Hedgehog & Nuclear Reactor

The Hedgehog’s Part in the Nuclear Reactor – GB826930

It’s not often that we hear what has inspired an inventor to make an particular invention, but there’s no doubt that invention like genius is 99% perspiration, as Edison observed. But where does the 1% inspiration come from- why, anywhere!

I had the privilege of speaking to an inventor, Dennis William Ginns, who worked for the UK Atomic Energy Authority in the early days of nuclear reactors. The nuclear fuel which powers a reactor is contained in nuclear fuel element cans (cans); these are very long, thin-walled cylindrical aluminium containers which allow heat and neutrons produced by the nuclear reaction to escape. On the one hand the cans had to be thin to allow the heat and neutrons to escape most efficiently, on the other hand they had to be strong (and therefore thick) enough to withstand mechanical handling, and it simply didn’t seem possible to reconcile these two contradictory needs. One of Dennis’s tasks was to solve the problem but he couldn’t see quite what to do. Then, one day walking to work, he came across his inspiration – a hedgehog! “There’s a well protected fellow in a soft coat.” he said to himself and the idea of soldering aluminium spines onto an aluminium can grew in his mind. A lot of work later and the spines had become fins, easier to produce, and patent GB826930 was filed.

Note: it was not published until some 13 years after application, the technology was considered so sensitive and important that it was classified as secret until 1960.

Figure 1 of GB826930, showing a perspective view of the can