Norwegian Heavy Water Sabotage - Historical Perspective

Historical Perspective

Recent investigation of production records at Norsk Hydro and analysis of an intact barrel that was salvaged in 2004 revealed that although the barrels in this shipment contained water of pH 14 — indicative of the alkaline electrolytic refinement process — they did not contain high concentrations of D₂O. Despite the apparent size of shipment, the total quantity of pure heavy water was limited, with most barrels only containing between 1/2–1% pure heavy water, confirming the success of the Operation Gunnerside raid in destroying the higher purity heavy water. Deuterium represents only 0.015% of the hydrogen in water and must be enriched to greater than 99% for use in a reactor. The Germans would have needed a total of about 5 t (5.5 short tons) of heavy water to get a nuclear reactor running; while the manifest indicated that there was only 500 kg (0.55 short ton) of heavy water being transported to Germany. Hence the Hydro was carrying too little heavy water to supply one reactor, let alone the 10 or more tons of heavy water needed to make enough plutonium for a nuclear weapon.

With the benefit of hindsight, the consensus on the German wartime nuclear program is that it was a long way from producing a bomb, even had the Norwegian heavy water been produced and shipped at the maximum rate. Nevertheless, the unsuccessful British raid (FRESHMAN) and the feats of the Norwegian saboteurs (SWALLOW, GROUSE, GUNNERSIDE) made the top secret war against the heavy water production internationally known and the saboteurs national heroes.