PARIS (AFP) — Nuclear power is responsible for 10 percent of the world's electricity production, but it remains a controversial source of energy, a decade after the tsunami that triggered the Fukushima nuclear crisis.

Here is a look at the state of nuclear energy around the world: 

Fewer reactors

"It was an industry in serious crisis globally before the Fukushima events happened. This crisis has worsened considerably since then," said Mycle Schneider, an independent analyst and consultant on energy and nuclear policy based in Paris.

The high costs of construction and concerns about safety have cooled interest in the industry.

The number of nuclear reactors has receded in the past decade, from 429 in 2010 to 412 at the end of last year, according to Schneider, author of an annual report critical of the sector.

But energy generation has increased, from 365.3 gigawatts in 2010 to 367.1 in 2020, as new reactors tend to be more powerful while older facilities were upgraded.

China power, Germany out

Germany decided to abandon nuclear power by 2022 following the Fukushima disaster.

Belgium and Switzerland also plan to phase out of nuclear power. 

But other countries are planning to develop the sector, with China at the centre of new projects.

The world's second largest economy is home of 25 of the 57 reactors under construction around the world in the past decade, but even China's plans have been affected by Fukushima.

"(Fukushima) deeply shocked policymakers in China, and this led to — if not a brutal halt — a considerable slowdown of nuclear ambitions in China," Schneider said.

Elsewhere, Bangladesh, Belarus, the United Arab Emirates and Turkey have launched nuclear projects.

Poland, which still relies on highly-polluting coal energy, wants to get into atomic power.

Cost and benefits

In addition to concerns about safety and the disposal of nuclear waste, the nuclear industry is facing growing competition from renewable energies, which have become more affordable.

Fukushima forced the nuclear sector to adopt new safety measures, increasing its costs by a third in the past decade, according to the Lazard financial group.

By contrast, costs for wind and solar energy have fallen by 70 percent and 90 percent, respectively, between 2009-2020.

Proponents of nuclear power argue that it is also a source of energy that emits very few carbon emissions.

"A range of technologies, including nuclear power, will be needed for clean energy transitions around the world," the International Energy Agency, which advises wealthy countries on energy policy, has said.

The future of nuclear energy is uncertain. 

In its latest projections, the International Atomic Energy Agency says global nuclear electrical generating capacity could increase by 82 percent by 2050 under a "high case scenario" — or drop by seven percent in its "low case scenario".

The future

The nuclear industry has focused its attention on small modular reactors (SMR), shifting away from bigger, more powerful structures.

With 300 megawatts of power, compared to over 1,000 MW produced by conventional reactors, SMRs were designed to be built in factory assembly lines and then transported to power plants.

Russia already uses the method. The United States, which has the most reactors in the world, and other nuclear countries such as France and Britain have also shown interest in the technology.

Several countries are developing fourth generation reactors that would produce less nuclear waste.