In the Pacific, Outcry Over Japan’s Plan to Release Fukushima Wastewater

To soothe Pacific concerns, Japanese authorities emphasize that their analysis shows that the wastewater plan is safe. Almost all radioactive particles will be removed from the wastewater before it is released, except for a hydrogen isotope called tritium that Japanese experts and others say poses a relatively low health risk.

“By diluting the tritium/water mixture with regular seawater, the level of radioactivity can be reduced to safe levels comparable to those associated with radiation from granite rocks, bore water, medical imaging, airline travel and certain types of food,” Nigel Marks, a nuclear materials researcher and associate professor at Curtin University, said in a statement distributed by the Australian Science Media Centre.

Mr. Suga pledged to “do our utmost to keep the water far above safety standards.” The Japanese government sees no alternative to the releases other than vaporizing the wastewater, which would be similarly controversial. Storage is becoming difficult as land runs short around the Fukushima plant, whose reactors have been off-line since the earthquake and tsunami in March 2011, which caused a catastrophic electrical failure that led to the meltdown.

Rafael Mariano Grossi, the director general of the International Atomic Energy Agency, has said the plan “​​is in line with practice globally, even though the large amount of water at the Fukushima plant makes it a unique and complex case.”

“The release of wastewater from the Fukushima reactors is an unfortunate necessity,” Brendan Kennedy, a chemistry professor at the University of Sydney, said in the Australian group’s statement. “The volume of contaminated water makes long-term storage of this impractical.”

Other nuclear plants around the world routinely discharge treated wastewater containing tritium. Unlike other common radioactive particles, tritium replaces the hydrogen atoms in water molecules, allowing it to pass unaffected through normal radiation filters. As a result, according to Dr. Kennedy, it is “essentially impossible” to remove.