聚变—裂变混合堆安全性初探

对聚变－裂变混合堆的安全性进行了初步分析和探讨。主要利用改进后的混合堆放射性程序ＦＤＫＲ对混合堆产生的核废物及放射性进行计算，并将结果与压水堆、高温气冷堆和液态金属冷却快中子增殖堆进行了比较。结果表明，混合堆与裂变动力堆相比有较好的安全性。     

D-~3He聚变堆MOONCITY的放射性及核废物处置问题

研究了D-~3He聚变堆设计MOONCITY的放射性及核废物处置问题。计算了在停堆时刻的放射性,衰变功率,BHP以及核废物处置指标WDR,给出了有关的计算结果和停堆后的衰减曲线。结果表明,MOONCITY的放射性及有关危害比D-T纯聚变堆低1个量级,比裂变堆或聚变一裂变混合堆低60倍左右。     

AF—DCDLIB:活化产物、裂变产物和锕系元素衰变链数据库

一、引言 DKR是美国威斯康星大学T·Y·Sung等研制的应用于纯聚变堆放射性计算的程序,配套的数据库不含裂变产物和锕系元素的数据,因此,它不能计及裂变问题。 FDKR程序是以DKR为基础为聚变一裂变混合堆的放射性计算而研制的。在混合     

聚变-裂变混合堆放射性计算

研制了聚变一裂变混合堆放射性计算程序FDKR和配套的衰变链数据库AF—DCDL—IB。应用该程序计算了磁镜混合堆(CHD)概念设计中活化产物、裂变产物和锕系元素的放射性、衰变功率和潜在生物危害因子BHP。本文简要介绍了该程序和数据库并给出了有关的计算结果。     

10MW高温气冷实验堆乏燃料元件贮存中放射性裂变产物的安全分析

高温气冷堆乏燃料元件的放射性裂变产物绝大部分滞留在燃料元件中。10MW高温气冷实验堆在设计寿命内将卸出约9万个乏燃料元件,其放射性裂变产物的活度高达1.9×1017Bq,因此正确实施乏燃料元件的贮存,减少放射性裂变产物向环境中释放和进行有效的屏蔽是极其重要的。本文根据乏燃料元件中放射性裂变产物的计算结果和德国高温气冷堆乏燃料元件贮存的经验．对我国10MW高温气冷堆乏燃料元件贮存中放射性裂变产物进行了安全分析。     

混合堆增殖乏燃料组件中子学特性初步研究

本文主要对聚变-裂变混合堆增殖乏燃料在压水堆组件中使用的可能性进行了初步研究。根据聚变 裂变混合堆增殖乏燃料的特点,给出了的聚变-裂变混合堆增殖乏燃料压水堆组件设计方案,分析组件的燃料温度系数、慢化剂温度系数等参数。结果表明：聚变 裂变混合堆乏燃料组件的特性与全铀组件的特性相似。在相同的易裂变同位素质量百分比情况下,本文给出的组件设计方案的功率不均匀系数更小。研究结果可为未来实现聚变 裂变混合堆和压水堆联合循环系统提供技术支持。     

核能源前景浅见

文章展望了裂变堆、纯聚变堆和聚变-裂变混合堆的前景,分析了混合堆的低聚变条件和很高的能量与燃料增殖能力等重大优点。认为作为由裂变能源过渡到纯聚变能源的桥梁,聚变-裂变混合堆应成为未来核能源的方向之一。     

实验混合堆FEB设计放射性计算与环境安全分析

应用混合堆放射性计算程序FDKR和衰变链数据库AF-DCDLIB,计算了托卡马克实 验混合堆FEB(Fusion Experimental Beeder)概念设计中活化产物、裂变产物和锕系元素的放射性、衰变余热和潜在生物危害因子BHP值。计算的结果表明,对于FEB设计来说,在150MW聚变功率下运行一年,停堆时刻的总放射性、余热和BHP值分别为5.74×10~(20)Bq     

实验混合堆FEB设计放射性计算与环境安全分析(英文)

应用混合堆放射性计算程序FDKR和衰变链数据库AFDCDLIB,计算了托卡马克实验混合堆FEB (Fusion Experimental Beeder)概念设计中活化产物、裂变产物和锕系元素的放射性、衰变余热和潜在生物危害因子BHP值。计算的结果表明,对于FEB设计来说,在150MW聚变功率下运行一年,停堆时刻的总放射性、余热和BHP值分别为5.74×10~(20)Bq,8.34MW和4.08×10~8km~3(空气)。放射性核废物处置的计算结果还表明:FEB的结构材料在卸出后的短时间内,可满足美国联邦法规10CFR61的C级(近地浅埋)核废物处置标准。对混合堆包层中的重要锕系元素~(232)U,~(237)Np的含量也作了计算分析。结果表明:它们的浓度值均不超过环境安全要求的限制值。文章还就混合堆的环境安全问题,与其它的核能装置如PWR进行了比较分析,表明混合堆不存在突出的环境安全问题。     

混合堆系统的事件树分析

本文介绍概率风险评价（ＰＲＡ）在聚变－裂变混合堆中的应用，用事件树对混合堆系统进行了分析，根据合肥聚变－裂变实验混合概念设计的特点，对几个典型的初因事件导致的事件序列进行了概率分析计算。结论表明，该设计是安全合理的。本文工作对于深入认识混合堆系统的安全设计提出了益的建议。     

Gas-cooled fusion-fission hybrid reactor systems

In this paper, the concept of the fusion-fission hybrid reactor is reviewed, and a system of classification for hybrid blanket designs is suggested. The advantages and disadvantages of gas cooling for hybrid reactor systems are discussed and the design implications of using gas cooling in a hybrid blanket are presented. Five of the more complete gas-cooled hybrid reactor conceptual design studies are discussed, and the fission-suppressed hybrid blanket concept is identified as offering potentially significant advantages in terms of inherent safety features and reduced technology development requirements compared to higher power fission blankets. It is concluded that helium is attractive as the coolant for hybrid reactor systems, and that technically viable reactor designs have been developed using helium cooling. The helium-cooled fission-suppressed hybrid blanket, based on thorium fuel for production of²³³U, is identified as being a particularly attractive candidate for further hybrid reactor development work.     

A hybrid method to generate few-group cross sections for fast reactor analysis

The accuracy of fast reactor core calculation is usually determined by the accuracy of self-shielded few-group cross sections. To further improve the accuracy of cross section generation, a hybrid method is proposed. In the hybrid method, the Monte-Carlo method is used to deal with the resonance effect in both the resolved and unresolved resonance range. The self-shielded ultrafine-group total, fission and elastic scattering cross sections are tallied by the Monte-Carlo method. The scattering transfer matrices are then generated in a synthesis way by using the tallied elastic scattering cross sections and a problem-independent elastic scattering function. The angular flux moments for the group condensation are calculated in an explicit deterministic way. Several tests are done to verify the hybrid method. The results show that the hybrid method avoids the disadvantages of both the traditional deterministic method and the pure Monte-Carlo method. It is a more accurate method to generate the few-group cross sections for fast reactor cores.     

Development of a hybrid method to improve the sensitivity and uncertainty analysis for homogenized few-group cross sections

In the framework of two-step method of reactor core calculation, few-group homogenized cross sections generated by lattice-physics calculations are key input parameters for the three-dimensional full-core calculation. Conventional method for few-group cross-sections sensitivity and uncertainty (S&U) analysis related to the nuclear data was performed based on the effective self-shielding cross sections instead of the continuous-energy cross sections, which means resonance self-shielding effect (implicit effect) is neglected. Furthermore, the multi-group covariance data is generated from the continuous-energy cross sections. Therefore, in order to perform S&U analysis with respect to the continuous-energy cross sections for both accuracy and consistency, a hybrid method is proposed in this paper. The subgroup-parameter sensitivity-coefficients are calculated based on the direct perturbation (DP) method. The sensitivity-coefficients of the effective self-shielding cross sections and the responses (k_eff and few-group homogenized cross sections) are calculated based on the generalized perturbation theory (GPT). A boiling water reactor (BWR) pin-cell problem under different power conditions is calculated and analyzed. The numerical results reveal that the proposed hybrid method improves the sensitivity-coefficients of eigenvalue and few-group homogenized cross sections. The temperature effects on the sensitivity-coefficients are demonstrated and the uncertainties are analyzed.     

Theoretical cross sections of Bi,Th, U and U on deuteron-induced reactions

There are many application fields for fast neutrons. The main application fields of the fast neutrons are accelerator-driven sub-critical systems (ADS) and fusion–fission (hybrid) reactor systems for fission energy production. Thorium (Th) and uranium (U) are nuclear fuels in fusion–fission (hybrid) reactor systems and bismuth (Bi) is also the target nucleus in the ADS reactor systems. In this study, neutron production cross sections produced by (d, xn) reactions for spallation targets such as ²⁰⁹Bi, ²³²Th, ²³⁵U and ²³⁸U have been investigated. New evaluated hybrid model and geometry dependent hybrid model have been used to calculate the pre-equilibrium neutron production cross sections. For the reaction equilibrium component, Weisskopf–Ewing model calculations have been preferred. The obtained results have been discussed and compared with the available experimental data and found in agreement with each other.     

Investigation of the properties of the nuclei used on the new generation reactor technology systems

The main application fields of the fast neutrons are accelerator-driven subcritical systems (ADS) and fusion–fission (hybrid) reactor systems for fission energy production. Thorium (Th) and uranium (U) are nuclear fuels in these reactor systems. Lead (Pb), bismuth (Bi) and tungsten (W) are the target nuclei in the ADS reactor systems. The technical design of ADS and hybrid reactor systems require much effort and data. The Hartree–Fock (H–F) method with an effective interaction with Skyrme forces is widely used for studying the properties of nuclei such as binding energy, root mean square (RMS) charge radii, mass radii, neutron density, proton density, electromagnetic multipole moments, etc. In this study, by using H–F method with interaction Skyrme RMS charge radii, RMS mass radii, neutron density and proton density were calculated for the ²³²Th, ²³⁸U, ²⁰⁷Pb, ²⁰⁹Bi and ¹⁸⁴W isotopes. The calculation results of charge radii were compared with experimental data. Obtained RMS mass radii, neutron density and proton density results were discussed for ADS and hybrid reactor systems.     

球床包层聚变—裂变混合堆热工安全分析

球床包层混合堆与板状元件包层混合堆相比较，前者在核燃料生产和安全方面可能具有更多的优越性。本应用ＴＨＥＲＭＩＸ程序和辅助程序对我国开发的托卡马克堆芯氮气冷却球床包层聚变－裂变合堆的包层进行了热工计算。计算中考虑了不同的燃料球材料及稳态，卸压和断流事故工况。计算结果表明，只要选用合适的燃料球材料和设置适当的控制保护系统，具有快速卸料罐的托卡马克堆芯氦气包层聚变－裂变混合堆的概念设计在安全上的可行的。     

Utilization of TRISO Fuel with LWR Spent Fuel in Fusion-Fission Hybrid Reactor System

HTRs use a high performance particulate TRISO fuel with ceramic multi-layer coatings due to the high burn up capability and very neutronic performance. TRISO fuel because of capable of high burn up and very neutronic performance is conducted in a D-T fusion driven hybrid reactor. In this study, TRISO fuels particles are imbedded body-centered cubic (BCC) in a graphite matrix with a volume fraction of 68%. The neutronic effect of TRISO coated LWR spent fuel in the fuel rod used hybrid reactor on the fuel performance has been investigated for Flibe, Flinabe and Li₂₀Sn₈₀ coolants. The reactor operation time with the different first neutron wall loads is 24 months. Neutron transport calculations are evaluated by using XSDRNPM/SCALE 5 codes with 238 group cross section library. The effect of TRISO coated LWR spent fuel in the fuel rod used hybrid reactor on tritium breeding (TBR), energy multiplication (M), fissile fuel breeding, average burn up values are comparatively investigated. It is shown that the high burn up can be achieved with TRISO fuel in the hybrid reactor.     

聚变-裂变混合堆程序开发及验证

针对聚变-裂变混合堆设计研究中原有燃耗计算程序MONK9A耗时长等问题,利用MCNP和SCALE5.1程序包中的Origen-s程序开发出1套可用于先进反应堆设计的燃耗耦合程序MOCouple-s.选取了压水堆燃耗基准题、ADS基准题对MOCouple-s程序进行了验证,结果表明,MOCouple-s程序关于反应性和核素成分的计算结果与实验测量结果和其他程序的计算结果符合良好,且在某些计算结果、参数设置、自动化执行等方面优于国内外类似程序.利用MOCouple-s程序对MONK9A程序在混合堆燃耗计算上的适用性进行了验证,结果差别不大,证明MONK9A程序用于混合堆初步研究设计得到的燃耗计算结果是可靠的.     

NAPTH: Neutronics analysis code system for the fusion–fission hybrid reactor with pressure tube type blanket

The fusion–fission hybrid reactor is considered as a potential path to the early application of fusion energy. A new concept with pressure tube type blanket has recently been proposed for a feasible hybrid reactor. In this paper, a code system for the neutronics analysis of the pressure tube type hybrid reactor is developed based on the two-step calculation scheme: the few-group homogeneous constant calculation and the full blanket calculation. The few-group homogeneous constants are calculated using the lattice code DRAGON4. The blanket transport calculation is performed by the multigroup Monte Carlo code. A link procedure for fitting the cross sections is developed between these two steps. An additional procedure is developed to calculate the burnup, power distribution, energy multiplication factor, tritium breeding ratio and neutron multiplication factor. From some numerical results, it is found that the code system NAPTH is reliable and exhibits good calculation efficiency. It can be used for the conceptual design of the pressure tube type hybrid reactor with precise geometry.