BURN IT OR BURY IT?
Burying Warhead Plutonium as Waste is Safer and Cheaper Than Burning it in Reactors
March 28, 1997
The Two Lead Contenders: MOX and Immobilization
Plutonium is a man-made element created by the fissioning (rapid, chain-reaction splitting) of uranium atoms in nuclear reactors. Less than 15 pounds of plutonium---about the size of an orange---is enough to make a nuclear bomb powerful enough to destroy a major city. Nagasaki was devastated by the "Fat Man" bomb containing about 13 pounds of plutonium. During the Cold War, the United States produced over 100 metric tons, and the Soviet Union perhaps as much as 150 tons, of plutonium for use in tens of thousands of nuclear weapons.
With the collapse of the Soviet Union, the United States and Russia have agreed to substantial reductions in their nuclear arsenals. As a result, about 50 tons of plutonium in each nation (a total of 100 tons or more) is likely to be declared surplus to defense needs and require disposal. But plutonium lasts hundreds of thousands of years, an eternity in human terms. Something must be done to minimize the chance that this plutonium might someday be turned back into nuclear weapons.
Both nations have studied this problem for several years, assessing dozens of options, ranging from dumping the plutonium in the ocean, to dropping it down mile-deep wells, to shooting it into the sun. The governments and national science academies of the United States and Russia have concluded that the two most realistic options are: (1) combining the plutonium with uranium into mixed-oxide ("MOX") fuel for irradiation in nuclear power reactors, and (2) immobilization of the plutonium in a mixture of glass or ceramic with highly radioactive fission products, which would be sealed in steel canisters for disposal as waste.
How Would MOX and Immobilization Work?
Both approaches require that the metallic plutonium "pits" be removed from nuclear weapons and converted into an oxide power. In the MOX approach, this powder would be transported to a fuel fabrication plant, where it would be mixed with uranium oxide, made into pellets, and placed in long metal tubes to form fuel assemblies. These fuel assemblies would then be transported to nuclear power plants, where they would be loaded into the cores of the reactors for three to four years of irradiation. The highly radioactive fuel elements would then be discharged and placed in the reactor's spent fuel pool to await final disposal in a geologic repository.
In the immobilization approach, plutonium oxide powder would be transported to a vitrification plant, such as the Defense Waste Processing Facility (DWPF) at the Savannah River Site in South Carolina. The DWPF is now being used to immobilize highly radioactive waste generated by the production of weapon plutonium during the Cold War. In the "can-in-a-canister" approach to immobilization---the simplest and least expensive method---warhead plutonium would be mixed with molten glass and poured into stainless steel cans. These cans then would be placed in larger stainless steel canisters, which would be filled with a mixture of molten glass and intensively radioactive waste. The canisters are then allowed to cool and are stored pending final disposal.
Both approaches produce final waste forms that are highly radioactive and would be likely to kill a thief or terrorist that attempted to steal them. Both approaches "imprison" the plutonium in a waste form, making it inaccessible for weapons use unless the plutonium is chemically separated in an expensive, complex facility known as a reprocessing plant. In this way, these approaches meet the "spent fuel standard" recommended by the U.S. National Academy of Sciences: warhead plutonium would be as difficult to access as the much larger amounts of plutonium now contained in highly radioactive spent fuel from civilian nuclear power plants.
Dual-Track: The Wrong Track
In December 1996, then-Energy Secretary Hazel O'Leary announced that the United States would pursue a "dual-track approach" to plutonium disposition. Research and development would move forward on both the MOX and immobilization approaches, and the President would make a decision in 1998 as to whether one approach, or a combination of both, should be employed. Soon after Secretary O'Leary's departure, the acting head of DOE's Office of Fissile Materials Disposition announced that DOE would "implement both tracks, not just study them for two years." Commercial contracts might even be concluded within the next year for the construction of a MOX fuel fabrication plant and the irradiation of MOX fuel by U.S. nuclear electric utilities. A proposal to send U.S. and Russian plutonium fuel to Canada for use in CANDU reactors is also being seriously considered.
The dual-track approach is being sold as a kind of "insurance policy": if one technology has problems, the other can take up the slack. In reality, by overturning a 20-year U.S. non-proliferation policy opposing the use of plutonium fuels, the policy could waste hundreds of millions, or even billions, of dollars, pose grave risks to human health and the environment, and pose a threat to our national security.
- It's Faster
The Department of Energy's own studies show that the immobilization approach could get started seven years earlier, and be finished 13 years sooner, than the MOX approach. The sooner plutonium can be disposed of, the sooner we can make the arms control and disarmament gains of recent years permanent.
- It's Cheaper
DOE estimates both approaches would cost about the same. This conclusion is wrong. It is based on several fantasies, including:
- the assumption that commercial electric utilities, whose goal is to make profits, will perform this service for free;
- the assumption that utilities will pay DOE just as much for MOX fuel as they would for conventional uranium fuel, when, in fact, they want MOX fuel for free or at a substantial discount;
- the assumption that nuclear utilities, which are unable to compete in a deregulated electricity market with non-nuclear generators of electricity, will continue to operate their reactors to burn MOX fuel without major federal subsidies.
Assuming utilities insist on fees to irradiate MOX fuel, and insist on receiving that fuel at a substantial discount over the price they would have paid for uranium fuel, DOE's own studies suggest that the MOX approach could cost as much as $2.6 billion---two and a half times more than the immobilization approach. Subsidies to keep uneconomic reactors operating could increase this cost by billions of dollars over the next 20 years.
- It's Safer
Neither the United States nor Russia have had significant experience with MOX fuel in light-water reactors, the type of reactor used in commercial nuclear-power plants, and there is no experience anywhere with use of weapons-grade plutonium in MOX fuel.
Use of MOX fuel:
- Reduces the stability of reactor cores, so that operators have less time to respond and maintain safety in the case of rapid changes in the state of the reactor;
- Increases the severity of certain accidents, such as those that cause a sudden cooling of the core;
- Increases the amount of certain extremely toxic radionuclides in the reactor core by a factor of five. In a catastrophic loss-of-containment accident, these additional radionuclides could increase the consequences by anywhere from 10 to 50 percent, and result in additional thousands of latent cancers.
- It's Best for National Security, Non-Proliferation, and Arms Control
Most serious, the "dual track" approach does not account for the MOX option's proliferation risks. The MOX option would clearly encourage the civil use of plutonium, as Arms Control and Disarmament Agency Director John Holum warned in a memorandum to Energy Secretary O'Leary last November:
I recommend strongly that you reject the hybrid option and select immobilization. . . . U.S. decisions on plutonium disposition are inextricably linked with U.S. efforts to reduce stockpiles as well as limit the use of plutonium worldwide. The multi-decade institutionalization of plutonium use in U.S. commercial reactors would set a very damaging precedent for U.S. nonproliferation policy. In contrast, an immobilization-only alternative would have no proliferation downside for either the U.S. or for influencing Russia, and potentially could have important benefits in supporting our continuing efforts with Russia to secure its stockpiles of weapon-usable material. [emphasis in original]
Under the dual-track approach, the U.S. Government would be engaging in MOX activities for the first time on a commercial scale, legitimizing the use of MOX in civil nuclear power programs. As ACDA Director Holum put it:
If the hybrid option is chosen, these countries [Russia, South Korea, and others] would hear only one message for the next 25 years: that plutonium use for generating commercial nuclear power is now being blessed by the United States. No matter how much effort we take in reducing these risks ... the overriding message that we will convey is that civil plutonium use is acceptable.
Such a sea change in U.S. policy would confuse and complicate U.S. nonproliferation diplomacy. It would send the wrong signal to Western Europe, Japan, and other nonnuclearweapon states. The MOX option also presents a greater risk of diversion primarily because of the fuelfabrication stage, a process that is difficult to safeguard effectively. Such uncertain verification could severely limit the trust nations place in an international nuclear armsreductions and n