This section explains Japan’s high-level radioactive waste disposal system, emphasizing vitrification, multi-layer containment, and geological isolation. It corrects common misconceptions by presenting concrete data on radioactive decay over time.

2016-03-16

Japan’s geological disposal system offers even greater safety, as high-level radioactive waste is uniformly dissolved into molten glass at high temperatures, sealed into stainless steel canisters to form vitrified waste, and then placed inside thick containers known as overpacks made of iron or copper before being disposed of underground.
These containers are placed into holes drilled into underground bedrock, and the holes are filled with water-resistant clay that absorbs radioactive materials, providing protection even in the event of a leak.
Opponents often claim that toxicity remains for 100,000 years, but by reprocessing and removing long-lived elements such as plutonium, and converting the waste into compact vitrified forms, high-level radioactive waste is reduced to one-thousandth of its original radioactivity within 40 years.
During the initial 40 years, the waste is stored inside buildings known as interim storage facilities, and such facilities already exist in Aomori Prefecture.
At these facilities, the waste is cooled by air, reducing radioactivity to one-millionth after 3,000 years.
At that point, the radioactivity is only ten times that of the original natural uranium ore.
It reaches a level that can be held safely in one’s hand.
To be continued.