Are there any spaceships with nuclei on the earth? Why?

There are spaceships with nuclei on the earth. Spacecraft (thought of rapid exhaust: explosion, high efficiency, as mentioned in the title, nuclear power. Controlled nuclear fusion is not considered here for the time being, because there is no essential difference between recoil caused by stable nuclear fusion and space nuclear explosion. We will load 300,000-ton hydrogen bombs on 3/4 of the spacecraft. Firecrackers are detonated one by one behind the ship's butt, and within one month, we can reach the speed of light of 10%. In 40 years, it will reach Alpha Centauri. But this is based on the fact that we don't need to slow down, but we can't suddenly brake at 10%! So we need to reserve nuclear bombs to slow down, so we need a lot of magazines and a certain amount of time to slow down.