Abstract: A refueling apparatus for charging nuclear fuel in a reactor vessel, the refueling apparatus including: a refueling unit loading new nuclear fuel to a core or extracting spent nuclear fuel from the core; and a waveguide sensor unit including an ultrasonic wedge to form a Lamb wave, a waveguide with an end connected to the ultrasonic wedge and with another end transmitting the Lamb wave into the reactor vessel, and an ultrasonic sensor connected to the ultrasonic wedge and sensing a reflection signal reflected from an inside of the reactor vessel, the waveguide being formed in a plate shape and mounted in an end of the refueling unit. The waveguide integrally moves with the refueling unit, and the waveguide sensor unit detects a condition of the inside of the reactor vessel, while the refueling unit refuels the fuel assembly in the reactor vessel.

Abstract: Disclosed are an apparatus and a method for calculating a temperature dependent Green's function using an appropriate weight function. The apparatus includes a material temperature change information input unit inputting change information of a material temperature; and a temperature dependent Green's function calculation unit receiving the change information of the material temperature through the material temperature change information input unit, calculating a temperature dependent Green's function using a weight function, and outputting the calculated result. According to aspects of embodiments, accuracy in the calculation of a thermal stress value can be improved by designing the weight function such that changes in physical properties of a material that change according to temperature changes are considered.

Abstract: Disclosed are an apparatus and a method for calculating a temperature dependent Green's function using an appropriate weight function. The apparatus includes a material temperature change information input unit inputting change information of a material temperature; and a temperature dependent Green's function calculation unit receiving the change information of the material temperature through the material temperature change information input unit, calculating a temperature dependent Green's function using a weight function, and outputting the calculated result. According to aspects of embodiments, accuracy in the calculation of a thermal stress value can be improved by designing the weight function such that changes in physical properties of a material that change according to temperature changes are considered.

Abstract: A refueling apparatus for charging nuclear fuel in a reactor vessel, the refueling apparatus including: a refueling unit loading new nuclear fuel to a core or extracting spent nuclear fuel from the core; and a waveguide sensor unit including an ultrasonic wedge to form a Lamb wave, a waveguide with an end connected to the ultrasonic wedge and with another end transmitting the Lamb wave into the reactor vessel, and an ultrasonic sensor connected to the ultrasonic wedge and sensing a reflection signal reflected from an inside of the reactor vessel, the waveguide being formed in a plate shape and mounted in an end of the refueling unit. The waveguide integrally moves with the refueling unit, and the waveguide sensor unit detects a condition of the inside of the reactor vessel, while the refueling unit refuels the fuel assembly in the reactor vessel.

Abstract: A seismic isolation bearing device is disclosed in which a laminated elastic rubber-steel bearing adapted to isolate horizontal seismic loading cooperates with a vertical isolation device employing a compression spring, or equivalent device, effective for isolating vertical seismic loadings whereby a three dimensional seismic isolation device is effective to isolate both vertical and horizontal seismic loadings to insure the structural integrity of a superstructure against damage induced by seismic events. The isolation device formed of an isolation cylinder fixed to the structure, with an upper fixing plate vertically movable within the cylinder. A plurality of steel balls being disposed within a space formed between the perimeter of the upper fixing plate and the interior wall of the isolation cylinder. The balls facilitating the guided relative vertical movement between the upper fixing plate and the isolation cylinder.