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

Mechanical Engineering Journal (Internet), 10(4), p.23-00043_1 - 23-00043_12, 2023/08

https://doi.org/10.1299/mej.23-00043

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.

Three-dimensional structural analysis for enhancing resilience of next-generation nuclear structures under extremely high temperature conditions

Futagami, Satoshi; Ando, Masanori; Yamano, Hidemasa

Transactions of the 26th International Conference on Structural Mechanics in Reactor Technology (SMiRT-26) (Internet), 9 Pages, 2022/07

Investigation of elastic deformation mechanism in as-cast and annealed eutectic and hypoeutectic Zr-Cu-Al metallic glasses by multiscale strain analysis

Suzuki, Hiroshi; Yamada, Rui*; Tsubaki, Shinki*; Imafuku, Muneyuki*; Sato, Shigeo*; Watanuki, Tetsu; Machida, Akihiko; Saida, Junji*

Metals, 6(1), p.12_1 - 12_11, 2016/01

https://doi.org/10.3390/met6010012

Elastic deformation behaviors of as-cast and annealed eutectic and hypoeutectic Zr-Cu-Al bulk metallic glasses (BMGs) were investigated on a basis of different strain-scales determined by X-ray scattering and the strain gauge. The microscopic strains determined by Direct-space method (DSM) and Q-space method (QSM) were compared with the macroscopic strain measured by the strain gauge, and the difference in the deformation mechanism between eutectic and hypoeutectic Zr-Cu-Al BMGs was investigated by their correlation. The eutectic ZrCuAl BMG obtains more homogeneous microstructure by free-volume annihilation after annealing, improving a resistance to deformation but degrading ductility because of a decrease in the volume fraction of WBRs (Weakly-Bonded Regions) with relatively high mobility. On the other hand, the as-cast hypoeutectic ZrCuAl BMG originally has homogeneous microstructure, but loses its structural and elastic homogeneities because of nanocluster formation after annealing. Such structural changes after annealing might develop unique mechanical properties showing no degradations of ductility and toughness for the structural-relaxed hypoeutectic BMGs.

The Tensile deformation behavior of nuclear-grade isotropic graphite posterior to hydrostatic loading

;

Journal of Nuclear Materials, 118, p.214 - 219, 1983/00

https://doi.org/10.1016/0022-3115(83)90227-1

no abstracts in English

Deformation behavior of medium manganese steels by neutron diffraction

Morooka, Satoshi; Yamashita, Takayuki; Harjo, S.; Tsuchiyama, Toshihiro*

no journal, , 

no abstracts in English

Development of failure mitigation technologies for improving resilience of nuclear structures, 15; Conceptual study for improving resilience of next-generation nuclear power plants under extremely high temperature conditions

Futagami, Satoshi; Ando, Masanori; Yamano, Hidemasa; Kasahara, Naoto*

no journal, , 

To improve resilience of next-generation nuclear power plants, the authors have performed a structural analysis assuming a protected loss of heat sink event, which may cause all decay heat removal systems to lose their functions immediately after reactor shutdown. The results show how the reactor vessel and guard vessel deform under extremely high temperatures.