[whizzter]

It seems like less well researched hunches on nuclear processes often led programs astray with bad calculations.

The Germans focused on heavy water for their reactors instead of just using graphite, because they miscalculated neutron absorption allegedly because of measuring graphite pieces rich in boron. The entire program was subsequently after the heavy water sabotages in Norways seemingly taking too long and was depriorititzed (Did the world luck out on small happenstances like this and Lenard?).

The Swedish program likewise initially overestimated the required amount of fissile materials needed by an order of magnitude and it wasn't clear until years later, could an accurate figure have made the program progress quicker before public opinion turned? (a lot of complex and expensive designs were worked out to produce at the higher rate)