China’s Policy of Plutonium Recycling
What's the Rationale?
Hui Zhang
Lately, China’s nuclear industry is entering a new round of fast development. China pursues reprocessing of civilian spent fuel and recycling the plutonium thus gained in mixed-oxide (MOX) fuel for light-water reactors (LWR) and in fast breeder reactors. At a time when plutonium recycling programs are being phased out worldwide, this paper will examine whether plutonium recycling makes sense for China, taking into account economic costs, nuclear energy security, and environmental aspects.
China’ Plutonium Recycling Programs
China decided to build nuclear power reactors in the mid-1980s. China’s first power reactor became operational in 1991. By 2004, China has nine reactors in operation at five nuclear power plant sites (with an installed capacity of about 7,010 MWe). These reactors account for about 2.3% electricity generation. Two more pressurized water reactors (PWR) will be in operation by 2005, and then the total installed capacity will be about 9,130 MWe. Because of recent electricity shortages in some provinces, in July 2004 China quickly approved to build four 1-GWe PWRs at Guangdong and Zhejiang. Now, China is considering to built another two 1-GWe PWRs at Guangdong. All these reactors are to be in operation by 2010. China officially plans to increase its nuclear capacity to 36 GWe (about 4% of its total electricity generation) by 2020.
To meet the long-term expansion of its nuclear power program, China adopted a policy of reprocessing and plutonium recycling in the mid-1980s. China plans to reuse the plutonium in LWR MOX fuel and fast breeder reactor fuel. According to the proponents of plutonium recycling, the major motivations for China’s push are the following: China needs to separate plutonium to conserve its limited uranium resources for its growing nuclear power program; it provides energy security; and it increases the safety of nuclear waste disposal.[1]
In July 1997, China began construction of a multi-purpose reprocessing pilot plant at the Lanzhou nuclear complex. This plant has an initial production capacity of 50 t heavy metal per year (tHM/a) and will later provide a capacity of 100 tHM/a. This plant began reception of spent fuel from the Daya Bay reactors in September 2003, and it is ready to reprocess. Commissioning of commercial reprocessing plant (800 tHM/a) is planned around 2020 at the Lanzhou nuclear complex. Recently, a Centralized Wet Storage Facility (CWSF) – with a capacity of 550 t HM spent fuel – has been build next to the pilot reprocessing plant. Since 1985, China has been investigating the disposal of high-level waste (HLW) from reprocessing. Now the Beishan area in Gansu has been pre-selected for deep geological disposal of HLW.
In May 2000,China started construction of the 25 MWe (65MWt) China Experimental Fast Reactor (CEFR). It is a sodium-cooled experimental fast reactor, located about 40 km from Beijing city. It was scheduled to be in commission by 2005. Because delivery of the main reactor vessel is delayed, this breeder is rescheduled to come into operation around 2007. An experimental MOX fuel facility (with a capacity of 500 kg/a) is projected. And a 600 MWe Prototype Fast Breeder Reactor is planed to be built by 2015.[2]
Economic Costs
Since China is focusing on economic development, the economic costs of plutonium recycling should be an important factor in the ongoing debate over the approaches to the management of spent nuclear fuel and the nuclear fuel cycle. The world is realizing that reprocessing and plutonium recycling is more expensive than a oncethrough cycle with direct disposal of spent fuel at least for the next several decades. Is China’s plutonium recycling rational in view of the economic costs?
As a case study, a comparison of the cost of reprocessing for MOX fuel fabrication with direct disposal of spent fuel is examined. Based on the projection of China’s spent fuel generation and the spent fuel storage capacity of the CWSF, it can be concluded that China needs no additional storage by 2020.[3] After 2020,China would have three options for its spent fuel: reprocessing, direct disposal and interim storage. As a reference scenario, the following is assumed:
Reprocessing for MOX: After 2020, additional PWR spent fuel is reprocessed for PWR MOX fuels. After production, the vitrified high-level waste (VHLW) will be stored for 25 years prior to final disposal (i.e., about 40 years after the spent fuel is discharged from reactors. China proposes to dispose of VHLW around 2050 at a prospecting site in Northwest China.)
Direct disposal: After the spent fuel is transferred from the at-reactor pools, it is stored for 25 years before disposal.
Estimates for the reference scenario show that, at a discount rate of 5%, the cost of reprocessing for the MOX fuel option would be over three times higher than that of the direct disposal option.[4] In the analysis, the current average value for the unit price of uranium purchases, reprocessing, MOX fabrication, etc. are used. However, even across a wide range of different assumptions concerning the specific prices for reprocessing and MOX fabrication services, uranium prices would have to increase several times for plutonium recycling to become economically competitive.
Similarly, the costs of recycling plutonium in breeders using current technology, which is dependent on the capital costs of breeders (generally much higher than that of LWR) and on the costs of fabricating and reprocessing breeder fuel and the like, would be much higher than that of the direct disposal option. For example, a new report of Harvard University shows that reprocessing and recycling plutonium in fast-neutron reactors with an additional capital cost, compared to new LWRs, of US$ 200/kWe installed will not be economically competitive with a once-through cycle in LWRs until the price of uranium reaches some US$ 340/kgU, given the central estimates of the other parameters.[5] It means that the uranium prices (current price around US$ 35/kgU) would have to increase over eight times for the breeder option to be economically competitive. This is very unlikely in the foreseeable future.
Nuclear Energy Security
One major motivation for plutonium recycling advocates in China is nuclear energy security. They argue that to continually supply its long-term expanding nuclear power base with its own limited uranium resources, China needs plutonium recycling in order to save uranium. However, such an argument could only make sense if China’s energy supply became much more dependent on nuclear energy and if worldwide uranium resources were much more expensive and would be used up soon. But this is not likely in the foreseeable future.
While China could use up its own currently-proven uranium resources (about 70,000 MTU=metric tons uranium) within a few decades under its current proposed nuclear power program, nuclear energy security would depend on world-wide uranium markets rather than domestic uranium resources, as shown by some countries, including South Korea, that do not have their own uranium production but in spite of this develop nuclear power plants. Unlike the common perception in the 1960s-70s that natural uranium was a scarce resource and breeder reactors had to be developed, now it turns out that natural uranium is abundant, cheap, and available worldwide. A recent estimate suggests that the total amount of uranium recoverable at price below US$ 130/kgU (still much less than the price at which recycling would be economic) is likely about 33-100 MTU, which would supply nuclear energy systems – at the current uranium consumption rate – for hundreds of years.[6] In practice, the amount of recoverable uranium would increase as the uranium price gets higher. Moreover, for the case of nuclear growth in the future, it is estimated that uranium resources at an acceptable price would continue to supply the power reactors with once-through cycles throughout the 21st century, and if the uranium (45 billion MTU) in the oceans is recovered, it will support the nuclear energy system for many centuries.[7]
Furthermore, unlike oil and natural gas that have a fairly limited geographic availability, with, for instance, the Middle East and the Russian Federation controlling about 70% of world crude oil and natural gas reserves, uranium suppliers in the world market are diverse geographically and politically, and unlikely to collude to raise prices or limit supplies. In practice, China is following a policy of “two resources, two markets” (domestic and international) to meet its natural uranium demands.
If disruption of the uranium supply becomes a concern, China can establish a “strategic” uranium stockpile which would be inexpensive to buy and easy to store. This would be a much cheaper strategy than reprocessing and recycling. In addition, the energy systems based on plutonium recycling would aggravate the concerns of energy supply disruption, since such systems are more complex and error-prone than the oncethrough systems,[8] and therefore could lead to a shutdown of nuclear power. For example, the sodium-cooled breeders are more accident-prone for the following reasons: sodium burns on contact with air; sodium reacts violently with water; and sodium is opaque, which makes fault detection much more difficult. Experience demonstrated that sodium-cooled systems suffer serious disruption even in the event of relatively minor failures. Some lessons could be learned from the experience with the French Superphenix breeder reactor. Since it went into commercial operation in 1987, it suffered a series of accidents including sodium leaks and the roof caving in. Before it was permanently closed down in 1997, this breeder stayed shut down for most of its lifetime. Besides breeders themselves, reliable operation of the other associated facilitates including reprocessing and fuel fabrication plants would be more difficult and costly than in the case of once-through PWRs. This is because large quantities of unirradiated plutonium will exist in those facilities, which increases radiological hazards, criticality risks, and security threats. Consequently, the increased possibility of accident or terrorist incidents involving plutonium recycling would has a negative impact on energy security.
Environment Aspects
Proponents of plutonium recycling argue that it can significantly reduce the long-term hazard of buried high-level wastes. However, there remain some questions about this argument. In conventional reprocessing, while about 99.5% of plutonium and uranium is separated, most of the minor actinides (americium, neptunium, and curium) will end up in the HLW together with the fission product. These long-live minor actinides and fission products (I-129, Tc-99) would contribute significantly to the long-term hazard of reprocessing HLW or spent fuels. On the very long term (105 to 106 years), e.g., Np-237, Tc-99 and I-129 constitute the most critical radionuclides. In addition, in the case of recycling plutonium for the MOX/LWR option, the peak dose rate is estimated to increase slightly based on the higher inventory of the dominant actinide isotopes.[9]
To reduce the concern of longterm hazard issues, the ambitious proposals of Partitioning and Transmutation (P&T) have been launched, which aims for chemical separation and neutron transmutation of all nonuranium, long-lived radioactive isotopes in spent fuel. While current P&T programs focus on removing and destroying all those actinides from spent fuel, performance assessments of the proposed repository sites at Yucca Mountain in the U.S. and at Olkiluoto in Finland show that longlived fission products, such as Tc-99 and I-129, are more important than most actinides as sources of long-term exposure risk.[10] And P&T studies have yet to show that this technology can deal effectively with these fission products. Moreover, no technology is yet available to completely remove all these actinides, and any such systems currently under consideration would significantly increase the economic costs of nuclear energy.
Moreover, the short-term costs of P&T activities will be significant. It is believed that plutonium reprocessing and recycling will increase workers’ and public radiation exposure and increase the accident risk. In addition, it will generate additional categories of waste that increase the waste management burden.[11] Consequently, the nuclear decision-makers should balance the long-term benefits of waste partitioning and transmutation with the increased short-term health, safety, environmental, and security risks involved. Based on a recent MIT study,[12] it seems unlikely that on the basis of waste management considerations alone the benefits of advanced fuel cycle schemes featuring waste partitioning and transmutation will outweigh the attendant risks and costs. In addition, many experts within the scientific and technical community feel highly confident that the geologic disposal approach is capable of safely isolating the waste from the biosphere for as long as it poses significant risks. In practice, the U.S. is planning to deposit about 63,000 MT of spent fuel in the Yucca Mountain repository.
Finally, the international community has long been concerned about the increasing proliferation and terrorist risks by plutonium recycling systems. China’s plutonium recycling policy could have an impact in this respect. For example, the civil use of plutonium in one country can serve as encouragement or an excuse for its use in other countries, thereby encouraging nuclear proliferation. Conversely, if China does not pursue reprocessing and recycling, this could set a good example for other countries that are contemplating reprocessing. All of these factors, as discussed above, show that China has no convincing rationale for pursuing plutonium recycling in the foreseeable future. While the debates on permanent options for management and disposal of spent fuel and nuclear waste are still continuing worldwide, it would be highly desirable for China to choose an interim storage option (e.g. designed for many decades) instead of rushing reprocessing and recycling. Thus China would leave all options open and gain time for technology to develop further and choices to become clearer. It is shown that that interim storage of spent fuel offers a safe, flexible, and cost-effective nearterm approach to spent fuel management.[13] The interim storage approach would give China a substantial opportunity to carefully develop a longterm policy for the nuclear fuel cycle.
