Japan’s Nuclear Regulation Authority Chairman Shunichi Tanaka summoned Tokyo Electric Power Co. (TEPCO) President Naomi Hirose to express concerns about growing problems at the crippled Fukushima plant. Human error is mostly to blame for the recent mishaps, as workers deal with a string of crises, AP reported. Hirose acknowledged that TEPCO is having trouble finding a stable pool of workers at the plant, but promised to send more staff from other locations to Fukushima.