Nuclear Waste Storage: Lessons from Japan

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Nuclear Waste Storage Lessons from Japan Fukushima Daiichi22 March 2011

The stricken Fukushima Daiichi nuclear power plant in Japan was stacked high with more uranium than it was originally designed to hold and had repeatedly missed mandatory safety checks over the past decade according to a Reuters special report.

The nuclear plant had become a growing depot for spent fuel in a way the American engineers who designed the reactors 50 years earlier had never envisioned, according to company documents and outside experts.

At the time of the March 11 earthquake, Reuters says that the reactor buildings at Fukushima held the equivalent of almost six years of the highly radioactive uranium fuel rods produced by the plant, according to a presentation by Tokyo Electric Power Co to a conference organized by the International Atomic Energy Agency.

The cascade of safety-related failures at the Fukushima plant is already strengthening the hand of reformers who argue that Japan's nuclear power industry will have to see sweeping changes from the top.

"I've long thought that the whole system is crap," said Taro Kono, a Liberal Democratic Party lawmaker and a longtime critic of nuclear power who sees the need for a government-directed reorganization of Tokyo Electric.

"We have to go through our whole nuclear strategy after this," Kono said. "Now no one is going to accept nuclear waste in their backyards. You can have an earthquake and have radioactive material under your house. We're going to have a real debate on this."

According to Reuters, the company's records show that when the quake hit almost 4000 uranium fuel assemblies were stored in deep pools of circulating water built into the highest floor of the Fukushima reactor buildings. Each assembly stands about 3.5 meters high and even a decade after use emits enough radiation to kill a person standing nearby.

The spent radioactive fuel stored in the reactors represented more than three times the amount of radioactive material normally held in the active cores of the six reactors at the complex, according to Tokyo Electric briefings and its presentation to the IAEA.

The build-up of used fuel rods in the Fukushima reactor buildings has complicated the response to the continuing crisis at the complex and deepened its severity, officials and experts have said.

That has been especially the case at the No. 4 reactor, which was out of service at the time of the quake and had some 548, still-hot fuel assemblies cooling in a pool of water on its upper floor, and has erupted into flames twice.

David Lochbaum, a nuclear engineer with the U.S.-based Union of Concerned Scientists, said the spent fuel was vulnerable because it was protected only by the relatively "flimsy" outer shell of the reactors and reliant on a single, pump-driven cooling system.

"It's a recipe for disaster and that disaster is now unfolding in Japan," Lochbaum said.

The pile-up of used radioactive fuel stored at Fukushima underscores a dilemma that the nuclear power industry has faced in Japan and in the United States for decades: there is no easy answer to the question of where to store radioactive nuclear waste.

japan nuclear wasteA Global Issue

In the United States, industry planners had once assumed that spent fuel rods would be moved to the Yucca Mountain Repository in Nevada. But political opposition in that fast-growing state helped put the plan on hold, meaning spent fuel has largely piled up in on-site cooling ponds.

"We have no plan for the back end of the (nuclear) fuel cycle, and we need one," said Allison Macfarlane, a professor at George Mason University in Virginia, who serves on a U.S. government panel studying the problem.

"When those plans changed, we just filled the pools up to capacity without ever rethinking whether we should provide better safety or barriers," he said.

The Japan nuclear crisis has raised concern for U.S. officials because of the areas where safety practices overlap. By contrast, Germany, for example, has relied more heavily on storage of spent fuel in casks that can be hardened against attack or accidents with concrete.

More than 60% of the uranium stored at Fukushima Daiichi made it through the quake and tsunami without being destabilized because it was kept in a separate pool built in 1997 and in a number of metal casks that do not rely on outside power, Japanese nuclear safety officials said.

But the location of the remaining fuel storage pools - on the highest floor of the reactor buildings - exposed the fuel to additional risks because the pools would have swayed more in the quake and could have lost water through sloshing or leaks, experts say.

According to the Reuters report, one of problems limiting the wider use of the dry storage units is their upfront costs: each cask costs about $1 million or more.

Critics say the costs are roughly comparable with cooling pools over the long run but require initial capital spending that can be a tougher sell to management and shareholders.

About 23 U.S. reactors share the same General Electric "Mark 1" design as the Fukushima Daiichi reactors, which date back to 1971.

"When the plants were originally designed, it was thought that the spent fuel would remain on the sites only two or three months after they came out of the reactor during a refueling outage and then the fuel would be shipped offsite for reprocessing or disposal," added Lochbaum.

         

            

         

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