This is continued from report(IV) to treat the extreme cases, in which recoil and knockout phenomena of fission products from fuel pellet, and surface contamination due to ejected UO₂ may cause abnormal contamination of primary coolant accompanied with enlargement of crack on cladding of fuel.
For these cases, transient behaviors of iodine concentrations 131I, 133I and 135I in primary coolant are analyzed, and variations of relations between ratios of 13I/133I and 135I/133I are explained.
These most unfavorable defects of fuel cladding should be caught by reactor operator so as to take a suitable and prompt action. The above analysis offers much information to judge phenomena occurring in the reactors.

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This report describes the dynamic analysis simulator, the condensate demineralizer operation, and the components of a monitoring system of the radioactive waste treatment system (R/W) for BWR power plant. The simulation and the monitoring system have the following features:
(1) The simulator can predict the few days future operating characteristics of R/W.
(2) The operating conditions of the condensate demineralizer are displayed on the cathode ray tube (CRT) as guidance. By following this guidance, the condensate demineralizer can be regenerated at regular and appropriate intervals.
(3) The plant conditions from the generation of liquid waste to final treatment process are displayed in the following steps: R/W total system ⇒ Particulars of each liquid waste treatment system ⇒ Each component of the treatment system.

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An application of the penalty finite element method to incompressible viscous flows is studied in this paper. We applied this method to a typical flow problem of the transient natural convection. Since, in this method, it is not necessary to deal with the incompressibility constraint and pressure can be eliminated from the equation systems, the computational efforts are considerably reduced. This method is proved to be effective in case of the natural convection analysis. We also analyze the turbulent flows with the simple method using the Prandtl's mixing length theory. The numerical results show good agreements with experimental as well as theoretical values.

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In order to obtain the optimum conditions for micro-hardness measurements of sintered UO₂, two kinds of hardness tests (Vickers and Knoop) were examined with non-irradiated UO₂ of 2.5 and 5μm in grain size. The hardness values were obtained as a function of the applied load in the load range of 25-1, 000g.
In the Vickers test, cracks were generated around the periphery of an indentation even at lower load of 50g, which means the Vickers hardness is not suitable for UO₂ specimens.
In the Knoop test, three stages of load dependence were observed for sintered pellet as well as for a single crystal by Bates. Load dependence of Knoop hardness and crack formation were discussed. In the range of applied load around 70-100g there were plateau region where hardness values were nearly unchanged and did not contain any cracks in the indentation. The plateau region represents a hardness of a specimen. From a comparison between the hardness values of 2.5μm and those of 5μm UO₂, it was approved that the degree of sintering controls the hardness in the plateau region.

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