Documents obtained by The Okinawa Times show that the United States government had detailed plans for constructing a nuclear power plant in Okinawa Prefecture in the 1960s when it was under U.S rule.

An artist's rendering in a 1960 U.S. government report shows a planned nuclear power plant in Okinawa Prefecture.

According to the plans, the site for the nuclear power plant with two reactors would have been where Okinawa Electric Power Co.’s Kin thermal power plant is now located. The plans call for the first reactor to be completed in December 1963, and the second one in 1965.

The finding comes 10 years after the Great East Japan Earthquake and subsequent tsunami and triple meltdown at the Fukushima No. 1 nuclear plant.

Though it was known that the U.S. had considered building a nuclear plant in Okinawa, it’s the first time detailed plans have been revealed. If the U.S. military, which possessed absolute power over Okinawa at the time, had gone ahead with the plan, Okinawa would have had to live with nuclear plants into the present day.

When fully operational, the two reactors were expected to generate a total of 80,000 kilowatts of electricity. At the time, the planned reactors were estimated to have boosted Okinawa’s total electricity supply by over twofold. Today’s Kin thermal power plant is capable of producing 440,000 kW of electricity.

The interior designs were laid out in the document. Enriched uranium, 14.3-tons per unit, would have fueled both reactors, would have been placed in a steel sphere with a 40-meter diameter. Seawater from Kin Bay was to be used as coolant.

Construction of underground storage for nuclear waste as well as 70-meter-tall chimneys was also part of the scheme.

The original report, “Study of Remote Military Power Applications,” was compiled by Kaiser, a U.S. construction and design firm, in 1960 as a part of a project by the now-defunct U.S. Atomic Energy Commission. As the U.S. Department of Defense designated locations to which the military would be deployed, Kaiser was responsible for planning nuclear plants at each site as well as giving an estimate of the operations’ financial efficiency.

Although Hokkaido was included in an initial 13 possible candidates in and out of the U.S. for a nuclear power plant site, it was left off the list due to its small electricity demand.

Out of the 10 final candidate sites to have been investigated closely, which included the Okinawa plan as well as a plan to build a plant at a military base in South Korea, construction actually materialized in two locations: Greenland and the South Pole, where a small, portable nuclear reactor was installed.

Although the reasons for the cancellation of the nuclear plant construction plan in Okinawa are still unclear, the scale of the project was the largest among the 10 listed sites. Okinawa was also the only place where plans called for construction on private land.

The U.S. government built an oil-fired power plant instead, and it began operation in 1965. The oil plant was decommissioned in 1986, but the coal-fired Kin thermal power plant has been operating on the site since 2002.