Actually I meant 45 kg and 9955 kg. I adjusted the numbers several times looking for values which would come out with round-ish quantities but %U235 values in the right ranges for HEU and DU.
Annnnd just spent an hour reading that delightful Colin Percival Putnam thread. Thanks for the reminder on that. Man, people really loved to hate on Tarsnap because of his perceived arrogance.
On the contrary, Colin is highly regarded on HN both for his technical ability, and his success in business (despite breaking from conventional wisdom in how to be successful in business).
You mean 40 kg and 9960 kg (so the sum is 10000 kg)? <insert "Were you a Putnam Fellow?" joke here>