Q. Could you introduce yourself?
Zhang Shishun: I am working for China Nuclear Power Research Institute(CNPRI) as the head of the branch of severe accident research at CNPRI. CNPRI has test facilities for severe accident research including In-Vessel Retention(IVR) test facilities, and it is currently planning to design the third-generation EPR reactor. Also, it is constructing two EPR units with French technology.
Zhang Huiyong: I am also from CNPRI in Shenzhen, China. I am mainly working on the IVR technology for CPR-1000. I designed and constructed a test facility for the IVR technology. The goal was to obtain critical heat flux on the outer surface of the lower head of the reactor pressure vessel(RPV).
Q. What is the purpose of your visit?
Zhang Shishun: The main purpose of this trip is to exchange technical information and to visit IVR test facilities in KAERI(Korea Atomic Energy Research Institute), especially the ones related to severe accident research. We are also going to visit some facilities of nuclear safety research. I hope we can get useful information of test facilities at KAERI. KAERI is very experienced in IVR research, and they already have IVR facilities for Korean reactors. In the future, our research will be applied not only to the third-generation reactors but also to the generation Ⅱ-plus Chinese reactors.
Zhang Huiyong: We have conducted many tests and got interesting results. This time, we would like to take this opportunity to share the information of the tests with the experts of KAERI. I also want to learn about integral test facility. We are going to visit test facilities related to the IVR technology and other test facilities such as ATLAS, which is KAERI's large-scale test facility for accident simulation. China is planning to construct a test facility like ATLAS in the future, so this trip will be very useful for our research.
Q. Could you explain the In-Vessel Retention technology?
Zhang Shishun: In case of a severe accident, the reactor core melts and flows down to the lower head of the reactor. In this case, the molten material has to be kept inside the reactor. We need to pour water from outside into the bottom of the reactor cavity and try to maintain reactor vessel integrity. By doing so, the nuclear materials do not go outside and do not leak to the environment. This technology is called IVR, and it was first applied to AP 1000 in America, and we imported the technology for our reactors such as the CPR-1000.
Q. Could you tell me about nuclear energy in China?
Zhang Shishun: Nuclear energy constitutes two percent of the total energy in China, and China is trying to increase the percentage. Currently, CNPRI has 14 new generation Ⅱ-plus and generation Ⅲreactor units under construction. A few month ago, CNPRI designed EPR reactors, which are third-generation and based on French technology. There are also AP 1000 units, which are third-generation. These two types of third generation are applied to Chinese reactors.
In addition, China developed and designed a new third-generation reactor with Chinese technology. In china, the reactors are mostly generation Ⅱ or generation Ⅱ-plus. Even though they are quite safe, after the Fukushima accident, the Chinese government asked the institute to design and construct third-generation reactors, which are more advanced and much safer.
Q. What is your plan in Korea?
Zhang Huiyong: We are going to stay at KAERI for three days and then stay in Seoul for two days to visit Seoul National University. We only have six days in Korea, so it is quite a short trip. We are scheduled to hold a meeting tomorrow morning to discuss test results. During the meeting, we are going to present our test results to the experts of KAERI, and they are also going to present their results. This is our first visit to Korea and KAERI, and I hope I can learn useful knowledge here.