After the city was evacuated, what did the Soviet Union use to seal off the reactor and attempt to contain radiation?
Bulldozers
O Airplanes
O Helicopters
O Tanks

Evacuation in the Soviet Union was the mass migration of western Soviet citizens and its industries eastward as a result of Operation Barbarossa, the German military invasion of June 1941. Nearly sixteen million Soviet civilians and over 1,500 large factories were moved to areas in the middle or eastern part of the country by the end of 1941.[1] Along with the eastern exodus of civilians and industries, other unintended consequences of the German advances saw the execution of previously held western state civilians by Soviet NKVD units,[citation needed] the removal of Lenin's body from Moscow to Tyumen, and the relocation of the Hermitage Museum collection to Sverdlovsk, Kuybyshev, the alternative capital of the Soviet Union 1941-1943. Soviet towns and cities inland or in the east received the bulk of the new refugees and high priority war factories, as locations such as the Siberian city of Novosibirsk, received more than 140,000 refugees and many factories due to its location away from the front lines. Despite early German successes in seizing control of large swaths of the western USSR throughout 1943, and semi-prepared contingency plans by the Soviets in their mobilization plans to the east, Soviet industries would eventually outpace the Germans in arms production, culminating in 73,000 tanks, 82,000 aircraft and nearly 324,000 artillery pieces being dispersed throughout the Red Army in their fight against the Axis Powers by 1945.[2]