Japan Atomic Energy Research Institute

About: Japan Atomic Energy Research Institute is a based out in . It is known for research contribution in the topics: Neutron & Irradiation. The organization has 7707 authors who have published 14471 publications receiving 207688 citations.

Nonuniform steam generator U-tube flow distribution during natural circulation tests in ROSA-IV large scale test facility

Abstract: Natural circulation experiments were conducted in a large-scale ( scale in volume) full-height simulator of a Westinghouse-type pressurized water reactor. This facility has two steam generators eac...

Stationary high confinement plasmas with large bootstrap current fraction in JT-60U

Abstract: This paper reports the results of the progress in stationary discharges with a large bootstrap current fraction in JT-60U towards steady-state tokamak operation. In the weak shear plasma regime, high-βp ELMy H-mode discharges have been optimized under nearly full non-inductive current drive conditions by the large bootstrap current fraction (fBS ~ 45%) and the beam driven current fraction (fBD ~ 50%), which was sustained for 5.8 s in the stationary condition. This duration corresponds to ~26τE and ~2.8τR, which was limited by the pulse length of negative-ion-based neutral beams. The high confinement enhancement factor H89 ~ 2.2 (HH98y2 ~ 1.0) was obtained and the profiles of current and pressure reached the stationary condition. In the reversed shear plasma regime, a large bootstrap current fraction (fBS ~ 75%) has been sustained for 7.4 s under nearly full non-inductive current drive conditions. This duration corresponds to ~16τE and ~2.7τR. The high confinement enhancement factor H89 ~ 3.0 (HH98y2 ~ 1.7) was also sustained, and the profiles of current and pressure reached the stationary condition. The large bootstrap current and the off-axis beam driven current sustained this reversed q profile. This duration was limited only by the duration of the neutral beam injection.

Hydration structure of Y3+ and La3+ compared: An application of metadynamics

Abstract: We studied the hydration structures of Y3+ and La3+ in aqueous solutions by applying the metadynamics method recently introduced as a tool to explore reaction pathways based on the Car–Parrinello molecular dynamics By employing the metal–water oxygen coordination number as a collective variable of the metadynamics a couple of aqua and chloroaqua complexes are successfully generated within the time scale of 10 ps The reconstructed free-energy surface captures the characteristics of the hydration of the light and heavy trivalent rare-earth ions The present study demonstrates that the metadynamics based on the Car–Parrinello molecular dynamics is a promising tool for exploring the free-energy surface of complicated systems such as solutions