Radiation Damage Theory: Past, Present and Future
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Radiation Damage Theory: Past, Present and Future Alexander V. Barashev1 and Stanislav I. Golubov2,3 1 Department of Engineering, University of Liverpool, Brownlow Hill, Liverpool, L69 3GH, UK. 2 Materials Science and Technology Division, ORNL, Oak Ridge, TN 37831- 6138, USA. 3 Department of Materials Science and Engineering, University of Tennessee, East Stadium Hall, Knoxville, TN 37996-0750, USA.
ABSTRACT Efforts of many scientists for more than a half of a century have resulted in substantial understanding of the response of various materials to irradiation. The theory has contributed significantly to this process but has not acquired a status allowing it to play a decisive role in creating radiation-resistant materials. Moreover, some theoretical predictions are in contradiction with observations, which indicates that something important has escaped attention. In the present paper, the current theoretical framework and experimental data are analyzed to elucidate the reasons for such a situation. A way of developing a predictive theory is proposed.
INTRODUCTION The development of the Radiation Damage Theory (RDT) can be subdivided into two periods according to defects, which were considered to be the mobile primary damage produced by irradiation. The first period, when the Frenkel pairs were believed to be the only species executing long-range diffusion, began in 1959, the year of publication by Greenwood, Foreman and Rimmer [1], where the void swelling was predicted. The beginning of the new period can be ascribed to around 1992, when the Production Bias Model (PBM) (e.g. [2-5]) was formulated, where the thermally-activated motion of the self-interstitial atom (SIA) clusters, which are produced directly in cascades of atomic displacement, was first introduced into the theory. Both periods boast a number of daring publications broadening our understanding of physical processes. From a critical point of view, however, the existing experimental information was not understood to a level sufficient to provide the theory with a leading role in creating radiationresistant materials. This lead to such an unbalanced situation of the present time, when the emphasis of theoretical works has shifted to modelling of processes on short time scales and the link between small and large scales, and hence comprehensive understanding of the radiation damage phenomena, has been lost. Below we present a brief overview of the history of the RDT and show that there were two general reasons that had lead to such a situation. First, no attempts have been made to construct a global picture, while different observations were considered separately from each other. Second, and as a natural consequence of the first, many observations contradicting the models developed were ignored. The analysis would allow us to identify the most critical missing parts of the RDT and outline the way of developing a predictive theory. We apologise for a very selective referencing here due to a limited space provided and refer the readers to ou
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