A Finite element analysis study on the fracture pattern change of fuel cladding under PCMI loading conditions

Li, F.; Mihara, Takeshi; Udagawa, Yutaka; Katsuyama, Jinya

Journal of Nuclear Science and Technology, 63(7), p.854 - 861, 2026/07

https://doi.org/10.1080/00223131.2025.2611411

Experimental evaluation of high-temperature fuel-coolant thermal interaction behavior using unirradiated fuel powder

Mihara, Takeshi; Urano, Kenta; Udagawa, Yutaka; Kakiuchi, Kazuo

JAEA-Technology 2026-009, 15 Pages, 2026/06

JAEA-Technology-2026-009.pdf:1.15MB

Mechanical energy generated during fuel failure under reactivity-initiated accident (RIA) conditions, such as pressure pulse and water hammer, strongly depends on the fragmentation state and temperature of the fuel. When failure caused by pellet/cladding mechanical interaction (PCMI) occurs rapidly at low temperature, fission gas release drives pellet fragments to move at high velocity in water, leading to extremely efficient heat transfer between the fuel and coolant. This results in rapid vapor generation and the production of impulsive mechanical energy. These observations indicate that both the particle surface area and the highly efficient heat transfer associated with high-velocity fragment motion are key influencing factors. In the 264-2 and 264-24 experiments, test conditions were designed to simulate fuel-coolant interaction under conditions where the driving force for pellet fragment motion, which is characteristic of RIA events, is absent. In the 264-24 test, the specific surface area of the pellet particles (surface area per unit mass) was designed to exceed that of previously tested high-burnup fuels. In addition, the fuel enthalpy (thermal energy per unit mass) was set based on prior observations to conditions where significant mechanical energy generation is expected. As a result, both the pressure pulse and water hammer energies were significantly lower than those observed in high-burnup fuel failure cases, where the driving force for pellet fragment motion is considered to be present. This clearly demonstrates the critical importance of the driving force for pellet fragment motion in the generation of mechanical energy.

Effect of rod internal gas state on FFRD behavior of high burnup fuel during LOCA conditions

Kakiuchi, Kazuo; Narukawa, Takafumi*; Udagawa, Yutaka; Katsuyama, Jinya; Mihara, Takeshi; Amaya, Masaki

Proceedings of TopFuel 2025; Nuclear Reactor Fuel Performance Conference (Internet), p.1440 - 1449, 2025/10

Fission gas dynamics test; Development of reactivity-initiated-accident testing technique devoted to investigation of fission gas release kinetics

Mihara, Takeshi; Urano, Kenta; Udagawa, Yutaka

Proceedings of TopFuel 2024 (Internet), 9 Pages, 2024/10

High-temperature rupture failure of high-burnup LWR-MOX fuel under a reactivity-initiated accident condition

Taniguchi, Yoshinori; Mihara, Takeshi; Kakiuchi, Kazuo; Udagawa, Yutaka

Annals of Nuclear Energy, 195, p.110144_1 - 110144_11, 2024/01

https://doi.org/10.1016/j.anucene.2023.110144

Behavior of high-burnup BWR UO fuel with additives under reactivity-initiated accident conditions

Mihara, Takeshi; Kakiuchi, Kazuo; Taniguchi, Yoshinori; Udagawa, Yutaka

Journal of Nuclear Science and Technology, 60(5), p.512 - 525, 2023/05

https://doi.org/10.1080/00223131.2022.2122616

Follow-up experimental study on causes of the low-enthalpy failure observed in the reactivity-initiated-accident-simulated test on LWR additive fuels

Mihara, Takeshi; Kakiuchi, Kazuo; Taniguchi, Yoshinori; Udagawa, Yutaka

Proceedings of TopFuel 2021 (Internet), 10 Pages, 2021/10

Mechanical failure of high-burnup fuel rods with stress-relieved annealed and recrystallized M-MDA cladding under reactivity-initiated accident conditions

Mihara, Takeshi; Udagawa, Yutaka; Sugiyama, Tomoyuki; Amaya, Masaki

Journal of Nuclear Science and Technology, 58(8), p.872 - 885, 2021/08

https://doi.org/10.1080/00223131.2021.1883143

Fracture-mechanics-based evaluation of failure limit on pre-cracked and hydrided Zircaloy-4 cladding tube under biaxial stress states

Li, F.; Mihara, Takeshi; Udagawa, Yutaka; Amaya, Masaki

Journal of Nuclear Science and Technology, 57(6), p.633 - 645, 2020/06

https://doi.org/10.1080/00223131.2019.1709996

Behavior of high-burnup LWR-MOX fuel under a reactivity-initiated accident condition

Taniguchi, Yoshinori; Udagawa, Yutaka; Mihara, Takeshi; Amaya, Masaki; Kakiuchi, Kazuo

Proceedings of International Nuclear Fuel Cycle Conference / Light Water Reactor Fuel Performance Conference (Global/Top Fuel 2019) (USB Flash Drive), p.551 - 558, 2019/09