Relation between measurable and principal characteristics of   radiation-induced shape-change of graphite
  On the basis of studies of radiation-induced shape-change of reactor graphite GR-280, through the series of measurements of samples with different orientation of cutting with respect to the direction of extrusion, a conclusion is made about the existence of polycrystal substructural elements - domains. Domains, like graphite as a whole, possess the property of transverse isotropy, but have different amplitudes of shape-change and random orientations of the axes of axial symmetry. The model of graphite, constructed on the basis of the concept of domains allowed to explain from a unified point of view most of existing experimental data. It is shown that the presence of the disoriented domain structure leads to the development of radiation-induced stresses and to the dependence of the shape-change on the size of graphite samples. We derive the relation between the shape-change of finite size samples and the actual shape-change of macro-graphite. 
M.V. Arjakov, A.V. Subbotin, S.V. Panyukov, O.V. Ivanov, A.S.   Pokrovskii, D.V. Kharkov
nucl-ex nucl-th physics.atm-clus physics.atom-ph