Eager to maintain its energy policy in the wake of the 1986 Chernobyl disaster, Japan made sure concerns about nuclear technology were downplayed at the 12th Group of Seven summit it chaired in Tokyo days after the disaster, according to Japanese diplomatic records declassified Wednesday.

References to “radiation” and “concerns” about the nuclear accident that took place in what is now present-day Ukraine were deleted from a draft of the G-7 statement. The final statement instead dubbed nuclear power as “an energy source that will be ever more widely used in the future.”

The declassified records show that Japan worked to build an international consensus on retaining nuclear power even while little was known about the cause of the Chernobyl accident or the scale of the damage.

Missing a chance to thoroughly debate strengthening safety regulations, Japan went ahead with its nuclear power strategy until the March 2011 Fukushima accident, triggered by a huge earthquake and tsunami, exposed what government-appointed investigators and others have dubbed a “safety myth.”

According to a Foreign Ministry official who was involved in the G-7 summit at the time, “There was no awareness in the government or the nuclear industry that Japan’s nuclear plants might be dangerous too, or that we could learn a lesson from (Chernobyl).”

After the nuclear crisis on April 26, 1986, the Soviet Union first publicly acknowledged it on April 29 JST, but released very few details as part of its tight control of information in the midst of the Cold War.

Among the declassified records is a Japanese government “plan to respond to the Soviet nuclear accident,” dated May 1 and marked secret.

The plan centered on “reaffirming the necessity” of nuclear power, while also aiming to set up an international information-sharing system for nuclear accidents.

This plan guided the Japanese delegation at the G-7 summit in Tokyo, which began on May 4, and served as a springboard for the statement adopted there the following day.

According to a document dated May 3, then-Prime Minister Yasuhiro Nakasone had told senior Foreign Ministry officials that “there is great interest in Japan in the ‘ashes of death (radioactive fallout).’ ”

The issue was a particularly sensitive one for the public due to the exposure of fishing boat Fukuryu Maru No. 5, also known as the Lucky Dragon, to radioactive fallout from a U.S. hydrogen bomb test in the Marshall Islands in 1954, as well as the 1945 U.S. atomic bombings of Hiroshima and Nagasaki in World War II.

The ministry later described Nakasone as having “shown initiative” at the summit.

Once the G-7 adopted its statement, Japan’s Agency for Natural Resources and Energy then wrote a memorandum to power companies and local authorities involved with nuclear plants on May 6, explaining that the government would “continue to promote (nuclear power) with a safety-first mindset.”

A note in the margin warned the recipients not to release the contents of the memo to the press.

Earlier, the Foreign Ministry had ordered Japanese embassies across Europe to gather information on the Chernobyl accident, according to a ministry cable dated April 29 in which it was described as something that “could have a grave impact on Japan’s nuclear energy policy.”

The cable also indicates Tokyo was mindful of the accident’s potential to stir up opposition to nuclear power within Japan, including in communities near power plants. It noted that “no marked protest activities have been observed.”

The G-7 then comprised of the United Kingdom, Canada, France, West Germany, Italy, Japan, and the United States.