Some japanese scientists have designed an accelerator to zap nuclear weapons with a high energy beam of neutrinos. When the neutrino interacts w/ the neutron it will cause the neutron to decay. If you do this to enough of the nuclear material the chain reaction will not be able to sustain itself and no "boom".

We'll just overlook the generation of rouge alpha (He+ particles) and high speed neutrons which will probably cause a lot of radiation poisoning.