Numerical analysis of heat transfer test of supercritical water in a tube using the three-dimensional two-fluid model code

Misawa, Takeharu; Yoshida, Hiroyuki  ; Tamai, Hidesada; Takase, Kazuyuki

In Japan, development of a supercritical water-cooled nuclear reactor (SCWR) is carried out as one of the next generation nuclear energy systems as proposed by GIF (Generation IV International Forum). In transient operation including start-up, shut-down, and accident, it is possible that coolant in a reactor changes over between supercritical pressure region and subcritical pressure region. In JAEA, three-dimensional two-fluid model analysis code ACE-3D has been developed, and has achievement of detailed thermal-hydraulic analysis code of supercritical light water reactor including transient phenomena, by enhancement of ACE-3D code to supercritical pressure region. This paper shows development and assessment of ACE-3D. It was confirmed that transient change between supercritical and subcritical pressure region can be simulated using ACE-3D, that ACE-3D can predict the results of the past heat transfer experiment in supercritical pressure region, and that introduction of thermal conductivity effect of the wall restrains temperature fluctuation on the wall.