Taking this one problem at a time, I might have the solution to one of those problems (only one ;p). To detonate the DEUT, you could use either CRAY(NEUT) or DRAY with static NEUT in front to copy a NEUT into a QRTZ capsule. I'm testing this out in my underground meth lab rn
you know, NEUT moves randomly, even if it is not moving.
If you at least allow PBCN (after all, it is destructible...) then you could make a PHOT laser with it and put INVS in front to make it a NEUT laser. The NEUT laser would fire in the reactor chamber and ignite the DEUT. The walls of the main reaction chamber would need to let in NEUT though
Put a pixel of ICE(NEUT) in each of the capsules. The initial energy you supply to the reactor to start it up could be used to heat up the first capsule to more than 0C, causing the ICE to melt into NEUT. Boom. The energy would then be used to heat up the next capsule.