• Proceedings of the KSME Conference
• /
• 2001.11a
• /
• pp.400-405
• /
• 2001

Nozzle of the double-plated grid plays the role of the spring to support a fuel rod as well as to provide the coolant path in grid. The nozzle was known to be necessary to reduce the spring stiffness for supporting performance. In this study the contact analysis between the fuel rod and the nozzle type spacer grid was performed by using ABAQUS standard to propose the preferable shape in tenn of spring performance. Two small cuts at the upper and lower part of the nozzle appeared to have a minor effect in decreasing the nozzle stiffness. A long slot at the center of the nozzle was turned out not only to decrease the spring constant as desired but also to increase the elastic displacement.

• Nuclear Engineering and Technology
• /
• v.24 no.3
• /
• pp.263-273
• /
• 1992

The study on the velocity distribution and the pressure drop characteristic of the nuclear fuel assembly is of importance for the thermal hydraulic design and safety analysis. The purpose of this experimental study is to investigate the hydraulic mixing behind the different kinds of spacer grids in the now or rod bundles. In this study, the detailed hydraulic characteristics in subchannels of 5$\times$5 PWR(Pressurized Water Reactor) rod bundles were measured using one-component He-Ne LDV(Laser Doppler Velocimeter). Measurements of the axial velocity, turbulent intensities and pressure drops were peformed Lateral velocity, turbulent intensities and Reynolds shear stress were also measured by adjust-ing LDV alignment. Friction factors in rod bundles and loss coefficients for spacer grids were evaluated from the measured pressure drops. Hydraulic mixing performance for different kinds of spacer grids could be investigated by estimating the turbulent cross-flow mixing rates between neighboring subchannels.

• Proceedings of the KSME Conference
• /
• 2007.05b
• /
• pp.3473-3478
• /
• 2007

A dual side cooling annular fuel having internal and external coolant channels has many advantages basically due to low fuel temperature and high DNBR margin, which can make a significant increase of core power density possible. So recently a 12x12 square annular fuel array was proposed for the fuel assembly to be reloaded without structural interference with operating reactors of OPR-1000s. Even through the inherent potential of the annular fuel on the high power density, it may be seriously eroded in the case of a severe unbalanced mass flux split to the internal and external channels in standpoint of DNB. Mass flux split is determined pressure drop characteristics between inner and outer channels. The spacer grids binding fuel array influence greatly the pressure drop in outer channels and the mass flux split. As an important factor of DNB behavior, the enthalpy differences at both channel exits were evaluated using the mass flux splits.

• Proceedings of the KSME Conference
• /
• 2001.11a
• /
• pp.355-360
• /
• 2001

Design requirements for the nuclear fuel assembly grid of the pressurized light water reactor(PLWR) are scrutinized from the mechanical/structural point of view. As a result of the scrunity, mechanical/structural test facilities on the spacer grid of the PLWR Fuel are set up in KAERI to find out their mechanical/structural performance.

• Proceedings of the Korean Nuclear Society Conference
• /
• 2004.10a
• /
• pp.837-838
• /
• 2004

• Proceedings of the Korean Nuclear Society Conference
• /
• 2001.05a
• /
• pp.328.2-328
• /
• 2001

• Proceedings of the Korean Nuclear Society Conference
• /
• 2001.05a
• /
• pp.330.2-330
• /
• 2001

• Proceedings of the Korean Nuclear Society Conference
• /
• 2002.10a
• /
• pp.133.2-133
• /
• 2002

• Proceedings of the Korean Nuclear Society Conference
• /
• 2003.05a
• /
• pp.257.2-257.2
• /
• 2003

• Proceedings of the Korean Nuclear Society Conference
• /
• 2003.05a
• /
• pp.258.2-258.2
• /
• 2003