Russian reactions22 May 2016
Fast reactor designs have changed over the decades. To a degree Russia, or the former USSR, led the way in their development. NEI looks at the role Russia has played and considers where fast reactor development is today, and will be tomorrow.
In the 1950s all those countries developing nuclear power - the US, USSR (subsequently Russia), France, the UK and later Germany, Japan and India - began work on fast reactors. Later, China and South Korea also started work in this area. Projects were eventually cancelled in the US, France, the UK and Germany, but Russia continued to develop fast reactor technology and now leads the world.
The first USSR fast reactor designs were drawn up in 1949 as a way of avoiding shortages of uranium, after physicist Alexander Leypunsky presented a special report to the government on reactors that could produce more fissile material than they consumed. As a result a fast reactor development programme was launched at the Institute of Physics and Power Engineering (IPPE) in Obninsk, with Leypunsky as its scientific leader.
In 1955 the BR-1 ((Bystry Reactor-1) critical assembly was commissioned at IPPE, fuelled with metallic plutonium and without a coolant. The compact plutonium core and uranium blanket allowed a breeding coefficient of approximately 1.8. BR-2 began operation in 1956. Both gaseous and liquid-metal coolants were considered and mercury was chosen. However the metal plutonium fuel was not stable under irradiation, even at low temperatures, and mercury leaked from pipe joints and corroded the steel cladding.
BR-2 was replaced in 1959 with the BR-5 (5MWt). It was cooled with liquid sodium and fuelled with plutonium dioxide to allow higher fuel temperatures and power densities (up to 500kW/litre) in the core. Its power was increased to 10MWt in 1973 and in 1983 reconstruction and vessel replacement significantly improved its safety. It was used to investigate fuel endurance, study different materials and produce isotopes for biological and medical purposes. Later, technical solutions to improve the safety of power reactors were verified and tested at BR-10, including experimental study of fission-product yield from failed fuel elements and study of structural material creepability. BR-10 operated until 2004.
Critical assembly BFS-1 started operation at IPPE in 1961, enabling simulation of fast-reactor cores fuelled by different mixtures of plutonium and uranium of varying enrichments, and with different configurations of control and safety rods. The effects of sodium voids on reactivity and other physical effects were also studied.
BFS-2, which started up at IPPE in the late 1960s, could simulate larger reactor cores. These two stands have been used to study models of other Russian reactors - IBR-2, BOR-60, BN-350, BN-600, BN-800 and BREST - as well as China's experimental fast reactor (CEFR). They are used extensively in international cooperation.
In 1969 BOR-60, which has a power capacity of 60MWe, was commissioned at the Research Institute of Atomic Reactors (NIIAR) in Dimitrovgrad, near Ulyanovsk. Vibro-packed fuel and other fast reactor fuel has been tested in this reactor, which is still operating, and is widely used for international research projects on fuel and structural materials. BOR-60 reactor is cooled by liquid sodium in two loops in the primary and secondary circuits. The third, water-steam, circuit has a turbine generator and a heating unit. It was originally designed for 20 years of operation but since 1988 its operating life has been extended several times - to 30, 40 and 45 years. By the end of 2014 it had recorded a total of 265,000 hours in operation. Over the past few years extensive work has been done to justify the possibility of further life extension, as a result of which regulator Rostechnadzor extended the operating licence until 2020. By then it is hoped the new MBIR research reactor will be in operation at NIIAR.
BN-350 was started up in 1972 at Aktau in Kazakhstan. More than ten specialist organisations worked on the project with IPPE as scientific leader focusing on reactor physics, sodium technology and security. Development Design Bureau of Motor Building (OKBM, Nizhny Novgorod) was the chief builder of the reactor. Development Design Bureau Gidropress (OKB Gidropress, Podolsk) provided the heat exchange equipment, including sodium-water nuclear steam generators. The All-Russia Science Research and Design Institute of Power Engineering Technology (VNIPIET, St Petersburg) was general designer of the facility.
BN-350 was a loop type reactor with three coolant circuits. The primary and secondary circuits contained sodium and the tertiary circuit water. In normal operation, five loops were in use with one on standby. About half of its 1,000MWt output was used for water desalination. It provided 8,000t/day of fresh water and 130MWe of electricity. It also functioned as an experimental base for large-scale testing of sodium technology, tests of fuel sub-assemblies and other core elements, studies in physics, and equipment tests. BN-350 used uranium enriched to 20-25% in mixed uranium-plutonium oxide (MOX) test fuel assemblies.
In late 1973, it experienced a major sodium fire when a steam generator failed as a result of poor welding. The reactor was shut down for repair for four months. The design life was 20 years; after 1993 it only operated through annual licence renewal. After its operating licence expired in 1995 it continued to operate far below capacity until operations ceased in 1999 and decommissioning began.
Even before BN-350 began operating the Russian government decided to construct a more powerful fast-neutron reactor (BN-600) as a step toward fast-neutron reactor commercialisation, using experience acquired during the initial period of BN-350 operation. This was used to make changes to the design of the BN-600, which was built at Beloyarsk. It is a three-loop design with the reactor and primary pumps submerged in a large pool of liquid sodium. The secondary circuits comprise three loops each with a steam generator and a secondary sodium pump. The steam supplies three 200MWe turbines. Each steam generator consists of eight sections comprising an evaporator, superheater and reheater, which are connected by manifold and can be isolated on both sodium and steam sides. It mainly uses uranium oxide fuel, enriched to 17-26%, although some MOX has been trialled in recent years. "About 100 such assemblies in small batches have been tested in this reactor over a number of years," the plant's operators said.
Altogether in the early years there were 27 sodium leaks and 12 steam generator leaks. The last one occurred in 1994. Half the
steam generator leaks occurred in the first year and were caused by manufacturing defects. None resulted in an emergency. The experience gained with the sodium leaks demonstrated the efficiency of the protection systems for localising the consequences. There was only one radioactive sodium leak, from an auxiliary pipeline of the primary circuit, and radioactivity release was below the permissible limit.
Over its operating life BN-600 has been upgraded and the lifetime of its key components - including the steam generators, sodium pumps and intermediate heat exchangers - was extended. In April 2010 Rostekhnadzor issued a licence for operation until 31st March 2020. During the licensing process studies were performed to validate the lifetime of the reactor components for 45 years of operation, which could make possible another five-year licence extension.
BN-600 has the best operating and production record of all Russia's nuclear power units.
Recently a milestone was achieved with the construction of Russia's next- generation sodium cooled fast reactor, BN-800 at Beloyarsk. Construction began in 1984, with start-up planned for 1992. But after the 1986 Chernobyl accident in Ukraine, construction of all new nuclear plants in Russia was halted. In the 1990s construction was further delayed because of financial difficulties in the wake of the Soviet collapse. During this period the project was improved to take account of state-of-the-art technology and revised regulations concerning reliability, safety and ecological requirements. Construction began in earnest in 2006.
Viktor Saruda, general director of Uralenergostroy, general contractor for all the Beloyarsk units, described the construction of Beloyarsk 4 as a "bridge between the past and the future." It has a large number of design and technological improvements over BN-600. It has an active reactor protection system with a passive system that works automatically in the event of loss of sodium-cooling liquid pressure, according to Rosenergoatom. During normal operation the reactor's control rods float in the cooling liquid on top of the reactor core. If cooling liquid pressure drops, the rods fall into vertical control rod channels in the reactor core and stop the chain reaction by absorbing neutrons. It also has a passive supplementary air-cooling system, used to remove residual decay heat. It has three loops containing 910t sodium in the primary and secondary circuits and its service life is 40 years.
Physical start-up of the 789MWe BN-800 was achieved in mid-2015 with the first achieved minimum controlled power around a year earlier and start-up planned for the end of 2014. However, in December 2014 Rosenergoatom announced that nuclear fuel for the unit needed to be developed further. In November 2015 Rostechnadzor approved Rosenergoatom's amendments to the unit's operating licence, allowing start-up. The unit was first connected to the grid the following month and by March 2016 it was operating at 85% power. Final tests were carried out in early April before the unit was shut down in preparation for commercial operation at the end of 2016.
State nuclear corporation, Rosatom, announced in early 2016 that by 2019 the BN-800 will use only MOX fuel. It currently uses a hybrid fuel based on uranium oxide and two types of MOX pellet and vibro- packed. The share of MOX is about 20%.
Possible construction of a larger BN-1200 fast neutron reactor at Beloyarsk (unit 5) has not yet been finalised and will depend on the results of operating Beloyarsk 4.
Afrikantov OKBM is designing BN-1200, completion of which was originally planned for 2016-17. However, in 2015, Rosenergoatom postponed construction citing the need to improve fuel for the reactor and amid speculation about its cost-effectiveness. Rosenergoatom said construction should be easier and faster because many of the infrastructure facilities already in place on the BN-800 site are designed for two power units. There is also a team of builders with experience accumulated in the course of building BN-800.
BN-1200 is significantly different from preceding BN models (four- loop rather than three-loop) and Rosatom plans to submit it to the Generation IV International Forum as a Generation IV design. It will generate 2,900MWt at 550°C, giving 1,220MWe gross with burn-up of up to 120GWd/t. It is planned to have a 60-year life including 30 years for steam generators. Fuel loading is 47t of MOX or 59t of plutonium- uranium nitride. It will have 426 fuel assemblies and 174 radial blanket assemblies surrounded by 599 boron-shielding assemblies. Used fuel assemblies will be stored at the reactor for two years.
BN-1200 is now tentatively scheduled to start commercial operation in 2025, assuming operation of the BN-800 goes well. Beloyarsk general director Mikhail Bakanov noted in December 2015 that BN-800 was already providing valuable operating and technological experience. "The main objective of the BN-800 is [to provide] operating experience and technological solutions that will be applied to BN-1200," he said. Rosenergoatom spokesman Andrey Timonov noted: "For us, the BN- 800 is not only the basis for development of a closed nuclear fuel cycle. It is also a test case for technical solutions that will later be used for commercial production of the BN-1200."
Among other things the BN-800 must answer questions about the economic viability of potential fast reactors because 'fast' technology does not compare well with commercial VVER units, he said. "However, we believe that if such a unit has more functions than just to generate electricity, then it becomes economically attractive." He said Rosenergoatom "does not intend to abandon" the BN-1200 project.
Vitaly Petrunin, deputy director of OKBM Afrikantov, told a conference in Nizhny Novgorod earlier this year that there was hardly any difference in the cost of developing BN-1200 and the VVER-Toi (typical optimised, with enhanced information) design based on the V-392M. He added OKBM Afrikantov would "defend" the BN-1200 project in a forthcoming meeting of Rosatom's Scientific and Technical Council (STC).
BN-1200 comes under the Federal Target Programme (FTP) "Nuclear power technologies of new generation for the period 2010-2015 and up to 2020" and the "Innovation Development Programme of Rosatom". FTP projects involve 30 organisations - of which 19 are scientific and educational entities - and the total number of engaged scientists exceeds 1,500.
As well as the BN-1200, the FTP includes development of:
- A MOX fuel production line for the BN-800 to fabricate 400 nuclear fuel assemblies a year (accomplished).
- Uranium-plutonium nitride fuel for fast reactors (accomplished).
- Design and construction of onsite closed fuel cycle facilities for the planned Brest-OD-300 lead-cooled fast reactor and construction of the reactor itself (the Proryv project).
- Construction of the multi-purpose fast research reactor MBIR.
The Proryv (Breakthrough) Project, based at the Siberian Chemical Combine (SCC) in Seversk, has three stages:
- A fuel production/prefabrication module for production of dense uranium plutonium (nitride) fuel for fast reactors.
- A nuclear power plant with the Brest reactor.
- A used fuel re-treatment module. The cost of the project is put at RUB102bn ($1.6 billion), of which RUB64 million is for the facilities in Seversk.
Construction of the Brest-300 reactor is expected to begin in 2016 for start- up in 2020 according to Vyacheslav Pershukov, deputy director general and director for innovations management at Rosatom. Fuel production is due to be commissioned in 2017 in order to test and produce the first fuel for the reactor. Start-up of a fuel-processing package to establish a non-waste technology and demonstrate the closed cycle is expected by 2022.
The NA Dollezhal Research and Development Institute of Power Engineering (Nikiet) completed the engineering design for the Brest reactor, using lead coolant, in September 2014. Rosatom said more than 25 divisions of Nikiet were involved in the two-year project to complete the technical design, plus 35 other nuclear industry organisations.
Brest is seen as a possible successor to the BN fast reactor series. It has a capacity of 700MWt (300MWe) at 540°C, with lead as the primary coolant and supercritical steam generators. No weapons- grade plutonium can be produced since there is no uranium blanket and all the breeding occurs in the core. The initial cores can comprise plutonium and used fuel including radiologically 'hot' fission products.
Subsequently any surplus plutonium that is not in pure form can be used as cores for new reactors. Used fuel can be recycled, indefinitely using onsite facilities.
Mashinostroitelny Zavod, part of Fuel Company TVEL, announced in October 2015 that it has fabricated mock-ups of experimental nitride fuel assemblies ETVS-12 and ETVS-13 for Brest. The fuel was fabricated to the order of the AA Bochvar Research Institute of Inorganic Material (VNIINM) and the acceptance commission included representatives of VNIINM, OKBM, SCC and others. Tests of earlier design prototype assemblies with nitride fuel are already being carried out at the BN-600.
After 2020 Rosatom plans to replace the BOR-60 at NIIAR in Dimitrovgrad with a 100-150MWt multi-purpose fast neutron research reactor (MBIR), which will have four times the irradiation capacity. MBIR is a multi-loop research reactor capable of testing lead or lead-bismuth and gas coolants, as well as sodium, simultaneously in three parallel outside loops. It will run on vibropacked MOX fuel with a plutonium content of 38%, produced at NIIAR's existing facilities. A 24% plutonium fuel may also be used.
NIIAR intends to set up an onsite closed fuel cycle for it, using pyrochemical reprocessing it has developed at pilot scale. There will be
ten horizontal and vertical channels as well as upgradeable experimental capabilities - more loops, irradiation devices, channels, neutron beams, etc.
Rosatom said MBIR would be open to foreign collaboration, in connection with the International Atomic Energy Agency's International Project on Innovative Nuclear Reactors and Fuel Cycles (INPRO) programme. In June 2013 an agreement with France and the US was signed to this effect. Rostechnadzor granted a site licence to NIIAR in August 2014, a construction licence in May 2015, with completion is expected in 2020. MBIR's cost was estimated at RUB16.4 billion ($454 million) in 2010. The full MBIR research complex is now budgeted at $1 billion, with $300 million already allocated from the FTP. Pre-construction shares of one percent are being offered for $10 million, allowing involvement in detailed design of irradiation facilities. From 2020 the fee will rise to $36 million for a one percent share. NIIAR is also expected to host SVBR-100.
In October 2015, Rosatom's STC approved the results of an expert review for the detailed design of the SVBR-100 fast reactor facility and for the design of a pilot production power unit with an SVBR-100 reactor. SVBR- 100 is a small, modular, fast-neutron reactor using lead-bismuth (Pb-Bi) cooling with a net output of 100MWe. Russia built seven Alfa-class submarines, each powered by a compact 155MWt Pb-Bi cooled reactor, and 80 reactor-years' operational experience was acquired with these.
It is an integral design with 12 steam generators and two main circulation pumps sitting in the same Pb-Bi pool as the reactor core, at 340-490°C. It is designed to be able to use a wide variety of fuels, although the pilot unit will initially use uranium oxide enriched to 16.3%. With U-Pu MOX fuel it would operate in closed cycle. The refuelling interval is seven to eight years over a 60-year operating life. The 280MWt SVBR-100 unit would be factory-made and transported - by railway, road or waterway - as a module.
In December 2009, AKME-engineering, a 50/50 joint venture between Rosatom and the En+ Group (a subsidiary of Basic Element Group), was set up as an open joint stock company to develop and build a pilot SVBR unit. Akme-engineering received a patent from the US for the SVBR-100 nuclear reactor trademark in 2015. The company said it wanted to protect its intellectual property. The trademark has already been registered in the European Union and South Korea. En+, an associate of JSC EuroSibEnergo, was to contribute most of the capital. In 2011 EuroSibEnergo's 50% share passed to its subsidiary, JSC Irkutskenergo, and Rosatom is now looking for another investor. The main project participants are OKB Gidropress, VNIPIET and IPPE. The prototype SVBR-100 unit is scheduled to start operating in 2019.
In September 2015 Rosatom's Pershukov told journalists the initial costing plans for the SVBR-100 project "turned out to be more optimistic than it is in actual fact", adding the project participants were not happy with the cost. No further federal funding is expected for the project and new investors are still being sought.