The Three-Dimensional Temperature Indication for the Reactor Core by Using Multiple Thermocouples

The premise of accident mitigation lies in the accurate diagnosis of the accident. The serious accident, in which the core of the nuclear reactor at the nuclear power plant (NPP) is melted, is a very serious problem. Examples of this kind of accident may be found in the Fukushima accident. Therefore, a rapid incident response and accurate diagnosis is more important than anything. The ultimate goal of severe accident mitigation at a nuclear reactor is to maintain the confidentiality of the containment building and the cooling of the core meltdown in the reactor. Confirming the progressive state of diagnosis and the cooling of the reactor core when the serious accident occurs is a very important factor in the development of response strategies after the accident. Japan has taken various measures to deal with accidents after the nuclear accident of Fukushima. Strengthening the reliability of the instrumentation system is also included in the counterstrategies. Therefore, this paper presents the expected effects and the temperature distribution display method of the core by using an in-core instrumentation (ICI) with multiple thermocouples. This research project is currently underway in Korea.