the rate of a nuclear reaction can be changed by??

Question

i know adding a catalyst to a normal reaction can but to a nuclear im not sure.

increasing temp
decreasing pressure
adding a catalyst
none

I suppose it all depends upon how you define a catalyst. Perhaps in a small way increasing T might help but it isn't likely. Decreasing pressure won't have much effect. A catalyst, in the usual sense of a catalyst, won't change it. I think the intent of the problem is to answer none. Adding a neutron or a proton or a helium nucleus to the nucleus of another atom can have a dramatic effect. And I suppose we might even consider a neutron as a catalyst. The definition of a catalyst is something that increases the rate of a reaction without being changed as a final product. In a nuclear reaction, a neutron can be added to another nucleus which will make it unstable and it can split. The original neutron is still a neutron. However, I have never heard of a neutron being used in the sense of being a catalyst for a nuclear reaction.