Megatons to Megawatts
The Megatons to Megawatts program is an initiative between the United States and Russia to turn Russian nuclear warheads into fuel for commercial nuclear reactors in the US. It is run by non-government agencies and is the first commercially-based nonproliferation agreement in the world.
The program was founded to address the potential threat posed by the surplus of nuclear weapons left in Russia after the fall of the Soviet Union. The weapons-grade uranium available in them could be sold by scientists or former Soviets, fueling proliferation of nuclear weapons and threatening international security. In an effort to prevent this, officials in the United States and Russia began collaboration on the concept of utilizing the salvage value of the warheads by recycling the fuel in 1990. A formal agreement, called the US–Russia Highly Enriched Uranium Agreement, was signed by both parties on February 18, 1993. It is commonly referred to as the Megatons to Megawatts program or the HEU deal. Additionally, in 1994 the United States, Russia, and the Ukraine signed the Trilateral Agreement, which called for Ukraine to send its nuclear weapons to Russia for inclusion in the project.
The agreement outlines the details of dismantling the highly enriched uranium (HEU) in the weapons into low enriched uranium (LEU) and shipping it to the United States, where it is used in commercial reactors. The planned lifespan of the project is twenty years, during which time 500 metric tons of HEU, equating to about 20,000 nuclear warheads, are scheduled to be used. The process is run by two commercial agents, the United States Enrichment Corporation (USEC) and Tekhsnabeksport (TENEX), a subsidiary of Russia’s Ministry of Atomic Energy (MinAtom).
The weapons are dismantled in one of four different facilities in Russia. The HEU is extracted and processed to obtain 5% low enriched uranium hexafluoride (UF6), which is then transported to St. Petersburg. From there it is shipped to USEC’s facilities in Paducah, Kentucky and distributed to utility companies like Westinghouse. They use the LEU to fabricate uranium dioxide pellets which are used as fuel in nuclear power plants in the US.
The program is completely a commercial enterprise, and worth $8 billion over the span of twenty years. The program’s foundation works in conjunction with the salvage value of unused nuclear warheads. At the beginning of the process, TENEX is logistically and financially responsible for the treatment of the HEU into LEU. Once the LEU reaches St. Petersburg, it is under USEC’s control, who buys it from TENEX at two-thirds of the full value of the uranium. USEC actually only pays for the enrichment process, but since that value is contained by the uranium itself, USEC must take all of the material. The remaining one-third of the price that USEC does not pay is the price of the “feed component”, which is the material that is left after the enrichment has been used up. USEC then sells the LEU to its customers, which is its sole source of profit since it is not government-funded. However, USEC must return the uranium material to TENEX to account for the difference in price, since TENEX holds ownership of the feed component. Therefore, USEC’s customers return natural uranium to USEC, who ships it back to TENEX in quantities equal to the amount of feed originally received. Also, 1.5% LEU is used by TENEX initially to treat the HEU. USEC pays for this in the form of natural uranium also. It is not actually used in the HEU process; it is simply compensation to TENEX, who can then sell it to other customers.
The price for this fuel is also a concern of this program. The United States was determined to have these nuclear weapons controlled as soon as possible, and therefore is paying a lot of money to have them reprocessed. So far USEC has paid over $2.5 billion and by the end of the program the total cost will be $8 billion. These high prices mean the price of this reprocessed fuel is much higher than using natural uranium, and thus the cost of the energy produced is much higher.
The conversion of High Enriched Uranium (HEU) Russian Nuclear Warheads into commercially useable Low Enriched Uranium (LEU) is a step by step process that takes place at several nuclear facilities in Russia. HEU is defined as uranium enriched to over 20% . Enrichment is necessary because naturally occurring uranium contains only 0.7% of the rest being . Uranium-235 is easier to use in the fission reaction. The down-blending process or de-enrichment is dismantlement, oxidation, fluorination, dilution, transfer to cylinders, shipment to St. Petersburg, arrival at USEC, and finally shipment to fabricators.
First, the nuclear warheads are dismantled at Russian assembly/disassembly facilities. The HEU components are then machined into metal shavings. These shavings are then heated and converted into uranium oxide and any contaminates are chemically removed. This HEU oxide is then fluorinated to HEU hexafluoride . The HEU hexafluoride is now ready to be down blended. The highly enriched UF6 is blended with 1.5 percent LEU to produce a final product of approximately 5% low-enriched UF6, which is desublimated for storage in steel containers. This LEU can now be fabricated into uranium dioxide fuel pellets which are widely used in the U.S. commercial nuclear power industry.
Essentially most nuclear power plants work off of the Rankine cycle. Steam is the working fluid which is created by heating water from a fission chain reaction. The reactor vessel, which is where the reaction occurs, can be modeled as the boiler. The steam then turns a turbine generator couple to produce power. Cooling water is then used to condense the steam back into liquid water. Finally a pump circulates the cooling water back into the reactor vessel. (See FIGURES 1-2 and 1-3)
So where does Megatons to Megawatts enter into this cycle? The LE is a fissile material, meaning it can be fissioned by neutron bombardment of any energy. After the fuel in inserted into the reactor core, it is bombarded with neutrons and fission occurs creating heat. Fission is essentially a neutron impacting a nucleus and splitting it usually into two fragments. The major products of this fission are the fragments, gamma rays, and neutrons. These neutrons then hit another uranium nucleus and another fission occurs, then another and hence a chain reaction. The heats from these reactions are what cause the water in the core to flash to steam and drive the turbine producing electricity. This LEU accounts for one-tenth of American’s electricity.
The greatest benefit of Megatons to Megawatts is that it protects national security while at the same time providing electricity to the U.S. economy. After the fall of the Soviet Union, Russia’s economy was crumbling. Scientists, military personnel and public officials looked to benefit by selling the nuclear warheads to third parties. Many nuclear warheads in Russia were located in facilities of low security, making it an ideal target for proliferation. The United States and Russia hoped to stop this threat by parenting a program called “Megatons to Megawatts.” Thus far, the program has proven to be successful. It helped to stimulate Russian’s economy, by utilizing the salvage value of the warheads to funnel money and employment to it.
Using uranium from recycled warheads is more environmentally friendly than other fuel sources. Nuclear power produces negligible emissions compared to producing coal power, and this recycling program provides most of the fuel for nuclear power generation. This energy source helps reduce the burden of powering the country, 10% of the electric power generated in the US is produced from converted weapons. One of the negative environmental impacts of nuclear energy is the mining of the uranium. This program provides fuel to nuclear plants that has already been mined, reducing the plants need to go and cause more damage by mining more uranium.
Like any program benefits, there will always be cons. Nuclear power generation still produces spent waste that needs to be disposed of. The difference is this waste is not as immediate a threat as an arsenal of nuclear weapons is. There are many people concerned about what happens to the fuel when it is separated from the weapons. After the weapons are taken apart the materials are stored before they are reprocessed. Often times the places where these materials are stored is even lower security then the missile storage. This material is highly dangerous and much easier to obtain in pieces, than stealing an entire warhead.
Megatons to Megawatts continues to perform as expected and on schedule. The first shipment of uranium from Russia arrived in the US in June of 1995. As of September 2005, enough uranium had been used to account for the elimination of 10,000 Russian warheads. Currently (up to September 2007), 315 metric tons of HEU have been disposed of, resulting in 9,200 tons of LEU and the destruction of 12,615 nuclear warheads. The program has thus far been successful with a reduced the threat of proliferation while at the same time providing an economically viable product to benefit the United States.
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Sonntag,Borgnakke,Van Wylen “Fundamentals of Thermodynamics” John Wiley & Sons, INC.: 2003