Sure, but it raises the number of nukes needed at launch considerably, holding the travel time constant. More than double, even leaving aside considerations li

Sure, but it raises the number of nukes needed at launch considerably, holding the travel time constant. More than double, even leaving aside considerations like the additional storage size. Also, designing nukes that last for 150 years before being used is non-trivial (can't use tritium in the initiator, for example; it decays too rapidly for that).