The recent extention of X-ray diffractimetry is really remarkable. This paper includes some practical considerations of safety handling of X-ray diffraction apparatus. Following points can be mentioned: (1) Most of accidental hazards result either from mishandling or carelessness. (2) Regal regulations are imperfect at present. (3) The interest of safety control are inadequate. Monitoring and survey techniques were investigated in detail, and it was suggested that the qualitative monitoring of leakage and scattered radiation is important rather than the quantitative dose rate measurements. From several work studies it was showed that unnecessary radiation exposure of operator occurs mainly in the process of tube adjustments and sample positioning. The authors emphasized that following attentions are necessary for practical X-ray protection design. (1) The effective shield is useful for protection. (2) To provide an operation manual is indispensable for safety handling. (3) The consideration for the special characteristics of each equipment is absolutely essential for safety program.
A literature review and the present status of thermoluminescent neutron dosimetry are presented. The theory on thermoluminescent dosimetry is given in detail. The applications of thermoluminescence phenomenon in thermal neutron dosimetry, in fast neutron dosimetry, and in mixed field dosimetry are discussed. Some experimental results are included. The prospective use of thermoluminescent dosimeters in other nuclear detection or measurement is also given.
The first Japanese fuel reprocessing test plant has been constructed at the JAERI since 1962 and this plant is scheduled to be in operation in the near future. The radioactive gases released from the plant are mainly iodine and krypton. Iodine is monitored by a special instrument with a charcoal filter paper and charcoal cartridges. This paper describes performance of a gas monitor designed to measure krypton-85. In order to measure krypton-85 which emits 0.7MeV β-rays, a gas sampler having a volume of 3.4l was used with a bundle of two side window type GM tubes. The minimum detectable amounts of this gas monitor obtained by calculation and experiment were of 2×10-7μCi/cm3 and 6×10-7μCi/cm3 respectively.
The causes of fires of plutonium and uranium in the nuclear facilities are summalized through the literature survey of accidents in the United States and the United Kingdom, and of metallurgical studies. It is noticeable that spontaneous ignition is due to the operations such as of degreasing, leaching, cutting and scraping, to the treatment with nitric acid, or to the existence of moisture, for example, after low-temperature experiment of the metals. The methods of fire-prevention and fire-fighting at the plutonium fires are also described with the recommendation on the view point of health physics: Aluminum icontaner is likely to have excellent property for the fire prevention. The data of particle size distribution and deposition velocity of plutonium emitted at the fire are also showed. Finally, the efficient agent and technique of fire extinguishing are described with some data from experiences in the accidents and the laboratory experiments.