Plant life management activities in Japan

More than 25 years have passed since the first commercial light water reactor (LWR) started operation in Japan. Accordingly, it has become important to assure the future safety and reliability of the older plants, which have a long period of operating experience. We have been investigating the possibility of assuring the integrity for long-term operation in view of technical considerations and have confirmed the feasibility of assuring sufficient safety and reliability through proper maintenance activities, in spite of long-term operation. We intend to complete the investigation and report the results within the coming 1–2 years, in order to incorporate the results into future inspection, repair and replacement plans for the actual plant. The aim being further enhancement of the safety of nuclear power plants.     

cis-Vaccenic acid in pulp lipids of commonly available fruits

Fatty acids of commonly available fruit pulps have been analyzed by capillary gas chromatography of their methyl esters and by gas chromatography-mass spectrometry as their dimethyl disulfide adducts. The gas chromatographic and mass spectrometric data proved that these fruits always containedcis-vaccenic (cis-11-octadecenoic) acid as a component fatty acid of their pulp lipids. The concentration ofcis-vaccenic acid in total octadecenoic acids ranged from 1.9% to 95.1% in the fruit pulps examined. The highest concentration of this acid was detected in pulp lipids of Japanese persimmon (Diospyros kaki). In fruit pulp lipids,cis-vaccenic acid was a common octadecenoic acid as well as oleic acid.     

Comparative study of turbines for wave energy conversion

IlltnductionSeveral of the wave energy devices cuntiy stUdiedin the United kingdom, Japan, POhogal, India and othercountries make use of the principle of the oscillatingwater-air coltUnn for convening wave energy to lowPneqmatic energy Which in tUrn can be converted intomechAncal energy. In this case, the developmellt of a bidirechonal air theme has come lip as an importantProblem. So far, a number of self-rechfying air onnesWith different configurations have been ProPOsed, and a; Wells…     

Ageing of SRC liquids

The ageing characteristics of a 30/70 (wt%) blend of SRC-I and SRC-II and of a SRC-II middle distillate (boiling-point range 450–565K), have been studied. Viscometric, ultimate analysis, solvent separation, gel permeation chromatography, and 600-MHz n.m.r. measurements have been used to monitor the ageing properties of the SRC liquids under various conditions. The viscosity of the blend increases significantly in ten days with oxygen bubbling through at 335K. However, copper, in addition to oxygen, is necessary to change the viscosity of the middle distillate significantly. For the blend, there is a rectilinear increase in log viscosity with increasing wt% of toluene-insolubles formed during oxygenageing. There is also a rectilinear decrease in log viscosity with decreasing content of toluene-insolubles resulting from hydroprocessing of the blend with Ni&z.sbnd;Mo catalyst. These observations indicate that under conditions of oxidative degradation the formation and content of larger molecular-size tolueneinsolubles are mainly responsible for the increased viscosity of the blend. The middle distillate does not contain toluene-insolubles, and oxygen-ageing occurs only in the presence of copper. Oxidative coupling of phenols is proposed as an ageing mechanism for both the blend and the middle distillate.     

A twin unidirectional impulse turbine for wave energy conversion

A twin unidirectional impulse turbine has been proposed in order to enhance the performance of wave energy plant.This turbine system uses two unidirectional impulse turbines and their flow direction is different from each other.However,the turbine characteristics have not been clarified to date.The performances of a unidirectional impulse turbine under steady flow conditions were investigated experimentally by using a wind tunnel with large piston/cylinder in this study.Then,efficiency of the twin impulse turbine have been estimated by a quasi-steady analysis using experimental results.     

A twin unidirectional impulse turbine topology for OWC based wave energy plants – Experimental validation and scaling

The twin unidirectional turbine topology was recently proposed with the promise of very significant improvements in the energy capture in Oscillating Water Column (OWC) based wave energy plants. Here, we present the initial results of the experimental validation of the twin unidirectional impulse turbine topology. A scale model of the concept was built and tested using simulated bidirectional flow. The model consists of two 165 mm impulse turbines each individually coupled to 375 W grid connected induction machines. An oscillatory flow test rig was used to simulate bidirectional flow to test the model. The results of the experiments validate the concept of the twin turbine configuration. The proposed topology utilizes no moving parts and achieves more than 50% efficiency over a broad range of flow coefficients. A comparison with other competing turbines (viz, a twin Wells’ turbine, a linked guide vane impulse turbine and a fixed guide vane impulse turbine) is done, based on actual measurements in the Indian wave energy plant. The results from the experiments are scaled to evaluate the design features of a 50 GWh wave energy plant.     

The rejection of polar organic solutes in aqueous solution by an interpolymer anionic composite reverse osmosis membrane

Reverse osmosis separation for many kinds of polar organic solutes (alcohols, phenols, monocarboxylic acids, amines, and ketones) was examined by an anionic charged composite membrane. The solute permeation was carried out in single-solute aqueous solution (200 mg/L) under applied pressure of 7.88 MPa at 25°C. The correlation between the solute rejection and polar parameters for these organic solutes have been investigated. For n-alkyl alcohols, monocarboxylic acids, and ketones, the solute rejection increases with molecular weight and/or molecular branching. For undissociable polar organic solutes such as alcohols and ketones, solute rejections are closely related with the Taft's number. For dissociable polar organic solutes, solute rejections depend greatly upon the dissociation constant and the degree of dissociation of solute. This membrane showed higher rejection (80%) for phenol in an undissociated state at a 98% rejection level of NaCl. Also, rejections of phenolic derivatives depend upon the pH value of the feed solution and the polar effect of substituted groups. For acetic acid and methylamine, the solute rejection increases proportionally to the degree of dissociation of solute. From these facts, the main factors in reverse-osmosis separation by an anionic composite membrane are discussed.     

A function to provide neutron spectrum produced from the 9Be + p reaction with protons of energy below 12 MeV

A function to give the total neutron production cross section, angular distribution, and energy spectrum via the ⁹Be + p reaction has been created by fitting experimental data to characterize compact neutron sources with thick Be targets bombarded by protons with energy below 12 MeV. To examine the suitability of the function, calculations of the angle-dependent neutron energy spectra produced in thick Be targets with 4- and 12-MeV protons using the function were compared with corresponding experiments and calculations using the nuclear data libraries of ENDF/B-VII.0 and JENDL4.0/HE. The function was in better agreement with the experiments than the calculations using the libraries except for at backward angles. The ¹¹⁵In(n,n’)^115mIn reaction rates calculated using GEANT4 with source neutrons given by both the function and ENDF/B-VII.0 were compared with that measured at the RIKEN Accelerator-Driven Compact Neutron Source to evaluate the neutron spectrum above 1 MeV. The function slightly overestimated the measurement by 14% and the calculation with ENDF/B-VII.0 underestimated by 35%. It was concluded that the function can be applied in compact neutron source designs.     

Observation of H/D isotope effects on polymer electrolyte membrane fuel cell operations

The hydrogen isotope effects upon operation of a polymer electrolyte membrane fuel cell have been observed. The deuterium concentration in the exhaust hydrogen gas from the cell was found lower than that of the hydrogen gas fed to the cell, which indicated that the heavier isotope of hydrogen was preferentially oxidized at the anode. The overall hydrogen isotopic separation factor between the oxidized and non-oxidized hydrogen ranged from 3.46 to 3.99 and increased with decreasing flow rate of the feed gas or increasing rate of hydrogen utilization.