Japan is considering evaporating tritium-laced water from the wrecked Fukushima nuclear plant or even storing it underground rather than releasing it into the ocean.
Water flushed over the reactors to keep them cool enough to prevent further radioactive releases is treated to reduce its radioactivity, but current technology can't remove tritium, a relatively harmless radioactive isotope.
The plant’s operator, Tokyo Electric Power (Tepco), has been forced to build hundreds of tanks to hold contaminated and treated water, but now wants to release the tritium-laced water into the ocean, a common practice at normally operating nuclear plants around the world.
But opposition from local fisherman, who are concerned about the impact on consumer confidence, has prompted the government taskforce overseeing the clean-up to look at letting the water evaporate or storing it underground, according to chief decommissioning officer Naohiro Masuda.
Speaking to Reuters at the close of a seminar on decommissioning, Masuda said he didn't know when the discussions would be completed and a decision made.
The evaporation method was used after the Three Mile Island disaster in the USA, but Dale Klein, an outside adviser to Tepco, said the amounts were much smaller
"They have huge volumes of water so they cannot evaporate it like they did at Three Mile Island," Klein said. "If they did it would likely be evaporated, go out over the ocean, condense and fall back as rainwater. There's no safety enhancement."
Missteps and leaks have dogged the efforts to contain the water, slowing down the decades-long process of decommissioning the plant after three reactors underwent meltdowns following an earthquake and tsunami in March 2011.
"They really do need to make a decision," Klein said. "Storing it in all those tanks, you are just asking for failure."