How dangerous is the Fukushima nuclear bomb plant today?

OKUMA, Japan (AP) – Ten years ago, a massive tsunami hit the Fukushima Daiichi nuclear power plant. Three of its reactors have been melted down, making it look like a bombed-out factory. Emergency workers risked their lives to prevent one of the worst nuclear crises in history from escalating.

The right equipment has now taken the place of frayed plastic hoses held together with tape and a rat-infested outdoor power switchboard, causing blackouts. Radiation levels have decreased, allowing workers and visitors to wear regular clothing and surgical masks in most areas.

But there is still danger deep in the plant. Officials aren’t sure how long the clean-up will take, whether it will be successful, and what could happen to the land where the plant is located.

Journalists from The Associated Press recently visited the plant to document the progress of the cleanup on the 10th anniversary of the meltdowns and the challenges ahead.

WHAT HAPPENED 10 YEARS AGO?

After a magnitude 9.0 earthquake on March 11, 2011, a 17-meter-high tsunami hit the coastal power plant, destroying the power supply and cooling system and collapsing reactors No. 1, 2 and 3.

The plant’s three other reactors were offline and survived, although a fourth building, along with two of the three molten reactors, had hydrogen explosions, which spewed out massive radiation and caused long-term pollution in the area.

The plant’s operator, Tokyo Electric Power Co., says the tsunami could not have been expected, but government reports and independent investigations and recent court rulings describe the plant disaster as man-made and the result of negligence and lax supervision. by regulators and collusion.

WHAT’S IN THE MOLTEN REACTORS?

About 900 tons of molten fuel remain in the three damaged reactors, and removing it is a daunting task that officials say will take 30-40 years. Critics say that’s overly optimistic.

Separate efforts to remove spent fuel from cooling pools in the reactor buildings have been hampered by high radiation and debris and have been delayed by up to five years. If the plant’s pools lose their cooling water in another major earthquake, exposed fuel rods can quickly overheat and cause an even worse meltdown.

The molten cores in units 1, 2 and 3 usually fell to the bottom of their primary containment vessels, some penetrated and mixed with the concrete foundation, making removal extremely difficult.

Remote-controlled robots with cameras have only given a limited view of the molten fuel in areas that are still too dangerous for humans.

Plant head Akira Ono says the inability to see what is happening in the reactors means details about the molten fuel are still largely unknown.

ARE THERE UNDERGROUND LEAKS?

Since the disaster, contaminated cooling water has been continuously escaping from the damaged primary containment vessels to the basements of the reactor building, where it mixes with the groundwater that seeps in. The water is pumped up and treated. Some of it is recycled as cooling water, the rest is stored in 1000 huge tanks that displace the factory.

Early in the crisis, highly polluted water leaks from damaged basements and maintenance ditches into the ocean, but major leak points have been closed, TEPCO says. Tons of contaminated sandbags used to plug the leaks at the start of the disaster remain in two basements.

Small amounts of radiation have continued to leak into the sea and elsewhere through underground passages, although the amount today is small and fish caught offshore is safe to eat, scientists say.

WHAT HAPPENS WITH THE STORED RADIOACTIVE WATER?

The 1,000 tanks filled with treated but still radioactive water tower over workers and visitors to the factory.

TEPCO says the 1.37 million tonne storage capacity of the tanks will be full by 2022. A government panel’s recommendation to discharge the water into the sea has met fierce opposition from local residents, particularly fishermen concerned about further damage to the area’s reputation. A decision on that recommendation is pending.

TEPCO and government officials say that tritium, which is not harmful in small amounts, cannot be removed from the water, but any other isotopes selected for treatment can be reduced to safe levels for release.

TEPCO has managed to reduce the amount of polluted water to a third of what it was through a series of measures.

HOW IS IT TO VISIT THE INSTALLATION?

The first thing visitors see is a stylish office building with the TEPCO decommissioning unit.

In another building, factory workers – now about 4,000 a day – undergo automated security checks and radiation measurements.

Because radiation levels have dropped significantly after decontamination, full protection equipment is only required in a few places in the plant, including in and around the molten reactor buildings.

On a recent visit, AP journalists donned partial protective gear to tour a low-radiation area: a helmet, double socks, cotton gloves, surgical masks, goggles, and a vest with a personal dosimeter.

Full protective equipment, i.e., hazmat overalls, full face mask, headgear, triple socks and double rubber gloves, was required at a shared storage pool where fuel transfer from No. 3 reactor pool was recently completed.

WHAT IS THE END GAME?

A decade after the accident, Japan has no plan to dispose of the highly radioactive molten fuel, debris and waste at the plant. The technology is also not yet advanced enough to manage waste by reducing its toxicity.

TEPCO says it should remove the water storage tanks to free up space at the plant so workers can build facilities that will be used to study and store molten fuel and other debris.

There are approximately 500,000 tons of solid radioactive waste, including contaminated debris and soil, sludge from water treatment, discarded tanks and other waste.

It is unclear what the plant will look like when the work is done. Local officials and residents say they expect the complex to one day be an open space where they can walk around freely. But there is no clear idea if or when that can happen.

Tokyo correspondent Mari Yamaguchi has visited the Fukushima nuclear power plant nine times, starting in 2012.