The purpose of this Commentary is to clarify as much as possible the whole history of reactor and containment pressure changes in the Fukushima meltdown accident. It is based on a new approach for film boiling, which is kept after the Zr-H2O reactions. Most important point of this approach is that the author applied film boiling based on boiling curve, which is basic theory in boiling phenomena, for the Fukushima accident phenomena. As the reaction rate is proportional to the reactor or containment pressure under film boiling, it increases rapidly and stops suddenly, keeping the film boiling. The containment pressure change consists of three phases, namely pressurizing, keeping the high pressure and de-pressurizing. The containment is pressurized by H2 gas and steam produced by the Zr-H2O reactions and de-pressurized by a heatsink such as the containment wall and inner shield concrete after reaction stops. The high pressure between these pressure changes is kept by balancing the H2 gas produced by reaction with the leaked gas from the gap between the top lid and the containment. Core decay heat is large, but its change is negligibly small. So, the pressurization is calculated from H2 gas and steam produced by the Zr- H2O reactions. The heatsink balances with the reaction during the high pressure condition. The de-pressurization occurs after the reaction is over, so the reaction heat rate can be calculated by the heat rate of the heatsink, which is equal to the condensation rate during de-pressurization. The leak rate of the leak gas can be calculated using the reaction rate. It is very important that the rection rate is slowed by the insufficient steam supply, as the melted reactor cores in the Fukushima accident were covered with H2 gas and steam (film boiling) at 0.8MPa or lower pressure. This is different from the rate (at approx. 7MPa) in the Three Mile Island accident, as the steam specific volume at 0.8 MPa is ten times larger than that at 7 MPa. The calculation results based on this assumption show that almost all the Zr in each core of Units 1, 2 and 3 reacted with water.
| Published in | International Journal of Science, Technology and Society (Volume 11, Issue 2) |
| DOI | 10.11648/j.ijsts.20231102.14 |
| Page(s) | 62-73 |
| Creative Commons |
This is an Open Access article, distributed under the terms of the Creative Commons Attribution 4.0 International License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution and reproduction in any medium or format, provided the original work is properly cited. |
| Copyright |
Copyright © The Author(s), 2024. Published by Science Publishing Group |
Fukushima Daiichi Nuclear Power Plant, Meltdown, Boiling Curve, Film Boiling, Steam Condensation, Zr-H2O Reaction, Containment Pressure
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APA Style
Tsuyoshi Matsuoka. (2023). New Approach for the Root Cause of Fukushima Meltdown Accident. International Journal of Science, Technology and Society, 11(2), 62-73. https://doi.org/10.11648/j.ijsts.20231102.14
ACS Style
Tsuyoshi Matsuoka. New Approach for the Root Cause of Fukushima Meltdown Accident. Int. J. Sci. Technol. Soc. 2023, 11(2), 62-73. doi: 10.11648/j.ijsts.20231102.14
AMA Style
Tsuyoshi Matsuoka. New Approach for the Root Cause of Fukushima Meltdown Accident. Int J Sci Technol Soc. 2023;11(2):62-73. doi: 10.11648/j.ijsts.20231102.14
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Download@article{10.11648/j.ijsts.20231102.14,
author = {Tsuyoshi Matsuoka},
title = {New Approach for the Root Cause of Fukushima Meltdown Accident},
journal = {International Journal of Science, Technology and Society},
volume = {11},
number = {2},
pages = {62-73},
doi = {10.11648/j.ijsts.20231102.14},
url = {https://doi.org/10.11648/j.ijsts.20231102.14},
eprint = {https://article.sciencepublishinggroup.com/pdf/10.11648.j.ijsts.20231102.14},
abstract = {The purpose of this Commentary is to clarify as much as possible the whole history of reactor and containment pressure changes in the Fukushima meltdown accident. It is based on a new approach for film boiling, which is kept after the Zr-H2O reactions. Most important point of this approach is that the author applied film boiling based on boiling curve, which is basic theory in boiling phenomena, for the Fukushima accident phenomena. As the reaction rate is proportional to the reactor or containment pressure under film boiling, it increases rapidly and stops suddenly, keeping the film boiling. The containment pressure change consists of three phases, namely pressurizing, keeping the high pressure and de-pressurizing. The containment is pressurized by H2 gas and steam produced by the Zr-H2O reactions and de-pressurized by a heatsink such as the containment wall and inner shield concrete after reaction stops. The high pressure between these pressure changes is kept by balancing the H2 gas produced by reaction with the leaked gas from the gap between the top lid and the containment. Core decay heat is large, but its change is negligibly small. So, the pressurization is calculated from H2 gas and steam produced by the Zr- H2O reactions. The heatsink balances with the reaction during the high pressure condition. The de-pressurization occurs after the reaction is over, so the reaction heat rate can be calculated by the heat rate of the heatsink, which is equal to the condensation rate during de-pressurization. The leak rate of the leak gas can be calculated using the reaction rate. It is very important that the rection rate is slowed by the insufficient steam supply, as the melted reactor cores in the Fukushima accident were covered with H2 gas and steam (film boiling) at 0.8MPa or lower pressure. This is different from the rate (at approx. 7MPa) in the Three Mile Island accident, as the steam specific volume at 0.8 MPa is ten times larger than that at 7 MPa. The calculation results based on this assumption show that almost all the Zr in each core of Units 1, 2 and 3 reacted with water.},
year = {2023}
}
TY - JOUR T1 - New Approach for the Root Cause of Fukushima Meltdown Accident AU - Tsuyoshi Matsuoka Y1 - 2023/03/21 PY - 2023 N1 - https://doi.org/10.11648/j.ijsts.20231102.14 DO - 10.11648/j.ijsts.20231102.14 T2 - International Journal of Science, Technology and Society JF - International Journal of Science, Technology and Society JO - International Journal of Science, Technology and Society SP - 62 EP - 73 PB - Science Publishing Group SN - 2330-7420 UR - https://doi.org/10.11648/j.ijsts.20231102.14 AB - The purpose of this Commentary is to clarify as much as possible the whole history of reactor and containment pressure changes in the Fukushima meltdown accident. It is based on a new approach for film boiling, which is kept after the Zr-H2O reactions. Most important point of this approach is that the author applied film boiling based on boiling curve, which is basic theory in boiling phenomena, for the Fukushima accident phenomena. As the reaction rate is proportional to the reactor or containment pressure under film boiling, it increases rapidly and stops suddenly, keeping the film boiling. The containment pressure change consists of three phases, namely pressurizing, keeping the high pressure and de-pressurizing. The containment is pressurized by H2 gas and steam produced by the Zr-H2O reactions and de-pressurized by a heatsink such as the containment wall and inner shield concrete after reaction stops. The high pressure between these pressure changes is kept by balancing the H2 gas produced by reaction with the leaked gas from the gap between the top lid and the containment. Core decay heat is large, but its change is negligibly small. So, the pressurization is calculated from H2 gas and steam produced by the Zr- H2O reactions. The heatsink balances with the reaction during the high pressure condition. The de-pressurization occurs after the reaction is over, so the reaction heat rate can be calculated by the heat rate of the heatsink, which is equal to the condensation rate during de-pressurization. The leak rate of the leak gas can be calculated using the reaction rate. It is very important that the rection rate is slowed by the insufficient steam supply, as the melted reactor cores in the Fukushima accident were covered with H2 gas and steam (film boiling) at 0.8MPa or lower pressure. This is different from the rate (at approx. 7MPa) in the Three Mile Island accident, as the steam specific volume at 0.8 MPa is ten times larger than that at 7 MPa. The calculation results based on this assumption show that almost all the Zr in each core of Units 1, 2 and 3 reacted with water. VL - 11 IS - 2 ER -
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