A new breed for China6 September 2017
Judith Perera looks at China’s experimental fast reactor and how it is paving the way for future FBR plans.
China’s experimental fast reactor (CEFR) began operating at full capacity in December 2014, after which it operated continuously for a trial period of three days, according to China National Nuclear Corporation (CNNC). At
the end of the trial operation, Xu Dazhe, head of the China Atomic Energy Authority and the State Administration of Science, Technology and Industry for National Defence (SASTIND), said the achievement had laid “a solid foundation for fast reactor technology development, commercialisation and nuclear fuel cycle technology development.”
The CEFR is a sodium-cooled, pool-type fast reactor with a thermal capacity of 65MWt and a power output of 20MWe. The project was given preliminary approval by China’s State Council in 1992 and finally approved in 1995. First concrete was poured in May 2000 at the China Institute of Atomic Energy (CIEA), near Beijing. Construction of the nuclear island started the next year. Installation of the reactor vessel and in-reactor components was completed in 2007 and the sodium coolant was delivered to the site the following year. The reactor achieved first criticality in July 2010 and was connected to the grid at 40% capacity in 2011.
The CEFR is a key energy project under the National High Technology Research and Development Programme of China (programme 863). Its operation has paved the way for larger fast reactors. A 600MWe unit is now in the design phase, and this is to be followed by a 1000MWe plant.
The reactor and most of the key components were designed and manufactured by Russian institutions. These included the OKBM Afrikantov Experimental Design Bureau for Mechanical Engineering, fuel company Tvel, the AI Leipunsky Institute of Physics & Power Engineering (IPPE), JSC Gidropress, JSC Atomenergoproekt (St Petersburg – SPbAEP).
China developed the buildings and support facilities and provided some of the equipment, according to CEFR project coordinator Vladimir Sedakov of JSC OKBM Afrikantov and chief engineer of Russia’s BN-800 project. “The CEFR is based on the principles of the BN-600 fast neutron reactor,” he said. “The technical reactor project was developed in Russia, while Chinese experts designed the buildings and facilities and made the station equipment. Successful implementation of this work created favourable conditions for further expansion of cooperation between Russian state nuclear corporation Rosatom and Chinese enterprises in nuclear energy development.”
In a joint paper to the conference on fast reactors held in Yekaterinburg from 26-29 June, Sedakov and Boris Silin, councillor of Rosatom’s Directorate for Nuclear Power Complex, described Russia’s involvement in the CEFR.
The objective of building a fast breeder reactor was first included in China’s state programme on high-tech development in
1987, and CIAE was appointed as the leading organisation. Between 1988 and 1990, CIAE carried out studies and practical research with a view to starting construction of a 65MWt experimental fast reactor in 1996. To minimise costs, China decided to involve foreign parties, and in particular Russia, which had the most experience in fast reactor development. Cooperation with Russia began in 1992.
Between 1992 and 1995, specialists from OKBM Afrikantov, SPbAEP and IPPE, together with CIAE and the Beijing Institute of Nuclear Engineering (Bine) developed the CEFR concept and technical requirements for the reactor and its main components. Russian specialists then developed a detailed design for the CEFR based on technical requirements specified by China. To validate design decisions for the equipment, special test facilities were constructed and prototype equipment and core dummy components were tested at a number of Russian sites.
Cooperation between China and Russia
Cooperation between China and Russia was underpinned by formal agreements. In March 1995, Russia’s Ministry of Atomic Energy (Minatom) signed an Inter-Agency Agreement for Cooperation in the Field of Developing the Experimental Sodium-Cooled Fast Reactor with the China Nuclear Energy Industry Corporation (CNEIC). In 2002 an intergovernmental agreement was signed by Russia and China for cooperation in construction and operation of the CEFR.
In early 1999, CIAE obtained formal approval from the government and National Nuclear Security Administration (NNSA) to build the reactor, clearing the way for the manufacture and testing of prototypes as well as the supply of equipment and fuel.
In all, Russian companies supplied more than 100 pieces of equipment for CEFR. Most of the equipment was supplied by OKBM Afrikantov, including: components for the reactor vessel and rotating plugs; primary and secondary pumps; FSA flow meter; control rod drive mechanisms; intermediate heat exchangers; refuelling mechanism; fuel loading/unloading elevators; special devices for equipment dismounting/mounting; and special devices for gas heating. Tvel and Mashinostroitelny Zavod (Elektrostal Elemash) supplied the fuel; Ziomar (Podolsk), the steam generators; IPPE, the steam generator emergency protection system; SPbAEP, the control and protection system; the DV Efremov Scientific Research Institute of Electrophysical Apparatus (NIIEFA), the electromagnetic pumps; SPC Elegiya, the ionisation chamber suspensions; and the State Research Institute for Heat Power Engineering Instruments (NII Teplopribor), level meters and other devices.
Simultaneously, CEFR operating personnel were trained using test facilities at OKBM, IPPE, and the Russian Institute of Atomic Reactors (NIIAR) in Dimitrovgrad (site of the BOR-60 fast reactor). Consultancy services were provided by specialists from OKBM, IPPE, and SPbAEP; lectures on BN reactors were delivered; and practical training was given.
According to Sedakov and Silin, Russian companies are continuing to cooperate with China in the following areas: the supply of equipment and provision of consulting services for repairs to technology of Russian origin (OKBM Afrikantov); training of CEFR operating personnel (NIIAR); provision of consulting services for operation of the plant (Rusatom Service – part of Rosatom); fuel supply (Tvel); and studies and model analyses of the CEFR core using the large physical test facility (IPPE).
CIAE’s Zhang Donghui, in a paper to the IAEA’s 49th meeting of the technical working group on fast reactors held in Buenos Aires in May 2016, said the main tasks of the CEFR are: to study fuel and material irradiation; accumulate operation data and experience; develop new technologies to enhance safety and reliability; provide feedback to improve the economics; and validate the technology of fuel cycle at the laboratory level. However, the CEFR has operated only sporadically since its 2014 start-up, reportedly only for 682 hours up to October 2015.
Zhang listed three events in 2015 that caused the reactor to trip: a feed water pump failure while the standby pump was out of service; an electricity grid voltage fluctuate; and shutting of a steam generator isolating valve because of low pressure of compressed air.
The CEFR is still operating using high- enriched uranium (HEU), although the aim was to transfer to mixed plutonium/uranium oxide (Mox) fuel by 2015 after a trial period. An experimental Mox fabrication line with 0.5t/year capacity was built in 2008 but further development has been delayed.
Zhang Donghui said in 2016 that a laboratory-size Mox fuel fabricating line was being updated and the first batch of Mox pellets for the CEFR had been fabricated. The fuel pin was expected to be ready in 2017 for insertion into the reactor in 2018. However, he had earlier said insertion of the fuel pin would take place in 2017. Russian fuel company Tvel, which supplies the HEU fuel for the CEFR, signed a new $50m contract in December 2016 to supply two reload batches of HEU fuel assemblies for delivery in 2017-2018 to be loaded into the reactor in 2019, suggesting that the deadline for the switch to Mox has slipped further.
In a paper presented to the conference on fast reactors in Yekaterinburg in June three researchers from CIAE (Qi Zhou, Xiaoliang Chen and Qingfu Zhu) note that as the CEFR is still using high enriched UO2 fuel, “urgent work” is needed for the transition to Mox.
The current targets are the manufacture and irradiation of a test Mox assembly; large batch production of Mox fuel assemblies; and the transition of the CEFR from UO2 fuel to Mox. However, “to determine the uncertainty of the CEFR Mox core design and improve the design codes and nuclear data, a zero-power reactor (ZPR) using Mox fuel will be built based on an existing fast zero power reactor, DF-VI, in CIAE”. A Mox fabrication plant with 40t/year capacity “will be the target in the next stage”.
The new DF-VI will be the first Mox fuel ZPR and experimental research platform in China to study the measurement technology, obtain important neutronic parameters and validate the design methods for the CEFR Mox core, according to the paper.
The old DF-VI was the first zero power fast reactor in China. It was designed and constructed by the reactor physics laboratory from 1967 and achieved criticality in 1970. It worked until 2007. The new DF-VI is designed as a fast reactor with uranium and Mox fuel in a hexagonal arrangement with stainless steel reflectors. The preliminary design has been undertaken by CIAE. The authors gave no timeline for completion of the new ZPR.
The next phase
The transition to Mox fuel will be crucial to the next phase of China’s fast reactor development programme. This originally envisaged construction of a larger CFR-600 (1500MWt and 600MWe) – the China demonstration fast reactor (CDFR) – for operation by 2023 using Mox and then metal fuel. This would be followed by the China commercial fast reactor (CCFR), which would be a CFR-1000 design (1000-1200MWe), for start-up in 2030 using metal fuel.
As with the CEFR and Mox programmes, the schedule has slipped. The original plan envisaged that construction of the CFR-600 would begin in 2017. However, according to Zhang Donghui’s 2016 paper in Buenos Aires the timeline for the CFR-600 is now the end of 2015 for the concept design; mid 2017 for the preliminary design; the end of 2018 for the detailed design; and start-up in 2025. The CFR-600 will provide an industry level demonstration; gain experience of a fast reactor power station; validate the reliability of a large sodium-cooled fast reactor; provide preliminary validation of its economics; realise an industry-level fuel cycle to develop key equipment; and develop standards and codes. The fast reactor development programme will also require in the first phase a reprocessing plant for light water reactor fuel to provide plutonium for the fast reactors, as well as a reprocessing plant for fast reactor spent fuel. The second phase will need a plant for the production of metal fuel and a pyroprocessing plant to recycle used fast reactor fuel.
Given the extent to which China depended on Russian technology for development and construction of the CEFR, the delays in its indigenous fast reactor development programme are understandable. Originally, China had planned to base its commercial fast reactor development on Russia’s BN-800 design. In October 2009, CIAE and China Nuclear Energy Industry Corporation (CNEIC) signed an agreement with Russia’s Atomstroyexport to start pre-project and design works for a commercial nuclear power plant with two BN-800 reactors – referred to by CIAE as ‘project 2’ of the Chinese Demonstration Fast Reactors. Construction was to start in 2013 for commissioning in 2018/19. However, the project appears to have been dropped, largely because of differences over cost and technology transfer. China is now seeking to develop its own fast reactor technology based on its experience gained with the CEFR.