Our Nuclear Legacy



Normally I am pro nuclear power but even I have to admit that Sellafield is a hell of a mess and that it impossible to make excuses for what was done there.

I was lucky enough back when I was somewhat younger to have been able to visit Sellafield.   Back then they had a visitors centre and you could get there from the station.   The train from Barrow along the coast is pretty amazing!   I will have to see if I can find my old photos.

The top photo here is from a more recent visit to Cumbria and shows the Pile number 1 cooling tower still with ‘Cockcroft’s Folly’ partially removed.   The lasting legacy of the 1957 Windscale Fire.   Listed as 4th on the list of worst nuclear accidents.   Originally designed to produce bomb grade plutonium, the two massive piles were re-purposed to  run hotter and to produce tritium for ever larger bombs.

American scientists had warned about the use of graphite moderated air cooled reactors due to the neutron bombardment causing stresses in the graphite structure.   Under pressure to produce tritium and with inadequate instrumentation the scientists and engineers thought they had it all under control.   Except that physics never quite works like that.

We will never know how close the concrete structure of pile number 1 came to complete failure.   Thankfully the efforts of the engineers and scientists succeeded in putting out the fire and averting total catastrophe but we are left with a partially burnt out mess filled with hundreds of melted fuel rods.

The beeb has been showing a series of programs on BBC4 relating to the 70th anniversary of the dropping of the bombs on Japan.   One of these was titled ‘Britain’s Nuclear Secrets: Inside Sellafield’.   Jim Al-Khalili was given amazing access to some of the key parts of the Sellafield site including the top of the #1 pile chimney and the Magnox fuel pond.

The scale of the cleanup is truly horrific.   I really am pro nuclear power as renewables are a long long way from providing base load capacity.   And it is pretty easy to blame the mess at Sellafield on the bomb program and the UK governments desire to first join the A-bomb club and later the H-bomb club.   But the short-sightedness really makes me cringe and feel embarrassed to be an engineer.

Apart from the burnt remains of pile 1, there is also the Magnox fuel storage ponds and the Magnox swarf silos.

The Magnox reactor was the UK’s first ‘commercial’ electricity producing nuclear reactor.   A fairly small gas cooled design using uranium fuel clad in magnesium casings.   I put commercial in quotes as the first Magnox sites were producing plutonium too.   The Queen didn’t mention that when the opened Calder Hall in 1956.

The reactors had quite a low burnup and required frequent refueling.   This meant a lot of fuel rods were passing through Sellafield for reprocessing.   The magnesium casings were stripped off and the contaminated parts were just dumped in huge silos.   There are 22 on site and they are all FULL!

During the coal miner’s strikes of the 1970s, the UK’s reactors were run as hard as they could be to try and keep the lights on.   They had more spent fuel than they could handle and it was pretty much dumped in the huge outdoor cooling ponds.   Where it sits today along with huge amounts of sludge, equipment and other radioactive detritus they wanted to be rid of.   All gently rotting.   What a mess!

I wasn’t too happy with Jim Al-Khalili’s description of half-lives as it left out a lot of detail.   It did give the impression that long half lives were more dangerous than short but this is getting into physics more suited to the old Open University programs rather than BBC4 evening viewing.   I do agree with his thoughts on transmutation of the waste.   The question is how.

The UK is busy trying to build a new generation of reactors to keep the lights on as coal is phased out.   However we’re looking to build the European pressurised water reactor (EPR) where the first reactor to be built is 6 years overdue and long over budget.   Or the Hitachi ABWR which does actually have some track record.   Both are Generation 3+ designs.   And both have the basic issue of producing the same sorts of waste that are currently sat rotting at Sellafield.

I have to ask why more research has not been done into generation 4 and higher reactors.   I don’t quite share the enthusiasm of some for the thorium reactors.   We have plenty of uranium piled up to keep us going for a while.   And even with thorium you can still make bombs and it doesn’t decrease the decommissioning.

So where do we go?   Well as a start the molten salt reactor is a better bet than the EPR or ABWR.   And it could be fed on Sellafield uranium and plutonium.   So rather than letting the French or Chinese dictate how we proceed and leaving us more waste to store (cos the French sure as heck won’t want it!) we should be forging ahead as world leaders in a new technology!   And helping to clean up the mess left for us by the race for mutually assured destruction.