Answer:
Chernobyl nuclear reactor
Step-by-step explanation:
Reactor number 4 was the Soviet Union's proudest technological advancements because it consists of a nuclear reactor of the RBMK-1000 design. The RBMK-1000 was a Soviet-designed nuclear reactor with graphite modified pressure tube type reactor, using uranium dioxide fuel. Chernobyl nuclear power plant was one of the technology advancement for the Soviet to show to the rest of the world especially the United States when both nations were fighting to be a world power.