Five Rosatom staff members died and a further three people were injured in a tragic accident that took place during tests on a liquid propulsion system involving isotopes at a military facility in Arkhangelsk region. 
We offer our deepest condolences, and all possible support, to the families and friends of those who died. Those injured have been admitted to hospital and are receiving treatment. 
Our thoughts are with the loved ones of all those affected.
Source: Communications Department of Rosatom