"The pain, struggles, and bravery of the people affected by the incident still continue," said Greenpeace E.U. "We should never forget them, nor allow another disaster like this to happen again."

"Instead of putting Diablo Canyon back on life support, dependent on a drip of taxpayer subsidies, California should turn a new leaf and lean into building the electric system of the future," said one campaigner.

Keeping Diablo Creek open is "the riskiest pathway to deepen California's commitment to fighting climate change while supplying reliable energy," said Friends of the Earth.

The discharge could release a number of radioactive isotopes into the Pacific Ocean, critics say.

Over two million homes in the Tokyo region were left without power.

Some of the plaintiffs in the newly filed case "have even given up on their dreams for their future," said one of their lawyers.

South Korea has said the release of the radioactive wastewater poses a "grave threat" to marine life.

"The decision is particularly disappointing as experts believe alternative solutions to the problem are available," said the three special rapporteurs.