Sergei Belyakov, a scientist who helped clean up debris after the Chernobyl disaster in 1986, is worried about Japanese workers now risking their lives to contain the aftermath of core meltdowns at the Fukushima No. 1 nuclear plant.

"I really feel sorry for the situation in Fukushima, honestly," the 55-year-old "jumper" in Chernobyl said.

Jumpers were the workers who risked their lives by "jumping" into highly contaminated zones at the damaged nuclear station in Chernobyl, rarely spending more than seconds in the danger zone before jumping back out to safety.