The meltdown of the reactors at Fukushima Daichi has changed how many people view the risks of nuclear power, causing countries around the world to revise their plans for further construction and revisit the safety regulations for existing plants. The disaster also gave the world a first-hand view of the challenges of managing accidents in the absence of a functional infrastructure and the costs when those accidents occur in a densely populated, fully developed nation.

Earlier this week, New York's Japan Society hosted a man with a unique perspective on all of this. Naomi Hirose was an executive at Tokyo Electric Power Company (TEPCO) when the meltdown occurred, and he became its CEO while he was struggling to get the recovery under control. Ars attended Hirose's presentation and had the opportunity to interview him. Because the two discussions partly overlapped, we'll include information from both below.

The accident and safety

During his presentation, Hirose noted that the epicenter of 2011's Tōhoku earthquake was only 180 kilometers from Fukushima. But initially, safety protocols kicked in; called a scram, the protocols led to control rods being inserted into the reactors to shut down the nuclear reactions and bring the plant to a halt. Since this had happened previously in response to earthquakes, Hirose said people were feeling confident the situation was under control.

But the earthquake itself had damaged the power lines that fed the plant, leaving it reliant on internal power to run the cooling pumps. And the source of that power was swept away when the tsunami generated by the quake inundated all six of the reactors on the site. This left the plant unable to cool its reactors; several melted down, and the hydrogen they generated ultimately led to explosions that wrecked the buildings that housed them. Hirose suggests that these explosions were likely sparked as things shifted and fell due to aftershocks.

This has led countries around the world to tighten their rules regarding backup equipment and to re-evaluate the infrastructure they assumed would be available to help manage the accident. We also got a chance to ask Hirose about how he viewed the risks of nuclear power after this experience:

We learned that safety culture is very important. We saw that we were probably a little arrogant. We spent a huge amount of money to improve the safety of that plant before the accident. We thought that this was enough. We learned that you never think this is enough. We have to learn many things from all over the world. 9/11 could be some lessons for nuclear power stations—it's not just nuclear accidents in other countries, everything could be a lesson. So we learn: "Do not stop improving the safety." This is a technical matter, a scientific matter, and we can make these risks as small as possible.

Re-establishing control

In the immediate aftermath of the accident, what had gone wrong in some of the reactors wasn't even clear; contaminated groundwater was a massive issue, and a substantial exclusion zone forced the evacuation of thousands of residents nearby. Just to do anything on the site required huge amounts of safety gear.

"[In the] first several years, we didn't have a really clear plan, because it's troubleshooting," Hirose told Ars. "Many, many things took place, so we had to settle down these things. Now the condition of the plant is very stable."

With the stability, one of the first steps chosen was to remove spent fuel, which was stored in elevated tanks in the reactor buildings. Reactor four shut down when the earthquake struck, and more than 1,500 fuel rods have since been safely removed. At reactor three, rubble covering the spent fuel pool has been cleared, and a new roof incorporating a crane has been built, paving the way to remove the spent fuel there.

But the melted-down reactors pose a much larger challenge. "We don't know exactly the condition of the debris, so we developed several different types of robotics and let them go into the reactor building," Hirose told Ars. "Now the robotics are taking movies, collecting all the data—temperature, radioactivity. Now we are planning how to attack, how to go to those debris. So maybe it takes a few more years; it depends on analyzing the situation."

Meanwhile, decontamination work and time have reduced the onsite risk so that workers only need to wear exposure-tracking badges. The area of the exclusion zone with above-background radiation levels has also shrunk considerably.

"There are only two towns left in the evacuation zone—it's getting smaller and smaller and smaller," Hirose said during our interview. "Even those two towns—they are planning to develop a new city hall, new spaces for commercial [activity]. Since it's been 7.5 years already, all the people will not come back. Kids start going to school in the places they went. Each has different situations. But we'd like to have those towns available for everybody. Still, those two towns are prohibited to come back, but we'd like to have that situation cleared."

Bearing the costs

None of this comes cheaply. When we were discussing risks, Hirose acknowledged, "Once there is a serious accident, the costs of these things is enormous. And we understood that, and everybody realized that."

But who carries that cost? In the US, the government steps in once costs exceed $12.6 billion. That's not the case for TEPCO. "Japanese law—it's called nuclear damage compensation law—clarified that no matter what the size of the damages, it's singly the nuclear operator that has all the responsibility without fault. So even if we did [make any] mistake, the operator has to pay. The Price-Anderson Act in the US stipulates the limit in the damage. Maybe we need that kind of limit. It's been discussed in Japan, and it's a really difficult point."

("I mean, we had the accident, so maybe we shouldn't say anything about this," he said at this point.)

In the immediate aftermath of the accident, this pushed TEPCO's finances to a very bad place. Once the site stabilized, so did the costs, but they remain enormous. During his public discussion, Hirose said that they're running at about $5 billion a year, and that's expected to continue for 30 years. "We've made enough for the past three years, but we have to do it for 27 more," Hirose told the audience. That will fundamentally limit the actions the company can take for the next several decades.

Japan’s future

What's that energy economy going to look like? Prior to Fukushima, Hirose was a big advocate of increasing electrification of energy use. He brought that up in our discussion as well.

Electrification definitely will expand—like electric vehicles and heat-pump technology. Those things are much, much more efficient compared to combustion engines or conventional heating systems. Electric vehicles are very efficient, so they don't use a lot of electricity. Based on our calculations, even if all the automobiles turn into electric vehicles in the Tokyo area, our demand for electricity only goes up 15 percent or so. So it's not a big, big potential transition. And still, the total energy consumption would decline very, very much, because we don't use any gasoline. And if that electricity is provided by renewables or nuclear, carbon dioxide would decrease dramatically. I think electrification is one of the things that will decrease the total demand for energy. It's just how to generate that amount of electricity, which depends on if it's nuclear, solar, wind... Electrification and decarbonization are the two key things.

Any increased demand due to electrification, however, will take place against a general decline in energy use in Japan. While already a very efficient society, the Japanese managed to curtail energy use even further as all of the country's nuclear plants were shut down in the wake of Fukushima. "Have you been to Tokyo? Shops are very bright, very, um, shining with lights. It's gorgeous—maybe you need sunglasses," Hirose suggested. "But people started thinking that maybe that was too much."

Critically, what might have been temporary measures have produced what appear to be permanent changes. "The consumption of electricity has not come back yet," Hirose told Ars. "Maybe it never will, because the population of Japan is declining. I don't know if in the long term the demand for electricity goes up."

Still, the country will need to continue to produce electricity while decarbonizing its grid to meet international agreements. And the government's plans for doing so include continued use of nuclear power. "The Japanese government set a target: 20-22 percent is generated by nuclear in 2030," Hirose said. "In order to keep this number, we need to develop new nuclear power. So far, all the electric power companies and operators focus on the restart of the already existing nuclear power plants. Everybody is not in the mood to build a new one, because they are busy handling the restart of the existing plants."

If the new plants are ever built, Japan will get the chance to see if it can avoid the massive cost overruns that have plagued projects elsewhere.

But that's a very large if, and during Hirose's presentation, an audience member pointed out that more than 60 percent of the Japanese population would like to see the country eliminate nuclear power. Other low-carbon sources, however, face significant hurdles in Japan. "Solar is very popular. Wind is possible, particularly offshore wind. But the Japanese Sea suddenly becomes deep, so it's not like Northern Europe," Hirose told Ars. "It's a little technically difficult. Geothermal is very possible. Unfortunately, all the possible places are in national parks or hot-spring towns, so there aren't many good places. But technically, it's possible."

All of which leaves Japan's long-term energy future unsettled. But, in the immediate future, attention will remain on the restart of the existing nuclear power plants and the identification of the melted fuel on the floor of the remaining reactors.