Thursday 10 October 2013

Windscale

I've written about how the mishaps at Fukushima, and Chernobyl, affected me at the time. I haven't really talked about being down wind from Three Mile Island in 1979, but I can remember a chilly breeze over my stiff upper lip knowing that I was a long way from home if I was going to be dusted with Becquerels. All too recently I was bloggin' about Kyshtym in the Urals and saying that we knew very little about it because the Soviets kept it a close secret.  As the cold war hotted up into a thermonuclear arms race, it was important to the various governmental players (UK, USA, USSR) that they didn't lose scientific or political momentum.  Just 11 days after Kyshtym , on 10th October 1957, the British suffered a serious set-back at their first ever atomic pile at Windscale.  The Brits still had pretensions to being a major technological power deserving parity of esteem with the US and the USSR by raising Cain with a few ounces of Plutonium.  The Windscale piles were designed to create radio-active isotopes of a number of different elements by bombarding precursors with neutrons: initially Plutonium and, after the Americans exploded their H-bomb, Tritium as well.  Tritium is an unstable isotope of hydrogen (H for hydrogen; H for bomb).  The pile was experimental, first of its kind, and air-cooled like the engine of my first car, a Citroen 2CV.

Making explodable matter was horrendously expensive.  In the US in the 1950s 10% of the entire electricity grid was passed through Oak Ridge Tennessee, so that the Atomic Energy Commission could make a handful of Plutonium.  That makes it a project proportionately as energy-intensive as The Cloud of Servers is now. Keeping all copies of all our photos, millions of identical copies of standard Justin Bieber songs, and every e-mail you've ever sent, now sucks up 10% of the electricity generated on the planet.

Construction of Windscale took 6 years, 6000 tons of graphite and a huge amount of concrete and steel.  After 15 months of operation, they gathered up the harvest of plutonium and found 132g.  Plutonium is dense at nearly 20g/cm^3, so this is about half a tablespoonful.  In order to increase the quantity of product, the core temperature was increased.  For normal functioning in an air-cooled reactor, when things heat up too much you switch the cooling fans on.The kiltotonnes of graphite absorb neutrons and thus control the activity of the pile. Every so often the molecular sheets of graphite used to buckle in a rather spotty pattern and start to heat up . . . or heat up and buckle. Nobody knew the direction of causation, just the appropriate fix. The solution to this problem was to heat the whole pile up a couple of hundred degrees which would enable the uneven surface to bed down again, it's called a Wigner Release.  On the 8th of October they carried out a Wigner cycle and after the requisite amount of time turned on the cooling fans to get the pile down to operating temperature.

So far SOP (Standard Operating Procedure) but if there is an actual conflagration in there, this will not just fan the flames but start them roaring like a Bessemer blast-furnace.  It took a while for the operators to realise, by careful analysis of the pattern of readings from the deeply embedded thermocouples, that normal had shifted to thermal.  The graphite, which is pure carbon, wasn't quite burning but some of the Aluminium/Lithium/Magnesium/Uranium fuel rods were. By staying at their posts, thinking clearly, being prepared to try a few possible solutions and not losing their nerve, the engineers and scientists at that artificial coal-face averted a much greater disaster more than 50 years ago today.  They were led by Tom Tuohy, Deputy General Manager, who was standing on top of the pile monitoring progress while waiting for the concrete underfoot to melt.

Last night I watched a documentary about the Fire by the BBC.  One remarkable achievement is that the government appointed Sir William Penney, the chief of the atomic bomb programme and a top-notch physicist, to carry out an investigation of what had happened.  He interviewed all the effectives over the next few days and had the finished report on the Prime Minister's desk on October 26th - 16 days!. Penney pointed to the enormous political pressure to blow up more and bigger bombs and the demand this put on supply as a major contributor to the disaster.  Last night the Irish Health Information and Quality Authority HIQA finally released the report into the death of one woman at University Hospital Galway 345 days after the event.  The British government was almost as good as the Soviets for covering up and covering their own backsides.  The Prime Minister, Harold Macmillan, one the Macmillan publishing family, was experienced at editing such inconvenient prose as the Penney Report.  All copies were recalled, most of them shredded and a White Paper released giving first place to "errors of judgment" with a minor role for "inadequacies of instrumentation".  And rather like Stalinists airbrushing Trotsky out of all the Party photographs after he fell from grace, the British Government renamed Windscale as Sellafield - redolent of meadows and daisies.  But a very short way from the Sellafield Business & Information Centre, the Windscale piles are still warm.  Decommissioning won't be complete until 2037.

A year after everything cooled down, during a visit to Windscale from their US counterparts, all the Suits were congratulating each other on still having a nuclear programme and how they'd minimised the impact of the little accident (like a puppy making a puddle on the kitchen floor) that their underlings had caused.  "I thought, what a shower of bastards", recalled Tom Tuohy for the BBC documentary.

1 comment:

  1. I remember learning about Chernobyl weeks after the event and watching the fancy wind and cloud graph that showed its spread across Europe. Discussing it later with a fishing pal, we both recalled the gentle mist that fell from the sky about the time the cloud was over Ireland, how still the weather was, how silent everything seemed; bizarrely fishermen talk and think this way, because its a factor in a successful catch. We remember talking like "bugger this, we'll catch nothing if the wind doesn't freshen from the S West...." We didn't say anymore about the cloud or the weather, but still I sometimes think about it and wonder did we catch more than we bargained on!

    ReplyDelete