Some basic considerations were made on the special characteristics of measurements for radiation protection activities. The authors emphasized that the measurement techniques should be thoroughly re-examined, not from the standpoint of pure radiation dosimetry, but from the standpoint of routine radiation protection practice. It is one of the most important characteristics that complicated uncertain factors are inevitably concerned with the measured value in the field of radiological protection. The authors indicated some error-introducing factors in several measurement techniques and emphasized that these techniques are yet fully effective in spite of those quantitative uncertain factors which are difficult to evaluate. The accuracy of the measured value is allowed to be less precise unless that quantitative uncertainty produces the qualitative uncertainty which has a hindrance in the normal performance of the radiation protection activities. This important understanding, being interdependent with the necessity of simplification of the techniques, can make a drastic improvement of measurement method really possible. From the standpoint mentioned above, the authors gave a typical example of the simplified method of urinary uranium analysis using sodium fluoride pellet, in which the trouble was remarkably saved and the time required for analysis was shortened to one third of that of the former method.
The application of Diffusion Tube Method to the physico-chemical analysis of a gas-particle mixture was reviewed, and some applications of D. T. Method to the following subjects were proposed: 1) Determination of size distribution of polydispersed small aerosol particles. 2) Determination of number concentration of monodispersed small aerosol particles. 3) Measurement of gas-adsorption to particulate matter.
High Speed α-Radioautographic technique, whch was developed by Hsieh et al, was applied to the detection of 239Pu skin surface contamintation to obtain an accurate information as to the contaminated area around the wound. Silver activated zinc sulfide is used as an intensifier in conjunction with high speed Polaroid film. The intensifier film mounted on the double alminum coated myler film is interposed between skin and photographic film. All procedure of above autographic technique was applicable without dark room in routine using special light-tight attachment. About 100dpm 239Pu contamination of skin can expose the shape of contaminated area by several minutes contact by this method.
This paper deals with skin contamination of plutonium, of which safe handling is a serious problem. Experiments were carried out by use of auto-radiographic analysis of plutonium contamination on pig skin. It was found that plutonium contaminated hair-tops, hair-shafts, hair-follicles, furrows and pores on the skin, and the hair contamination could not be disregarded in the decontaminating treatment. Exact analysis of skin contamination by plutonium is, however, in need of further investigation.
In order to reuse Pt plates which are soiled by 239Pu on the counting sample preparation, the decontamination experiments have been carried out with washing and immersion process. Results obtained show that water washing has not any effect but diluted HCl and HNO3 washing have fair effects for removal of 239Pu from Pt plates in the cause of an ion exchange reaction. It is also found that 239Pu decontaminabilities of these acids are increased with increasing of their acidifies. The conclusion is that one of the most excellent decontamination processes of 239Pu may be a long period (more than one day) immersion in concentrated HCl without corrosion of Pt plates.