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- Author or Editor: H. Tanabe x
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Abstract
A point source of212Pb was prepared from228Th source by the gaseous electrodeposition method. A conical tube was placed between the electrodes and it served as a metallic shade to make lines of electric force converge to the collector cathode. The source was utilized to measure the rate of208Tl emission and the rate of electrodeposition in various gaseous matrices. The mechanism of the mass transfer of recoiled species from the source to the collector was also revealed predominantly to be migration of the recoiled ions.
Abstract
In order to better understand nuclear energy, the radiation counter for public acceptance (PA) activities are now widely used. The radiation counter which detects 
-rays and 
-rays, respectively, has been developed and supplied commercially, but there is no counter for PA use which detects 
-rays. Plutonium has been becoming the center of public interest in regard to transportation by the shipAkatsuki-maru, Rokkasho Reprocessing Plant, and the prototype FBR (fast breeder reactor) 
Monju.
People in general are very concerned about plutonium, which emits -rays, because of its toxicity and possible use in nuclear weapons. In this connection, we have decided to develop a portable -particle counter for PA activities which detects -rays easily. We use Si surface barrier type semiconductor as a detector, and the total system is compact, light in weight, easy to handle, and inexpensive. Four kinds of samples are prepared; soil gathered from a hot spring field, sinter (siliceous material deposited by springs), uranium ore, and monazite. People in general can easily understand the nature of -rays which exits around us.
Abstract
Three commercial nuclear fuel cycle facilities, a reprocessing plant, an uranium enrichment plant and a low level radioactive waste disposal center, have been constructed or are in partial operation at Rokkasho-mura in Aomori prefecture, about 700 km north of Tokyo. A monitoring program has been settled on the modulation between Japan Nuclear Fuel Ltd. (JNFL) and Aomori Prefectural Govemment. The basic goal of environmental monitoring is to make sure that the dose equivalent received by the public, living around the facilities, is much lower than the annual dose equivalent limit. The target is as follows: (1) to estimate the dose equivalent received by the public, (2) to understand the accumulation of radioactive materials in the environment and (3) to estimate the influence on the environment due to unexpected release from the nuclear facilities and to make judgement for the enforcement of routine monitoring or not. This paper describes the contents of the monitoring program such as the object of nuclides, measuring/sampling point, kinds of samples etc.
Abstract
Aomori Prefectural Govemment and Japan Nuclear Fuel Limited started environmental radiation monitoring around Nuclear Fuel Cycle Facilities in April 1989. External radiation is measured by NaI(TI) scintillator and Themoluminescence dosimeter. The level of external radiation is relatively low in the winter due to snow. We have collected terrestrial samples of drinking water, soil, agricultural products and marine samples of seawater, sea sediment, seafood, etc. periodically. We have measured many radionuclides and fluoride in these samples. In soil sample,239+240Pu ratio to137Cs was almost constant at all sampling points. A correlation was observed between salinity and concentration of tritium, uranium and fluoride in lake water of Lake Obuchinuma. The correlation between137Cs and239+240Pu in lake sediment was observed in each lake.
Abstract
The degradation and mineralization of dibutyl phthalate (DBP), one of endocrine disruptors, by g-ray irradiation were demonstrated. The degradation was enhanced by the effective energy conversion of g-rays to low-energy electrons and photons with the assistance of the interactions between g-rays and metals, which is especially in the case of high Z materials effective. Numerical simulations using EGS code supported the experimental results. Improvements of the energy conversion process are also suggested by controlling the shape of the metal and its spatial configuration in the DBP solution.
