The Russia-US agreement for utilization of 68 metric tons of weapon-grade plutonium is under special control of both Vladimir Putin and George Bush. However, the eight-years-old agreement is far away from the finalization. In fact, its realization is not yet started [1].
What are the pitfalls who keep waiting the biggest joint plutonium project in the history of Russia and United States?
PD-8 Directive Legacy
In September 1998, Presidents Boris Eltsin and Bill Clinton have signed in Moscow a bilateral agreement for the excess plutonium disposition [2]. This document has created a basis for unique nonproliferation project, namely, for elimination of quite a third of Russian and American weapon-grade plutonium stockpile.
In July 2000, the quantitative aspects of the agreement have been elaborated. It has been fixed at presidential level that the Russian Federation and United States of America would somehow or other eliminate 34 metric tons of weapon-grade plutonium each [3]. At the same time, Washington has reserved to himself the freedom of choice - either fabricate the MOX-fuel from the weapon-grade plutonium and burn it in the nuclear reactors or immobilize plutonium, i.e. seal cans of plutonium inside the vitrified high-level radioactive waste and put it for long-time geological storage.
It is easy to understand the reason of U.S. doubts. Talking about "a principal U.S. security objective", which is "to prevent the spread of nuclear explosive capabilities" and "to prevent the direct access to plutonium", President Jimmy Carter has signed the unfortunate PD-8 directive in March, 1977. In particular, then-president has decided "indefinitely defer the commercial reprocessing and recycle of plutonium in the U.S." [4].
The PD-8 directive has killed the U.S. fast reactor program and heavily damaged the researches in field of closed nuclear fuel cycle. Tens of billions dollars began to leak toward Yucca Mountain, Nevada, where the federal government was expected to build the huge repository - terminal storage facility for spent fuel and radioactive wastes [5]. As a result, the U.S. nuclear industry is now behind the nuclear times, especially in the field of dealing with the "peaceful" plutonium, and the U.S. negotiators have to adopt a dual-track weapon-grade plutonium disposition policy - either burn or immobilize.
Unlike its former most likely rival, the Russian Federation does not have any scruples in the plutonium problem. Even in the Soviet times, the Russian nuclear engineers have mastered the plutonium fuel technologies for power reactors, first of all in the fast breeders. The special review group under heading of deputy minister for nuclear energy Lev Ryabev has reported in 1998 [6] that the Soviet Union has manufactured, tested and studied several thousands of fuel pins with total amount of some 1 metric ton of plutonium including 410 kg of weapon-grade plutonium.
One can say that the choice for disposal of Russian plutonium share is crystal clear - to use it as a fuel in the BN fast reactors.
Stumbling Blankets
According to the Soviet/Russian concept of the nuclear power engineering development, the BN fast sodium reactors shall serve for extended production of the fissile materials at the time when the industry would feel the lack of uranium. In other words, the BN reactor can use the plutonium fuel and produce both electricity and new plutonium, and the total mass of new plutonium would be greater than the mass of burned plutonium. A small technical digression. Taking about the efficiency of the plutonium breeding, one shall say that the sodium is not the best choice for cooling the breeder [7]. Only water is worse than the sodium. The light chemical element - the atomic weight is equal to 23 - would be considered inside the reactor core as a moderator. The neutron spectrum would be considerably softened - the fraction of low-energy neutrons would be increased - and the fuel breeding ratio would be dropped.
However the sodium has very important hydraulic and so on advantages in comparison with the heavy-weighted coolants such as the lead and lead-bismuth. Therefore the reactor designers were forced to compromise. One of implication of sodium cooling in the BN reactors is the spatial diversity of the energy production and plutonium accumulation. The new fissionable isotopes are created in the axial and lateral breeding zones, which cover the reactor core like a blanket. This, in fact, explains why such zones have been named the blankets. In U.S. opinion, the extended plutonium production in the BN reactors will violate the very idea of nonproliferation agreement. Indeed, while converting the weapon-grade plutonium into nuclear fuel and loading into the reactor core, the Russian federation will destroy the initial fissile material but simultaneously will create the new plutonium in bigger quantity and of near-to-weapon-grade quality.
Technically, this contradiction could be removed at one stroke. If we remove the blankets from the BN reactor, then the production of new plutonium would be severely lowered. One shall remind that the lateral breeding zones are the fuel assemblies with depleted uranium located at the periphery of reactor core, which could be easily replaced by the assemblies with stainless steal pins or so. The removal of the axial breeding zone would request some insignificant modifications of the fuel pin design.
VVER and Plutonium - Compatibility of Incompatibles
Today, the United States prefer that the utilization of the weapon-grade plutonium will be provided in parallel with 2 tons/year rate as the MOX-fuel for the light water reactors, in Russian case - VVER reactors. For U.S. share, the Department of Energy is planning to build the proper facilities in Savannah River [1]. By some estimation, the American nuclear industry could eliminate up to 4 metric tons of weapon-grade plutonium annually using the capabilities of their biggest in world nuclear park.
Considering the price of the MOX-fuel fabrication plant construction in the U.S. - some 3-4 billions USD - one can say that such a scenario would be too expansive and completely unacceptable for Russia.
First of all, Russia does not have the commercial plant for metal plutonium conversion and VVER MOX-fuel pellet fabrication. Russia has to buy such technology from France but who will pay this deal? It is worthy to mention that Paris and Washington are in troubling dispute now concerning the possible transfer of MOX-plant documentation.
The VVER conversion even to partial MOX-fuel loading will request a lot of money [8] - for re-designing of reactor safety and protection system and so on. The rate of plutonium utilization in the VVER would be still low, lesser than 2 tons/year.
Probably the most important objection against the MOX-fuel utilization in the VVER reactor has been said by the review group of Lev Ryabev: "There is no demand now for plutonium as a nuclear fuel in Russia." The operation of MOX-fueled VVER reactors would be more costly than for uranium-fueled ones, and the problem of future of converted reactors shall be carefully studied, as well as the destiny of the spent MOX fuel enriched by minor actinides.
Certainly, the Russian Federation may decide for conversion of some of its VVER reactors for MOX-fuel utilization. However, Moscow is adamant - due to the complete vainness of such approach for Russian nuclear power engineering, it could be only if the foreign donors will give legally binding guarantees for complete covering of all related Russian expenses.
High Temperatures and Heavy Costs
Besides VVER reactors, there is one more plutonium rival of the fast reactors. This is the high-temperature reactors of the HTGR type or, more precisely, the GTMHR reactor [9]. The Gas Turbine - Modular Helium-cooled Reactor (GTMHR) is the joint Russian-US project where the gas-cooled core is combined with advanced gas turbine technology. Another small technical digression. The high-temperature reactors give at the output both the electricity and the working media heated over 1000°C. Such temperatures open the possibility to use the nuclear power plants for hydrogen production and many chemical, oil-refining and other processes [10].
The gas coolant is requested to obtain high temperatures. This affects to the fuel element design. As a HTGR fuel element, the small covered balls from fissionable dioxide are often used. The most advanced HTGR program has existed in Germany but it is closed now. Recently, the high-temperature reactors - uranium-fueled! - are under development in China [11] and South Africa [12]. Some interest to the HTGR could be seen in the U.S., France and Japan. The GTMHR supporters say that there is no reason for weapon-grade plutonium utilization in the BN-800 reactor, which is under construction right now. They claim that the fast sodium reactors shall be the breeders and shall be used inside the closed nuclear fuel cycle rather than eliminate plutonium.
The fathers of the GTMHR project - including U.S. "General Atomics" [9] and Russian Kurchatov institute and OKBM - propose to build one demonstration and four commercial units in Seversk in the frame of the plutonium project. If the demonstration unit would be completed in 2016-2017 and later one commercial unit would be commissioned per year, then Russia can finish the utilization of 34 tons of weapon-grade plutonium till 2030-2035, they say. Total estimate of whole project would be equal to 3-3.5 billions of USD, and considering possible profits due to electricity and heat selling this could be reduced down to 1.5-2 billions of USD.
But is everything so swimmingly in the GTMHR scenario?
First, one shall not forget that there is no reference unit for GTMHR. Therefore, one shall concern about the marketability of this project.
Second, the BN-800 reactor can consume 2.4 tons of weapon-grade plutonium as the first batch and 1.68 tons annually as a make-up fuel [13]. Therefore, the BN-800 reactor can eliminate the 34 tons of weapon-grade plutonium in 19 years - till 2030. With all this going on, we will get near the same amount of reactor-grade plutonium, which can be released after reprocessing and used to start new fast breeders.
Unlike the BN-800 reactor, the GTMHR facility will really destroy the weapon-grade plutonium rather than convert it to the reactor-grade one. In other words, the GTMHR reactor operation will shorten the total recourse potential of the Russian nuclear power engineering.
The GTMHR fuel cycle is to be the open one due to very low content of fissionable isotopes in the spent fuel and lack of technologies for GTMHR spent fuel reprocessing. Therefore, all the irradiated fuel with considerable total amount of plutonium and minor actinides shall be considered as the nuclear wastes, and the extra expenses would be requested to deal with.
Very unfortunate feature of the GTMHR reactor is the creation of radioactive graphite, up to 30 m3/year in the reactor core only. The graphite to be removed will contain the 14C radioisotope with 5000 year half-life as well as the activation products of mechanical impurities and the fission products leaked through the fuel element cladding. One shall design and construct the expensive repository for GTMHR's graphite disposal.
The plutonium-fueled GTMHR is not good from the point of view of neutronics safety. The temperature reactivity coefficient would be too low, and the accurate manipulations with the burnable absorber, such as erbium, would be required. The load factor and the reactor life values do not correspond to the up-to-date achievements.
Definitely the high-temperature reactors are the new heading for Russian nuclear industry. But the analysis of German HTGR program proves that the most difficult time for each high-temperature reactor is the decommissioning stage. Initially the German nuclear body has estimated the decommissioning price for small research reactor AVR (15-MW power) [14] as 20 million euros. This price has been grown by leaps and bounds because of spent fuel disposal and other aspects. Recently, the AVR decommissioning expenses are going to some 500 million euro level.
The AVR decommissioning is so difficult and complicated because the reactor is highly contaminated by beta-activity. The technology to treat the fuel element's graphite cover is also very expensive. Even more, it is not easy to remove the high-contaminated fuel elements from the reactor core. So, the Germany authorities are now seeking for money for AVR decommissioning. Under such conditions, the "General Atomics" proposal to use the GTMHR for Russian plutonium utilization only seems to be very strange and questionable. The main argument against the plutonium GTMHR is crystal clear. Unlike the fast breeders, the plutonium utilization in the frame of the closed nuclear fuel cycle is not included in the mission of the high-temperature reactors.
Let suppose that the GTMHR reactors would be constructed and commissioned, although this seems to be very doubtful. After completion of the 34-tons weapon-grade plutonium utilization program, the Russian Federation would have the spent MOX-fuel with unknown destiny, the MOX-fuel fabrication plant with no order and with five GTMHR units, which shall be either re-designed for new type of fuel or decommissioned. Naturally nobody would pay the expenses for each aforesaid item except the Russian Federation!
Conclusion
The excess weapon-grade plutonium released for peaceful usage is the important fuel material. The decision regarding its utilization shall be done based on the national interests. Considering the strategic value of this material, one shall be especially careful while analyzing any idea or advice coming from foreign countries.
The application of this simple rule to the Russian-U.S. bilateral agreement for utilization of 68 metric tons weapon-grade plutonium gives the clear alternative - either the Russian share would be used as a fuel in the BN-800 fast breeder reactor or the agreement would be postponed until that time when the United States would realize itself the advantages of the fast reactors.
There are some indications that the U.S. nuclear philosophy could be changed. The U.S. Congress postponed the financing of MOX-fuel plant [15], and the U.S. administration has declared the GNEP nuclear initiative where many countries are invited to cooperate in the field of the fast reactor designing.
It would be reasonable if the Russian Federation will propose the international initiative for joint development of the BN-800 reactor without blankets for parallel fulfillment of bilateral agreement for weapon-grade plutonium utilization.
References
[1] - http://www.iranatom.ru/news/media/year04/may/pluton.htm
[2] - http://www.pircenter.org/data/gp/sogl_rf-usa3.pdf
[3] - http://www.pircenter.org/data/gp/sogl_rf-usa4.pdf
[4] - http://www.fas.org/irp/offdocs/pd/pd08.pdf
[5] - http://www.ocrwm.doe.gov/ym_repository/index.shtml
[6] - http://www.armscontrol.ru/start/rus/publications/pu-c1.htm
[7] - G.B.Usynin, E.V.Kusmartsev. Fast reactors. Moscow, 1985
[8] - http://www.iranatom.ru/news/aeoi/year06/july/repr.htm
[9] - http://www.okbm.nnov.ru/index.php?option=com_content&task=view&id=90&Itemid=88
[10] - N.N.Ponomariov-Stepnoy, Rosenergoatom Magazine, Ή4, 2004
[11] - http://www.iranatom.ru/news/aeoi/year06/february/shan.htm
[12] - http://www.iranatom.ru/news/aeoi/year05/november/pbmr.htm
[13] - V.N.Mikhailov et al. Nuclear Energy, volume 76, issue 4, April 1994
[14] - IAEA-TECDOC-1043: Technologies for gas cooled reactor decommissioning, fuel storage and waste disposal
[15] - http://www.iranatom.ru/news/aeoi/year06/july/scpu.htm
SOURCE: IranAtom.Ru, Yuri Khmylov