Unlike Dimona, Iran's Bushehr Reactor Not Useful for Weapons-Grade Plutonium

By Thomas R. Stauffer

Is Iran actually on the path toward nuclear weapons? Is there hard evidence of any substantive activities? Or is this claim simply yet another canard, echoed and reinforced in the Israeli and Jewish media? Recent precedents for such warmongering disinformation have been all too plentiful: the faked story about Iraq's imports of uranium ore and the "intelligence reports" of Iraq's inventory of aluminium tubes for constructing centrifuges are but two examples of widely promulgated—but false—stories.

Testable evidence of Iran's nuclear weaponry activity is, in fact, quite fragmentary at best. Independent verification is non-existent, and the sources which claim that Iran is "going nuclear" are the same which have been discredited in earlier agitprop efforts to assert Iraqi possession of nuclear or other weapons of mass destruction.

Indeed, it is impossible to say whether or not Tehran is lurching toward a nuclear weapons program; only still secret sources could establish that point. Nor, of course, can the negative ever be proven. It is possible to note, however, that the affirmative arguments thus far are either purely speculative or testably false. In particular, one key piece of the claimed evidence—the argument that the power reactor being built at Bushehr is part of a weapons program—is nonsensical and implausible. Just as was the case with Iraq's alleged centrifuge tubes, the physics are wrong.

Simply put, the reactor at Bushehr is the wrong kind of nuclear reactor for producing weapons-grade fissile material. It will produce the wrong kind of plutonium (all uranium-fueled nuclear reactors produce some plutonium as a byproduct, but only one isotope is desirable for weapons). It can be operated only in the wrong way with regard to yielding plutonium, and it is the wrong kind of reactor as well, in the sense that a facility such as Iran's is easily amenable to close surveillance, not lending itself at all to any covert diversion—of even the wrong kind of plutonium.

What is crucial are the reactor's technology and nuclear chemistry. We can highlight what constitutes a feasible route to producing bombs from a reactor versus what does not by comparing the planned reactor at Bushehr with Israel's reactor at Dimona, which has been in operation for almost 40 years to produce plutonium-based nuclear bombs. While both are "reactors," there are crucial differences.

Israel's weapons reactor has certain key characteristics. It is graphite and heavy water-moderated, a configuration which optimizes production of weapons-quality plutonium. Too, the Dimona reactor can be refueled "on line," i.e., irradiated fuel bundles can be removed while the reactor continues to run. It is not necessary to shut down the entire reactor in order to extract the fuel rods containing the fresh plutonium. Also, it yields the right kind of plutonium—i.e., a very high percentage of Pu-239. Finally, reprocessing of the fuel pins to extract the plutonium is comparatively easy in the case of Dimona because the radioactivity level is relatively low.

In particular, "on-line" refueling provides three extremely important advantages for the production of plutonium bombs. First, fuel pins containing the uranium fuel and the new plutonium can be extracted regularly and after very short exposure in the reactor. Residence in the reactor can be as little as several weeks or, at most, a month or two (compared with 212 to 312 years in the case of other reactors). Short exposures are highly desirable for a bomb designer because the longer a fuel pin remains in a reactor, the lower the quality and usefulness of the plutonium. True, there is more plutonium, but relatively more of the wrong kind. The desirable isotope is Pu-239. If a fuel pin is irradiated for long periods, more and more of the heavier isotopes are produced: Pu-240, 241 and 242. Because these cannot be separated from the desired Pu-239, the more the heavier isotopes are present the much more difficult—and dangerous—designing a bomb becomes.

Secondly, since the reactor is not shut down, it is much easier to conceal the fact that pins are extracted and replaced with fresh ones—making control or surveillance much more difficult.

Lastly, it is much easier to reprocess the "low burn-up" fuel pins in order to separate the fissile plutonium from the non-fissile uranium fuel. The radioactivity level of a fuel pin is roughly proportional to the length of time it resides in the reactor. Dimona-type fuel is some 30 times less radioactive, and therefore some 30 times less hazardous to handle, than that from a reactor of the type being built at Bushehr. Reprocessing power reactor-grade fuel pins involves much larger, more complex, and more elaborate facilities because of the need to provide protection against high radioactivity levels.

The contrast between the Dimona reactor and the one being built at Bushehr is telling. In Iran the Russians are constructing one of their VVER models—a pressurized water reactor (PWR) of a type widely used in Russia and exported to Finland and former COMECON countries. It is quite different from the RBMK, graphite-moderated reactor of the type which burned at Chernobyl—the key difference being that the VVER reactors must be shut down completely before one can even begin to remove irradiated fuel. Any effort at unscheduled or unsupervised diversion of fuel pins, therefore, is easily detected. It is thus technical error—or willful disinformation—to equate VVER reactors with weapons programs.

With respect to diversion of plutonium, whether of the "right"or "wrong" kind, the Russians have specified that all spent fuel will be returned to Russia. Indeed, such a clause is contained in all of Moscow's export contracts, and has been scrupulously observed to date. Is it even remotely probable that any diversion would escape detection—and not elicit a response—by Russia, quite aside from the fact that Western intelligence also would be alerted? To argue otherwise is to imply Russian complicity.

Once again it is instructive to review the case of the Israeli production of bombs at Dimona. In spite of the secrecy of that operation, it was known to U.S. intelligence that Israel was producing weapons-grade plutonium at the Dimona site—just as it was later known that they had stolen weapons-grade uranium from the U.S. Since it is much more difficult to conceal any diversion from a PWR, and since the Iranians have little or no ability to suppress reporting, it is scarcely credible that the Bushehr plant could be used to support a nuclear weapons project—even if the plutonium otherwise were useful.

To reinforce the charge that the Bushehr reactor is part of a covert Iranian weapons program an economic argument also is pulled out of the hat. Former CIA director James Woolsey, currently a board member of the Jewish Institute for National Security Affairs (JINSA), has neatly encapsulated the Israeli argument:

"Well," Woolsey has postulated, "there is no underlying [reason] for one of the greatest oil producers in the world to need to get into the nuclear [energy] business…unless what they want to do is train and produce people and an infrastructure that can have highly enriched uranium or plutonium, fissionable material for nuclear weapons."

While the question is valid, however, the conclusion does not follow. Iran does enjoy very large reported reserves of natural gas in offshore Gulf reservoirs. Ironically, however, natural gas is both a) in short supply and b) relatively expensive. The economics of having several nuclear stations to provide base-load power, therefore, are not necessarily unfavorable. More insightful analysis is required. Indeed, the overall cost calculations of domestic gas versus nuclear power are close.

The Russians have offered an attractive price, given their surplus manufacturing capacity and need for foreign exchange. The design of the reactor is proven, is simple, and has been particularly successful when adapted to international safety standards, as in the case of the two smaller versions built in Finland. Those two Loviisa reactors have exhibited record levels of reliability and performance.

Another consideration for Tehran is the fact that there are valuable alternative uses of available natural gas. It is used to substitute for oil wherever possible, in order to free up oil for export—clearly a high priority. Gas also is vitally needed for reinjection into the existing, producing oil reservoirs. The projects for secondary recovery, which would require very large volumes of natural gas, are long overdue, constrained by lack of capital and also by lack of access to the best technologies for such projects—one area in which the U.S. sanctions have had an effect upon Iran.

Additionally, Iran has the opportunity to export natural gas, either by pipeline to Turkey or as liquefied natural gas (LNG) to the subcontinent. Indeed, if one invokes the analyses used by U.S. diplomats to justify gas from Azerbaijan or Turkmenistan to Europe, that export value is very high indeed. Thus, reflecting once again the inconsistencies in U.S. diplomacy, Washington's own arguments support the economic rationale for nuclear power in Iran.

The earlier proposal for nuclear power in Iran, raised by the late shah, was indeed unjustifiable. Nor is it a model. In the mid-1970s, shortly before he was overthrown, the shah announced a program of 12 world-scale nuclear power plants. Like the 1,000-plus attack helicopters which gathered dust on airstrips near Isfahan, this was chutzpah. The number of reactors was grossly disproportionate to the technical capacity of Iran's power grid, and gas was a free good, being burned off for lack of market or need. At the time Iran's almost desperate need for gas for reinjection was not recognized at the highest level, where it was believed that Iran could continue to increase oil production without constraint. While the economics then were distinctly implausible, it is quite irrelevant to rehash the fallacy of that posture of 30 years ago in the light of the quite different circumstances which prevail today.

The testable evidence, therefore, that the Bushehr reactor is part of an Iranian nuclear weapons program is either false or immaterial. That may be irrelevant, however, since a political truth can be created if a point is repeated often enough. The mainstream American media refer to Iran's weapons program not as supposition or allegation, but as fact—exactly analogous to the media's repetition of the connection between Iraq and al-Qaida. Even though there was never a shred of evidence, polls show that some 60 percent or more of Americans believed in that link.

The current campaign vis-ˆ-vis Iran may be no less successful—illustrating once more that truth is an early casualty of war.

Thomas R. Stauffer is a Washington, DC-based engineer and economist who has taught the economics of energy and the Middle East at Harvard University and at Georgetown University's School of Foreign Service.