By Paul Anderson BBC correspondent in Kozloduy, Bulgaria

In the accident simulator room of the Kozloduy nuclear power plant, alarms ring and warning lights spring to life.

In the last 10 years, many safety improvements have been made

The signs of impending nuclear nightmare - here an exercise involving a cooling pipe rupture - flash across the screens.

The tough reality, as the Bulgarians explain to a team of visiting experts, is that the chances of it actually happening now are miniscule - and no more than at any other nuclear plant, anywhere in the world.

In the past 10 years, they argue, they have introduced so many safety improvements, they have exceeded international standards.

Safety concerns

The Bulgarians have agreed to close down the two oldest reactors at the Kozloduy nuclear power station on the Danube at the end of this year. But the EU wants the next two reactors closed as well, despite the decade of safety improvements.

"This unit is now subject to large and very important reorganisation program", said Sabin Sabinov, Deputy Chief Engineer, "In addition to improvement of safety it is a source of a lot of profit."

The profit is the millions of dollars Bulgaria earns from exporting electricity. Kozloduy provides around 50% of country's power.

I want Bulgaria to be accepted in Europe. But, on an equal basis. Not to be forced to enter like a beggar

Maya Hrisova, Kozloduy worker

Closure of four of its six plants, as demanded by the European Union for accession talks to continue, would have a catastrophic economic impact.

"The EU has a responsibility for the safety of our citizens and also for the citizens of future member states," said the EU head of mission in Bulgaria, Dimitris Kourkoulas.

"We don't ask the Bulgarians to close Kozloduy altogether but only the first four units which we believe have some designs problems that could not be upgraded."

'No Chernobyl'

But the Bulgarians now reject the pressure. They say Kozloduy is no Chernobyl - the nuclear plant in Ukraine, one of whose reactors exploded in 1986.

Many people will lose their jobs if the reactors close

Milko Kovachev, Minister of Energy, said: "Some people are judging this as blackmail because to put some conditions to someone coming to the club you have to the same conditions within a club."

Maya Hristova may be hit badly by the closure of Kozloduy's old reactors. Currently, she and her husband both work there.

She said, "I want Bulgaria to be accepted in Europe. But, on an equal basis. Not to be forced to enter like a beggar".

But the slow pedal to the European Union could become even slower if they don't accept the terms. In Kozloduy, like everywhere else, living standards border on dismal.

The people are learning what price they have to pay for improvement.