[in Japanese]

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[in Japanese]

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This paper reviews vibration phenomena of reactor internal structures in French prototype LMFBR "Super Phénix-1", being observed during its pre-service operation. French efforts to solve the phenomena are outlined, including countermeasures applied to the plant. Also, CRIEPI's study on this issue is briefly explained.

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As a course of research program of Light Water Reactor Pressure Vessel Surveillance Dosim-etry Improvement Program (LWR-PV-SDIP), the intercomparison study has been done on the surveillance data processing procedure using the same input data, that is called as the PSF Blind Test. This technical report shows the Japanese replies to this Blind Test, that have been made by the special working group members of the AESJ research committee on Data Evaluation of Neutron Irradiation. Main contents of this report are description of the PSF experiment as the data-origin of the PSF Blind Test, description of the open data for this Blind Test that cover physics-dosimetry data and metallurgy data of irradiated specimen (tensile-data, Charpy-V test results and fracture toughness test results) with our data analysis procedure adopted. In addition, preliminary comparison was made between the measured and predicted (answered) values from several partici pants including Japan. From the results obtained, it can be pointed out that the accuracies for the evaluation of neutron irradiation embrittlement were known under the current procedure and some of the items were extracted for the accuracy improvement of the reactor pressure vessel surveil lance procedure in future.

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The uranium enrichment by redox chromatography using an ion-exchanger was studied. As a result, the isotope separation factor in this process is smaller than that determined from the equilibrium constant of solution. There exist three kinds of equilibrium reactions in this process: isotope equilibrium by electron exchange, that by adsorption/desorption of complexes(U⁴⁺, UO²²⁺) to resin, and phase equilibrium of U⁴⁺ and UO²²⁺. We made it clear that small isotope separation factor mainly dependes upon the adsorption characteristics of complexes (U⁴⁺, UO²²⁺) to the ion-exchanger among those reactions. On the other hand, computer simulation of chromatographic development was carried out to analyze the details of experimental results theoretically. The separation column was hypothetically divided into equilibrium stages, and the equilibrium condition of each stage was simulated. A comparison between the calculated and observed separation factors was made. By this theoretical treatment, it was clarified that the separation factor decreases drastically in the region where development length is short.

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Performance of high efficiency particulate air (HEPA) filters at temperatures from ambient to 240°C was measured to prove that HEPA filters kept up their regulated decontamination factor (DF) at elevated temperatures. The DF for NaC1 aerosol was measured by using a laser particle spectrometer. Pressure drop of HEPA filters at elevated temperatures was also measured. The DF increased at elevated temperatures. The DF at 200°C was an order of magnitude higher than that at ambient. The change of DF at elevated temperatures of various HEPA filters was effectively evaluated by using the ratio of single fiber collection efficiencies at ambient to those at elevated temperatures. Pressure drop of HEPA filters also increased at elevated temperatures. The pressure drop at 200°C was 1.3 times larger than that at ambient. The change of DF and pressure drop at elevated temperatures was explained by applying Kirsh's theory to elevated temperatures.

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