[en] Load relaxation tests, creep and abrupt stress change tests, and tension tests were performed on unirradiated, annealed Zircaloy-2 and stress-relieved Zircaloy-4 at temperatures ranging from 473 to 648 K. Experimental results were analyzed by using a unified phenomenological consitutive model originally proposed by Hart. All the parameters included in the model were determined. Using the parameters, the model was employed to integrate numerically along the loading conditions under which experiments were performed. The model showed reasonable accuracy and was demonstrated to be applicable for describing nonelastic deformation of Zircaloy cladding

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[en] The authors' developed technique of 2.0-T three-dimensional MR myelography (3D-MRM) by using a fast, heavily T2-weighted imaging technique (subtraction TurboFLASH) was performed in 15 patients with lumbar intervertebral disk disorders. The purpose of this exhibit is to evaluate the clinical ability of 3D-MRM for spinal nerve root abnormalities. This paper presents 3D-MEM reconstructed from the subtraction TurboFLASH technique (TR was 6,000-8,000 msec, TE was 80-120 msec) in three normal volunteers and 15 patients with lumbar spinal nerve root disorders. Their conventional myelograms, CT images, conventional MR images, and surgical macroscopic findings were compared with 3D-MRM images. Emphasis is placed on illustrating the clinical advances and limitations of this noninvasive technique in evaluating the correct surgical sites of nerve root disorders

[en] The cylindrical core test facility (CCTF) is one of the facilities of the large scale reflood test program which was initiated in April, 1976. The first series of the CCTF test (CCTF CORE I Test) was completed in April, 1981 and the second series (CCTF Core II Test) has been conducted since April, 1982. In the test, the following has been intended to be examined: (1) The conservativeness of the assumption of the safety analysis with the evaluation model (EM) code. (2) The refill and reflood phenomena for analytical modeling of thermo-hydrodynamics in the core and the system. (3) The validity of the models in the EM code and the application to the best estimate code development. In this paper, presented are the quantative evaluation of the REFLA code and the discussion of some CCTF Core II Test results. The REFLA code consists of REFLA-1D core code developed with the results of small scale tests and a simple system model developed with the results of the CCTF Core I Test. The CCTF Core II Test was perfored for developing more realistic model for the alternative ECCS as well as for the cold leg injection type ECCS

[en] A major primary source of radium isotopes in sea water is leaching from rocks and sediments on the sea floor. In the marine environment, the distributions and behaviour of radium are affected not only by vertical mixing and the horizontal circulation of sea water (i.e. a physical process), but also by adsorption to and desorption from particulate matter in sea water (i.e. a chemical process). The radioactive decay of the radium isotope also influences the distribution of concentrations in those cases where the half-life of a radium isotope is shorter than that of particular ocean phenomena. The distribution of radium in sea water is thus not uniform and concentrations vary in each water mass as a result of the above mentioned properties of this element. Most studies so far reported on radium in sea water have concentrated on the longest lived isotope, ²²⁶Ra, but the distribution of ²²⁸Ra, which has a shorter half-life (5.76 a) than that of ²²⁶Ra has been recently studied in detail. In this chapter, the distributions and behaviour of ²²⁶Ra and ²²⁸Ra are summarized. 67 refs, 11 figs, 1 tab

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