Radiation warning signs posted on the exterior of radiation facilities become faded and discolored with time. There are various types of commercially available laminating films for protecting signs from ultraviolet light. We examined the protection effect of polyvinyl chloride (PVC), acrylic resin and fluororesin films applied to the surface of radiation warning signs. The laminated signs were exposed to direct sunlight on the wall of an air filter chamber of a radiation facility for 1200 days. Simultaneously, another set of laminated signs was exposed to light from a xenon-arc weatherometer for 1200 hours. After exposure, the colors on the surface of each sign were evaluated digitally by using a spectrum colorimeter. The results indicated that lamination with a film that blocks ultraviolet light is effective for protecting the signs from fading and discoloration. For long-term protection under direct sunlight, PVC was the most effective among the three materials tested.
In this report, we introduced our project of the extension and the rebuilding of the building of Central Institute of Isotope Science (CIS), Hokkaido University, which has been planned in terms of the present state and the future outlook for the management of CIS. We first fixed a layout of that building and the dose of radioisotope (RI) in the renewed CIS building in consideration of the present usage states, and then carried out a sort of designing of building such as calculation of the wall thickness corresponded to the RI usage dose, arrangement of exhaust and drainage equipments, and so on. Furthermore, we attempted to design the building with an appropriate function for education and safety control of radiation and RI as well as flexibility in response to user's demands on performing a various kind of researches.
Radioisotope center in the University of Tokyo had approval of waste disposal operator only in the universities of Japan since 1983. However, the radioisotope center abolished the waste disposal office in December 2013. In this paper, we summarize the history of the waste disposal operator in the radioisotope center, and report the procedure of office abolition under the Japanese law and regulations concerning prevention from radiation hazards due to radio-isotopes, etc. revised after April 2012.
The Saga Medical School Radiation Facility was founded in 1980, and is now The Division of Radioactive Compound Utility of Analytical Research Center for Experimental Sciences, Saga University. The facility provides laboratories to handle unsealed radioactive materials and gamma- and X-rays irradiating apparatuses for our faculties and students. We reduced the scale of this facility in 2012, because the use of the facility has decreased during the last two decades. The number of users in the last year was only a fifth of the peak one in 1995. The renovated facility has two-thirds of its floor space and some remodelings including removes of the inside lavatories and the disposal for radioactive waste organic solution. We here report detail of this renovation and the related approvals.
The accelerator facility at Research Center for Nuclear Physics, Osaka University equipped with AVF and ring cyclotrons, has been utilized for experiments in nuclear physics and nuclear chemistry since 1976. In the Japanese Fiscal Year 2012, a part of the AVF cyclotron building, including the radiation control area, was renovated for anti-earthquake reinforcement and the floor arrangement of the building was fully changed. The radiation control area was reduced on the first floor and one gate of the radiation control area was added on the second floor. The radiation control interlock system for safety of the cyclotron facility was renewed in this renovation period. A complicated relay array for the interlock circuit was replaced by an intelligent PLC system, and a new physical access control system by identification through fingerprints or an IC card was installed. In this report, we introduce a change of the radiation control area border and a renewal of the radiation safety interlock system for the cyclotron facility.