While Iran in principle has the right to enrichment as a member of the Nuclear Non-Proliferation Treaty (NPT), the West has insisted that it suspend all enrichment activity until it can assuage international concerns that it is conducting nuclear weapons-related work under the guise of a civilian nuclear power program.
Article IV of the NPT does make reference to the "inalienable right of all the Parties to the Treaty to develop research, production and use of nuclear energy for peaceful purposes without discrimination" – but under the condition that that right is exercised in conformity with Articles I and II, which prohibit the development and/or transfer of nuclear-weapons technology.
"Under NPT, uranium enrichment is a definite right of the Islamic Republic of Iran and any other NPT member. There is no prohibition under NPT over any kind of enrichment for peaceful purposes," Saeed Jalili, Iran's top nuclear negotiator, told parliament yesterday, according to Bloomberg. "It's possible that we may need higher or lower enrichment for other peaceful applications. This is our right, and we must be able to exercise this right."
Iran has enriched uranium not only to the 5 percent level required for nuclear energy, but also to 20 percent, which it says is necessary for a medical research reactor.
But Western powers involved in negotiations – comprised of the five permanent members of the United Nations Security Council plus Germany, and known as the P5+1 – are concerned because enriching to 20 percent is a process that is technically close to enriching to weapons-grade of 90 percent or more.