Tepco’s recent decision to decommission its Fukushima No. 2 nuclear power plant highlights one of the big challenges for both the power industry and the government — which has pushed for nuclear power as a matter of state policy — in the wake of the 2011 Fukushima nuclear disaster. Combined with the Fukushima No. 1 plant where three reactors suffered catastrophic meltdowns more than eight years ago, Tokyo Electric Power Company Holdings Inc. now faces an unprecedented job of scrapping 10 reactors at around the same time, an effort that is estimated to take more than 40 years.

Decommissioning a nuclear plant takes so long it extends across generations, and the operator needs to train and secure people with the needed skills and technology to sustain the work through to completion. The decommissioning of Fukushima No. 1 entails the extra tasks of removing the melted fuel debris from reactor containment vessels as well as disposing of enormous amounts of contaminated water.

How and where to finally dispose of the large volume of radioactive waste from the decommissioned plants is a question for which the nation still does not have a clear answer. Steadily and safely scrapping reactors in large numbers is a challenge that must be taken on not just by the power companies that ran them, but the government as well.

Tepco’s Fukushima No. 2 facility, about 12 km from the No. 1 plant, has four reactors. Each is capable of generating 1.1 million kilowatts of electricity for the Tokyo metropolitan area. Unlike the No. 1 plant, Fukushima No. 2 survived the onslaught of tsunami in the March 2011 Great East Japan Earthquake. Three of its four reactors temporarily lost their core cooling functions when the plant was flooded by the tsunami, but eventually they were safely shut down.

That did not stop the Fukushima Prefectural Government and the No. 2 plant’s host municipalities of Naraha and Tomioka from calling for its decommissioning since immediately after the 2011 disaster, arguing that its continuing operation would hinder reconstruction efforts in areas affected by the nuclear crisis.

But it was only in June last year that Tepco indicated its intention to decommission the No. 2 plant — and the final decision was made last month. Tepco reportedly explored the possibility of restarting the No. 2 plant, which has remained offline since 2011, as a way to save on imported fuel costs to run thermal power plants and rebuild the company’s finances. It’s questionable whether it was wise to hold off on the decision for so long: Given the huge impact the nuclear disaster has had on local people, there was little chance that the prefecture or the host towns would give their consent to restarting the No. 2 plant.

To date, 24 commercial reactors have been earmarked for decommissioning, including the four at Fukushima No. 2. Before the nuclear crisis, 54 reactors were operating nationwide. Three reactors had been selected for demolition before 3/11, meaning that 21 — roughly 40 percent of the total — were chosen to face the wrecking ball after the disaster. Aside from the 10 reactors at Tepco’s Fukushima No. 1 and No. 2 plants, the decisions by the plant operators were influenced mainly by economic calculations.

Rules introduced after the Fukushima disaster limited the lifetime of reactors to 40 years after construction — but that can be extended by up to 20 years. Safety regulations introduced by the Nuclear Regulation Authority post-3/11 require power companies to make massive investments to ramp up measures against accidents and natural disasters such as major earthquakes and tsunami before they can reactivate reactors idled in the wake of the 2011 accident.

Seeking the NRA’s approval to extend a reactor’s operation beyond the 40-year limit also requires the owner to make additional safety investments. The power companies have decided to decommission many of their aging reactors that had relatively small output capacity when they determined they couldn’t recoup the cost of such investments even if they extended the reactor’s operation.

While the total expense of decommissioning the Fukushima No. 1 plant is expected to reach ¥8 trillion, scrapping the No. 2 plant is projected to cost ¥400 billion, although that amount does not include the cost of building a storage facility there to store more than 10,000 spent fuel assemblies.

While Tepco has promised to take all of the No. 2 plant’s spent fuel out of Fukushima Prefecture before the plant’s decommissioning is completed — which it expects to take more than 40 years — it is not clear where the company eventually plans to ship the fuel assemblies.

Decommissioning is an integral part of a nuclear plant’s life cycle. Uncertainties linger over some elements of the work involved, such as the disposal of highly radioactive waste. It remains to be tested whether Tepco, still under reconstruction from the impact of the 2011 disaster, has the manpower and resources to take on the hard task of scrapping 10 reactors more or less simultaneously.

The government needs to explore what steps it can take to ensure that the decommissioning of large numbers of nuclear reactors will proceed steadily and safely.

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