Gholamreza Aghazadeh said: "This project is considered to be a remarkable feat for our country, through which Iran will acquire heavy water technology, thus placing our country's name alongside world manufactures of this industry."
Tehran has told the International Atomic Energy Agency (IAEA) that the reactor will be used for research and development purposes. But arm experts note that heavy water can also be used in the production of nuclear weapons.
Jack Boureston is director of First Watch International, a private research group that deals with international security issues:
"In a way, it's a dual use, it's a dual-purpose type of a machine. Basically, the civilian purpose would be for producing isotopes which could then be used for medical and agricultural purposes. In addition, the military purpose of this type of a reactor would be to produce plutonium," Boureston said.
According to the Federation of American Scientists, heavy water provides a route for producing the plutonium needed for nuclear weapons. It bypasses uranium enrichment and all of the related technological structures. Heavy water reactors can use natural nonenriched uranium as fuel. The spent fuel can then be reprocessed to extract weapons-grade plutonium.
"The heavy water reactor is a good, fertile ground for producing spent fuel, which can then be separated for producing plutonium. This plutonium will be most probably at a grade that would be easily usable for developing nuclear weapons," Boureston said.
John Eldridge, editor of "Jane's Nuclear, Biological, and Chemical Defence," says heavy water can also be used in the development of thermonuclear weapons.
"It's the thermonuclear weapons that use that science where the two nuclei are fused together. So the development of heavy water -- deuterium and tritium are the two elements that you need that are suitable for this kind of activity -- that is of concern," Eldridge said.
Boureston says Iran's plan to build a heavy water nuclear reactor, called the IR-40, is raising eyebrows given the fact that similar reactors have been used by other countries to produce plutonium.
"Well, this is what makes this such a concern. Many of the reactors that are similar to this particular heavy water reactor have been used in the past for military purposes. India has a reactor that it used for producing the plutonium that is suspected of being for their [nuclear] weapon, and there are other countries that have done similar [things] -- in particular China and perhaps -- we don't know, but perhaps -- Israel and others," Boureston said.
According to Aghazadeh, the basic design of the reactor has been completed. Construction is set to begin early this year.
Last month, Iran signed the additional protocol to the nuclear Non-Proliferation Treaty (NPT), which allows snap inspections of its nuclear facilities. Tehran says that signing the additional protocol proves that it is not pursuing a weapons program.
"Jane's" Eldridge says it is now up to the IAEA to determine the legitimacy of Iran's heavy water project:
"Well, I can't see that [Iran] would need a heavy water plant for civilian use. At least they're being honest, the Iranians, saying they're declaring it. So now it's up to the International Atomic Energy authority inspectors to decide how legitimate and whether there is actually any legitimate use for this particular plant. It may be that there is a use for it which, you know, hasn't been revealed yet or something. So it is possible, but it is very suspicious. I think that that kind of plant has classically in the past been leaning towards the development of nuclear weapons," Eldridge said.
Given the dual use of heavy-water reactors, determining the real purpose behind Iran's efforts will not be easy at this early stage.
"At this point, there wouldn't be a way for inspectors to know whether the 40-megawatt reactor would be used for developing civilian isotopes or for producing plutonium -- and the reason why is because the process is identical," Boureston said.
But he says Tehran's signing of the additional protocol to the NPT treaty will make it easier for UN inspectors to investigate Iran's activities.
"Once this reactor becomes operational, it will go under IAEA safeguards. In addition, most recently Iran has signed the additional protocol. That means that all design information is being made available to the IAEA for their investigations and for their understanding, and that will continue for the life of the reactor. And once the reactor is actually decommissioned, then it will still have to report at certain times," Boureston said.
The IAEA last month condemned Iran for concealing parts of its nuclear activities over the past two decades and warned the country over future violations. However, the agency said it had found no evidence that Iran is developing nuclear weapons.
Iran says its nuclear program is peaceful. An IAEA spokesman told RFE/RL recently that it will take many months to verify that claim.