“Unsolvable” is an absolute term. Certainly the reactor had technical problems that had defied solution up to that point. When we looked at the possibilities, all of them were highly risky, expensive, and lengthy. It was clear to us that it was not just the existence of a positive power coefficient of reactivity. It was that the actual behaviour of the reactor did not mirror the modelled behaviour of the reactor. For this reason, we were unable to state unequivocally that we knew what was causing the readings we got.
