Subchannel Analysis to Investigate the Fuel Assembly for the Supercritical-water-cooled Power Reactor

• Published in: Journal of nuclear science and technology Vol. 41; no. 11; pp. 1075 - 1082
• Main Authors: KITOU, Kazuaki, NISHIDA, Kouji, ISHII, Yoshihiko, FUJIMURA, Kouji, MATSUURA, Masayoshi, SHIGA, Shigenori
• Format: Journal Article
• Language: English
• Published: Tokyo Taylor & Francis Group 01.11.2004; Atomic Energy Society of Japan
• Subjects: Applied sciences; coolant flow distribution; coolant temperature distribution; Energy; Energy. Thermal use of fuels; Exact sciences and technology; Fission nuclear power plants; fuel assembly; fuel cladding surface temperature; Fuels; Installations for energy generation and conversion: thermal and electrical energy; Nuclear fuels; SILFEED code; subchannel analysis; supercritical-water-cooled power reactor; supercritical-water-cooled power reactor; Coolant; fuel cladding surface temperature; coolant flow distribution; Temperature effect; coolant temperature distribution; Surface temperature; Clad; Cooling by water; Light water reactor; subchannel analysis; Water cooled reactor; SILFEED code; Fuel assembly; Thermal reactor; Thermal efficiency; Cost lowering
• ISSN: 0022-3131; 1881-1248
• DOI: 10.1080/18811248.2004.9726332

The supercritical-water-cooled power reactor (SCPR) is expected to reduce power costs compared with those of current LWRs because of its high thermal efficiency and simple reactor system. The high thermal efficiency is obtained by supercritical pressure water cooling. The fuel cladding surface temperature increases locally due to a synergistic effect from the increased coolant temperature, the expanded flow deflection due to coolant density change and the decreased heat transfer coefficient, if the coolant flow distribution is non-uniform in the fuel assembly. Therefore, the SCPR fuel assembly is designed using a subchannel analysis code based on the SILFEED code for BWRs. The SCPR fuel assembly has many square-shaped water rods. The fuel rods are arranged around these water rods. The fuel rod pitch and diameter are 11.2 mm and 10.2 mm, respectively. Since coolant flow distribution in the fuel assembly strongly depends on the gap width between the fuel rod and the water rod, the proper gap width is examined. Subchannel analysis shows that the coolant flow distribution becomes uniform when the gap width is 1.0 mm. The maximum fuel cladding surface temperature is lower than 600°C and the temperature margin of the fuel cladding is increased in the design.