聚变堆增殖包层概念特征比较研究

在广泛调研国际上现有的聚变堆包层概念的基础上,对聚变堆包层的发展现状和需要解决的关键问题进行了总结。从工程可行性、氚增殖提取与控制特征、经济性以及安全和环境影响方面对固态和液态氚增殖剂包层进行了比较分析,系统阐述了各种包层概念的优缺点,从现实可行性与发展潜力方面为未来聚变堆包层概念发展提出建议。     

Can Fusion and Fission Breeding Help Civilization Survive?

As apparent from the title, this author feels that civilization faces a real threat, one which will become obvious and serious within the lifetimes of many readers of this article. This threat is not global warming, but lack of affordable energy. We take for granted turning on a light, or adjusting our thermostats in winter or summer, or filling our cars gas tank; and lose sight of the fact that there are huge and complicated industrial systems which make this possible. But as we run out of petroleum and natural gas, and worry about the environmental and climatic effects of burning coal on the required scale, how can this continue? This paper makes the case that breeding nuclear fuel, by both fusion and fission, is the only way our civilization as we know it, can continue beyond the next half century or so.     

Characterization of the effects of continuous salt processing on the performance of molten salt fusion breeder blankets

Several continuous salt processing options are available for use in molten salt fusion breeder blanket designs: fluorination only, fluorination plus reductive extraction, and fluorination, plus reductive extraction, plus metal transfer. The effects of processing on blanket performance have been assessed for these three levels of processing and various equilibrium uranium concentrations in the salt. A one-dimensional model of the blanket was used in the neutronics analysis, which incorporated transport calculations with time-dependent isotope generation and depletion calculations. The method of salt processing was found to have little affect on the level of radioactivity, toxicity, or the thermal behavior of the salt during operation of the reactor. The processing rates necessary to maintain the desired uranium concentrations in the suppressed-fission environment were quite low, which permitted only long-lived species to be removed from the salt. The effects of the processing therefore became apparent only after the radioactivity due to the short-lived species diminished. The effects of the additional processing (reductive extraction and metal transfer) could be seen after approximately 1 year of decay, but were not significant at times closer to shutdown. The reduced radioactivity and corresponding heat deposition were thus of no consequence in accident or maintenance situations. Net fissile production in the Be/MS blanket concept at a fusion power level of 3000 MW at 70% capacity ranged from 5100 kg/year to 5170 kg/year for uranium concentrations of 0.11% and 1.0%²³³U in thorium, respectively, with fluorination-only processing. The addition of processing by reductive extraction resulted in 5125 kg/year for the 0.11%²³³U case and 5225 kg/year for the 1.0%²³³U case.     

Fast-fission tokamak breeder reactors

A fast-fission blanket around a fusion plasma exploits high neutron multiplication for superior breeding and high-energy multiplication to generate significant net electrical power. A major improvement over previous fast-fission blanket concepts is the use of mobile fuel, namely a pebble-bed configuration with helium cooling. Upon loss of coolant, the mobile fuel can be gravity-dumped to a separately cooled dump tank before excessive temperatures are reached. The pebble bed is also compatible with rapid fuel exchange and a low-cost reprocessing method. With the ignited tokamak plasma producing 620 MW of fusion power, the net electric power is 1600 MW_e and the annual fissile production exceeds 3 tonnes.     

Selection of a toroidal fusion reactor concept for a magnetic fusion production reactor

The basic fusion driver requirements of a toroidal materials production reactor are considered. The tokamak, stellarator, bumpy torus, and reversed-field pinch are compared with regard to their demonstrated performance, probable near-term development, and potential advantages and disadvantages if used as reactors for materials production. Of the candidate fusion drivers, the tokamak is determined to be the most viable for a near-term production reactor. Four tokamak reactor concepts (TORFA/FED-R, AFTR/ZEPHYR, Riggatron, and Superconducting Coil) of approximately 500-MW fusion power are compared with regard to their demands on plasma performance, required fusion technology development, and blanket configuration characteristics. Because of its relatively moderate requirements on fusion plasma physics and technology development, as well as its superior configuration of production blankets, the TORFA/FED-R type of reactor operating with a fusion power gain of about 3 is found to be the most suitable tokamak candidate for implementation as a near-term production reactor.This paper represents work carried out from 1980 to 1982 and was in draft form in 1982. It was received for publication with only minor editing from its 1982 version (except for Tables II and III and Fig. 1), explaining the fact that some of the material is dated.     

聚变—裂变混合堆及其在我国核能发展中的作用

本文概要介绍聚变和聚变-裂变混合堆基本原理及其作用。聚变-裂变混合堆可以为压水堆或快堆提供充足的核燃料。它和压水堆或快堆组成的系统具有经济可行性。在解决我国核能发展中燃料短缺问题和促进纯聚变能源的发展方面可望发挥重要的作用。     

Feasibility study of a magnetic fusion production reactor

A magnetic fusion reactor can produce 10.8 kg of tritium at a fusion power of only 400 MW —an order of magnitude lower power than that of a fission production reactor. Alternatively, the same fusion reactor can produce 995 kg of plutonium. Either a tokamak or a tandem mirror production plant can be used for this purpose; the cost is estimated at about $1.4 billion (1982 dollars) in either case. (The direct costs are estimated at $1.1 billion.) The production cost is calculated to be $22,000/g for tritium and $260/g for plutonium of quite high purity (1%²⁴⁰Pu). Because of the lack of demonstrated technology, such a plant could not be constructed today without significant risk. However, good progress is being made in fusion technology and, although success in magnetic fusion science and engineering is hard to predict with assurance, it seems possible that the physics basis and much of the needed technology could be demonstrated in facilities now under construction. Most of the remaining technology could be demonstrated in the early 1990s in a fusion test reactor of a few tens of megawatts. If the Magnetic Fusion Energy Program constructs a fusion test reactor of approximately 400 MW of fusion power as a next step in fusion power development, such a facility could be used later as a production reactor in a spinoff application. A construction decision in the late 1980s could result in an operating production reactor in the late 1990s. A magnetic fusion production reactor (MFPR) has four potential advantages over a fission production reactor: (1) no fissile material input is needed; (2) no fissioning exists in the tritium mode and very low fissioning exists in the plutonium mode thus avoiding the meltdown hazard; (3) the cost will probably be lower because of the smaller thermal power required; (4) and no reprocessing plant is needed in the tritium mode. The MFPR also has two disadvantages: (1) it will be more costly to operate because it consumes rather than sells electricity, and (2) there is a risk of not meeting the design goals.This paper represents work carried out from 1980 to 1982 and was in draft form in 1982. It was received for publication with only minor editing of its 1982 version, explaining the fact that some of the material is dated.     

Mechanical design of a magnetic fusion production reactor

The mechanical aspects of tandem mirror and tokamak concepts for the tritium production mission are compared and a proposed breeding blanket configuration for each type of reactor is presented in detail, along with a design outline of the complete fusion reactor system. In both cases, the reactor design is developed sufficiently to permit preliminary cost estimates of all components. A qualitative comparison is drawn between both concepts from the view of mechanical design and serviceability, and suggestions are made for technology proof tests on unique mechanical features. Detailed cost breakdowns indicate less than 10% difference in the overall costs of the two reactors.This paper represents Work carried out from 1980 to 1982 and was in draft form in 1982. It was received for publication with only minor editing of its 1982 version, explaining the fact that some of the material is dated.     

Fusion technology for a magnetic fusion production reactor

The tandem mirror and tokamak are being considered as candidate fusion drivers for a materials production reactor that could be implemented in the 1990s. This report considers, in detail, the required performance characteristics of the fusion plasma and the major technological subsystems for each fusion driver. These performance characteristics are compared with the present state of the art, corresponding development needs are identified, and technology program requirements, in addition to those now being supported by the Department of Energy, are pointed out. The tandem mirror and tokamak fusion drivers are also compared with regard to their required advancements in plasma performance and technology development.This paper represents work carried out from 1980 to 1982 and was in draft form in 1982. It was received for publication with only minor editing of its 1982 version, explaining the fact that some of the material is dated.     

The Fusion Hybrid as a Key to Sustainable Development

If world development is to continue, mid-century energy requirements are daunting. For world development, per capita energy use in the developing world must be brought up to levels in the already developed world. Restrictions on how much CO₂ mankind can responsibly put into the atmosphere may complicate the task further. Studies show that by 2050 the world will require an additional 10–30 terawatts (TW) of carbon free power, at least as much additional, as the 10 TW generated today with fossil fuel. This paper suggests that the fusion hybrid is one of rather few possibilities for generating this power economically, in an environmentally acceptable way, and with little proliferation danger.     

Thermal-hydraulic design of water-cooled pressure tube blanket for a fusion driven subcritical reactor

A Water-cooled Pressure Tube Energy production blanket (WPTE) for fusion driven subcritical reactor has been designed to achieve 3000 MW thermal power with self-sustaining tritium cycle. Pressurized water has great advantages in energy production; however the high pressure may cause some severe structural design issues. This paper proposes a new concept of water-cooled blanket. To solve the problem of the high pressure of the coolant, the pressure tube was adopted in the design and in the meantime, the thickness of the first wall can be significantly reduced as result of adopting pressure tube. The numerically simulating and calculating of temperature, stress distribution and flow analyses were carried out and the feasibility of using water as coolant was discussed. The results demonstrated the engineering feasibility of the water-cooled fusion–fission hybrid reactor blanket module.     

The fusion breeder concept

Some practical aspects and broader consequences of strategies that have been proposed for the association of fusion and fission processes are reviewed.It is concluded more particularly that the build-up of the technology necessary for the ultimately desired substitution of fusion for the present fission source of nuclear power could be much advanced by an interim period of the application of fusion entirely to the breeding of U-233 for the large number of fission reactors that will be coexisting during this period.Principal reasons for this view are the considerable technical easements of this approach, and the very large gain in effective energy release per fusion event, which offers economic advantage long before achievement of the classic definition of the fusion “break even” point.     

Modification of PROMETHEUS Reactor as a Fusion Breeder and Fission Product Transmuter

This study presents the analyses of the fissile breeding and long-lived fission product (LLFP) transmutation potentials of PROMETHEUS reactor. For this purpose, a fissile breeding zone (FBZ) fueled with the ceramic uranium mono-carbide (UC) and a LLFP transmutation zone (TZ) containing the ⁹⁹TC and ¹²⁹I and ¹³⁵Cs isotopes are separately placed into the breeder zone of PROMETHEUS-H design. The neutronic calculations are performed by using two different computer codes, the XSDRNPM/SCALE4.4a neutron transport code and the MCNP4B Monte Carlo code. A range of analyses are examined to determine the effects of the FF, the fraction of ⁶Li in lithium (Li) and the theoretical density (TD) of Li₂O in the tritium breeder zone (TBZ) on the neutronic parameters. It is observed that the numerical results obtained from both codes are consistent with each other. It is carried out that the profiles of fission power density (FPD) are flattened individually for each FF (from 3 to 10%). Only, in the cases of FF ≥ 8%, the system is self sufficient from the point of view of tritium generation. The results bring out that the modified PROMETHEUS fusion reactor has capabilities of effective fissile breeding and LLFP transmutation, as well as the energy generation.     

Economic analysis of a magnetic fusion production reactor

The magnetic fusion reactor for the production of nuclear weapon materials, based on a tandem mirror design, is estimated to have a capital cost of $1.5 billion and to produce 10 kg of tritium/year for $22,000/g or 940 kg/year of plutonium in the plutonium mode for $250/g plus heavy metal processing. A tokamak-based design is estimated to cost $1.5 billion and to produce 10 kg of tritium/year for $29 thousand/g. For comparison, a commercially sized tandern mirror fusion breeder selling excess electricity and fissile material to commercial markets is estimated to cost $3.6 billion and to produce tritium for $2.6 thousand/g and plutonium for $34/g plus heavy metal processing.This paper represents work carried out from 1980 to 1982 and was in draft form in 1982. It was received for publication with only minor editing of its 1982 version, explaining the fact that some of the material is dated.     

Nuclear design and analysis of a magnetic fusion production reactor

Tandem-mirror- and tokamak-based magnetic fusion production reactors are predicted to have tritium breeding ratios of 1.67 and 1.49, respectively. The latter value replaces one (1.56) that is used elsewhere in the sequence of papers in this issue. Blanket energy multiplication for both is predicted to be about 1.3. With the tandem mirror operating in the plutonium production mode, the net plutonium-plus-tritiurn breeding ratio is 1.74. Blanket energy multiplication for the plutonium mode is predicted to be 2.4 at a plutonium-uranium ratio of 0.7% and a uranium volume fraction of 3%.This paper represents work carried out from 1980 to 1982 and was in draft form in 1982. It was received for publication with only minor editing of its 1982 version, explaining the fact that some of the material is dated.     

The case for the fusion hybrid

The use of nuclear fusion to produce fuel for nuclear fission power stations is discussed in the context of a crucial need for future energy options. The fusion hybrid is first considered as an element in the future of nuclear fission power to provide long term assurance of adequate fuel supplies for both breeder and convertor reactors. Generic differences in neutronic characteristics lead to a fuel production potential of fusion-fission hybrid systems which is significantly greater than that obtainable with fission systems alone. Furthermore, cost benefit studies show a variety of scenarios in which the hybrid offers sufficient potential to justify development costs ranging in the tens of billions of dollars. The hybrid is then considered as an element in the ultimate development of fusion electric power. The hybrid offers a near term application of fusion where experience with the requisite technologies can be derived as a vital step in mapping a credible route to eventual commercial feasibility of pure fusion systems. Finally, the criteria for assessment of future energy options are discussed with prime emphasis on the need for rational comparison of alternatives. This approach is contrasted with the dual standard too often used in judging the risks and benefits of nuclear power where, for example, rather minor radiological effects are highlighted while much larger exposures to radiation from medical x-rays, airplane travel, color television sets, etc., are ignored. It is concluded that the fusion hybrid deserves a prominent place among new energy resources but that early attention to insure an adequately informed public is a vital ingredient in assuring reasonable prospects of success.     

Three-dimensional neutronic calculations for a fusion breeder APEX reactor using some libraries

The effects of evaluated nuclear data files on neutronics characteristics of a fusion–fission hybrid reactor have been analyzed; three-dimensional calculations have been made using the MCNP4C Monte Carlo Code for ENDF/B-VII T = 300 K, JEFF-3.0 T = 300 K, and CENDL-2 T = 300 K evaluated nuclear data files. The nuclear parameters of a fusion–fission hybrid reactor such as tritium breeding ratio, energy multiplication factor, fissile fuel breeding and nuclear heating in a first wall, blanket and shield have been investigated for the mixture components of 90% Flibe (Li₂BeF₄) and 10% UF₄ for a blanket layer thickness of 50 cm. The contributions of each isotope of Flibe (⁶Li, ⁷Li, ¹⁹F, ⁹Be) and UF₄ (²³⁵U, ²³⁸U) to the integrated parameter values were calculated. The neutron wall load is assumed to be 10 MW/m².     

Conceptual design study of fusion DEMO plant at SWIP

The basic definition and development strategy of the DEMO plant based on the Chinese fusion power plant (FPP) program are presented briefly. A conceptual design study of fusion HCSB-DEMO reactor with a fusion power of 2550 MW and a neutron wall loading of 2.3 MW/m² is performed recently. Three sets parameters of core plasma for different DEMO design objectives are proposed. A helium-cooled blanket system with ceramic breeder (Li₄SiO₄), the structure material of low-activation ferritic steel (LAF/M) and Be neutron multiplier based on Chinese ITER HCSB-TBM design foundation are considered. The design parameters, preliminary analyses and the basic structure as well as development strategy of HCSB-DEMO reactor are introduced.     

Systematic study of anomalous fragment anisotropies in subbarrier complete fusion—fission reactions

The complete fusion-fission is separated from the transter-induced-fission with the fragment folding angle technique.The cross sections and fragment angular distributions for the complete fusion-fission reactions of 11B 238U(237Np),237NP,16O 232Th(238U) and 19F 232Th at near-and sub-barrier energies have been measured.The present fusion and fission standard models can reproduces both the excitation functions and the fragment anisotropies for the systems of 11B 238U(237Np)and 12C 237Np;but fail to explain both the experimental data for the other 3 systems simultaneously,The evidence of the entrance-channel dependence of fission-fragment anisotropies is revealsed by comparison of the 11B 237NP and ^16O 232Th data.Based on the observations a new version model of preequilibrium fission is put forward to explain the anomaly.     

聚变发电反应堆概念设计研究

在广泛分析聚变能相关领域研究发展状况和国际热核聚变实验堆(ITER)物理与技术基础上,提出了一个考虑了技术可行性的聚变发电反应堆概念(称之为FDS Ⅱ)。这个概念具有ITER参数适量外推的等离子体物理与技术水平的聚变堆芯和具有发展潜力的液态锂铅氚增殖包层,在对这个概念进行中子学、热工水力学、力学、安全与环境影响和经济学等一系列计算分析的基础上,给出了初步的概念设计和进一步设计优化的共性原则。