In keeping with Non Proliferation Treaty
This option draws the red-line for the international community exactly where it is aready drawn by the Non-Proliferation Treaty—i.e. between civilian and military capability.
At the heart of the NPT is the obligation of states parties, other than existing weapons states, not to have a nuclear weapons program: there is no such obligation on states not have an enrichment program, so long as that program does not produce fissile material of weapons grade.