Mine is an assumption and an ideal case scenario, most likely it will be 3-4 mirv since for the 2nd strike role you probably aim for heavy hits ie high yield item which is to do the job intended for. Smaller sized lower yield more numbers are probably ok for a land based first strike option, but I too have doubt about feasibility for use when it comes as a 2nd strike role that is for the SLBM to deliver. So its a case of suitability rather than need. Plus the SLBM also has to cater for added penetration aid, mirv bus & liquid RCS + VTP stage, fuel capacity all of which also need to be covered under the total payload mass. So design also face challenge.My God thats 120 warheads per sub. The only critical piece of the puzzle is what is the yield of these warheads? Considering their weight and size they must be in the hundreds of kt. Of course, whether it is boosted fission or pure fusion will change the yield. I'd reckon they are indeed 250 kt hydrogen MIRVs.
If this SLBM is capable of delivering 2 ton class payload via 4 mirvs (excluding everything else) as was originally intended for, then it is ok. Assuming 8 tube silo, 32 high yield warhead is very good for our need. Maintenance for such high end secret goodies is the major challenge in the entire project, to keep every single item in ready condition, so the quality over quantity should be preferable. A good chunk of the resource needed will be for upkeeping and maintaining all elements of it over the intended 40-50 years lifetime.
