[en] Since nickel is a metal of high stacking fault energy, it is of interest to study the arrangement of dislocations in the plastic zone for propagating cracks and to compare the results with those found in metals of low stacking fault energy. It has been found that two distinct distributions of dislocations in the plastic zone are associated with cracks in nickel. In one of these, the plastic zone appeared as a thin ribbon and consisted of a number of partial dislocations with stacking fault fringes. From contrast analysis and stereoscopic observations, the crack was found to be approximately mode III type, and the plane of the plastic zone was identified as (111). The crack geometry was very similar to that observed in metals of low stacking fault energy, namely, stainless steel and copper. The second type of plastic zone observed was not in the form of a thin ribbon; that is, the dislocations in the plastic zone were not split into partial dislocations. Since the dislocations were not split, they cross-slipped readily from the original slip plane and formed a broad plastic zone

[en] This issue is the collection of the paper presented at the title meeting. The 23 of the presented papers are indexed individually. (J.P.N.)

[en] Bose-Einstein correlations in the reaction e⁺e^- → hadrons have been studied by the AMY detector at TRISTAN. A total of about 3900 hadronic events was analyzed based on the recent quantum statistical prediction of the correlated Q² distribution. Preliminary results of the chaoticity and the source size were obtained by the two-body and the three-body analysis, consistent with each other within the accuracy. (author)

[en] The geometrical effects in a large-area scintillation counter are discussed on the basis of a model simplified by the theory of optics. For the observed amplitude and time resolution, this model seems to give a reasonable explanation when one uses some appropriate parameters on the reflectivity and the transmissivity for the scintillation light. (Auth.)

[en] N.M.R. relaxation of ⁶⁵Cu N.M.R. in small Cu particles 100 A, 50 A, 25 A and 15 A in diameters, are measured at 1.4 K and 0.66 K. The relaxation in 25 A and 15 A particles is found to be much slower than that of bulk metal. It is concluded that this enhancement of T₁ is the result of electron energy level quantization in small particles

[en] 'Oxidation-sintering pellets' and 'Al₂O₃/SiO₂ additive pellets' were developed. Both pellets will be used for high burnup due to their good FGR and PCI properties. In the 'oxidation-reduction sintering process', U₃O₈ powder is added to UO₂ powder as a source of oxygen to produce U₄O₉ and to get large grain pellets. Atmosphere of the oxidation sintering process is O₂+N₂ and the sintering temperatures for both the oxidation and the reduction processes are relatively low compared with that for the standard sintering process. In Al₂O₃/SiO₂ addition, Al₂O₃/SiO₂ covers UO₂ grain and enhances its grain growth. Contents of Al₂O₃ and SiO₂ are very low (∼50,50 PPM), therefore there is little impact on a reprocessing process. Both type of pellets are under irradiation in test reactors and a commercial reactor as demonstration fuels. We will choose one type of pellet after PIE, and will use it for high burnup (55 GWd/t) as commercial fuels. (author)

No abstract available

[en] The current status of a Regional Co-operative Agreement (RCA) project on 'strengthening of radiation protection' is described. All the RCA Member States, i.e. Australia, Bangladesh, China, India, Indonesia, Japan, the Republic of Korea, Malaysia, Pakistan, the Philippines, Singapore, Sri Lanka, Thailand and Viet Nam are participating in the project and providing the financial and human resources necessary for its implementation. The objective of the project is to strengthen radiation protection capabilities in the RCA region with emphasis on the establishment and development of the infrastructure, in particular, manpower development in dosimetry, dose and risk assessment, protection practices, emergency countermeasures, regulatory provisions, and educational and training systems. The activities include practical training, the acquisition of fundamental knowledge and techniques; workshop and study tours at an advanced level; a co-ordinated research programme to obtain data essential for radiation protection measures in the region; assignment of experts to address specific problems; provision of long term fellowships to supplement short term training; provision of instruments and equipment; participation in the radiation protection advisory team (RAPAT) programme of the IAEA; and periodic evaluation of the project. These activities are applied in a concerted way to industrial applications, including nuclear energy and medical and biological applications. In the field of industrial applications, two training courses and two workshops including study tours were implemented in 1988 and 1989, and one training course and two workshops are envisaged for 1990. In the medical and biological field, efforts have been concentrated on the co-ordinated research programme which aims at compiling essential data of the region for setting Reference Asian Man. 1 tab

[en] Transmission electron microscopy was used to directly observe the distribution of dislocations in the plastic zone of propagating cracks during in-situ tensile deformation of various metals including stainless steel, nickel, molybdenum, and niobium. The results show a number of new findings regarding dislocation behavior in the plastic zone and its relationship to crack propagation. The observations, generally in agreement with the fracture model proposed by Bilby et al., are the first experimental confirmation of the theory. In-situ transmission electron microscopy is expected to contribute greatly to understanding fracture phenomena

[en] Traditional societal and cultural background of Japanese in general indicates the intrinsic difficulty in involving the public as stakeholders in the process of any type of decision making in policy matters. It is characterized by the long-taught virtue of harmonization and obedience to others. In addition, characteristic system of Japanese traditional industrial society, such as lifetime employment, seniority-based wage system, and enterprise-based labour union, encourages the loyalty to the employer/company, but not to the public. The public or ordinary citizens would seldom come out as stakeholders and express their true feelings or real opinions, even though younger generation is notably getting out from such a trend. On the other hand, it is a common practice in Japanese society for any business or administrative transactions to try to obtain 'consensus' among relevant parties concerned (stakeholders) by negotiations behind the curtain prior to the formal discussion. In this sense, 'stakeholders involvement' is accepted and practised as a matter of course, but mostly for actions between parties of equivalently influential status levels or between 'directly relevant' parties such as those between the different government agencies, between regulators and industries. The concept of 'Involving the public in decision making as stakeholders' is not yet fully understood nor accepted in Japan both by regulators and by the public so far as the issue of radiation protection is concerned. These situations are explained with some examples. (author)