摘要
在核反应堆一回路系统中,裂变中子产生的反冲质子通过电离、多次散射以及韧致辐射后,与冷却剂中的^(16)O、^(18)O和^(11)B反应生成具有β^+放射性的^(13)N、^(18)F和^(11)C等核素,采用符合测量方法可以探测这些核素从而推断一回路水的泄漏情况。采用GEANT4程序对秦山二期压水堆全堆芯进行建模及源抽样描述,编制C++工具自动生成GEANT4计算所需的中子源分布,实现了G4-NONU功能以及GEANT4程序中中子固定源的输运计算。充分考虑反冲质子电离、多次散射以及韧致辐射等因素,计算了压水堆一回路水中由质子反应产生的^(13)N、^(18)F以及^(11)C等核素的产生率、浓度以及活度,拓展了反应堆源项计算工具。
[Background]In reactor core,recoil protons produced by fission neutrons may interact with coolant of the primary circuit and produce radioactive nuclides through reactions ^（16）O（p,α）^（13）N,^（18）O（p,n）^（18）F and ^（11）B（p,n）^（11）C.Positrons emitted by the radioactive nuclides,^（13）N,^（18）F and ^（11）C,etc.,can be detected by coincidence measurement,hence the leakage of the reactor coolant inferred.However,calculation of the source terms of the nuclear reactor core are mainly based on solving the point burn-up equation or simulation of the reactivity based on Monte Carlo method,lacking the capability to simulate（p,α）and（p,n）reactions for protons at 0~20 Me V.[Purpose]This study aims to simulate the production of source terms generated by protons for the reactors of Qinshan’s second nuclear plant.[Methods]Full reactor core of the reactor was modeled in GEANT4.Source sampling description based on general particle source（GPS）was achieved in consideration of radial and axial power distributions of the reactor core.G4-NONU was developed using C＋＋for neutron transportation to realize the function of NONU card in MCNP（Monte Carlo N Particle Transport Code）by modifying the fission model in GEANT4.Energy spectrum of recoil protons in water of the primary circuit was calculated,so were the reactivities of ^（16）O（p,α）^（13）N,^（18）O（p,n）^（18）F and^（11）B（p,n）^（11）C.Eventually,concentrations and activities of ^（13）N,^（18）F and ^（11）C of the primary circuit were computed.[Results and Conclusion]Methods for description of source terms for pressurized water reactor in GEANT4 were established and nuclear reactor problems involving charged particles can be simulated by self developed G4-NONU,which is an enrichment of the simulations tool for nuclear reactor.
作者
刘斌
李兰
吕焕文
肖峰
景福庭
应栋川
魏述平
唐松乾
杨俊云
LIU Bin;LI Lan;LYU Huanwen;XIAO Feng;JING Futing;YUNG Dongchuan;WEI Shuping;TANG Songqian;YANG Junyun(Science and Technology on Reactor System Design Technology Laboratory, Nuclear Power Institute of China, Chengdu 610023, China)
出处
《核技术》
CAS
CSCD
北大核心
2018年第4期85-89,共5页
Nuclear Techniques
关键词
GEANT4模拟
压水反应堆
带电粒子
一回路源项
GEANT4 simulation, Pressurized water reactor, Charged particles, Source terms of the primary circuit
