The Tokyo Electric Power Co (TEPCO) said the danger of another hydrogen explosion, like the one that blew the roof and upper walls off the reactor building in March, was “extremely low.” But it warned that more hydrogen could build up in the damaged reactor and that it planned a similar procedure for reactors 2 and 3.
Hydrogen buildup is a symptom of overheated fuel rods in the cores of the reactors, Bellona nuclear physicist Nils Bøhmer, said, which plant workers have been struggling to keep under control since the March 11 earthquake and tsunami. The nitrogen injections are aimed at displacing oxygen in the reactor shell, reducing the possibility of an explosion.
In addition the hydrogen explosion at reactor No 1, reactor No 3’s building – which burns mixed plutonium and uranium, or MOX, fuel, also was blown apart in a hydrogen explosion that is though to have ruptured its containment vessel on March 14. Hydrogen is also believed to be the cause of the explosion at reactor No 2 the following day.
In Bangkok, discussions of scraping nuclear plants, which emit no greenhouse gases blamed for global warming ran up hard against arguments that such a move would force nations to turn to fossil fuels that are the main cause of climate change.
Nuclear vs fossil fuels a red herring
But environmental activists say the tragedy could provide an opportunity to strike a decisive blow against both.
“It’s a false choice to give the public an alternative between a climate change disaster or a nuclear disaster. We need renewable energy,” Tove Maria Ryding of the environmental group Greenpeace told the Associated Press. “Now, we can either have a kick back or a leap forward.”
Christiana Figueres, the UN’s top climate change official, said that all countries are reviewing nuclear policies in the wake of Japan’s crisis.
“It remains to be seen what they decide,” she said at the173-nation conference running through Friday in Bangkok. The gathering aims to build on a climate summit held last December in Cancun, Mexico
In Japan, climate negotiators expect a greater, short-term reliance on fossil fuels to fill the nuclear power gap and are concerned the country could reduce its pledge to cut emissions by 2020 – from 25 percent down to 20 percent.
But Prime Minister Naoto Kan said alternative new energy would become “a major pillar” after the Fukushima accident.
“Taking this as a lesson, we will lead the world in clean energy such as solar and biomass, as we take a step toward resurrection,” he told Japanese lawmakers.
Containing radioactive water – can Russia help?
TEPCO and Japanese regulators believe reactor No 2 is the source of the highly contaminated water they are now struggling to contain at Fukushima Daiichi, 240 kilometers north of Tokyo. Plant workers are pouring 8 tons of water into that reactor every hour to keep it cool, and the water that flows out carries extremely high concentrations of radioactive particles.
That highly radioactive fluid is building up in the turbine plant and the service tunnels around the unit, leaving Japanese officials grasping for ways to contain it.
Japan is currently consulting with Russian’ state nuclear corporation Rosatom on whether an aboard ship decontamination plant on a vessel called the Suzeran, has the capability of dealing with this wastewater. Japan, however, has not yet broght the vessels into the struggle, said Tomosaburo Esaki, an official with Japan’s Foreign Ministry, according to CNN.
The Suzeran was built by Japan in the 1990s to help Russia take aging submarines out of service and was designed to process up to 35 tons of radioactive waste a day and can store up to 800 tons
Sergey Novikov, a Rosatom spokesman, told Bellona Web that, “The ball is now in their court.”
“We have responded to their questions regarding the plant, and they sent us their additional questions, to which we responded as well,” Novikov said. “They are still studying this issue, and we hope to hear from them soon.”
Prior to Wednesday, some of the water pooled in reactor No 2 water had been gushing out into the Pacific Ocean through a cracked utility shaft behind the plant. On Saturday, the day the leak was discovered, concentrations of the reactor byproduct iodine-131 in seawater next to the shaft was as 7.5 million times higher than the legal limit, according to sampling data taken by the utility.
Plugged leak at reactor No 2 could cause other leaks
The leak has been plugged for the time being by sealing the shaft with silica-based polymer called “liquid glass,” which only showed signs of working yesterday. An attempt to stop the leak by dumping concrete into the shaft had failed. Bellona’s Bøhmer said the polymer plug will only last for some time, and the problem will have to be addressed on a more permanent level later.
Hidehiko Nishiyama, a spokesman for Japan’s Nuclear and Industrial Safety Agency, said Wednesday that the now-contained water “may lead to more leakage somewhere else,” and the utility said Thursday that the water level in a service tunnel leading out of the reacto’s turbine plant had gone up about 2 cm since the leak was plugged.
The levels of radioactivity in the water in the shaft measure 1000 millisieverts, some 330 times what someone living in an industrialized nation is exposed to per year.
Those levels prompted Japanese authorities to start dumping nearly 11,500 tons of less-radioactive water into the Pacific on Monday night, largely to make room in a waste treatment reservoir for the No. 2 reactor coolant. The water being dumped is said by Yukio Adano, Japan’s Chief Cabinet Secretary, to contain 1/200,000ths of the amount of radiation that was belching from reactor No 2, but that is still 100 times over Japan’s legal limit.
Pooled water that resulted from aerial and ground dumps of water on the overheating reactors was also dumped into the sea from reactor Nos 3, 4, 5 and 6.
The move enraged the country’s fishing industry and drew protests from neighboring South Korea, but Japan’s government called it an emergency move to prevent a worse discharge.
Water ‘screaming with radioactivity’ must be contained
“They have to be injecting water,” said Michael Friedlander, a former senior operator at U S nuclear power plants. “They have to keep the core covered. And I can tell you, you do not want to take that water out of containment right now, because it’s screaming with radioactivity and you have absolutely no capabilities whatsoever to process it.”
How will the world view nuclear as a climate friendly energy?
Before the March 11 9.0 magnitude eathwuake tsunami ravaged Japan’s Fukushima Daiichi plant, the Paris-based International Energy Agency had estimated that nuclear plants would add 360 gigawatts of generating capacity to the global inventory by 2035.
After the accident, that projection has been cut in half, agency chief economist Fatih Birol told AP, citing the pressure to halt new nuclear plants and phase out older ones sooner than planned.
Experts gathered in Bangkok are wondering whether countries really will slash nuclear power as much as their initial reactions to the Fukushima tragedy suggest, and if so, whether they will they speed toward renewables or simply burn more coal.
Greenpeace’s Ryding said she is concerned that several governments, already backtracking on earlier pledges to reduce emissions, may use Fukushima as an argument to do even less.
Plans including nuclear power are hardly uniform around the globe, where there are currently 507 nuclear power plants in operation or under construction and where oil, coal and gas still provide the bulk of energy in most countries.
China looks poised to provide some 70 percent of its energy from clean sources, and may also scale back its nuclear program in light of the Japan emergency, Chinese climate envoy Xie Zhenhua told reporters.
US President Barack Obama has defended nuclear energy, but also strongly supports development of solar cells, clean coal and biofuel technology.
The most dramatic developments are likely to occur in Western Europe. Germany had planned to phase out nuclear power over 25 years. But the Fukushima crisis – which Chancellor Angela Merkel called a “catastrophe of apocalyptic dimensions” – has accelerated those plans.
The government almost immediately took seven of its 17 reactors offline for three months of safety checks. Most of Germany’s leaders now seem determined to swiftly abolish nuclear power, possibly by 2020, and are willing to pay for intensive development of renewable energy, already a major industry in Germany.
The country currently gets 23 percent of its energy from nuclear power – about as much as the U.S. Germany’s Environment Ministry says that in 10 years, renewable energy will account for 40 percent.
That kind of plan would not work for countries such as France, which relies on nuclear for 70 percent of its power and has no intention of shifting, but could provide a map for other countries, activists say.
Sven Teske, Greenpeace’s renewable energy director, told AP that Germany was able to fill its energy gap left by idled nuclear plants with wind and solar power, though it has had to import some energy from nuclear-reliant neighbors.
“Switching to renewable is a matter of years, not decades,” Teske said.
The International Panel on Climate Change, a scientific body set up by the UN and winner of a Nobel Peace Prize, says a global phase-out of nuclear power plants is feasible at moderate costs and without taking away from climate change efforts.
Artur Runge-Metzger, a European Union climate change official in Bangkok, said the issue is often seen in terms of “two kinds of evils.”
“On the one hand you say we can’t use nuclear energy because we might have nuclear disasters, but everybody at the table is also saying if we have climate change it is also going to lead to disaster,” he said. “So we have to find a way forward.”