"K-19" refers to the Soviet submarine K-19, which was launched in 1959 and became known for a significant nuclear accident in 1961. The submarine was part of the Soviet Navy and was designed to carry ballistic missiles. During a mission, a cooling system failure led to a radiation leak, putting the crew's lives at risk. The incident on K-19 is often highlighted in discussions about nuclear safety and military operations during the Cold War. The submarine's story was later dramatized in the 2002 film "K-19: The Widowmaker," which depicted the crew's struggle to contain the crisis and prevent a catastrophic disaster.