After the dissolution of the Soviet Union, Russia and its former Soviet neighbours were left to deal with the legacy of the Soviet nuclear programme.

From warheads and decaying submarines to radioactive lakes, a complete map of the area's radiation hazards has not yet been drawn.

The world's worst nuclear disaster in Chernobyl, Ukraine, in 1986 is a nightmare that will haunt scientists and engineers for years to come.

The structure - which covers nearly 200 tonnes of highly radioactive fuel, dust and debris - is leaking and unstable, prompting fears of another nuclear disaster.

But as power sources in Ukraine are scarce, the remaining reactors of the plant are still used to produce electricity. The US Vice President, Al Gore, renewed calls for the closure of the plant by the year 2000 on his recent visit to Ukraine.

More Chernobyls?

Chernobyl was not the first accident of the Soviet nuclear programme. The secret Mayak bomb-making plant near Chelyabinsk in the Ural mountains was responsible for a whole series.

Chernobyl has contaminated the countryside for miles around

According to some reports, radioactive waste equivalent to roughly 20 Chernobyls was pumped from Mayak into a lake that even today is capable of delivering a fatal dose of radiation within an hour.

Mayak was also the scene of an explosion in a nuclear waste storage tank in 1957, when an estimated 70 to 80 tonnes of radioactive materials blasted to the air.

A similar explosion happened at Tomsk in Siberia in April 1993.

Several tonnes of uranium and plutonium salts were scattered over the surrounding countryside. Tomsk is described as the worst post-Chernobyl disaster.

Russia's main nuclear reprocessing plant is in Krasnoyarsk, some 600km to the east of Tomsk.

The two plants are responsible for the radioactive contamination of two of Siberia's great rivers, the Ob and the Yenisei, which flow north into the Kara Sea.

Nuclear hotspots are still being discovered, sometimes in unexpected places.

One source of contamination was located in 1997 in a military base outside the Georgian capital Tbilisi, after soldiers mysteriously began to fall ill.

Unmotivated staff

The Russian nuclear facilities have faced serious economic problems which have had direct effects on their safety.

There have been drastic cuts in the defence budget.

And heavy industry and other electricity consumers do not or cannot always pay for the electricity the nuclear power stations deliver.

This means that the operators at the stations can go months without being paid, and general maintenance becomes neglected.

Recently, workers at several Russian nuclear centres have been striking in protest against huge wage backlogs.

In Soviet times, Russia's nuclear specialists were among the privileged who had access to special shops and luxury items, but now their families are going hungry.

Scrap sub problem

Neither has there been enough funds to dismantle the rusting submarine fleet in the north of the country.

No funds to scrap rusting subs

The environmental threat was highlighted in 1996 by the Norwegian environmental group, Bellona.

Their report says the Kola peninsula, which borders on Norway and Finland, has a mountain of nuclear waste, comprising 29,040 fuel elements, nine reactor cores and 21,067 cubic meters of solid-fuel nuclear waste.

In May this year, a Russian official report voiced alarm at the situation in the Adreyev Bay area used as a dumping ground for nuclear waste.

Some 95 submarines have been decommissioned and dumped at the site and demand constant and costly work to keep them from deteriorating dangerously, or even sinking, the report says.

Smuggling fears

Environmental groups say the Russian nuclear industry has not managed to address the question of nuclear waste disposal in general.

The Bellona group says the storage facilities for radioactive waste and used fuel elements are filled to capacity and in very bad condition at all the 11 nuclear power stations in Russia.

Used fuel elements are stored temporarily in ponds at the stations, awaiting transport to the reprocessing facility, the group says. There is no central storage for such nuclear fuel.

Russia has also been embarrassed this year by a series of reports in US newspapers that it has been supplying sophisticated nuclear and missile technology to India and Iran.

The West is worried about leakage of technology and expertise. There are allegations that private companies are selling technology without the government's consent.

President Boris Yeltsin's administration maintains that Russia is creating special supervisory bodies at all companies dealing with nuclear technologies to prevent illegal export.