Thirteen years ago the world experienced its worst ever nuclear accident following a reactor meltdown at the Chernobyl power plant in the Ukraine.

But despite the thousands of deaths and environmental damage that will take centuries to clear up, several nuclear reactors of exactly the same design continue to operate throughout the former Soviet Union.

The reactor provides 85% of Lithuania's power

Two weeks ago I visited the Ignalina nuclear power plant in Lithuania. It's been described by the US department of Energy as one of the most dangerous nuclear installations in the world and the European Union are also demanding its early closure.

To add to the safety worries, the plant is built on a tectonic crack and last year alone Ignalina experienced over 20 low-level accidents, four of which led to temporary shut downs.

But Ignalina also provides Lithuania with more than 85% of its electrical power, making this small Baltic state the most nuclear reliant country on the planet. Many Lithuanians argue that closing down Ignalina to satisfy western safety concerns would be a devastating blow to the country's fledgling market economy.

According to the plant's director, Gardanij Negrivoda, Ignalina is safe. The litany of accidents are dismissed as "minor incidents" and he is quick to point out the millions of dollars of short-term safety measures that have been spent on Ignalina by concerned neighbouring countries in the wake of the Chernobyl disaster.

But the fate of the Ignalina plant has become a serious stumbling block to Lithuania's ambitions of joining the European Union. EU officials say the previous Lithuanian government already promised not to extend the working life of the reactors beyond 2007.

The current government says that decision was "a mistake" and argues that with reactor core replacements, the plant can run for at least another 20 years.

Flawed design

But Henrik Schmiegelow, the EU's ambassador to the Lithuanian capital Vilnius, says that no matter how much money is invested, Ignalina cannot be made safe because the fundamental design is flawed.

Lithuanians say, with some work, the reactor could last for 20 years

Lithuania now has only a few weeks left to give a firm commitment to the early closure of Ignalina or face exclusion from EU membership talks at the very time the Baltic States are hoping to increase their ties to western Europe.

The Ignalina Nuclear Power Plant operates two Soviet-era RBMK-1500 water cooled reactors - the most powerful nuclear reactors in existence. They feed off the nearby Druksiai Lake and by returning heated water to the lake, have raised its temperature by three degrees, prompting concern from local environmentalists.

But this is a minor worry compared to some of the problems at Ignalina. The two reactors, both of which are more powerful than the ones at Chernobyl, have no protective containment shells.

Pumping used cooling water back into the lake, affects Ignalina's environment.

The plant's supporters say its water piping control systems are just as safe, but none of this diminishes from the general air of decay and neglect surrounding the plant. Concrete walls and corridors are crumbling and cracked to the open air, paint is peeling from nearly all the walls, while most of the underpaid staff look lethargic and disinterested in their work.

Lithuania's Prime Minister, Gedeminas Vagnorious, says that closing Ignalina would cost Lithuania between two and six billion US dollars, money the country simply doesn't have. Vagnorious says the EU want Ignalina closed not for safety reasons, but in order top prevent Lithuanian access to lucrative energy export markets - an argument dismissed as facile by EU officials.

The EU says that if Lithuania wants to join Ignalina must be closed down, but the Lithuanian government says it simply can't afford it.