Four monolithic refractory ceramics (Al2O3, SiC, TiC and TiN) were exposed to severe thermal shock caused by thermite reaction. Such experiments were intended to simulate the exposure of a core catcher to hot debris of melted core in nuclear reactor. Moreover, the chemical interactions between tested materials and products of thermite reaction were investigated by holding samples in laboratory furnace for 5 hours at 1000oC in air. None of the materials entirely withstand such sudden temperature rise, o...
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Molten Core Concrete Interaction and Development of Core Catcher (2) Thermal shock effects for advanced high temperature ceramics

This paper describes how to write a manuscript of the 18th PES Proceedings. In the Fukushima Daiichi Nuclear Power Plant accident, a great deal of radioactive material was released to surrounding environment. After the accident, the Filtered Containment Venting System (FCVS) that can remove radioactive material from steam in containment vessel has attracted a great deal of attentions. However, there is few knowledge of filtered vent in Japan because almost filtered vent were developed in Europe after ...
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Research related to Filtered Venting System

There are various leak phenomena in nuclear power plants, such as thermal or vibration fatigue crack, grand of valve, valve sheet, mechanical seal and SG tubes, and so on. In the current power plant, engineers should find such probl ems by annual inspection. But, in case of severe accident, operators should conduct a prompt action without mistake. It is very difficult to do such action with limited information and AM tools. Therefore, authors have conducted to develop online leak rate evaluation method for...
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Development of Online Leak Rate Evaluation Method for Various Leak Phenomena in NPPs

Various leak events have happened in nuclear power plants so far. And plants have bad conditions because of these leakages. Several leak events must be investigated, and we have to prepare these leakages. Like this, systematizing evaluation s of several leak events brings upgrades in regulations or new system of inspections, plans for aging deterioration. By using this method, we know deeper about Fukushima-Daiichi NPP. For example, here, from changes of CV pressure, we can conclude that SB-LOCA was NO...
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Studies about Development of Leak Event Evaluation Method in Nuclear Power Plant

Evaluation of wastage speed for nuclear power plant maintains plant reliability and power up rating is important. There are two main cause of wastage flow accelerated corrosion (FAC) and mechanical erosion. This study is to develop evaluating the wastage speed by liquid droplet impingement erosion (LDIE). LDIE oft en occurs at downstream of corner of pipe or orifice. In this study, the liquid drop impinging tests were conducted with the test pieces mounted on a high speed rotating disk that cross thin wate...
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Study on pipe wastage mechanism by Liquid Droplet Impingement Erosion

Fukushima Daiichi NPP accident would be terminated, if sufficient accident countermeasures, such as water proof door, mobile power, etc. In case of Europe, it had already recommended to install core catcher from the lessons of Chernobyl Accidents. In this paper we introduce simplified core catch by using core catcher that used Basalt. Hokkaido University has tested the simplified core catcher, by using thermite process. We found that molten thermite debris and concrete interaction make concrete to erod...
英字タイトル:
Molten Core Concrete Interaction and Development of Core Catcher

FuNushima Daiichi NPP accident would be terminated, if sufficient accident countermeasures, such as water proof door, mobile power, etc. In case of Europe, it had already installed the heat removal system and filtered containment venting system (FCVS) from the lessons o f TMI and Chernobyl Accidents. Decay heat removal system and CV spray cooling system with FCVS are ensured by using mobile generators and heat exchangers to Neep the ultimate heat sinN even in any natural disaster, such as large earthquaNe,...
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Development of High Efficiency Filtered Containment Venting System by using AgX

In this study, we aimed to quantitatively evaluate cooling capacity of isolation condenser (IC) for core cooling in FuNushima Daiichi Nuclear Plant Unit 1. In order to evaluate cooling capacity, decay heat em ted from fuels in reactor core was calculated. We used the data of nuclear fuel and rated thermal power which is released by TEPCO. We analyzed IC with TRAC code. We made an experiment in order to checN IC’s input data. Because analysis data is close to experimental data, we made sure validity of inpu...
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Evaluation on Decay Heat Removal Capability of Isolation Condenser for Depressurization and Cooling System

Wastage phenomena occur when a heat transfer tube is failed in a Steam Generator (SG) of Fast Breeder Reactor (FBR) and its mechanism is still unexplained. We focused on Liquid Droplet Impingement Erosion (LDIE) as a factor of the wastage phenomena and performed a basic study with a partial mock-up water test simulating a piping group in SG for quantitative evaluation of LDIE. First, we did visualization tests of high pressure and high speed jet into water. The test section consists of a failure heat ...
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Study on Rapid Wastage due to Liquid Droplet Impingement on Heat Transfer Tube in SG of Fast Breeder Reactor