Development of failure mitigation technologies for improving resilience of nuclear structures, 5; Resilience improvements of fast reactors by failure mitigation for beyond design high temperature accidents

Futagami, Satoshi; Ando, Masanori; Yamano, Hidemasa

Transactions of the 27th International Conference on Structural Mechanics in Reactor Technology (SMiRT 27) (Internet), 10 Pages, 2024/03

Structural analysis of a reactor vessel in a sodium-cooled fast reactor under extremely high temperature conditions

Yamano, Hidemasa; Futagami, Satoshi; Ando, Masanori

Proceedings of 29th International Conference on Nuclear Engineering (ICONE 29) (Internet), 7 Pages, 2022/08

This study has conducted a detailed structural analysis of a reactor vessel (RV) in a loop-type sodium-cooled fast reactor using a general-purpose finite element analysis code, FINAS/STAR, to understand its deformation behavior under extremely high temperature conditions and to identify the areas which should be focused to mitigate impacts of failure. The RV was heated from the normal operation condition to the sodium boiling temperature in the upper sodium plenum during 20 hours assuming depressurization. The analysis has revealed less significant stress and strain which were sufficiently lower than failure criteria. The upper body of RV was identified as the important area in terms of mitigation of structural failure. The RV was eventually deformed downward about 16 cm, resulting in no failure. This effect contributes to maintaining RV sodium level in a long term, thereby enhancing the RV resilience.

Improvement of engineer ethics education using resilience engineering concept

Oba, Kyoko; Yoshizawa, Atsufumi*; Kitamura, Masaharu*

Kogaku Kyoiku, 69(3), p.3 - 10, 2021/05

https://doi.org/10.4307/jsee.69.3_3

The purpose of engineering ethics education is to understand the effects and impacts of technology on society and nature and the responsibilities that engineers have to fulfill for society. There are many cases used in the educational method so that the students can understand the problems surrounding the engineers. However, most of the cases correspond to event scenarios where engineers have failed to maintain safety. Resilience engineering was born from the criticism of safety measures for the purpose of preventing recurrence by seeking human error and organizational culture as the cause of accidents in the field of ergonomics. Its features are that people are considered as beings that realize safety in dangerous systems, and that they focus on good practices. This paper describes the improvement of engineering ethics education by utilizing resilience engineering concept.

Study on improving safety by applying Safety-II concept based on accident responding analysis for Fukushima Daiichi Nuclear Power Plant

Yoshizawa, Atsufumi*; Oba, Kyoko; Kitamura, Masaharu*

Ningen Kogaku, 54(1), p.1 - 13, 2018/02

AA2017-0637.pdf:1.46MB

The two approaches as the concepts to ensure safety of the complicated socio-technical systems have been proposed by Hollnagel. They are the safety concepts called "Safety-I" to reduce risks and "Safety-II" to expand successes. The resilience engineering is suggested as the methodology to achieve Safety-II. The study analyzes the recovery of the water injection of Unit 3 based on the resilience engineering, focusing on the fact that preventing further progress of the accident case in Fukushima Daiichi Nuclear Power Plant which has been evaluated for extracting risk factors. Based on those results, the study has clarified the method of learning to enhance safety which has a different view from existing accident investigation.

System safety and resilience engineering, 2

Oba, Kyoko

Sangyo, Kagaku Kikai To Anzen Bumon Nyusu Reta, (31), P. 3, 2016/04

https://www.jsme.or.jp/icm/uploads/sites/18/2019/07/newsletter_No31.pdf

no abstracts in English

Investigation into execution program of safety improvement based on Resilience Engineering, 2; Program aiming at staff's attitude improvement by organization learning

Yoshizawa, Atsufumi*; Matsumoto, Atsushi*; Oba, Kyoko; Kitamura, Masaharu*

no journal, , 

no abstracts in English

Enhancement of organizational resilience in light of the Fukushima Dai-ichi Nuclear Power Plant accident, 4; Consideration of nurturing attitude to achieve the safety-II

Oba, Kyoko; Yoshizawa, Atsufumi*; Kitamura, Masaharu*

no journal, , 

no abstracts in English

Relations among the concepts of Safety-I, Safety-II and defense in depth, 1; Studies on the safety concepts based on the lessons learned from great east japan earthquake

Oba, Kyoko; Yoshizawa, Atsufumi*; Kitamura, Masaharu*

no journal, , 

no abstracts in English

Enhancement of safety by incorporating aspects of Safety-II, 1; Evaluation of effects based on defense in depth and necessity of safety

Oba, Kyoko; Yoshizawa, Atsufumi*; Kitamura, Masaharu*

no journal, , 

no abstracts in English

Consideration of realization socio-resilience about the responding and the following elements

Oba, Kyoko

no journal, , 

no abstracts in English