In the last months of the Second World War, many devout Nazis believed Hitler had a final ace
up his sleeve. The media had played up German research into so-called “Wonder Weapons” for
years, and even as things crumbled around them, people believed these secret weapons could still
win them the war. It’s true — Germany did have a few secret weapons programs, including plans for a
nuclear device, but they were stymied early on by a plucky gang of Norwegians and Danes. This is the
story of the Scandinavians who fought to ensure the Third Reich would never get a nuclear bomb.
In the 1930s, it seemed German scientists were making all the discoveries in nuclear physics.
It was Austrian and German scientists who discovered nuclear fission in 1938,
and the German experimental physicist Wilhelm Hanle who first proposed the
idea of using fission inside a machine to create large amounts of energy. Georg Joos was
fascinated by the idea and formed a research group called the Uranium Club
to investigate possible uses of nuclear fission in early 1939. Within a few months,
Joos and Hanle notified the Reich of the possible military applications their research had.
The day World War Two began, a second Uranium Club formed. It was organised by Kurt Diebner,
the head of the Reich’s nuclear energy project, and its first meeting was held on September 16th.
The invitees represented the top physicists and nuclear chemists in Germany. The big
brains included Hans Geiger, inventor of the Geiger counter, and Werner Heisenberg,
who helped discover quantum mechanics. Heisenburg became the scientific leader,
and the Kaiser-Wilhelm Institute for Physics was placed under military jurisdiction and put
at his disposal. At this early stage, Heisenburg believed that “in principle,
atomic bombs could be made,” but he was unsure how long it would take.
He reportedly didn’t want to get Hitler’s hopes up, saying, “I didn't report it to the Führer
until two weeks later and very casually because I did not want the Führer to get so interested that
he would order great efforts immediately to make the atomic bomb.”Heisenburg knew,
as did the other scientists, that they couldn’t promise anything right away. If Hitler heard
about a world-ending weapon in 1939, he would have given the Uranium Club unlimited resources,
but an extremely limited timeframe. Unsatisfactory results could have had deadly consequences.
Nevertheless, the physicists got to work. Their main problem, which is no different for anyone
wanting to acquire a nuclear weapon, was producing enough fissile material for an explosive chain
reaction. Normal uranium that you can dig out of the ground, uranium-238, is too stable to make a
bomb out of—it requires too much energy to get a chain reaction going. But hidden deep inside
that boring form of uranium is the good stuff, uranium-235, which is just waiting to explode.
If you enrich uranium (i.e increase the ratio of 235 to 238—of boom to boring),
you can get a fission reaction to happen. One of the products of this reaction is uranium-239,
which decays into plutonium. The core of Fat Man, the nuke dropped on Nagasaki in 1945,
was made of plutonium. It’s some of the best stuff for making nuclear weapons.
The German scientists had worked all this out theoretically, but they were hung up on
the details. If they got the enrichment process wrong, they might waste some of
their valuable uranium—which the Reich had in very short supply. They tried to moderate their
first fission reactions with graphite but, due to impurities, couldn’t make it work.
The next best thing was heavy water—a rare molecule that can be made via electrolysis.
In the 30s and 40s, Norsk Hydro in Telemark, Norway was the world’s only mass supplier of
heavy water. French intelligence secretly took Norway’s heavy water stocks to Scotland in 1940,
but the plant could make more. When Germany occupied Norway in June 1940,
getting the Norsk Hydro plant running was one of their top priorities.
By mid-1942, British intelligence had worked out that Germany was stockpiling heavy water from
the Norwegian plant to use in the German nuclear program. They had to be stopped,
so a plan was put together. Special Operations Executive recruited plant worker-turned-resistance
fighter Einar Skinnarland, a Norwegian patriot who had escaped to England during the German invasion.
He knew the area well and was to scope it out for an advance party of four more Norwegians.
The operation was codenamed “Grouse,” and the saboteurs were rigorously trained.
In the Scottish highlands, they learnt to plant bombs, navigate by night, and silently kill.
Skinnarland was ready after just ten days of training and parachuted into Telemark to
make contact with the resistance. The other Norwegians followed on October 18th. They
gathered intelligence on German defences, which was used to train two units of Royal
Engineer saboteurs. The plan was for each unit to be loaded into a Horsa glider and
towed to the drop point by a Halifax bomber. They would land the glider silently in the snow, then
navigate to the plant and set up explosives. This part of the Operation was codenamed “Freshman.”
But Operation Freshman went awry. Ice formed on the wings of one Halifax mid-flight,
and the bomber started losing altitude. The glider had to be detached early,
and it crash-landed in Fyljesdal, 200km from the plant. Many of the engineers were badly
wounded and could not go on with the operation. Turbulence forced the second Halifax to descend,
and it crashed into a mountain. The glider was detached just beforehand, though,
and managed to land. Again, most of its occupants were badly injured. Within 24 hours, the Germans
knew of the operation and had arrested all of the British soldiers. Every one of them was executed
as per Hitler’s infamous “Commando Order.” The Norwegians, however, were still at large.
Keen to avoid another debacle, the British decided to let the Norwegians do the sabotaging instead.
Six more special operators parachuted into Telemark in February 1943
and made contact with the original Operation Grouse crew.
This time, they brought their explosives. The operation was called Gunnerside.
The men infiltrated the plant in the dead of night by crossing a frozen river and scaling
a rock face. Once inside, they ran into the elderly caretaker, a man named Johansen. He was a
patriot and decided to help out. Charges were set underneath the heavy water tanks, and a Thompson
SMG was left behind to incriminate the British special forces—sparing the local Norwegians from
Gestapo reprisals. By the time the charges blew, the saboteurs were safely hidden in the forest.
Five hundred kilograms of purified heavy water was destroyed,
making Operation Gunnerside a striking success.
While they may not have had the opportunity to blow up a power plant,
the Danes also helped prevent Germany from building a nuclear device.
Copenhagen’s leading nuclear scientist, Niels Bohr, was spirited away by the resistance.
Bohr made foundational contributions to quantum theory and was well aware
that the physics he investigated could be weaponized to make a bomb.
Heisenburg discussed this possibility with him during a secret meeting in 1941, but Bohr was
firmly against it. It’s not entirely clear what transpired in that meeting, but it seems likely
that Heisenburg wanted Bohr to take an active role in the nuclear program. This, Bohr couldn’t abide.
On September 29th 1943, the Danish resistance transported Bohr and his family to a ship which
took them to Sweden. Rumours had spread that his family was Jewish, and the Gestapo may have been
out to arrest him. This experience gave Bohr a new perspective. He petitioned Sweden’s king,
Gustav V, to declare Sweden a safe haven for Jews fleeing Nazi persecution.
Gustav agreed. Seven thousand Jews, many of whom were scientists, began a mass exodus from Denmark.
Their expertise would not benefit the Axis cause.
Around the same time, scientists working for Heisenburg in the Uranium Club in Germany
were shifted to other projects. Hitler had lost interest in a nuclear device, and Albert Speer,
Reich Minister of Armaments and War Production, felt the resources devoted to the project
could be better spent elsewhere. The Nazis never got their nuke,
in part due to the efforts of a few brave Norwegians and Danes.
But what if they had? If Hitler had become fixated on the idea back in 1939, the Uranium Club might
have gotten the resources and expertise necessary to create a nuclear device before the Allies made
one. What do you think he would have done with it? Drop it on Moscow? Threaten the Allies with
annihilation? Turn Europe into a radioactive wasteland? Let us know in the comments!