A decaying Russian nuclear dump inside the Arctic Circle is threatening to catch fire or explode, turning it into a "dirty bomb" that could impact the whole of northern Europe, including the British Isles.
Experts are warning that sea water and intense cold are corroding a storage facility at Andreeva Bay, on the Kola Peninsula near Murmansk. It contains more than 20,000 discarded fuel rods from nuclear submarines and some nuclear-powered icebreakers. A Norwegian environmental group, Bellona, says it has obtained a copy of a secret report by the Russian nuclear agency, Rosatom, which speaks of an "uncontrolled nuclear reaction".
John Large, an independent British nuclear consultant who has visited the site, told The Independent on Sunday: "The nuclear rods are fixed to the roof and encased in metal to keep them apart and prevent any reactions from occurring. However, sea water has eroded them at their base, and they are falling to the floor of the tanks, where inches of saltwater have collected.
"This water will begin to corrode the rods, a reaction that releases hydrogen, a gas that is highly explosive and could be ignited by any spark. When another rod falls to the floor and generates such a spark, an enormous explosion could occur, scattering radioactive material for hundreds of kilometres."
Mr Large, who was decorated by Russia's President Vladimir Putin for his role in the salvage operation that retrieved nuclear material from the Kursk submarine in 2000, added: "This wouldn't be a thermonuclear or atomic explosion, as in a bomb, but the outcome is just as bad. Remember Chernobyl? If you had the right weather conditions and wind pattern, this would mean a radioactive cloud drifting over the UK."
The three storage tanks contain more than 32 tons of radioactive material. But the Kola Peninsula is littered with relics of Soviet nuclear facilities, housing more than 100 tons of nuclear waste - the largest concentration in the world.
Experts predict that a major explosion at Andreeva Bay could destroy all life in a 32-mile radius, including Murmansk and a sliver of Norway, whose border is only 28 miles away. But a much wider area of Norway, north-west Russia and Finland would be rendered uninhabitable for at least 20 years, and huge quantities of radioactive material would be dumped into the Barents Sea.
"In the best case a small, limited explosion in just one of the stored rods could lead to radioactive contamination in a 5km radius," Aleksandr Nikitin, a Russian former submarine officer and nuclear safety inspector turned environmental activist, told the Norwegian newspaper Aftenposten. "In the worst case, such a single explosion could cause the entire tank facility to explode. We have no calculations for what that could lead to."
Mr Nikitin, whose work for Bellona led to continuing treason charges in Russia, added: "We are sitting on a powder keg with a burning fuse, and we can only guess about the length of the fuse." Nils Bohmer, nuclear physicist and head of Bellona's Russian division, told the newspaper: "It will at least, at a careful estimate, hit northern Europe. There are enormous amounts of radioactivity stored in these tanks."
Other activists have voiced concern about the security of stored nuclear waste in the Kola Peninsula, amid reports that some is left outside in barrels, protected by only a link fence and a couple of guards. Washington-based GlobalSecurity.org reported that in 1993 about 1.8kg of enriched uranium was stolen from the Andreeva Guba fuel storage area. Although the material was quickly recovered, the fact that some of the uranium is enriched to between 30 and 40 per cent, much higher than the 2 to 3 per cent used in civil nuclear reactors, could make it tempting to terrorists seeking to make a "dirty bomb".
Apart from the decay at the Andreeva Bay facility, said Ben Ayliffe, senior climate and energy campaigner at Greenpeace UK, "security is so lax that almost anyone who wants to can just walk in. It's like Homer Simpson meets Dad's Army."
As the 1986 Chernobyl disaster showed, drifting atmospheric radiation can contaminate crops and water supplies more than 1,000 miles from the site of the explosion. In the world's worst civilian nuclear incident, the four explosions that ripped through the power plant in what is now eastern Ukraine resulted in the dispersal of a radioactive cloud containing at least 100 times as much radiation as was released by the combined effect of the atomic bombs dropped on Hiroshima and Nagasaki.
Although only three people were killed by the Chernobyl blast, it has been estimated that around 100,000 people have since died from cancers caused by exposure to radiation, with thyroid cancers increasing by 88.5 per cent. A further 300,000 people have developed non-fatal tumours even though half a million people were evacuated immediately after the accident.
The economic and social effects remain devastating, despite large-scale international assistance. Many industries have collapsed, and 1.4 million acres of prime agricultural land and forest destroyed by the explosion are still unusable. Residents are banned from entering a zone some 20 miles around the site, yet hundreds of elderly people have ignored government restrictions and gone back to their homes in surrounding villages, where they raise animals and eat fruits and berries from the radiation-soaked land.
But experts using the Chernobyl "radioactive release" to predict the likely effects of a disaster on the Kola Peninsula point out that Britain and the rest of Europe escaped remarkably lightly. The 1986 explosion occurred on a still summer night sending radioactive particles straight upwards for the most part, until they encountered winds in the upper atmosphere.
Although the radiation was widely dispersed, there was little rainfall in the immediate area, or across Europe, in the following week. The only area of Britain where rain brought the radiation to earth is relatively lightly populated: north Wales, parts of Cumbria and south-western Scotland. Care still has to be taken with meat from the affected area, but there are no reliable statistics that show any impact on human health in Britain.
Another Chernobyl-type meltdown, this time in the Arctic, could have much more far-reaching effects. The worst case would be widespread fallout caused by rain in a densely populated area, causing untold social and economic disruption beyond the threat to life.
Even without a catastrophic explosion, contamination from the Kola Peninsula facility is spreading. The region is outstandingly beautiful, with jutting cliffs, snow-covered peaks and deep fjords. The soil is rich in minerals, the rivers swim with Atlantic salmon, and the land is home to reindeer and their nomadic Saami herders. But Andreeva Bay is already devoid of marine life, and much of the area around it, a landscape of rusting submarine hulks, cranes, workshops and a disused power station, now stands empty.
A rupture or fire in the storage tanks would spread radiation further, probably forcing the evacuation of the nearest town, Zaozersk, which is less than four miles away. But Andreeva Bay is merely one of five naval bases on the Kola Peninsula, a testament to the era when the Soviet Union vied for supremacy with the US and nuclear capability, both in weapons and energy, was seen as the means to that end.
The ice-free harbours of the White Sea have always been the base of the Northern Fleet, which has two-thirds of the navy's nuclear-powered vessels. Its submarines, which can circle the globe without surfacing or refuelling, were a source of pride in superpower days. But with this came an attitude of careless arrogance towards the environment - apart from the effects on land, many spent nuclear fuel rods were dumped into the Kola and Barents seas - and the region is now paying the price.
In the economic crisis that followed the collapse of communism and the breakup of the Soviet Union, the nuclear submarine fleet and its support structure were hit by drastic cutbacks. The decommissioning of submarines rapidly became a major national problem, with suitable storage facilities filled to capacity and little money to carry out the necessary expansion.
The fuel rods at Andreeva Bay first began to leak radioactive material in 1982, when they were stored in flimsy navy warehouses. In a precursor of the emergency action taken at Chernobyl, a startled government hastily erected three massive concrete tanks filled with metal pipes in which the rods could be safely stored. These facilities were intended only as a provisional measure, to last no more than five years, yet they have now been housing potentially lethal uranium for more than two decades. The problem has been compounded by confusion over who is directly responsible for the area: the nuclear agency Rosatom, which controls all Russian nuclear sites, or the defence ministry, which has authority over military bases.
President Putin's administration denied Norwegian claims that the tanks at Andreeva Bay were unstable, claiming that the nuclear waste posed no environmental hazard. This was echoed by Rosatom's deputy head, Andrei Malyshev, who declared that "the possibility of a nuclear event that is significant in terms of safety is excluded".
Mindful, however, that the Soviet authorities sought to deny there had been an accident at Chernobyl, Russia's neighbours have been pressing for action to tackle contamination in the Kola Peninsula for years. In the 1990s European leaders began efforts to help secure the region. A 2003 agreement between Sweden, France and Russia pledged more than £30m, a deal described by the Swedish Foreign Minister as "a historic event". But little has happened since, partly due to the enormous costs.
It is estimated that a clean-up of the Kola Peninsula, either by moving radioactive material to permanent storage facilities or transporting it to a reprocessing plant, will cost around £2.2bn. Although Britain, the EU and the US have offered help, with Norway saying last month that it would pay to decommission two nuclear submarines, Russia will still end up footing most of the bill. It also faces the hazardous task of shifting the waste to where it can be dealt with, making Britain's problems in handling waste from old, and possibly new, nuclear plants seem minor.
After the radioactive material has been extracted from the dumps by remote-controlled vehicles, it will have to be transported in sealed containers down the coast to Murmansk, where the government hopes to construct new long-term storage facilities. Material which can be reprocessed will be carried in trains hundreds of miles to Mayak, in the heart of the Ural mountains. The residents of the city, who face the prospect of having tons of highly dangerous material passing through for several years, formally learned of the proposals only last autumn.
The latest controversy shows, however, that doing nothing is no longer an option. Mr Ayliffe said: "The Andreeva Bay nuclear dump is incredibly dangerous... a disaster waiting to happen that underlines the intractable problem of how to deal with the thousands of tons of highly toxic waste created by nuclear power."
Best scenario: a limited explosion of one rod could contaminate a three-mile radius around Andreeva Bay. Wildlife could die out. Worst scenario: the entire facility explodes, radiation could destroy life in a 32-mile radius and make areas of Norway, Finland and Russia uninhabitable. Contamination could reach the UK and beyond.
7,000 nuclear fuel rods are stored in each tank. Each rod hangs separately, encased in a metal tube to prevent any uncontrolled reaction.
Seawater enters through cracks in the tank and erodes the rods, causing them to fall into the salt water that has collected in the tube.
Hydrogen is released when the rods corrode. A spark from another falling rod could ignite this highly explosive gas, setting off an "uncontrolled explosion".
Unlike a nuclear bomb, which requires costly precision engineering, the construction of a "dirty bomb" requires only the combination of radioactive material with a standard explosive, which serves to scatter the particles.
Few people might be killed in the explosion, but the disruption caused by contamination in a city centre would be huge. Authorities in several countries claim to have foiled such plots by terrorists.
In 1995 Russian police said they had prevented Chechen separatists from detonating radioactive isotopes wrapped in explosives in a Moscow park. Londoner Dhiren Barot, jailed in 2004 for planning to detonate dirty bombs in underground car parks in London and New York, sought radioactive material from hospital equipment such as X-ray machines.
Further reading: 'The Russian Northern Fleet: Sources of Radioactive Contamination', by Nilsen, Kudrick and Nikitin (Bellona)