TY - JOUR
T1 - Safety function reliability evaluation and risk management during decommissioning of accident-damaged nuclear power plant -Based on results of confinement function reliability evaluation-
AU - Aoki, Takayuki
AU - Masuko, Junya
AU - Ikeda, Atsuo
AU - Negishi, Takayuki
N1 - Publisher Copyright:
© 2020 Atomic Energy Society of Japan, All Rights Reserved.
PY - 2020
Y1 - 2020
N2 - During the decommissioning of accident-damaged nuclear power plants, three fundamental safety functions, i.e., stopping the reactor, cooling the reactor, and confining radioactive materials, have to be maintained as well as normally operating plants. However, for severely accident-damaged nuclear power plants such as Fukushima Daiichi units 1 to 3, the stopping function is lost and the confinement function is degraded. Even in such cases, it is very important to suppress the additional release of radioactive materials to outside during the decommissioning. Because of the high radiation level, it is very difficult to access the inside of the primary containment vessel and reactor building to investigate and repair equipment or components. Because of this, a lot of time and effort may be needed to complete the project, and it may be necessary to take a strategic, efficient, and effective step by taking a risk-informed approach. In this paper, we focused on a negative pressure control system for a primary containment vessel and a reactor building during fuel debris retrieval, evaluated its reliability, and, on the basis of the evaluation results, considered appropriate safety management for nuclear decommissioning.
AB - During the decommissioning of accident-damaged nuclear power plants, three fundamental safety functions, i.e., stopping the reactor, cooling the reactor, and confining radioactive materials, have to be maintained as well as normally operating plants. However, for severely accident-damaged nuclear power plants such as Fukushima Daiichi units 1 to 3, the stopping function is lost and the confinement function is degraded. Even in such cases, it is very important to suppress the additional release of radioactive materials to outside during the decommissioning. Because of the high radiation level, it is very difficult to access the inside of the primary containment vessel and reactor building to investigate and repair equipment or components. Because of this, a lot of time and effort may be needed to complete the project, and it may be necessary to take a strategic, efficient, and effective step by taking a risk-informed approach. In this paper, we focused on a negative pressure control system for a primary containment vessel and a reactor building during fuel debris retrieval, evaluated its reliability, and, on the basis of the evaluation results, considered appropriate safety management for nuclear decommissioning.
KW - Accident-damaged reactor
KW - Confinement function
KW - Nuclear decommissioning
KW - PRA
KW - Radioactive material release frequency
KW - Safety functions
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U2 - 10.3327/TAESJ.J19.003
DO - 10.3327/TAESJ.J19.003
M3 - Article
AN - SCOPUS:85092420724
VL - 19
SP - 85
EP - 109
JO - Transactions of the Atomic Energy Society of Japan
JF - Transactions of the Atomic Energy Society of Japan
SN - 1347-2879
IS - 2
ER -