聚变-裂变混合能源堆球模型参数敏感性分析

在聚变-裂变混合能源堆球模型基础上,使用蒙特卡罗方法中子学程序对中子源、铀水体积比、产氚区等相关参数进行了中子学的敏感性计算。分析了各参数对混合能源堆能量放大倍数M和氚增殖比TBR的影响,并总结其基本规律,为开展进一步的混合能源堆概念设计提供了重要参考。     

激光惯性约束聚变裂变混合能源包层中子学数值模拟

对三维输运与燃耗耦合程序MCORGS进行了适应性改造,并对利弗莫尔实验室提出的激光惯性约束聚变裂变混合能源(LIFE)概念进行了分析和改进。输运计算采用MCNP程序,燃耗计算采用ORIGENS程序,增加氚控制模块和功率控制模块。建立了与LIFE等价的以贫化铀为燃料、Be为中子增殖剂的包层方案,通过数值模拟验证了MCORGS程序的可靠性。针对Be资源短缺及冷却复杂问题,设计了以贫化铀为燃料、Pb为中子增殖剂的包层方案,包层能量放大了4倍,可在55a内稳定输出2 000 MWt功率。     

次临界能源堆包层中子学概念研究

介绍了次临界能源堆包层中子学概念研究进展。采用MCNP与ORIGENS耦合的输运燃耗程序MCORGS开展研究。利用一维模型改进了产氚区和屏蔽区的设计。产氚区采用多区分层布置,降低水对中子的吸收,大幅减少了Li₄SiO₄的用量。屏蔽区采用铁和水多区分层布置,包层泄漏中子数为10^-4量级,超导线圈沉积热小于60 kW,28 a内中子注量小于10²²m^-2。针对不同的铀水体积比（R_V）,探讨了相应的后处理策略。随着R_V的减小,需去除的裂变产物相应增加。建议采用R_V=2的物理设计,平常只需作燃料重整,每隔几十年作1次高温干法去除沸点在3 600 K以下的裂变产物即可。最后,参考国际热核实验堆几何结构,建立三维包层模型,进行了初步研究。     

聚变-裂变混合能源堆一维计算模型燃耗分析

聚变-裂变混合能源堆包括聚变中子源和以天然铀为燃料、水为冷却剂的次临界包层,主要目标是生产电力。利用输运燃耗耦合程序系统MCORGS计算了混合能源堆一维模型的燃耗,给出了中子有效增殖因数k_eff、能量放大倍数M、氚增殖比TBR等物理量随时间的变化。通过分析能谱和重要核素随燃耗时间的变化,说明混合能源堆与核燃料增殖、核废料嬗变混合堆的不同特点。本文给出的结果可作为混合堆中子输运、燃耗分析程序校验的参考数据,为混合堆概念研究提供了基础数据。     

氦气、水和熔盐冷却的混合堆中子学性能研究

氦气、水、熔盐(Flibe)在强磁场中流动不存在严重的MHD问题,因此适合在基于磁约束的聚变-裂变混合堆中作为冷却剂.针对氦气、水、Flibe这3种冷却剂对混合堆包层中子学性能的影响进行研究,分析包层中能谱特点及燃料增殖特性.通过燃耗计算,研究氚增殖率(TBR)、能量倍增因子(M)、keff等随运行时间的变化.中子学输运采用三维蒙特卡罗程序MCNP.计算结果表明,不同的冷却剂对混合堆系统中子能谱影响很大:氦冷系统的能谱最硬,主要发生快中子裂变,氚增殖效果最好;水冷系统的能谱最软,产能最多,但需提高TBR;Flibe冷系统的能谱较硬,产能最少.     

聚变裂变混合发电堆水冷包层中子学设计分析

主要针对聚变裂变混合发电堆FDS-EM水冷包层的能量倍增因子M和氚增殖率TBR等中子学参数进行优化计算。FDS-EM包层主要设计目标是在氚自持的基础上获得约1 GW的电功率,并且尽可能长时间连续运行不换料。通过初步设计分析给出一个使用核废料(压水堆卸出的废料钚、锕系加上贫铀)作为裂变燃料,能够实现氚自持、能量倍增因子约为90等设计目标,且连续运行至少10年不换料的中子学方案。     

等效天然铀燃料中子学性能分析

采用10种回收铀（RU）和贫铀（DU）成分情形,根据等效天然铀（NUE）燃料混合比计算程序ALPHA算得配成NUE燃料的混合比。以标准CANDU 6栅元结构为载体,采用WIMS程序,通过比较NUE燃料与天然铀（NU）燃料的中子学性能参数,以及NUE燃料入堆示范验证试验中实际入堆的燃料信息,对NUE燃料与NU燃料的中子学性能等效性进行了论证分析。研究表明,与NU燃料相比,各种情形下NUE燃料在无限增殖系数、卸料燃耗、冷却剂空泡反应性以及燃料温度效应等中子学性能参数上吻合较好,NUE燃料与NU燃料具备较好的中子学等效性,可应用于重水堆核电站,实现回收铀的有效利用。     

气冷托卡马克商用混合堆中子学设计

完成了气冷托卡马克商用混合堆的中子学设计,采用单零偏滤器等离子体位型,在一维计算中考虑了共振能量和空间自屏效应的影响,用具有连续能量截面的蒙特卡洛程序MCNP完成了多维计算;研究了中子源密度分布对包层中子学性能的影响,结果:氚增殖率和裂变燃料增殖率分别达到1.0和0.60,聚变功率2000Mw,负荷因子0.75,每年产~(239)Pu为4000kg。     

聚变裂变混合堆燃耗计算及燃料成本分析

基于轻水冷却的压力管式混合堆,采用压水堆卸载的乏燃料以及天然铀氧化物陶瓷燃料,建立混合堆包层的换料方案,详细计算了包层中子学性能随燃耗的变化情况,计算结果表明,包层在维持3000 MW热功率输出的同时,可以保证氚自持(氚增殖比TBR>1.20),而每5 a仅需向包层添加80 t左右的重金属燃料。基于建立的平衡循环计算了包层采用不同燃料时的单位发电燃料成本。结果表明,采用乏燃料和天然铀时的单位发电燃料成本分别为1.82×10-3、1.35×10-3$/(k W·h)。     

聚变-裂变混合堆水冷包层中子物理性能研究

研究直接应用国际热核聚变实验堆（ITER）规模的聚变堆作为中子驱动源,采用天然铀为初装核燃料,并采用现有压水堆核电厂成熟的轻水慢化和冷却技术,设计聚变-裂变混合堆裂变及产氚包层的技术可行性。应用MCNP与Origen2相耦合的程序进行计算分析,研究不同核燃料对包层有效增殖系数、氚增殖比、能量放大系数和外中子源效率等中子物理性能的影响。计算分析结果显示,现有核电厂广泛使用的UO₂核燃料以及下一代裂变堆推荐采用的UC、UN和U₉₀Zr₁₀等高性能陶瓷及合金核燃料作为水冷包层的核燃料,都能满足以产能发电为设计目标的新型聚变 裂变混合堆能量放大倍数的设计要求,但只有UC和U₉₀Zr₁₀燃料同时满足聚变燃料氚的生产与消耗自持的要求。研究结果对进一步研发满足未来核能可持续发展的新型聚变-裂变混合堆技术具有潜在参考价值。     

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.     

A fusion–fission hybrid reactor with water-cooled pressure tube blanket for energy production

A fusion–fission hybrid reactor is proposed to achieve the energy gain of 3000 MW thermal power with self-sustaining tritium. The hybrid reactor is designed based on the plasma conditions and configurations of ITER, as well as the well-developed pressurized light water cooling technologies. For the sake of safety, the pressure tube bundles are employed to protect the first wall from the high pressure of coolant. The spent nuclear fuel discharged from 33GWD/tU Light Water Reactors (LWRs) and natural uranium oxide are taken as driver fuel for energy multiplication. According to thermo-mechanics calculation results, the first wall of 20 mm is safe. The radiation damage analysis indicates that the first wall has a lifetime of more than five years. Neutronics calculations show that the proposed hybrid reactor has high energy multiplication factor, tritium breeding ratio and power density; the fuel cannot reach the level of plutonium required for a nuclear weapon. Thermal-hydraulic analysis indicates that the temperatures of the fuel zone are well below the limited values and a large safety margin is provided.     

MCORGS及次临界能源堆包层概念研究进展

次临界能源堆是以能源供应为目的的一种聚变裂变混合堆,以聚变驱动,天然铀为裂变燃料,轻水为冷却剂。本文针对该混合堆开发了基于MCNP与ORIGENS的三维中子输运燃耗耦合程序MCORGS,分析了包层三维中子学模型。提出简化干法后处理,设想利用衰变热将乏燃料加热到2 100K,将沸点低于该温度的裂变产物挥发去除。计算了包层各区材料每年发生的原子移位数,建议采用10a左右的换料周期,乏燃料经后处理后可多次复用。第1个寿期内氚增殖比TBR平均约1.15,包层能量放大倍数M平均约12;第2~9个寿期内TBR平均约1.35,M平均约18。利用流体动力学程序完成了包层CAD模型建立、网格划分及稳态传热计算分析,各区材料的最高温度均低于许用温度并有较大裕量。     

Investigating Neutronic Parameters of a Thorium Fusion Breeder with Recurrent Neural Networks

Artificial neural networks (ANNs) have recently been introduced to the nuclear engineering applications as a fast and flexible vehicle to modeling, simulation and optimization. In this paper, a new approach based on recurrent neural networks (RNNs) was presented for the neutronic parameters of a thorium fusion breeder. The results of the RNNs implemented for the tritium breeding ratio computation, energy multiplication factor and net ²³³U production in a thorium fusion breeder and the results available in the literature obtained by using Scale 4.3 were compared. The drawn conclusions confirmed that the proposed RNNs could provide an accurate computation of the tritium breeding ratio computation, the energy multiplication factor and the net ²³³U production of the thorium fusion breeder.     

3D Neutronic Analysis in MHD Calculations at ARIES-ST Fusion Reactors Systems

In this study, we developed new models for liquid wall (FW) state at ARIES-ST fusion reactor systems. ARIES-ST is a 1,000 MWe fusion reactor system based on a low aspect ratio ST plasma. In this article, we analyzed the characteristic properties of magnetohydrodynamics (MHD) and heat transfer conditions by using Monte-Carlo simulation methods (ARIES Team et al. in Fusion Eng Des 49–50:689–695, 2000; Tillack et al. in Fusion Eng Des 65:215–261, 2003) . In fusion applications, liquid metals are traditionally considered to be the best working fluids. The working liquid must be a lithium-containing medium in order to provide adequate tritium that the plasma is self-sustained and that the fusion is a renewable energy source. As for Flibe free surface flows, the MHD effects caused by interaction with the mean flow is negligible, while a fairly uniform flow of thick can be maintained throughout the reactor based on 3-D MHD calculations. In this study, neutronic parameters, that is to say, energy multiplication factor radiation, heat flux and fissile fuel breeding were researched for fusion reactor with various thorium and uranium molten salts. Sufficient tritium amount is needed for the reactor to work itself. In the tritium breeding ratio (TBR) >1.05 ARIES-ST fusion model TBR is >1.1 so that tritium self-sufficiency is maintained for DT fusion systems (Starke et al. in Fusion Energ Des 84:1794–1798, 2009; Najmabadi et al. in Fusion Energ Des 80:3–23, 2006).     

Neutronic analysis of Indian helium-cooled solid breeder tritium breeding module for testing in ITER

India has proposed the helium-cooled solid breeder blanket concept as a tritium breeding module to be tested in ITER. The module has lithium titanate for tritium breeding and beryllium for neutron multiplication. Beryllium also enhances tritium breeding. A design for the module is prepared for detailed analysis. Neutronic analysis is performed to assess the tritium breeding rate, neutron distribution, and heat distribution in the module. The tritium production distribution in submodules is evaluated to support the tritium transport analysis. The tritium breeding density in the radial direction of the module is also assessed for further optimization of the design. The heat deposition profile of the entire module is generated to support the heat removal circuit design. The estimated neutron spectrum in the radial direction also provides a more in-depth picture of the nuclear interactions inside the material zones. The total tritium produced in the HCSB module is around 13.87 mg per full day of operation of ITER, considering the 400 s ON time and 1400 s dwell time. The estimated nuclear heat load on the entire module is around 474 kW, which will be removed by the high-pressure helium cooling circuit. The heat deposition in the test blanket model (TBM) is huge (around 9 GJ) for an entire day of operation of ITER, which demonstrates the scale of power that can be produced through a fusion reactor blanket. As per the Brayton cycle, it is equivalent to 3.6 GJ of electrical energy. In terms of power production, this would be around 1655 MWh annually. The evaluation is carried out using the MCNP5 Monte Carlo radiation transport code and FEDNL 2.1 nuclear cross section data. The HCSB TBM neutronic performance demonstrates the tritium production capability and high heat deposition.     

Preliminary design of hybrid energy reactor and integral neutron experiments

We propose a preliminary design for a fusion–fission hybrid energy reactor (FFHER), based on current fusion science and technology (with some extrapolations forward from ITER) and well-developed fission technology. We list design rules and put forward a primary concept blanket, with uranium alloy as fuel and water as coolant. The uranium fuel can be natural uranium, LWR spent fuel, or depleted uranium. The FFHER design can increase the utilization rate of uranium in a comparatively simple way to sustain the development of nuclear energy. We study the interaction between the fusion neutron and the uranium fuel with the aim of to achieving greater energy multiplication and tritium sustainability. We also review other concept hybrid reactor designs. We design integral neutron experiments in order to verify the credibility of our proposed physical design. The combination of this program of research with the related thermal hydraulic design, alloy fuel manufacture, and nuclear fuel cycle programs provides the science and technology foundation for the future development of the FFHER concept in China.