The Heavy Water War

The Heavy Water War Teaser
We started watching this series on Netflix last night. It's pretty good. Back during WW2, the USA wasn't the only country trying to build an atomic bomb, Nazi Germany was working on the idea as well. 'Working' might be exaggerating their effort a bit, flailing might be a more apt description. But we didn't know how inept their efforts were, I mean the Germans are obviously very talented technically. Maybe they will succeed, and we sure don't want that, so we need to stop them if we can. Failing that we need to slow them down as much as possible, hence the raids on Norsk Hydro.

We started watching this and I'm wondering how it is that Norway has this monopoly on heavy water? Do they have some mystical spring where they get an abundance of the stuff? It took a little digging, but what I eventually figured out was that they were electrolysing water to get hydrogen so they could make fertilizer. They had built a power plant and factories, in fact a whole town, all to produce mass quantities of fertilizer.

All water contains a very small amount of heavy water, something like 0.03%. Electrolysis tends to preferentially break down light (normal) water, so after you have been running your electrolysis for a while, the water you are left with has a higher concentration of heavy water. Since heavy water is such a small percentage of natural water, in order to get useful amount of heavy water, you need to be electrolysing tons of water, which is what they were doing to Norsk Hydro.

Norsk Hydro Power Plant. The pipes running down the side of hill supply water to the turbines that drive the generators that make the electricity that is used to electrolysis the water.

There have been a number of films made about this. I saw one some time ago. There is one from 1948 available on YouTube.