Seismic proof test of a reinforced concrete containment vessel (RCCV): Part 1: Test model and pressure test

In Japan, the Nuclear Power Engineering Corporation (NUPEC), sponsored by the Ministry of Economy, Trade and Industry (METI), has been conducting a series of seismic reliability proving tests using full-scale or close to full-scale models to simulate actual important equipment that is critical for seismic safety of nuclear power plants. The tests are intended to validate the seismic design and reliability with a sufficient margin even under destructive earthquakes. A series of tests was carried out on a reinforced concrete containment vessel (RCCV) for advanced boiling water reactor (ABWR) from 1992 to 1999. A large-scale high-performance shaking table at Tadotsu Engineering Laboratory, the largest in the world, was used for this test. Part 1 reports the test model and the results of pressure and leak tests. Part 2 describes test procedures, input waves and the results of verification tests such as changes of stiffness, characteristic frequency and damping ratio, the failure of the model and the load deflection. Part 3 shows the seismic safety margin that was evaluated from the energy input during the failure test to a design basis earthquake. Part 4 reports simulation analysis results by a stick model with lumped masses.     

Structural,Thermal and Magnetic Properties of Thin Metal Films and Adsorbate–Substrate Systems Studied by XAFS and XMCD

Thin metal films often exhibit interesting properties that are essentially different from the bulk ones. XAFS (X-ray absorption fine structure) and XMCD (X-ray magnetic circular dichroism) techniques are quite suitable to investigate structural, thermal and magnetic properties of thin metal films. In this proceeding, we will present following two topics concerning structural and magnetic properties of adsorbates on thin metal films. The first one is the adsorption geometry of SO₂ on a 1-monolayer (ML) Pd thin film grown on a Ni(111) single crystal. It was found by S K-edge XAFS that SO₂ is lying flat on 1-ML Pd/Ni(111). This result is not similar to the bulk Pd surface but to the bulk Ni one. This finding indicates significant modification of the electronic structure of the 1-ML Pd film compared to the bulk one. The second topic is the magnetic moment induced on CO adsorbed on Ni epitaxial films grown on Cu(001). The O K-edge XMCD results revealed that in the perpendicularly magnetized 10-ML Ni film the orbital moment of CO is parallel to the substrate Ni magnetization, while it is antiparallel in the in-planar magnetized 6-ML and thick (>100 ML) films. The origin of the induced orbital moment at CO is discussed.     

Marangoni flow at the gas/melt interface of steel

Direct observation with a scanning laser microscope was made to determine the direction and velocity of surface flow of steel melt in the vicinity of the solid/melt (S/M) interface. During solidification, a fast solutal Marangoni flow moving away from the S/M interface was confirmed to exist on steel melts containing oxygen and sulfur of 10 to 105 ppm. Even in such a low range of oxygen and sulfur content, the solutal Marangoni flow can be very fast, carrying inclusion particles up to the free surface along the S/M interface. During heating and holding, however, a thermal Marangoni flow combined with convective flow generated a reverse flow directed toward the S/M interface. These features have important relevance to inclusion entrainment and solute segregation during the solidification of steel. This article is based on a presentation given in the Mills Symposium entitled “Metals, Slags, Glasses: High Temperature Properties & Phenomena,” which took place at The Institute of Materials in London, England, on August 22–23, 2002.     

Hydrogen production by combining two types of photosynthetic bacteria with different characteristics

The double-layer photobioreactor using two types of photosynthetic bacteria, Rhodobacter sphaeroides RV and its reduced-pigment mutant, MTP4, was developed for efficient hydrogen production. The two types of bacteria had different characteristics on light energy, hydrogen production rate and conversion efficiency. MTP4 produced hydrogen more efficiently under high light conditions and RV did so under low light conditions. Illuminated light toward the surface of a photobioreactor quasi-exponentially declines as it penetrates into the reactor. When two types of bacteria were placed using the developed reactor according to this light distribution, the hydrogen production rate reached 3.64 l/m²/h at a light intensity of 500 W/m² in 24 h and the conversion efficiency of light energy to hydrogen was 2.18%. These values were 33% higher than those of only using RV. The low light in the deep part of the reactor was utilized efficiently, resulting in a higher hydrogen production rate.     

Efficient hydrogen production using a multi-layered photobioreactor and a photosynthetic bacterium mutant with reduced pigment

A multi-layered photobioreactor (MLPR), where the light paths were formed by the localization of bacterial cells, was constructed for efficient hydrogen production. The performance was investigated under several conditions in order to clarify the effect of this reactor on hydrogen production. An analysis of the hydrogen production profile showed that the MPLR utilizes both the light that directly illuminates its surface and the light induced and diffused from its light paths for hydrogen production. It was also found that the hydrogen productivity in the MLPR was more than twice that in a plate-type reactor. When a photosynthetic bacterium mutant with reduced pigment, MTP4, was used, the maximum hydrogen production rate reached 2.0 l/m² h, which was 38% higher than that of a conventional plate-type reactor. The synergistic effect of the improvement in the reactor and the modification of the bacteria was brought about by the combination of the MLPR and MTP4, and resulted in an improvement in the hydrogen production.     

Development of a hybrid ECT sensor for JSFR SG double-wall tubes

A new design has been adopted for the steam generator (SG) tubes of the Japan Sodium-cooled Fast Reactor (JSFR) using double-wall tubes. This paper estimates and assesses the effectiveness of detecting defects in SG double-wall tubes of the JSFR by using combined high-frequency eddy current testing (ECT) and low-frequency remote field eddy current sensors. We confirm that the proposed hybrid ECT sensor is highly sensitive to small defects, fatigue cracks, and other defects even when located under support plates of tubes. The parameters of the hybrid ECT sensor are designed and optimized to detect small defects using accurate numerical simulations based on the finite element method, using an in-house developed code. The sensitivity and high performance of the hybrid ECT sensor was validated with experimental measurements.     

Thermal conductivity of near-stoichiometric (U, Ce)C and (U, Pu, Ce)C solid solutions

The thermal conductivities of near-stoichiometric (U, Ce)C and (U, Pu, Ce)C solid solutions containing CeC up to 10 mol% were determined in the temperature range from 740 to 1600 K by the laser flash method. The thermal conductivity decreased with the cerium content in the solid solutions. The electrical resistivities were also measured for the purpose of analyzing the heat conduction mechanism. It was found that the decrease of electronic heat conduction caused by the addition of cerium resulted in decreasing the thermal conductivities of (U, Ce)C and (U, Pu, Ce)C compared with UC and (U, Pu)C.     

Integrated circuits for television receivers

Integrated circuits are being investigated for use in as many television circuits as feasible. In Japan, considerable work has been done by different groups within the TV industry to develop ICs that will permit cost reduction, increased reliability, and simplification of assembly-line operations. This article is a report on results of the concentrated efforts made by five major television set manufacturers to develop and produce black-and-white and color receivers, in collaboration with four universities, two institutes, and seven components manufacturers.     

Morphology of composite film prepared by polymerizing styrene in poly(vinyl chloride) film

Styrene and the styrene-additive mixtures (kerosene, dioxane, ethylene dichloride, or dioctylphthalate) were soaked into a poly(vinylchloride) film and then styrene was polymerized. Subsequently, poly(styrene) was extracted with CCl₄ and the microporous membrane was obtained, of which the morphology was studied. It is elucidated that the additives affect the morphology of the resultant composite films.