APPLICATION OF ION IRRADIATION FOR MECHANISTIC STUDY ON NEUTRON IRRADIATION EMBRITTLEMENT IN STEELS

离子辐照在钢中子辐照脆化机理研究中的应用

基本信息

批准号：
04558028
负责人：
ISHINO Shiori
金额：
$ 11.26万
依托单位：
THE UNIVERSITY OF TOKYO
依托单位国家：
日本
项目类别：
Grant-in-Aid for Developmental Scientific Research (B)
财政年份：
1992
资助国家：
日本
起止时间：
1992 至 1993
项目状态：
已结题

项目摘要

Neutron irradiation embrittlement in pressure vessel steels in light water reactors is one of the critical issues to understand mechanisms of embrittlements and prediction of lifetime of the component. In this study, ion irradiation experiments which have excellent controllability of irradiation conditions such as temperature and ion flux are applied to establish physical models of irradiation embrittlement in steels. Specimen chamber for ion irradiation is designed and installed in the HIT facility of the University of Tokyo. This irradiation chamber technically requires temperature control between liquid N2 temperature and 573K,electric resistivity capability and ion beam profile measurements. These are completed by detailed design of the irradiation chamber and specimen size. Ion irradiation experiments are performed at liquid N2 temperature and room temperature with 1 MeV and higher energy of protons. The alignments of ion beams to the position of specimens and Faraday cups are successfully made during ion irradiation. An iron-copper model alloy irradiated with protons has radio-activity which causes difficulty to handle the irradiated specimen after irradiation. On-beam electric resistivity measurements is found to be difficult because of the noise signals from the specimen during irradiation, but electric resistivity at low temperatures can be measured by interrupting ion beam. The annealing processes of defect clusters in irradiated iron specimens are analyzed after ion irradiation, and fundamental information on defect formation and hardening behavior in steels are obtained.

轻水堆压力容器钢的中子辐照脆化是了解脆化机制和预测部件寿命的关键问题之一。本研究采用对温度和离子通量等辐照条件具有良好可控性的离子辐照实验来建立钢辐照脆化的物理模型。用于离子辐照的样品室是在东京大学 HIT 设施中设计和安装的。该辐照室在技术上需要液氮温度和 573K 之间的温度控制、电阻率能力和离子束轮廓测量。这些是通过辐照室和样品尺寸的详细设计来完成的。离子辐照实验是在液氮温度和室温下用1 MeV和更高能量的质子进行的。在离子辐照过程中，离子束成功对准样品和法拉第杯的位置。经质子辐照的铁-铜模型合金具有放射性，导致辐照后难以处理经辐照的样品。由于辐照期间样品发出的噪声信号，束上电阻率测量很困难，但可以通过中断离子束来测量低温下的电阻率。分析了离子辐照后辐照铁试样中缺陷簇的退火过程，获得了钢中缺陷形成和硬化行为的基本信息。