加速器驱动的次临界行波堆中子物理关键问题研究

Traveling wave reactor (TWR) is an innovative nuclear system, which is based on the design concept of dynamic breed-and-burn equilibrium of fissile nuclides at the orient location of reactor core. After ignited by enriched fissile nuclide or external neutron source, the reactor will achieve the breed-burn self-stable operation. External source driving subcritical reactor operates in the subcritical state and realizes the continuity of breeding wave and burning wave in radial direction. The requirement of core material and high burn-up can be reduced when the breeding and burning wave propagating and the feasibility of TWR will be improved effectively. In this project, theoretical analysis and engineering feasibility will be combined to analyze the neutron transport mechanism and key physical problem of external source driving subcritical traveling wave reactor. The project mainly include: (1) Neutron importance of external source and its effect to the wave: the influence to dynamic parameters, the contribution to the fuel breeding and fission of external source in the subcritical reactor core, and transportation influence regular to the breeding wave and burning wave. (2) Research the detailed calculation method for of space-time related breeding and burning under the subcritical and deep burn-up condition. (3) Based on the above research, design of nuclear fuel components and research of fuel cycle strategy. A preliminary core physical scheme will be obtained and the reactor can achieve the breed-burn-transmutation integration.

行波堆是一种利用可裂变核素转换成易裂变核素，再通过易裂变核素裂变释放能量，从而形成具有稳定规律的增殖波和燃烧波的新概念反应堆。该堆由易裂变燃料或外中子源进行点火启动后，实现增殖-燃烧自稳运行。外源驱动的次临界行波堆，通过外源中子启动反应堆，使其运行在次临界状态并实现增殖波和燃烧波的径向延续，可降低增殖波和燃烧波行进中对堆芯材料和高燃耗的要求，可有效提高行波堆的现实可行性。本项目拟从理论分析与工程可行性相结合的角度出发，开展加速器驱动的次临界行波堆中子输运机理及关键物理问题研究，主要包括：（1）外源中子价值及其对波的影响研究：即外源中子价值及其对动态参数的影响、对燃料增殖裂变的贡献大小、对增殖波和燃烧波径向传播的影响规律；（2）次临界、深燃耗条件增殖与燃耗精细计算方法研究；（3）基于以上两点研究，开展核燃料布置及燃料循环研究，完成堆芯初步物理方案使得该堆能够实现增殖-燃烧-嬗变一体化的功能。

本项目主要针对外源驱动的次临界行波堆开展研究，包括：（1）外源中子价值及其对堆芯参数的影响研究，基于蒙特卡罗方法，结合中子时空变量分离方法，发挥蒙特卡罗方法和数值计算方法各自在中子学计算中的优势，用于加速器驱动次临界系统中的次临界堆内的外源中子价值计算，并研究外源中子对动态参数的影响。（2）为了精细计算反应堆的特性，本项目开展了高能核数据库，并基于蒙特卡罗粒子输运方法，结合指数欧拉法求解燃耗方程，建立输运-燃耗耦合计算方法，以期计算分析次临界行波堆堆芯物理参数。（3）进行堆芯核燃料布置及燃料循环研究，包括堆芯布置方案、换料倒料方案、反应性控制方案等，完成了堆芯初步物理方案使得该堆能够实现增殖-燃烧-嬗变一体化的功能。目前的研究成果对于未来先进反应堆设计，具有一定的参考价值和应用前景。