In the RBMK reactor design, the lower part of each control rod was made of graphite and was 1.3 metres shorter than necessary, and in the space beneath the rods were hollow channels filled with water.
No deseño do reactor RBMK, a parte inferior de cada barra de control estaba feita de grafito e eran 1,3 metros máis curtas do preciso, e no espazo debaixo das mesmas había canles ocas cheas de auga.