Measurement and evaluation of the irradiation test parameters for a specimen in a HANARO material irradiation capsule
A material capsule system has been developed for irradiation tests of nuclear materials in the core region of the High-flux Advanced Neutron Application Reactor (HANARO) and has been actively utilized for the various material irradiation tests requested by numerous users. For an irradiation test in the reactor, nuclear characteristics and irradiation temperature of the capsule parts are basically necessary for the safety analysis of the capsule and capsule detail design. The irradiation temperature and neutron fluence of the specimens are key parameters required by a user to analyze any neutron irradiation damage effects. Based on a basic design of a capsule, the reactivity effect, neutron flux/fluence, and gamma heating of specimens are calculated by the MCNP code. To compare the calculated neutron fluence of the specimens, thermal and fast fluence monitors (F/Ms) are installed in a capsule. After an irradiation, the F/Ms are dismantled and analyzed to obtain a neutron spectrum. The obtained fast neutrons (E>1.0MeV) by using the SANDII code are located within about a 20% error range of the theoretical values calculated by the MCNP code. The irradiation temperature of the specimens is analyzed preliminary by using the GENGTC or ANSYS codes based on the basic design of a capsule and gamma heating. During an irradiation test, the temperatures of the specimens in a capsule are measured and monitored by thermocouples. The DPA (Displacement Per Atom) and activation of the irradiated specimens are also evaluated by using the SPECTOR and ORIGEN2 codes, respectively, at HANARO.
Development and Application of Irradiation Technology in HANARO
A material capsule system including a main capsule, a fixing, a control, a cutting, and a transport system was developed for an irradiation test of non-fissile materials in HANARO. This capsule system has been actively utilized for the various material irradiation tests requested by users from research institutes, universities, and the industries. Based on the accumulated irradiation experience and the user’s sophisticated requirements, the instrumented capsule technologies for a more precise control of the irradiation temperature and fluence of a specimen were developed in HANARO. 6,000 specimens from domestic research institutes, nuclear industry companies and universities, were irradiated in HANARO for 54,000 hours by using the developed capsule irradiation system. Recently, development of new instrumented capsule technologies for an IP/OR irradiation test and a high temperature irradiation test has been performed in HANARO for relevant ongoing R&D for the international Gen IV Program. New irradiation technologies are also under development for the production of new functional materials including superconductor and optical/electrical materials.
Joint strength of aluminum ultrasonic soldered under liquidus temperature of Sn–Zn hypereutectic solder
Abstract In order to obtain high-strength aluminum joints, ultrasonic soldering of 1070 aluminum was conducted under liquidus temperature of Sn–Zn hypereutectic solder. A device for ultrasonic soldering was assembled, which propagated ultrasonic vibrations in a direction perpendicular to joining surfaces. This device joined 1070-Al using quasi-melting Sn–Zn hypereutectic solder without using any artificial spacers. The strength of the solder joints was evaluated by tensile tests. The optimum joining conditions were determined, and the effects of solder compositions and soldering temperature on the joint strength and the solder layer thickness were examined. In this ultrasonic soldering process, the highest tensile strength was obtained for the solder joints fabricated at 220 °C for the Sn–23Zn and Sn–40Zn solder compositions. The joint strength was equivalent to that of 1070-Al heat treated at 220 °C. The sound joints were obtained at 300 °C using Sn–82Zn solder, the liquid phase volume fraction of which was theoretically only 0.24. The present work also revealed that the thickness of retained solder layer in the joint after ultrasonic soldering could be estimated. Accordingly, ultrasonic soldering under the liquidus temperature of Sn–Zn hypereutectic solder could be a spacer-free soldering method to obtain high-strength aluminum joints.