The Ecologist has received a shocking set of leaked images showing decrepit and grossly inadequate storage facilities for high level nuclear waste at the Sellafield nuclear plant.

The images (right), from an anonymous source, show the state of spent nuclear fuel storage ponds that were commissioned in 1952, and used until the mid-1970’s as short term storage for spent fuel until it could be re-processed, producing plutonium for military use. However they were completely abandoned in the mid-1970s and have been left derelict for almost 40 years.

The photographs show cracked concrete tanks holding water contaminated with high levels of radiation, seagulls bathing on the water, broken equipment, a dangerous mess of discarded items on elevated walkways, and weeds growing around the tanks.

The fuel storage ponds, the largest measuring 20m wide, 150m long and 6m deep, are now completely packed with spent fuel in disastrously poor condition.

If the ponds drain, the spent fuel may spontaneously ignite

The ponds are now undergoing decommissioning in order to restore them to safe condition. But the process is fraught with danger – and nuclear expert John Large warns that massive and uncontrolled radioactive releases to the environment could occur.

“This pond is build above ground”, he said. “It’s like an concrete dock full of water. But the concrete is in dreadful condition, degraded and fractured, and if the ponds drain, the Magnox fuel will ignite and that would lead to a massive release of radioactive material.

“Looking at the photos I am very disturbed at the degraded and run down condition of the structures and support services. In my opinion there is a significant risk that the system could fail.”

“If you got a breach of the wall by accident or by terrorist attack, the Magnox fuel would burn. I would say there’s many hundreds of tonnes in there. It could give rise to a very big radioactive release. It’s not for me to make comparisons with Chernobyl or Fukushima, but it could certainly cause serious contamination over a wide area and for a very long time.”

State of fuel is ‘very unstable’

The ponds were abandoned after they were overwhelmed with spent fuel in 1974. This was the time of Prime Minster Edward Heath’s ‘three-day week’ when coal miners were on strike, causing fuel shortages in Britain’s power stations.

In order the ‘keep the lights on’, the UK’s fleet of nuclear power stations were run at full tilt, producing high volumes of spent fuel that the Sellafield re-processing facilities were unable to keep up with.

“During the three-day week they powered up the Magnox reactors to maximum, and so much fuel was coming into Sellafield that it overwhelmed the line, and stayed in the pool too long”, says Large.

“The magesium fuel rod coverings corroded due to the acidity in the ponds, and began to degrade and expose the nuclear fuel itself to the water, so they just lost control of the reprocessing line at a time when the ponds were crammed with intensely radioactive nuclear fuel.”

“This left the fuel in a very unstable condition, with actual nuclear fuel complete with uranium 238, 235 and all the fission products, in contact with water. The problem then is that you get corrosion with the formation of hydride salts which leads to swelling, outside cracks, and metal-air reactions”, said Large – who gave evidence on the topic to the House of Commons Environment Comittee in 1986.

The whole fuel ponds began to look like milk of magnesia, and what with the poor inventories that had been kept, no one even knew what was in there any more. Even the Euratom nuclear proliferation inspectors complained about it as there was by some estimates over a tonne of plutonium sitting there in the fuel rods and as sludge that was never properly accounded for.”

All part of Britain’s nuclear WMD programme

The two adjacent fuel storage ponds, which lie between the old Windscale nuclear piles, were part of the military plutonium production line using the Windscale spent fuel until the Windscale diasaster in 1957.

With the Windscale piles out of commission, they were then adapted to receive nuclear waste from civilian power stations such as Calder Hall and Hinkley Point.

The first pond in the plutonium production line is B30, which is open to the elements. From there underwater tunnels were used to convey the fuel-bearing skips to other ponds and silos within the adjacent building, where the fuel rods were ‘decanned’ from their cladding.

The fuel was then dissolved in concentrated acids in the B203 reprocessing plant, where the plutonium for Britain’s nuclear weapons programme was chemically separated using the PUREX process. Both ponds contain a mix of fuel, sludge, and other miscellaneous nuclear wastes.

Concrete is riddled with cracks

But in the 40 years since the ponds were abandoned, the entire system has broken down. Locks, gantries, lifts and valves are all broken, missing or seized up.

The concrete is riddled with cracks – including not just the ones that you can see, but also those out of sight in the connecting tunnels. The entire environment is far too radioactive for anyone to be able to enter.

The Nuclear Decommissioning Authority (NDA) has now started work on the ponds, but reassuring statements have been shown to be over-optimistic. “It’s very disturbing”, says Large. “They have been saying it was all under control, and they thought well cleared out. Now we know it’s not.”

However an important first stage has been completed – the ‘de-flocculation’ of the water so that it’s finally possible to see what’s there. This had previously been impossible due to particulate suspension and algal growth.

“For the first time in decades we can see down into the pond and see the contents, and it’s breathtaking!” comments Large. “It’s all thanks to the whistle blower that I’m looking at them. If the Euratom inspectors could see what we can see now, my there would have been a row! Maybe we should invite them back right now!”

A particlar problem arises from the sludge that has accummulated at the bottom of both ponds and skips, which requires especially careful handling. The sludge has to be kept under water in order to prevent its spontaneous ignition.

But it’s also essential to keep it undisturbed as if the sludges are resuspended into the main body of water, a part of the sludge will add into the surface ‘oil’ of fine particulates which can be released to the atmosphere with any surface water disturbance – giving rise to high radiation levels above the water.

This seriously complicates both the removal and packaging of the sludge itself, and of the fuel-containing skips.

The Ecologist has contacted the Office of Nuclear Regulation, the statutory nuclear safety regulator, with pressing questions about the safety of the site, safety plans in the event of water loss or radioactive release, and whether anyone will be prosecuted over the abandonment of the ponds in this highly dangerous condition.

We await their reply.