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NATIONAL REPORTS

Russia's nuclear cycle: An industrial perspective

An overview of policies, plans, and experience in producing and reprocessing nuclear , and in the utilization of

by I rom the very beginning, the development of not for , whose spent fuel is placed in Yu.K. Bibilashvili nuclear in the former was storage. and F.G. based on a closed fuel cycle. Plans included the The decision not to reprocess fuel from Reshetnikov reprocessing of spent fuel from RBMK-1000 and RBMK-1500 reactors was plants, and the recycling of recovered taken largely for economic reasons. Reprocess- and plutonium in newly fabricated fuel elements. ing would be uneconomical because of the fuel's For the most part, this policy has not changed, low content of fissile and and today it encompasses a new generation of plutonium. Spent fuel from RBMK reactors is reactors whose construction is being planned. placed in sealed canisters and stored in facilities In and countries of the Commonwealth at the nuclear plant site having a capacity of of Independent States (CIS) and Eastern Europe, about 2000 tonnes heavy metal (tHM). -cycle services currently are required For other types of fuels, one reprocessing for 62 nuclear power plants operating with reactors plant is operating and another one is being built. that were designed in the former Soviet Union. • The RT-1 plant in Chelyabinsk. Located Forty-five of these are pressurized- reactors at the "Mayak" complex, this plant was commis- known as WWERs. Of these, 19 are WWERs sioned in 1971 and intended for reprocessing having an electrical generating capacity of 1000 fuel from WWER-440 reactors, fast reactors, megawatts and 26 are WWERs having a capac- and the propulsion reactors of ice-breakers and ity of 440 megawatts. The remaining operating submarines. The plant's capacity for the main plants include 15 channel-type, -moder- type of fuel (WWER-440 fuel) is 400 tHM per ated reactors known as RBMKs and two fast- year. It operates with an aqueous extraction tech- breeder reactors known as BNs. nology using with a hydrocar- This article reviews Russia's nuclear fuel bon diluent. The process takes places in multi- cycle industry from a technical and industrial stage extractors with mechanical and pulsed perspective. It specifically focuses on reprocess- mixing of phases. The clean-up factor for high ing experience and plans, the fabrication of fuel fission products is between 10 and 109, which for WWER, RBMK, and fast reactors; the man- ensures that pure uranium and plutonium, as well agement of ; and the current as , are produced. The technology also situation and prospects for using mixed oxide allows extraction of -90, caesium-137, (MOX) fuel in Russia's nuclear power reactors. technetium-99, and other from the spent fuel. Once reprocessed, the uranium is returned to Reprocessing of nuclear fuel fuel-element production. The final uranium product of the plant is a fused cake of uranyl The reprocessing option is followed for the nitrate hexahydrate with the required uranium- spent fuels of all WWER and BN reactors, but 235 enrichment. The fused cake is obtained after mixing and concentration of the uranium re- extract and a solution of highly enriched ura- nium. The adjustment of the solution for correct enrichment also can be done at the Ust- Mr Bibilashvih is the Deputy Director of the Scientific and Kamenogorsk plant in Kazahkstan, where the Research Institute of Inorganic Materials, Ministry of Atomic , Russian Federation. Mr Reshetnikov, the former fuel pellets are made. Currently, most of the Deputy Director of the Institute, is a senior consultant. fused cake obtained at RT-1 has a uranium-235

28 IAEA BULLETIN, 3/1993 NATIONAL REPORTS

Be/ow: The automated production line for WWER-440 fuel assemblies at the Electrostal fabrication plant near . At left: Centrifuges at the uranium enrichment plant at Krasnoyarsk. (Credit: Minatom, Russian Federation) content of 2% to 2.5% and is used to make fuel pellets for RBMK-1000 reactors. now is being done to include in the fuel cycle of the RBMK-1500 reactors at the Ignalina in Lithuania and in the fuel cycle of BN- and WWER-type reactors. Plutonium obtained at RT-1 is temporarily stored on site in dioxide form. • The R1-2 plant, under construction at Krasnoyarsk. This plant, which is being built to reprocess nuclear fuel from WWER-1000 reactors, is scheduled to come on stream in lines. The first line will be able to reprocess up to 1000-to-1500 tHM per year of spent fuel from WWER-1000s. Like at RT-1, the final uranium product will be a fused cake of hexahydrate. It will first go to production and then to uranium enrichment. Until the first line is commis- sioned, spent fuel from WWER-1000 reactors will be stored in the a central facility at RT-2 that already has been built. This facility has a design capacity of 6000 tHM and will be fully packed by the year 2005. Storage capacity presently is 3000 tHM.

Fuel enrichment and fabrication

The demand for nuclear fuel to supply WWER-type plants currently determines the re- quired of industrial fuel element produc- tion. (See graphs.) All these reactors use en- riched uranium (Russia has no reactors operating on ).

IAEA BULLETIN, 3/1993 29 NATIONAL REPORTS

By country and region: By reactor type: 2000 1100

: CIS and - ^^ 1000 1750 - Lithuania ^^^ ^^^^ RBMKs "^x 900 1500 800

1 1250 - « 700 x Z ; Russia ^.,»* ••.., S 600 a : ...---" " §• 1000 in o> 8 500 WWERs c c o 750 £ 400 300 500 200 Bilibino and 250 Lithuania 100 AST-500 ^ - _^^

0 i i i 0 1990 1995 2000 2005 2010 1990 1995 2000 2005 2010 Years Years

Fuel requirements A number of uranium enrichment and fuel used in serial production. The specific energy for water-cooled fabrication plants are operating. consumption of this centrifuge model per sepa- reactors, 1990-2010 • Enrichment plants. The first uranium en- rative work unit is 25 times less than with the richment plant in Russia started operation in gaseous diffusion process. 1949 in Sverdlovsk. Three further plants came In the enrichment process, two methods can into operation later at Tomsk, Angarsk, and be employed to obtain the uranium hexafluoride Krasnoyarsk. The method used in all four ura- used to enrich the uranium — direct fluorination nium enrichment plants was the gaseous diffu- of uranium oxides with gaseous fluorine or fluo- sion method. Development of an innovative en- rination of uranium tetrafluoride. Both methods richment method using gas centrifuges started in are used in Russia. Economically speaking, the the early 1950s. The world's first industrial plant second method is the more attractive since less equipped with gas centrifuges came into opera- expensive gaseous fluorine (by a factor of three) tion in 1964 in Sverdlovsk. Gas centrifuges were is required. In both cases, the processes are exo- then also introduced in the other three plants. thermic and great quantities of are released, The transition to gas centrifuges meant that the with extremely high temperatures developing in separation capacity of the plants increased by a the reaction vessel. When designing equipment factor of 2.4 while at the same time for these processes, therefore, particular atten- consumption was reduced by a factor of 8.2. tion must be paid to the removal of heat and to Nowadays fifth-generation gas centrifuges are the choice of material for the reaction vessel.

Industrial nuclear fuel and cladding Plant Type of production Annual capacity Production in 1992 production (tonnes) (tonnes) Reactor Final product

Electrostal WWER-440 fuel assemblies 700 230 (near Moscow) RBMK fuel assemblies 570 570 BN fuel for reactor core 20 BN fuel for reactor breeding blanket 15 Novosibirsk WWER-1000 fuel assemblies 1000 210 Ust-Kamenogorsk WWER fuel pellet 2650 220 (Kazakhstan) RBMK 570 Glazov WWER alloy 2000 RBMK tubing 6000 km/a (tubing) 2000 km/a (tubing)

30 IAEA BULLETIN, 3/1993 NATIONAL REPORTS

• Fuel fabrication facilities. Industrial fab- rication of fuel elements, fuel assemblies, and Plant/Facility Reactor Annual capacity Production fuel pellets is carried out at three plants: two in in 1992 Russia ( and Novosibirsk) and one in "Paket" at Mayak, BN-350 10-1 2 FAs 4 FAs Kazakhstan (Ust-Kamenogorsk). Elektrostal Chelyabinsk BN-600 300 kg MOX 100 Kg MOX produces fuel elements, assemblies, and pellets (about 20% Pu) for WWER-440, BN-350 and BN-600 reactors. "Paket" (modified) BN-600 40 FAs It also produces fuel elements and assemblies for since 1993 1 tonne MOX RBMK-1000 and RBMK-1500 reactors using Facility at RIAR BOR-60 1 tome MOX 600 kg MOX fuel pellets supplied from Ust-Kamenogorsk. (Dimitrovgrad) BN-600 (vibropack) The Novosibirsk plant manufactures fuel ele- Plant at Chelya- BN-600 60 tonnes HM ments and assemblies for WWER-1000 reactors. binsk complex BN-800 Fuel pellets for the WWER-1000 fuel elements (50-60% complete) (WWER-1000) are supplied from Ust-Kamenogorsk. Zirconium Plant in WWER-1000 planned for future production and the manufacture of articles made Krasnoyarsk of zirconium-based alloys take place in Glazov (Udmurtia, Russian Federation). Note: FA= fuel assembly HM = heavy metal Two methods are used to convert uranium hexafluoride into . The plant at nium and plutonium recovered from spent fuel, Fabrication of Elektrostal employs the flame spraying process, it also has a negative side: the generation of mixed oxide (MOX) which is one of the gaseous or "dry" methods. considerable amounts of high-level radioactive fuel The uranium dioxide powder obtained using this waste (HLW). The half-life of some nuclides is technology is not sufficiently free-flowing and many thousands of years. For this entire period so undergoes further treatment to obtain what is they must be kept reliably contained and pre- known as press-powder, a powder from which vented from coming into contact with the envi- pellets are pressed. ronment. At Ust-Kamenogorsk in Kazakhstan, where A deciding factor for reliable disposal of the bulk of Russia's fuel pellets are fabricated, is the choice of a matrix uranium hexafluoride is processed into uranium material having sufficient chemical stability to dioxide using the ADU-process. This process contain solidified waste. Such materials in- involves hydrolysis of uranium hexafluoride, clude phosphate and borosilicate glass and precipitation of ammonium polyuranate, drying, mineral-like materials. The merit of these ma- calcination, and reduction to uranium dioxide. terials is their high resistance to leaching of the The fused cake from the RT-1 plant serves as the elements contained within them. raw material for fabrication of the fuel pellets for Russia has opted for vitrification. The first RBMK fuel elements. pilot industrial facility for HLW vitrification went into operation in 1987 at the RT-1 plant. The process took place in a reaction Management of spent nuclear fuel vessel. Water-cooled molybdenum rods posi- tioned appropriately in the vessel served as While the closed fuel cycle has a positive electrodes. This facility processed some 1000 side, namely the possibility of re-using the ura- cubic meters of actual HLW, producing 160

Reprocessing and Facility Reactor Capacity Product spent fuel management in RT-1 reprocessing plant at WWER-440 400 tonnes heavy Reprocessed uranium returned to Russia Mayak complex in Chelyabinsk Fast and transport metal/annum fuel fabrication for RBMK (since 1971) reactors (tHM/a) Plutonium stored in dioxide form RT-2 reprocessing plant in WWER-1000 1st line: 1 500 tHM/a Reprocessed fuel will be returned Krasnoyarsk 2nd line: 1500 tHM/a to fuel fabrication for WWER and Total: 3000 tHM/a BN. Storage facilities at each RBMK RBMK 2000 tHM nuclear power plant site Storage facility at RT-2 plant WWER-1000 6000 tHM (3000 tHM in opera- tion)

Note: The RT-2 reprocessing plant is under construction; the date for completion is still under discussion.

IAEA BULLETIN, 3/1993 31 NATIONAL REPORTS

tonnes of glass blocks containing ap- carried out in the BOR-60 and SM-2 reactors at proximately 4 million curies, before operation the Scientific Research Institute for Nuclear of the furnace was discontinued in 1988. Reactors, Dimitrovgrad. During the first stage of In 1991, a new electric furnace having a this research, mechanical mixing of uranium and capacity of 500 liters of solution per hour plutonium oxides was the main technique used to started operation at the same complex. Several produce the fuel. A fairly large number of fuel of the shortcomings of the first furnace were elements was manufactured using this technique. taken into account in its development. To date, Reactor tests were carried out to evaluate the approximately 5000 cubic meters of liquid influence of many factors on the performance of HLW have been processed in the new furnace, these fuel elements. Some assemblies achieved producing some 900 tonnes of phosphate glass rates of up to 20% with no impairment of with a total incorporated activity fuel element integrity. of about 135 million curies. The positive and stable test results ob- The problems associated with the tained with the MOX fuel in the BOR-60 reac- reprocessing and reliable disposal of radioac- tor were followed up with more extensive tests tive waste would be greatly reduced if a way in the industrial-scale BN-350 (Kazakhstan) could be found to sort the radionuclides in and BN-600 reactors. advance according to their half-lives, toxicity, The fuel cycle for BN-350 and BN-600 and possible usefulness. Much work is now reactors was initially planned to use uranium going into achieving this goal. oxide fuel, which is certainly not ideal for In addition to the HLW produced at nuclear breeder reactors. A complete conversion of fuel cycle facilities, immeasurably greater these reactors to MOX fuel is not possible quantities of low-level liquid waste are owing to their design and physical features. formed. Radioactive water at nuclear power However, these reactors can be used for testing plants and radiochemical facilities is purified up to 25-to-30 fuel assemblies containing by filtration, evaporation, , and uranium-plutonium oxide fuel. other means. The solutions are purified to the For this purpose, a pilot industrial facility point where they can be recycled. The con- called "Paket" was set up at the Mayak com- centrates and intermediate-level liquid wastes plex in Chelyabinsk capable of manufacturing formed in the process are either stored in spe- up to 10 fuel assemblies per year for these cial tanks or solidified. Several nuclear power reactors. The same structural materials were plants already have facilities for solidifying used as for uranium fuel (namely, austenitic liquid waste by the bituminization method. for the fuel element cladding and ferritic By the year 2000, all operating nuclear martensitic steels for the six-sided cans). In the power plants and all those scheduled for BN-350 and BN-600 reactors, a burnup rate of decommissioning in Russia must have built 9% to 11% of heavy atoms was achieved. facilities for solidifying and subsequently stor- There was no loss of integrity in any of the fuel ing liquid waste. elements. Tests performed on the fuel ele- ments after they had been removed from the reactor showed that they had not reached the Plutonium utilization in nuclear fuels end of their useful lives. Work on this type of fuel was given an Russia started work on the use of plutonium added impetus when the decision was taken to as a nuclear fuel in the late 1950s. In 1957, a build BN-800 reactors designed to use MOX core made of metallic fuel (plutonium alloy) fuel in Russia (at the South Urals and was manufactured for the IBR-30 pulsed reac- Beloyarsky nuclear power plants). At the tor. In 1959, the BR-5 sodium-cooled fast Mayak complex, a project was started for the reactor was commissioned at the Power design and construction of a plant which Physics Institute, Obninsk. It used plutonium would produce MOX fuel and fuel assemblies dioxide fuel and had an overall core charge of for these reactors and for the BN-600. Par- about 150 kg. The same type of fuel was used ticular emphasis was placed on in 1965 for the core of the IBR-2 pulsed reac- safety both in the plant itself and in the sur- tor, which weighed around 120 kg. Both rounding area. This meant minimizing opera- pulsed reactors are still operating at the Joint tions which generated dust. One of the most Nuclear Research Institute, . important of these is the mechanical mixing of These activities were not part of any the oxides. Therefore, work began on the broader programme but were individually development of other processes for producing commissioned projects. Systematic research MOX fuel which generated less dust. The first on plutonium fuel began in 1970. Tests were of these was a sol-gel process producing

32 IAEA BULLETIN, 3/1993 NATIONAL REPORTS granulated MOX fuel which was then pressed into pellets. This technique was used to manufacture several experimental fuel assemblies which were successfully tested in the BN-350. However, the manufacture of the pellets from granules obtained by the sol-gel process involves a number of difficulties which make it impossible to achieve a high and stable pellet quality. Therefore, in parallel, the technique of Tubes for nuclear fuel co-precipitation of uranium and elements at the Glazov plutonium using surfactants was developed. plant. (Credit: Minatom) This technique produces irregularly shaped produce this type of fuel, which had been granules which generate little dust and can be suspended, is now being resumed with a view easily worked into pellets meeting the required to supplying the BN-800 and BN-600 reactors standard. Twelve fuel assemblies were made with uranium-plutonium fuel. It is estimated for the BN-600 using this technology. Most of that this plant is 50% to 60% complete, so it these have already been removed from the will take several years to finish it. reactor following lifetime tests, and the For the immediate future, therefore, it is remaining ones are being irradiated. planned to reconstruct the "Paket" pilot in- As an alternative to this technique, carbonate dustrial facility and increase its output to 40 co-precipitation of uranium and plutonium is fuel assemblies per year for the BN-600. A being investigated. No reactor tests have been similar quantity of fuel assemblies are to be performed as yet on fuel produced using this made at the Scientific Research Institute for method. Another technique for producing MOX Nuclear Reactors using vibration technology. fuel — plasmochemical denitration of a mixture This will allow further study of various ' of uranium and plutonium nitrate solutions — is problems raised by the use of MOX fuel. still in an early stage of research. At the same time it must be admitted that All five techniques mentioned above have Russia, like other countries with well-developed the same aim: the production of pellets for fuel nuclear power programmes, is not now able to elements. However, Russia is also conducting a recycle quickly all of its accumulated and ac- significant amount of research into vibro-com- cumulating reactor-grade plutonium stocks. pacted fuel elements based on granulated fuel Russia already has around 30 tonnes of such produced using various techniques. In particular, plutonium. Moreover, the RT-1 plant, reprocess- the Scientific Research Institute for Nuclear ing about 400 tonnes of irradiated fuel annually, Reactors in Dimitrovgrad has developed an produces approximately 2.5 tonnes of plutonium electrochemical technique for co-precipitation per year. of uranium and plutonium oxides. After the The situation is further complicated by the cathode precipitate has been processed and prospective substantial increase in the quantity reduced to a fine powder, it is divided into six of unused plutonium due to nuclear weapons fractions graded according to particle size. The reductions. Scientists are agreed that total powder is then loaded into the fuel element clad- plutonium recycling can only be achieved by ding and compacted in a vibration machine. A expanding the use of fast reactors, but it looks high mean fuel can be achieved in the as if this will only be possible in the next fuel element by controlling the ratio of the frac- century. At present, the prospects of using tions. light-water reactors to solve this problem are Up to now, all the fuel elements which even more limited. have been loaded into the BOR-60 have been In Russia, work is just starting on the use of manufactured using this technology. In addi- plutonium in light-water reactors. The necessary tion, two fuel assemblies have been tested in the physical calculations are being performed for BN-350 and six in the BN-600. WWERs. Another possibility we are considering is to set up — at the plant being built in Chelya- binsk to produce fuel for fast reactors — a pilot Plans and prospects industrial facility to produce uranium-plutonium fuel elements and assemblies for WWER-1000 Over the past decades, a sufficiently large reactors. In the more distant future, we plan to amount of work has been carried out to en- build a special plant in Krasnoyarsk — alongside visage undertaking the industrial-scale the large-scale RT-2 spent fuel reprocessing development of MOX fuel fabrication technol- plant currently under construction — to produce ogy. Work on the construction of a plant to MOX fuel for WWER reactors. a

IAEA BULLETIN, 3/1993 33