Introduction to the cold neutron source at HANARO

This article aims to introduce the development of a Cold Neutron Source (CNS) at HANARO. The reactor has been safely operating for 13 years since its initial criticality in February of 1995. The reactor was designed for a multi-purpose use in the science research and engineering field such as a neutron scattering, a material irradiation, a nuclear fuel test loop, a neutron transmutation for silicon, and etc. All the aforementioned purposes except for the CNS have been successively developed for their inherent aims. In order to complete the remaining aim, a development project for the CNS has been underway since 2003. Also, it is intended to enhance the utilization capacity of HANARO as a research reactor. The development was divided into two stages for 7 years depending on the characteristics of the stage such as a design and implementation. It was intended to effectively achieve its final goal on schedule. The first stage has been finished in 2006 and the second stage should be finished in 2009. The HANARO CNS basically consists of a hydrogen system, a vacuum system, a gas blanketing system, and a helium refrigeration system because it has adopted liquid hydrogen as a moderator. The liquid hydrogen contained in the moderator cell evaporates due to a gamma heating. The hydrogen vaporizes up to the condenser, where it is re-liquefied then it returns down to the moderator cell. This thermo-siphon loop can only be established under a very low temperature environment, which requires a method for a thermal insulation. All of the CNS equipment and systems except for the IPA (In-Pile Assembly) will be installed in September 2008 and it will start its commissioning at the end of 2008. The IPA will be installed in the first half of 2009. On the other hand, the cold neutron laboratory building, which was designed for a guide hall to accommodate cold neutron scattering instruments, has been constructed in May 2008. At the beginning of 2010, it is hoped that HANARO will successively provide a cold neutron source including a research facility for international users who want to use a good experimental environment to do their researches by using the cold neutron source. (author)