CRAM在放射性核素存量计算中的应用  

Application of Chebyshev rational approximation method in inventory calculation of radioactive nuclides

作　　者：张竞宇[1] 马亚栋 陈义学[1] 高强[2] 

机构地区：[1]华北电力大学核科学与工程学院,北京102206 [2]环境保护部核与辐射安全中心,北京100082

出　　处：《核技术》2017年第8期55-62,共8页Nuclear Techniques

基　　金：国家自然科学基金(No.11605058);国际热核聚变实验堆计划专项(No.2014GB119000);中央高校基本科研业务费专项资金(No.2017MS041)资助~~

摘　　要：在反应堆中,组成材料的稳定核素经受强中子辐照后,会被活化成放射性核素。这些核素及其衰变产物对工作人员的职业辐照剂量具有重要贡献。为了更好地进行人员的辐射防护工作,需要对放射性核素的存量进行精确计算。相对于核素平衡方程的其它求解方法,切比雪夫有理逼近方法(Chebyshev Rational Approximation Method,CRAM)在计算精度和效率方面具有综合性优势。首先介绍了CRAM的基本理论,随后选取典型的例题进行了测试验证。与解析解对比的结果表明,采用CRAM进行中子辐照下的核素活化衰变计算能够取得不错的效果,但是用于核素长期衰变计算可能导致计算错误。针对此问题,将收缩乘方技术与CRAM相结合,取得了正确的计算结果,拓展了CRAM的适用范围。Background： The material suffering from strong neutron irradiation in the nuclear reactor will be activated to be radioactive nuclides. These nuclides and their decay products contribute a significant part to the occupational radiation exposure （ORE） of personnel. Purpose： For better radiation protection of the workers in nuclear reactor, it is supposed to calculate the inventory of radioactive nuclides accurately. Methods： Compared with other methods for solving the equilibrium equations of nuclides, the Chebyshev rational approximation method （CRAM） has comprehensive advantages on computational accuracy and efficiency. In this paper, the theory of CRAM method is described firstly, and then some typical cases are tested to verify CRAM method. Results ＆ Conclusion： Compared with the analytical solution, CRAM method shows good effect on activation and decay calculation of nuclides under neutron irradiation, but may cause obvious error on long-term decay calculation of nuclides. After coupling with technique of scaling and squaring, CRAM method can derive accurate results for long-term decay calculation of nuclides and its scope of application is extended.

关 键 词：切比雪夫有理逼近方法 放射性核素 存量计算 收缩乘方 

分 类 号：TL99[核科学技术—核技术及应用]