我国快堆发展战略目标研究

我国是一个发展中大国,能源需求量大且增加迅速。考虑到资源的有限性和环境问题,核能必将成为我国主要能源之一。政府已决策2020年我国核电装机容量将达到40 GW。据预测到2050年需发展到240 GW。铀资源的有限性和国际铀市场的不确定性,促使我们认真考虑快中子增殖堆及其闭式燃料循环的发展。设想的快堆发展战略目标是:(1)2030年实现一址多堆运行800～900 MW商用增殖快堆;(2)2050年核电装机容量发展到240 GW;(3)2050年以后逐步实现核能大规模替代化石燃料。     

中国示范快堆实现土建开工

正12月29日,示范快堆工程土建开工。示范快堆工程建设,是我国核能战略"三步走"的关键环节,也是新时代、新形势下中国核工业发展的标志性工程。示范快堆工程对于实现核燃料闭式循环、促进我国核能可持续发展,推动地方经济建设具有重要意义。我国核能发展战略"三步走"——热中子反应堆、快中子增殖堆、受控核聚变堆。目前,我国已形成世界上少数国家才有的完整的核燃料循环体系,建立压水堆、快堆匹配发展,     

俄面向闭式燃料循环的新型反应堆技术发展布局

<正>俄罗斯副总理亚历山大·诺瓦克2022年2月宣布,俄罗斯将在2030年前开始建设VVER-S改进型压水堆。该反应堆可以通过调节中子能谱,提升核燃料利用率。俄罗斯近年来逐渐确立“二元核能体系”（即热堆闭式燃料循环和快堆闭式燃料循环相结合）的发展蓝图并列入核工业国家计划,目标是通过更高增殖比的新型反应堆和铀钚混合燃料的应用,提升铀资源利用效率,解决当前核电可持续性不足的问题。对此,俄罗斯基于已有技术,     

压水堆核燃料循环情景模式初步研究

根据我国核电发展现状和中长期发展规划及中长期（2030、2050）发展战略研究,假设2050年前我国压水堆核电发展规模,基于压水堆乏燃料后处理,回收的钚做成MOX燃料放入压水堆中使用,MOX燃料只使用1次的循环模式,进行核能发展情景研究。基于压水堆可装载30%比例MOX燃料的已有研究结果,考虑我国主要的两种压水堆堆型M310和AP1000,进行压水堆核燃料循环分析。利用核能发展情景动态分析程序DESAE-2,给出了不同情景模式下天然铀需求量、乏燃料累计量等。结果表明：至2050年,B₁和B₂模式较A模式分别节省天然铀4.1万t和2.9万t。     

三种核燃料循环方案的综合效益比较

核燃料循环产业发展的最佳状态是消耗最少的核资源,产生最好的经济效益,造成最小的环境危害。本研究从铀资源消耗、废物排放、循环成本三个方面,对开路热堆循环、闭式热堆循环、快热联合循环三种核燃料循环方案的综合效益进行比较。研究表明,在铀资源利用方面,与开路热堆循环比较,闭式热堆循环节省天然铀22.3%,快热联合循环节省天然铀65.2%,闭式热堆循环铀资源利用率提高28.7%,快热联合循环铀资源利用率提高165.5%,闭式热堆循环节省分离功12.5%,快热联合循环节省分离功60.8%。增加后处理环节的闭式核燃料循环能大幅度节约天然铀资源并减少能耗,显著提高铀资源利用率。在经济性方面,与开路热堆循环比较,闭式热堆循环成本平均提高6%,快热联合循环成本平均降低27.3%。开路热堆循环经济性优势随着天然铀价格降低而增强,闭式循环经济性优势随着后处理价格越低而增强,快热联合循环的经济性始终优于闭式热堆循环。本研究确定了三种循环间的经济平衡点,可根据不同天然铀价格和后处理价格比较三种循环方案经济性的优劣,选取经济可行的核燃料循环方案。在环境保护方面,与开路热堆循环比较,闭式热堆循环的废物产生量减少84.1%,体积减少87.7%,快热联合循环的废物产生量减少95.4%,体积减少99.0%。闭式循环的环境效益明显优于开路循环,快热联合循环优势最大。研究结论,快热联合循环的综合效益最好,是核燃料循环产业发展的最佳选择。     

核燃料循环“一次通过”情景分析研究

在我国大力发展核电和建立先进闭式燃料循环体系的前提下,为了核燃料循环各环节相互匹配,有机协调地发展核电,需对核燃料循环各环节的规模、布局等开展模拟分析研究。为了综合比较闭式燃料循环在铀资源利用率、环境友好型等方面的优势,还需对核燃料循环的"一次通过"方式进行分析研究。根据我国核电目前和中长期发展规划,假设2050年中国核电装机容量分别达到100GW、200GW和300GW,核电站全部采用压水堆,核燃料循环采用"一次通过"方式,利用简化模型,计算分析了近100年内累计需要的天然铀、每年需要的天然铀、每年需要的分离功、累计产生的乏燃料和需要离堆暂存的乏燃料量等关键数据。     

我国先进核燃料循环技术发展战略的一些思考

从核裂变能可持续发展的角度,分析了各种核燃料循环方式的特点,指出了核燃料“一次通过”方式不符合核能可持续发展战略。为了充分利用铀资源并实现核废物的最少化,快堆燃料闭式循环是核裂变能可持续发展的根本出路。本文在介绍了国内外核燃料循环关键技术研究现状和发展趋势的基础上,探讨了我国核燃料循环科技的发展战略,并指出了为实现上述发展战略目标应采取的若干措施。     

热电两用快堆的产氢技术

日本核燃料循环机构在快堆（FBR）循环战略的可行性研究中，对采用多用途小型快堆产氢的可能性进行了研究。研究项目之一就是以水为原料，研究不排放二氧化碳的高效率的产氢方法，对日本国内用于核能生产汽车燃料电池（FCV）的设备容量以及引入电力-产氢用核能设备的最大可能性进行了评价。     

采用DESAE程序对我国核能发展情景的初步分析

根据IAEA大会决议，创新型核反应堆和燃料循环国际项目（INPRO）于2000年启动。我国是INPRO项目成员国之一，主要参与基于快堆的闭式燃料循环技术的联合评价研究。根据本国的核能发展规划或设想建立核能发展情景并进行评价是联合研究的一项主要内容。     

堆后核燃料循环的发展

堆后核燃料循环是充分利用核资源和保障核安全的重要环节.本文分析了堆后核燃料循环,包括辐照核燃料的运输、中间贮存、后处理,混合氧化物燃料制备及放射性废物最终处置的发展现状。根据核能发展规划,至2000年从我国核电站卸出的辐照核燃料估计达1900吨左右。在实现核能计划的同时,应相应地发展堆后核燃料循环。     

中国快堆及先进核燃料循环体系发展战略思考

中国是世界上最大的发展中国家,能源消耗位列世界第一。为实现社会、经济的可持续发展,确保能源供应安全和降低环境压力,大力发展包括核能在内的清洁能源是能源发展战略的必然选择。目前,中国的核能经过近30年的发展取得了长足进步,但在能源体系中依然占比很小。鉴于中国的铀资源总体储量有限,仅靠热中子反应堆支撑核能作为主力能源发展难以实现。快堆具有资源利用率高、固有安全性好等优点,配以先进核燃料循环系统,可实现核能的大规模、可持续、环境友好的发展。其中,快堆的发展应遵从先增殖、后嬗变的路线,燃料方面在经过氧化物陶瓷燃料后应尽快过渡到金属燃料;后处理方面初期主要通过水法处理压水堆乏燃料,为快堆提供初装料,后续要尽快实现干法后处理,以缩短增殖燃料的倍增时间和提高整个体系的经济性;同时,还需要同步发展高放废物的处理处置技术。在快堆和先进核燃料循环体系的支撑下,我国的核能能实现在千年量级上作为主力能源发展。     

快堆核燃料循环模式的经济性评价

以快堆核电厂的核燃料循环过程及核燃料循环模型为基础,利用注销法对2种核燃料循环方式进行经济性计算和分析;同时,也将快堆燃料循环经济性与压水堆(PWR)燃料"一次通过"的经济性进行对比。按目前价格水平计算,PWR"一次通过"的核燃料循环方式比快堆核燃料循环模式的经济性好,但随着天然铀价格的上涨以及燃料后处理技术水平的进步,快堆核燃料循环费用有望达到或低于PWR"一次通过"的核燃料循环费用。     

Georgia Tech Studies of Sub-Critical Advanced Burner Reactors with a D-T Fusion Tokamak Neutron Source for the Transmutation of Spent Nuclear Fuel

The possibility that a tokamak D-T fusion neutron source, based on ITER physics and technology, could be used to drive sub-critical, fast-spectrum nuclear reactors fueled with the transuranics (TRU) in spent nuclear fuel discharged from conventional nuclear reactors has been investigated at Georgia Tech in a series of studies which are summarized in this paper. It is found that sub-critical operation of such fast transmutation reactors is advantageous in allowing longer fuel residence time, hence greater TRU burnup between fuel reprocessing stages, and in allowing higher TRU loading without compromising safety, relative to what could be achieved in a similar critical transmutation reactor. The required plasma and fusion technology operating parameter range of the fusion neutron source is generally within the anticipated operational range of ITER. The implications of these results for fusion development policy, if they hold up under more extensive and detailed analysis, is that a D-T fusion tokamak neutron source for a sub-critical transmutation reactor, built on the basis of the ITER operating experience, could possibly be a logical next step after ITER on the path to fusion electrical power reactors. At the same time, such an application would allow fusion to contribute to meeting the nation’s energy needs at an earlier stage by helping to close the fission reactor nuclear fuel cycle.     

乏燃料后处理湿法工艺技术基础研究发展现状

为了保持核能可持续发展,必须相应发展乏燃料后处理技术,以实施快堆闭合核燃料循环。湿法后处理工艺仍以PUREX流程为基础,从乏燃料元件首端处理工艺、萃取工艺的简化和无盐调价等方面开展相应的研究。同时随着动力堆乏燃料元件燃耗的增加,Np、Pu以及高产额裂变产物元素Ru、Tc、Zr等在水法后处理工艺中的行为及形态等影响日趋凸显。本文针对上述问题进行了论述,并提出了相应的研究重点。     

Utilization of spent PWR fuel-advanced nuclear fuel cycle of PWR／CANDU synergism

High neutron economy, on line refueling and channel design result in the unsurpassed fuel cycle flexi-bility and variety for CANDU reactors. According to the Chinese national conditions that China has both PWR and CANDU reactors and the closed cycle policy of reprocessing the spent PWR fuel is adopted, one of the advanced nu-clear fuel cycles of PWR/CANDU synergism using the reprocessed uranium of spent PWR fuel in CANDU reactor is proposed, which will save the uranium resource (-22.5%), increase the energy output (-41%), decrease the quantity of spent fuels to be disposed (-2/3) and lower the cost of nuclear poower, Because of the inherent flexibility of nuclearfuel cycle in CANDU reactor, and the low radiation level of recycled uranium(RU), which is acceptable for CANDU reactor fuel fabrication, the transition from the natural uranium to the RU can be completed without major modifica-tion of the reactor core structure and operation mode.It can be implemented in Qinshan Phase Ⅲ CANDU reactors with little or no requirement of big investment in new design. It can be expected that the reuse of recycled uranium of spent PWR fuel in CANDU reactor is a feasible and desirable strategy in China.     

Metallic fuels for advanced reactors

In the framework of the Generation IV Sodium Fast Reactor Program, the Advanced Fuel Project has conducted an evaluation of the available fuel systems supporting future sodium cooled fast reactors. This paper presents an evaluation of metallic alloy fuels. Early US fast reactor developers originally favored metal alloy fuel due to its high fissile density and compatibility with sodium. The goal of fast reactor fuel development programs is to develop and qualify a nuclear fuel system that performs all of the functions of a conventional fast spectrum nuclear fuel while destroying recycled actinides. This will provide a mechanism for closure of the nuclear fuel cycle. Metal fuels are candidates for this application, based on documented performance of metallic fast reactor fuels and the early results of tests currently being conducted in US and international transmutation fuel development programs.     

Nuclear fuel considerations for the 21 century

There are many external influences that may control the path that nuclear power deployment follows. In the next 50 years several events may unfold. Fear of the consequences of the greenhouse effect may produce a carbon tax that would make nuclear power economically superior very quickly. This, in turn, would increase the rate at which uranium reserves diminish due to the increased rate of nuclear power deployment. However, breakthroughs in the extraction of uranium from the sea or deployment of fast breeder reactors would greatly extend the uranium reserves and, as well, utilize the thorium cycle.On the other hand, carbon sequestering technology breakthroughs could keep fossil fuels dominant for the remainder of the century. Nuclear power may only then continue, as today, in a lesser role or even diminish. Fusion power or new developments in solar power could completely displace nuclear power as we know it today.Even more difficult to predict is when the demand for mobile fuel for transportation will develop such that hydrogen and hydrogen rich fuel cells will be in common use. When this happens, nuclear power may be the energy source of choice to produce this fuel from water or methane. In a similar vein, the demand for potable and irrigation water may be another driver for the advent of increased deployment of nuclear power.With all these possibilities of events that could happen it appears impossible to predict with any certainty which path nuclear power deployment may take. However, it is necessary to define a strategy that is flexible enough to insure that when a technology is needed, it is ready to be deployed.For the next few decades there will be an evolutionary improvement in the performance of uranium oxide and mixed uranium oxide-plutonium oxide (MOX) LWR fuels. These improvements will be market driven to keep the cost of fuel and the resulting cost of nuclear power electricity as competitive as possible. The development of fuels for accelerator transmutation and for reactor transmutation with inert matrix fuels is in its infancy. A great deal of research has been initiated in a number of countries, which has been summarized in recent conferences. In Europe the work on these fuels is directed at the same problem as their utilization of MOX; namely to reduce the inventory of separated plutonium, minor actinides, and Long Lived Fission Products (LLFP). In the United States there is no reprocessing and thus no inventory of separated civilian plutonium. However, in the United States there is a resistance to a permanent spent fuel repository and thus accelerator transmutation presents a possible alternative. If nuclear power does have a long-term future, then the introduction of the fast reactor is inevitable. Included in the mission of the fast reactors would be the elimination of the inventory of separated plutonium while generating useful energy. The work that is ongoing now on the development of fuel concepts for assemblies that contain actinides and LLFP would be useful for fast reactor transmutation.There is still a great deal of work required to bring the fast breeder reactor option to maturity. Fortunately there is perhaps a fifty-year period to accomplish this work before fast breeders are necessary. With regard to fast reactor fuel development, future work should be considered in three stages. First, all the information obtained over the past forty years of fast reactor fuel development should be completely documented in a manner that future generations can readily retrieve and utilize the information. Fast reactor development came to such an abrupt halt world-wide that a great deal of information is in danger of being lost because most of the researchers and facilities are rapidly disappearing. Secondly, for all of the existing fast reactor fuels, and this includes, oxides, carbides, nitrides, and metallic fuels, the evolutionary work was far from being completed. Although mixed oxide fuels were probably the furthest advanced, there were many concepts for improved claddings and advanced fabrication methods that were never fully explored. Finally, with such an extended period before fast reactors are needed there is ample time for truly innovative fuels to be developed that are capable of performing over a wide range of conditions and coolants.     

Choice of the capacity of a fast reactor for nuclear power

Analytical assessments, associated with the choice of the unit capacity of a serially built fast reactor under conditions of the future advancement of nuclear power, are presented. It is shown that considering the limited resources of natural uranium, the development of a reliable raw materials base must be based on the development of fast reactors with expanded breeding of fuel and fuel cycle closure. Since fast reactors, together with energy production, are also producers of new fuel, their parameters must be optimized taking account of this factor on the basis of systems analysis. Calculations show that the optimal capacity for fast reactors is in the 1 GW range. __________ Translated from Atomnaya énergiya, Vol. 103, No. 2, pp. 83–88, August, 2007.