Telemark, Occupied Norway · November 16, 1943

In the spring of 1940 Norway fell under the Nazi jack­boot in a cam­paign that lasted 62 days and cost 5,000 lives on both sides. Three and a half years later, on this date in 1943, a mas­sive day­light bombing raid by 143 U.S. Army Air Forces B‑17s caused ex­ten­sive damage to Norway’s German-controlled Norsk Hydro’s plant near Rjukan in Tele­mark County. The fortress-like electro­chemi­cal and hydro­electric plant was im­por­tant to the German nuclear energy project, which needed heavy water (deu­te­rium oxide) to pro­duce nuclear wea­pons. (Along with graphite, heavy water was and is a prime can­di­date for mod­er­ating the energy of neut­rons so that it can sus­tain a nuclear reaction, or nuclear fission.)

Earlier in February 1943 the plant had been sabo­taged by a team of Brit­ish Special Opera­tions Execu­tive (SOE)-trained Nor­we­gian com­man­dos in an opera­tion code­named Oper­a­tion Gun­ner­side that turned out to be the most suc­cess­ful act of sabo­tage in World War II. The entire in­ven­tory of heavy water pro­duced during the Ger­man occu­pa­tion—over 500 kilo­grams—was de­stroyed along with some criti­cal piping and tubes. By April, how­ever, the plant was again pro­ducing heavy water and attracting the atten­tion of the U.S. Army Air Forces brass.

The severity of the November 16 American bombing raid and the likeli­hood of further Allied air raids con­vinced the Germans to aban­don the Norsk Hydro plant and move the remaining stocks and cri­ti­cal com­po­nents to Germany. A Nor­we­gian sabo­teur thought other­wise. On Febru­ary 20, 1944, Brook­lyn-born Knut Hau­kelid, using 19 lb (8.6 kilo­grams) of plas­tic ex­plo­sive, sank the rail­way trans­port ferry on Lake Tinn (Tinnsjå) and with it pretty much all of Germany’s nuclear wea­pons research. A largely fic­tional Holly­wood account of the sabo­tage, The Heroes of Tele­mark (1965), starred Richard Harris as Knut Haukelid.

Even before the sinking, the num­ber of Ger­man scientists working on applied nuclear fis­sion had begun to shrink, with many applying their talents to more pressing war­time demands, while some were drafted into the Wehr­macht to serve (and die) on the East­ern and West­ern fronts. At the end of the war, the Allied powers com­peted to ob­tain sur­viving com­po­nents of the Ger­man nuclear indus­try (person­nel, facili­ties, and materiel, just as they did with the V‑2 rocket program.

The Norsk Hydro Plant and Railway Ferry

Norsk Hydro's Hydrogen Production Plant at Vemork Hydroelectric Plant, Rjukan, Norway, 1935Norsk Hydro's SF "Hydro"

Left: Norsk Hydro’s Vemork Hydroelectric Plant at Rjukan, Nor­way, in 1935. At Rjukan a large water­fall was har­nessed to pro­duce chemi­cals related to the pro­duc­tion of artifi­cial ferti­lizer, including am­monia, potas­sium nitrate, heavy water (deu­terium), and hydro­gen. In 1925 the plant part­nered with the Ger­man com­pany IG Farben and later with Britain’s Im­perial Chemi­cal Indus­tries (ICI). Starting in Decem­ber 1934, the Rjukan plant was the only loca­tion in Europe that mass-pro­duced high con­cen­tra­tions of heavy water by means of elec­trol­y­sis in the Hydro­gen Pro­duc­tion Plant shown in the fore­ground of this photo­graph. The heavy water plant was closed in 1971. Today the origi­nal power plant is an indus­trial museum. One of its exhibi­tions covers the five heavy-water sabo­tage opera­tions conducted between 1942 and 1944.

Right: The twin-stack steam-powered railway ferry SF <i>Hydro</i> operated on Lake Tinn (Tinnsjå, Tinnsjø). The 19‑mile‑long ferry trip made it pos­sible for Norsk Hydro to trans­port its chemi­cals from the plant at Rjukan to the coastal port at Skien. On Febru­ary 20, 1944, the ship was blown up by the Nor­we­gian resis­tance move­ment at Lake Tinn’s deepest point (1,411 ft) with a load of heavy water on­board headed for Nazi Germany for use in that coun­try’s nuclear wea­pons pro­gram. After the war it was dis­covered that the Germans were not as close to making an atomic bomb as the Allies had ini­tially feared. The wreck of the ferry and its invalu­able contents were discovered in 1993.

History of Norway-Based Efforts to Sabotage German Nuclear Weapons Program