The eccentric engineer: The darkest days in Rjukan

Rjukan, in Telemark, Norway, is a city that owes its existence to an engineer. Sam Eyde completed his engineering degree at Berlin in 1891, and went into business planning new railways first in Germany and then back in his native Norway, building up one of the largest civil engineering companies in Scandinavia.

This business took him to the area of Rjukan in 1902. At the time, this wild area in the south of the country was only sparsely inhabited, and where the town would one day spring up was just a deep valley – so deep that for six months of the year sunlight does not even reach the bottom.

What Rjukan did have was what Eyde was discovering to be one of Norway’s greatest assets – waterfalls – in particular, the eponymous 100-metre-tall Rjukan waterfall. Eyde realised that the power of this reliable and massive waterfall could be harnessed to produced hydro-electric energy, which in turn could be used in industrial processes. So, the Vemork power plant came into existence to feed the insatiable power demands of Eyde’s potassium nitrate fertiliser factory. And with those two installations, the town of Rjukan came into being as a rather gloomy home for the employees of Eyde’s famous company, Norsk Hydro.

If the name Vemork rings a bell, you may have been watching too many repeats of ‘The Heroes of Telemark’. Like many chemical plants, the Vemork site had unexpected by-products. In particular, the fixation of nitrogen by electrolysis to synthesise potassium nitrate produced deuterium oxide, better known as ‘heavy water’. In fact, Vemork in the 1930s was the world’s largest producer of heavy water (about 12 tonnes a year). As Europe edged towards war, this started to bother the Allies, particularly after Lise Meitner and Otto Frisch concluded that deuterium oxide would make an excellent neutron moderator in the production of plutonium for an atomic bomb.

Keen not to let the Nazi regime develop atomic weapons, the French secret service managed to spirit away the entire stock of heavy water before war broke out, but the plant remained in operation and when Germany invaded Norway, the possibility of Germany gaining the atom bomb again reared its ugly head. This is where ‘The Heroes of Telemark’ comes in – a surprisingly accurate version of the three planned sabotage missions by SOE-trained Norwegian commandos and British Royal engineers.

For the full details I suggest you watch the film, but, in short, despite the failure of the second operation and the capture, torture and execution of many of the local commandos, the third operation succeeded in getting saboteurs down into the dark valley, across the river and up into the plant where they successfully destroyed the heavy water electrolysis chambers with explosives. The Germans tried to ship away the extant stock of deuterium oxide, but Norwegian partisans managed to sink the rail ferry that was carrying it in one of the deepest parts of Lake Tinn, ending Germany’s heavy water ambitions.

At this point the people of Rjukan might reasonably have wished than Sam Eyde had never ventured into their shadowed valley. Despite commandos deliberately leaving a Thompson sub-machine gun at the site to show that the raid was British and not Norwegian, retaliations against the partisan forces in the valley were frequent and savage. To add to their troubles, the USAAF now began a series of high-intensity bombing raids on the site to ensure production was not restarted. Locals may have been grateful for this, but they all had to work in the factories under bomb attack from their own allies, until the occupiers abandoned the plant in 1944.

Yet the brave people of Rjukan put up a large statue of Sam Eyde in the town square, perhaps thanks to another of his ideas – or rather, an idea from one of his workers that he attempted to put into action, to bring winter light into the town. He failed due to the technological limitations of his day, and instead, Norsk Hydro paid for a cable car to take townsfolk up the mountain to where the sun still shone.

Since 2013, though, the winter sun has penetrated the heart of the town thanks to three large, solar-powered, computer-controlled mirrors, 450 metres up the hillside, steadily tracking the sun and reflecting its rays down on to the square, bathing it in bright sunlight.

While an unfortunate by-product nearly brought disaster to Rjukan, and perhaps the world, the man who built the town now basks in a far more friendly form of nuclear power – that great warming fusion ball we call the Sun.