ineson General Tarakanov Actor Mark Lewis Jones General Pikalov Actor David Dencik Gorbachev Actor Craig Mazin Executive Producer, Writer Carolyn Strauss Executive Producer Jane Featherstone Executive Producer Johan Renck Director