South Korea has big plans to become a major nuclear energy player, but they are unfolding at a time when the global industry is under intense scrutiny after the 2011 Fukushima disaster.

And its ambitions have not been helped by a series of domestic scandals and forced reactor shutdowns in 2012 that rattled public confidence and exposed a glaring lack of regulatory transparency.

Around $400 billion is riding on South Korea's ability to sell its technology to potential clients as it aims to take on the United States, France and Russia and grab a 20 percent share of the nuclear energy market.

With around half of the world's 430 reactors due for retirement by 2030, according to the International Atomic Energy Agency, the next 15 years or so offer the prospect of a sales bonanza.

Spearheading South Korea's global drive is its ARP-1400 reactor. It won a $20 billion deal in 2009 to build four of them in the United Arab Emirates and it aims to export another 80, worth around $400 billion, by 2030.

It is also planning a domestic energy expansion that would see it build 16 new reactors by 2030. South Korea currently operates 23 nuclear power reactors which meet more than 35 percent of the country's electricity needs.

"Our reactors are safe," Lee Young-Il insisted as he guided a group around an ARP-1400 nearing completion at the Gori nuclear power complex.

"We also have an excellent record of operating the reactors with a comparatively low annual rate of forced outage," said Lee, who heads the complex where South Korea's first commercial reactor came on line in 1978.

But the Fukushima disaster in Japan forced a number of countries to rethink their energy strategy, as public concern placed an even greater emphasis than before on reactor safety.

A survey commissioned by the Economics Ministry and published in November showed only 35 percent of South Koreans considered nuclear power to be safe, sharply down from 71 percent in January 2010.

"You are never free from worry as long as your country depends heavily on nuclear energy," Yangyi Won-Young, head of Nuclear-Free Korea, a coalition of civic groups, told AFP.

"Our nuclear power plants are vulnerable to natural disasters because of lax safety regulations which have been applied to construction, operation and parts," Yangyi said.

-- Shutdowns and scandals --

In the wake of the earthquake and tsunami-triggered meltdown at the Fukushima Daiichi nuclear plant in Japan, the state-run Korea Hydro and Nuclear Power Co (KHNP) launched a $1.0 billion-dollar safety upgrade due to be completed by 2015.

The project involves building higher seawalls around the country's four nuclear power complexes, and equipping plants and reactors -- including the ARP-1400 -- with advanced watertight doors and ventilation systems, as well as new quake sensors.

But the upgrade coincided with a series of shutdowns and scandals in 2012 that triggered a warning from the International Energy Agency (IEA) in November about the need to rebuild public trust.

In May, five senior KHNP engineers were charged with trying to cover up a potentially dangerous power failure at the country's oldest Gori-1 reactor.

Later in the year, the government shut down two reactors at the Yeonggwang nuclear complex to replace components provided with fake quality certificates.

And a third reactor was taken offline at Yeonggwang when cracks were found on control rod tubes during maintenance work.

"Recent incidents at Korean nuclear facilities should serve as a timely reminder to the government that the nuclear regulatory authority must maintain an enhanced profile... and be able to take independent decisions," the IEA said in a report on South Korea's energy policies.

-- Transparency concerns --

The South has been criticised in the past for a lack of transparency in the nuclear sector -- largely attributed to the regulatory bodies' mixed supervisory and promotional roles.

President Park Geun-Hye, who took office this week, looks set to further muddy the waters with her proposal for the nominally independent Nuclear Safety and Security Commission.

Park wants to affiliate the commission with a newly created super-ministry in charge of policies on science research, information communication technology and atomic energy development.

Scientists, environmentalists and a number of politicians -- including some from Park's ruling party -- say the move would undermine the watchdog's independence and weaken its safety management authority.

"The Republic of Korea is going to be the only country across the globe where regulators and basically developers or promoters might be working all together under the same roof," said Suh Kune-Yull, a nuclear engineering professor at Seoul National University.

"A conflict of interest is inevitable," Suh said.