[en] Recently, the use of short-lived radionuclides in medical, biological, and pharmaceutical research and clinical applications has increased. Activity measurement of radionuclides that are not commonly used are often required. Even though calibration setting numbers (factors) are given for ∼200 radionuclides for some dose calibrators, one may not find the calibration setting number for the radionuclide of interest. The calibration setting number can be calculated if one has data on gamma-ray (and beta-ray and electron capture when applicable) intensity, x-ray fluorescence yield associated with decay of nuclides of interest, and the detector sensitivity of the calibrator to radiations. When one tries to measure the production yield of radionuclides that are not commonly used, the first question that may have to be solved is the accuracy of the activity measurement. The accuracy of an activity measurement can be affected by the following: 1) calibration accuracies of calibrator and spectrometer, 2) accuracy of calibration setting numbers, 3) sample configuration and size, 4) presence of radioactive impurities, 4) presence of radioactive impurities, 5) presence of radioactive daughters, 6) accuracy of time measurement (for short-lived nuclides), 7) accuracy of decay data, 8) effects from background radiations, especially for low activity, 9) instrument adjustment, such as zero, and 10) other experimental factors, such as fractionation, saturation of instruments, decay correction, etc

[en] The final-state interaction in multichannel decay processes is systematically studied with application to B decay in mind. Since the final-state interaction is intrinsically interwoven with the decay interaction in this case, no simple phase theorem like 'Watson's theorem' holds for experimentally observed final states. We first examine in detail the two-channel problem as a toy-model to clarify the issues and to remedy common mistakes made in earlier literature. Realistic multichannel problems are too challenging for quantitative analysis. To cope with mathematical complexity, we introduce a method of approximation that is applicable to the case where one prominent inelastic channel dominates over all others. We illustrate this approximation method in the amplitude of the decay B to pi K fed by the intermediate states of a charmed meson pair. Even with our approximation we need more accurate information of strong interactions than we have now. Nonetheless we are able to obtain some insight in the issue and draw useful conclusions on general features on the strong phases

[en] The present invention concerns an emergency core cooling system, and it efficiently cools a dryer, a shroud and a damaged reactor core in a pressure vessel. It suppresses the amount of inner structural materials and a damaged reactor core flowing from the pressure vessel to a container. Then, integrity of the reactor is maintained. Namely, coolant supply channels are connected from a coolant pool at the outside of the container to the upper head of the pressure vessel in the container by way of a pump. With such a constitution, if an imaginal accident should occur such that an existent emergency reactor core cooling system does not work, coolants can be supplied from the pool at the out side of the reactor to the upper head of the pressure vessel. Supplied coolants flow from the upper portion to the lower portion in the pressure vessel to provide cooling performance for materials in the pressure vessel. (I.S.)

[en] Two-channel final-state interaction problem is exactly solved and applied to the B meson decay. The final-state interaction in multichannel decay processes is systematically studied in the hadronic picture with application to B decay in mind. Since the final-state interaction is intrinsically interwoven with the decay interaction in this case, no simple phase theorem like 'Watson's theorem' holds for experimentally observed final states. We first solve exactly the two-channel problem as a toy model in order to clarify the issues. The constraints of the two-channel approximation turns out to be too stringent for most B decay modes, but realistic multichannel problems are too complex for useful quantitative analysis at present. To alleviate the stringent constraints of the two-body problem and to cope with complexity beyond it, we introduce a method of approximation that is applicable to the case where one prominent inelastic channel dominates over all others. We illustrate this approximation method with the amplitude of the decay B → Kπ fed by the intermediate states of a charmed-meson pair. Even with our approximation we need more accurate information of strong interactions than we have now. Nonetheless we are able to obtain some insight in the issue and draw useful conclusions on general features on the strong phases

[en] A water injection vessel equipped with feedwater pumps and connected to a coolant recycling system is disposed outside of a reactor container, and there is disposed a pipeline system having one end connected to reactor container pipelines of the coolant recycling system and the other end in communication with an open space just below a pressure vessel and having a control valve at the midway, and the feedwater pumps and a control valve are caused to operate to inject water only upon occurrence of such an accident that debris of the reactor core is discharged to the open space. Further, spray headers are used for injecting water to the open space below the pressure vessel, and the injection of water to the open space below the pressure vessel is automatically controlled by a sensor. Further, it is adapted such that injection of water to the open space below the pressure vessel can be controlled by a remote operation, and the water injection depends on the temperature of circumstance. Then, portions where radioactive materials are leaked can be reduced without immersing control rod drives under water upon occurrence of ordinary accidents. (N.H.)

[en] The tunnel conductance G(V) at various temperatures was measured for the planar junction fabricated on the cleaved face (0 0 1) of Bi₂Sr₂CaY_xCu_1.94Zn_0.06O_8+y (BSCYCZO). When a temperature T decreases, the pseudo-gap (PG) opens at 194 K for x=0 and at 238 K for x=0.03, and the superconducting gap (SG) opens at 83 K for x=0 and at 64 K for x=0.03. The SG peak was highly symmetric around zero bias both for x=0 and 0.03. While, the PG peak was highly symmetric around zero bias for x=0 across 194 K but was strongly suppressed in negative bias for x=0.03 below T_c=64 K. Furthermore, the PG was observed to coexist with the SG at a temperature between T_c and 4.2 K for x=0 and 0.03. This suggests that the PG is not the precursor for superconducting transition

[en] The recent results on solar neutrinos from Super-Kamiokande are presented. The data from 1117 effective days taken between 31st of May, 1996 and 24th of April, 2000 are used for the oscillation analysis. The absolute flux and day-time and night-time fluxes are presented as well as the spectrum measurement. The spectrum shape agrees with that expected from the convoluted effect of the ⁸B-neutrino spectrum, the recoil electron spectrum of neutrino electron scattering and the detector responses. There is a 3.4% difference between the day- and nighttime fluxes, but statistically not significant. There is no strong smoking gun evidence for oscillation yet, however the precise measurement of the spectrum shape and day/night fluxes have given a constraint on the oscillation parameters. Those results, if analyzed as neutrino oscillations, indicates at 95% confidence level that the large mixing angle solutions (MSW LMA and LOW) are preferable

[en] Purpose: To prevent the production of adhesive scales upon the concentration of the liquid waste and to prevent the corrosion of a gaps in the concentrating equipment by adding oxine to the liquid waste. Method: The liquid waste of an atomic plant is concentrated by adding approx. 3wt% of oxine (8-hydroxyquinoline). Calcium and magnesium in the liquid waste form a complex with the oxine, the complex is insoluble in water, but dose not form adhesive scales even if it is concentrated and reduced in volume, nor does it corrode the gap in the concentrating equipment and so enables safe operation for a long time. (Yoshihara, H.)

[en] The magnetic properties of a quasi-two-dimensional (2D) superconductor, Sn-metal graphite (MG), are studied using DC and AC magnetic susceptibility. Sn-MG has a unique layered structure where Sn metal layer is sandwiched between adjacent graphene sheets. This compound undergoes a superconducting transition at T_c=3.75 K at H=0. The H-T diagram of Sn-MG is similar to that of a quasi-2D superconductors. The phase boundaries of vortex liquid, vortex glass, and vortex lattice phase merge into a multicritical point located at T*=3.4 K and H*=40 Oe. There are two irreversibility lines denoted by H_gl (de Almeida-Thouless type) and H_gl^' (Gabay-Toulouse type), intersecting at T₀^'=2.5 K and H₀^'=160 Oe. The nature of slow dynamic and nonlinearity of the vortex glass phase is studied

[en] Recent results on solar neutrino measurements are discussed. The results from radio-chemical experiments are briefly summarized. The new data from 1117 effective days of Super-Kamiokande shows that the spectrum shape agrees with that expected from the convoluted effect of the ⁸B-neutrino spectrum, the recoil electron spectrum of neutrino electron scattering and the detector responses and that there is a 3.4% difference between the day- and night-time fluxes, but statistically not significant. There is no strong smoking gun evidence for oscillation yet, however those precise measurements of the spectrum shape and day/night fluxes have given a constraint on the oscillation parameters, indicating at 95% confidence level that the large mixing angles solutions (MSW LMA and LOW) are preferable