Bryukhanov was summoned to Moscow and attended a turbulent meeting with the Politburo, on 3 July in which the causes of the accident was discussed.[9] In attendance was the RBMK designer Anatoly Alexandrov, Efim Slavsky of the Ministry of Medium Machine Building (Sredmash) and Valery Legasov of the Kurchatov Institute. Bryukhanov was accused of mismanagement and that operator error was the primary cause of the accident, while reactor design flaws were also a factor.[2] Mikhail Gorbachev was furious and accused the nuclear designers of covering up dangerous problems with the Soviet nuclear industry for decades.[2] Following that meeting, Bryukhanov was expelled from the CPSU.[2][10]