If that simulation would be conscious, wouldn't it be just as bad (if not worse) as performing experiments on animals ? and if it wouldn't be conscious, wouldn't it conflict with the beliefs of most scientists on the origin of consciousness ?
If the HBP is really a success and the simulation is conscious, then the simulation should probably get similar rights and protections as a human. ( Whatever freedom of movement means for a supercomputer is a rather interesting additional question. ) And this would likely mean, that the possible experiments on such a simulation need to be severely restrained. On the other hand, if a sufficiently advanced simulation of the human brain would not be conscious, then we run into trouble regarding the purely physical nature of human brains.
However, I tend to think that a more rigid definition of consciousness is needed ( and may well be one of the major results of the HBP). I think this, because I am thinking about similar complex programs as a full brain simulation, which demonstrate complex behavior, but no consciousness. ( For example very detailed simulations of super nova explosions.)
A digital computer simulation would be fundamentally different from a brain. It could be replicated, backed up, and restored with perfect fidelity. In my view that completely changes the ethics of experimentation.