GEOFF BENNETT: While the world is focusing on the controversial radioactive water being released from the damaged Fukushima nuclear plant in Japan, the country itself is grappling with other big questions about its use of nuclear energy.

Japan had dramatically changed its attitudes about nuclear power after Fukushima melted down back in 2011.

But, since then, it's faced its share of problems with other energy sources and prices.

And now the nuclear question is tied up in a debate over energy and security.

Science correspondent Miles O'Brien has the story, the last in his series of stories from Japan.

MILES O'BRIEN: A few miles from the Fukushima fence line, another radioactive contamination story continues to unfold 12 years after the meltdowns.

Here, they are gathering bagged topsoil tainted with radioactive cesium.

It was scraped off the surface all throughout the contaminated region.

I went there with producer Fumiyo Asahi.

The cesium will persist in the soil for 300 years.

So, on the land side, you got the bags.

Towards the sea, you have got the tanks full of water.

It's a mess in both directions.

FUMIYO ASAHI, Producer: I know.

It's everywhere, ocean to the mountains.

MILES O'BRIEN: Many of the towns in the former evacuation zone are still only partially inhabited.

FUMIYO ASAHI: And so this used to be the house.

MILES O'BRIEN: People are reluctant to come back, aren't they, even after 12 years?

FUMIYO ASAHI: Especially young people don't want to come back.

MILES O'BRIEN: The older generation is more inclined to return.

I visited Katsuhiko Nakagawa, who lives nearby in Minamisoma.

When I first met him 12 years ago, he was living in tiny, temporary quarters.

He lost his mother, wife, and eldest son when the tsunami swept his home away.

Today, he's in more spacious permanent housing, where, every day, he prays before a shrine to his lost loved ones.

KATSUHIKO NAKAGAWA, Minamisoma Resident (through translator): For the first couple of years, it was unbearably tough.

These days, I play golf and do other exercises with my friends.

But I have never forgotten those days.

MILES O'BRIEN: No one here has.

The memory of March 11, 2011, is seared in Japan's national psyche.

And it feeds some strong opposition to nuclear power.

Do you think Japan should return to nuclear power?

KATSUHIKO NAKAGAWA (through translator): Well, honestly, I don't want to use nuclear power.

But we can't do anything about that.

MILES O'BRIEN: Before the meltdowns, Japan generated about 30 percent of its electricity with 54 nuclear reactors.

The entire fleet was shut down in the immediate aftermath.

KEN KOYAMA, The Institute of Energy Economics, Japan: We lost that very important contribution of a reliable so-called baseload power supply.

MILES O'BRIEN: Baseload, meaning energy that is online all the time.

Ken Koyama is chief economist and senior managing director at the institute of energy economics, Japan.

That's a big shock to the system, isn't it?

KEN KOYAMA: Exactly.

MILES O'BRIEN: Japan, which has no fossil fuel resources, now generates 70 percent of its power from liquid natural gas and coal imported from Australia, Malaysia, and, despite the Ukraine war, Russia.

It is building new coal-fired power plants.

KEN KOYAMA: If we really want to achieve net zero, we need complete and revolutionary change in overall energy system.

MILES O'BRIEN: Before the Fukushima meltdowns, Japan was aiming to build enough nuclear reactors to meet half of its electricity demand.

Solar and wind were not prioritized.

Shinobu Komatsuzaki is hoping the winds will shift.

She is vice president of Wind Power Energy, founded 20 years ago.

SHINOBU KOMATSUZAKI, Vice President, Wind Power Energy (through translator): We were very interested in global warming.

We felt the problem was imminent.

MILES O'BRIEN: But it's been slow going.

Absent a history of oil extraction, Japan had no lease laws governing structures in the ocean until 2019.

Wind power has just started building 19 turbines offshore.

It's part of a nationwide push to generate 10 gigawatts of wind power by 2030.

SHINOBU KOMATSUZAKI (through translator): In response to the accident, Japanese people's view of energy changed, and utility companies also changed their approach, because they realized they had to change.

MILES O'BRIEN: Since the meltdowns, solar power capacity has increased 18-fold.

Renewables now accounts for about 20 percent of energy production.

As for nuclear, polls now show a slim majority support restarting nuclear plants.

Ten reactors are now generating power after meeting new, stringent safety requirements.

The Japanese government would like to restart 17 more.

YASUTOSHI NISHIMURA, Japanese Minister of Economy, Trade and Industry (through translator): Our policy is to restart nuclear power plants, ensuring their safety and gaining the understanding of the local community.

MILES O'BRIEN: Yasutoshi Nishimura is the minister of economy, trade, and industry.

Japan is vowing to reach carbon neutrality by 2050.

Its ambitious plan focuses on emerging technologies, hydrogen and ammonia as alternative fuels, and carbon capture technology.

It is also exploring newer nuclear power plant designs, small, modular, and alternative fuels and cooling regimes.

YASUTOSHI NISHIMURA (through translator): In cooperation with American companies, we would like to develop safer next-generation nuclear reactors, including small ones.

We need to cross very high technical hurdles.

Innovation is the key.

MILES O'BRIEN: But innovation has its limits here.

Japan is endowed with the third largest geothermal resource in the world.

And yet it only generates less than 1 percent of its electricity this way.

Heated opposition to the idea comes from owners of hot spring resorts like this, called onsen, where bathing in the buff is a requirement.

They fear geothermal wells will dry out their springs and spoil the environment.

And yet, in the onsen resort town of Tsuchiyu, they are proving it can be done with no apparent adverse consequences.

Up the river from the town center, they have built a small 440-kilowatt geothermal power plant.

It's only enough to power about 80 homes and run a small fish farm, but none of the hot springs are diminished.

A tiny system, but the owners hope it is a proof of concept.

Emiko Kato is COO of Genki-up.

EMIKO KATO, COO, Genki Up Tsuchiyu (through translator): The water merely goes through the machine.

So, the volume and quality of water supplied from the hot springs have not been affected at all.

MILES O'BRIEN: Japan needs to be creative and aggressive to increase its energy security and reduce its carbon footprint.

But it would be a tragedy to destroy this to keep the lights on in Tokyo.

For the "PBS NewsHour," I'm Miles O'Brien in Fukushima Prefecture.