The restart of reactors at the Sendai nuclear power plant in Kagoshima Prefecture appears unlikely before January, as the plant's operator only submitted the necessary documentation to regulators on Tuesday, months later than originally planned.

Kyushu Electric Power Co. submitted roughly 600 pages of documents concerning reactor 1 — one of two reactors at the complex that have obtained safety clearance by the Nuclear Regulation Authority — but that accounts for only a fraction of the operator's 20,000-page construction plan, which needs to be submitted for the plant to be restarted.

Kyushu Electric had originally planned to submit the documentation to the NRA in late May. It plans to submit the remaining documents, including those regarding reactor 2, later this month, company officials said.