High Energy Transport Code (HETC) based on the intranuclear-cascade-evaporation model is modified for calculating the proton-induced fragmentation cross sections. The systematics of the fragmentation reaction are empirically formulated using the excitation energy after the cascade collision. The systematics are incorporated into the HETC as a subroutine set. The free-space nucleon-nucleon collision cross sections in the HETC were replaced by the in-medium ones. The fragmentation cross sections by the modified HETC (HETC-FRG) are compared with the results by other codes based on the intranuclear-cascade-evaporation model. It is shown that the HETC-FRG reproduces experimental data particularly on emission of fragments such as ⁷Be typically within an accuracy of a factor of 2.

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This paper addresses how to utilize artificial neural networks (ANNs) for detecting anomalies of nuclear power plants in operation. The basic principle of this methodology is to detect the anomaly with deviation between process signals measured from the actual plant and the corresponding output signals from the plant model, which is developed using three-layered auto-associative ANN; the auto-associativity has the advantage of detecting unknown plant conditions. A new learning technique adopted here compensates for the drawback of the conventional backpropagation algorithm, and is presented to make plant dynamic models on the ANN. The test results showed that this plant monitoring system is successful in detecting the symptoms of small anomalies in real-time over the wide power range including start-up, shut-down and steady state operations.

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Fluid turbulence is affected by the presence of transported particles in a variety of engineering problems. In particulate flow large particles increase the turbulence intensity while small particles damp it. Numerical simulation of turbulence due to vortex shedding by large particles is made satisfactorily by adding corrective terms in the k-ε model equations. Damping of turbulence due to the shear action of small particles which are entrained by the oscillating motion of the fluid is however more difficult to simulate. This article applies the method proposed by Al Taweel and Landau for turbulence attenuation due to small particles which consists of evaluating a damping function depending on the spectral distribution of turbulence. The method, originally applied in the dissipation range only, is extrapolated to the full spectrum of turbulence and the resulting numerical algorithm is linked to the general purpose computer program COMMIX-M which describes three dimensional multi-phase fluid-dynamic problems. An analytical treatment is presented, which generalizes the Al Taweel-Landau method to the inertial subrange of the spectral domain. Numerical calculations of particulate flow in upward pipe flow, with particles transported by air, are discussed. Comparison with experimental results enables to infer about future work necessary to cope with present limitations of the method proposed.

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The effects of the rate of intentional secondary-side depressurization and of the break area on the core liquid level behavior during a PWR small-break LOCA with total failure of the high pressure injection (HPI) systems were studied using experimental data from the Large Scale Test Facility (LSTF) and using analysis results obtained with the REFLA/TRAC code. The LSTF is a 1/48 volumetrically scaled full-height integral model of a Westinghouse-type PWR. The code reproduced the thermal-hydraulic responses observed in the experiment for important parameters such as the primary and secondary-side pressures and core liquid level. The sensitivity of the core minimum liquid level to the depressurization rate and break area was studied by using the code assessed above. It was found that the core liquid level took a local minimum value for a given break area as a function of secondary-side depressurization rate. The core temperature was kept below about 1, 000K when the secondary depressurization rate was greater than -200K/h in the saturation temperature for break areas smaller than 2.5%.

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With the view to avoiding the difficulties encountered in estimating thermodynamic activities of the multiple chemical species in two-phase liquid system, a set of forward, reverse, net and total transport potentials are defined to represent the chemical state of a transferring solute during transient using bulk concentrations. The net transport potential corresponds to that in the conventional two-film model of diffusion-controlled processes. The overall driving forces of mass transport are redefined as the derivatives of the relevant transport potentials differentiated with respect to a state variable newly defined in terms ofthe bulk concentrations of the solute contained in both phases. Net and total quantities, i.e. transport potentials, overall driving forces and the molar fluxes are obtained as linear combinations of those for forward and reverse directions. The topical features presented by these quantities and their mutual relations are discussed in detail.
The experimental new overall transport coefficient for U(VI) varied in accord with the changes in the theoretical net transport potential and overall driving force.
The present method permits describing the extractive mass transport consistently both to forward and reverse directions of transport.

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For trivalent actinide and lanthanide separation, the solvent extraction system which employs neutral bifunctional extractant n-octyl(phenyl)-N, N-diisobutylcarbamoylmethylphosphine oxide (CMPO) and aminopolyacetic acid was investigated. The system is based on CMPO-tri-n-butylphosphate (TBP) mixed solvent and diethylenetriaminepentaacetic acid (DTPA)-sodium nitrate solution. The separation is achieved by complexing trivalent actinide preferentially with DTPA in aqueous phase and extracting lanthanide into organicphase. Mutual separation between light lanthanide, Am and Cm was mainly governed by complex formation with DTPA. The acidity is most affecting parameter for partitioning and its increase results in decrease of distribution ratio. For selective stripping of trivalent actinide from 0.2M CMPO-1.0M TBP in n-dodecane at room temperature, 0.05M DTPA and 2-4M sodium nitrate solution (pH 2) is useful. From the observed distribution behavior, a basic flow sheet which is composed of four steps was proposed. In batchwise experiments with radioactive nuclides, separation factor of larger than 13 and 27 for Ce/Am and Cm/Eu, respectively, were obtained and the applicability of the system was indicated.

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In pyrochemical reprocessing of spent metallic nuclear fuels in a molten salt bath, it is important to recover Cs, significant fission products, with electrochemically negative potentials. In order to develop an electrowinning method, the electrochemical behavior of Cs⁺ on a solid graphite electrode in the molten FLINAK system (LiF: 49.6mol%, NaF: 14.7mol%, KF: 36.7mol%) was examined by the cyclic voltammetry and the chronopotentiometry. The charge transfer number and the diffusion coefficient for Cs⁺ were determined by cyclic voltammograms with two kinds of conventional, semi-integral and semi-differential methods and by chronopotentiograms. It was revealed that an irreversible anodic reaction Cs→Cs⁺+e^- and cathodic reaction Cs⁺+e^-→Cs on the solid graphite electrode take place in the molten FLINAK system at 773K. Additionally, the cathodic electrochemical behavior of Cs⁺ on the liquid Pb electrode in the FLINAK melt was investigated by cyclic voltammetry and chronopotentiometry. It was revealed that an irreversible cathodic reaction Cs⁺+e^-→Cs on the liquid Pb electrode takes place in the molten FLINAK system at 773K. In order to examine possibility of recovery of Cs⁺, we investigate the selectivity on liquid metallic cathodes. We found that Cs are concentrated in the liquid Pb cathode and we can selectively recover Cs on liquid Pb cathode in the molten FLINAK system.

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Pakistan Research Reactor-1 (PARR-1) has been converted to low enriched uranium (LEU) fuel and upgraded to a maximum power level of 9MW. During conversion and upgradation most of the reactor systems were modified and several additional facilities were provided. Major changes were carried out in the cooling system. These include installation of new primary pumps, set of heat exchanger assemblies, a cooling tower and piping system. Vibration tests on these systems were performed to check the integrity and detect any abnormality in normal operation. Results of the tests performed on the primary pumps and core support structure comply with the requirements for pre-operational and initial startup vibration testing of nuclear power plant (NPP) system. Attempt is now being made to analyze vibrations of primary piping.
The Primary Water Inlet Pipeline (PW-IPL) is of stainless steel conveying demineralized water from holdup tank to the reactor pool. The section of the pipeline from heat exchangers to the valve pit is hanger supported, and the rest from valve pit to the reactor pool is embedded. Vibration of the PW-IPL may be categorized into steady state and transient. The reactor pumps mainly contribute the steady state vibrations, while transient vibrations arise due to instant closure of check valves (water hammer). The ASME Boiler and Pressure Vessel code provides data only about the limits of acceptable vibrations and stresses related to the primary static stress due to steady state vibrations. However, due to complexity and diversity in the pipe structure, stresses related to the transient vibrations are neglected in the code.In this paper steady state and transient vibration behavior of PW-IPL of PARR-1 has been analyzed. In the analysis vibration data was used for comparison with the allowable limits, estimations of pressure wave velocity, deflection, natural frequency, tensile and shear load on hanger support, and to obtain the ratio of maximum combine stress to the allowable.

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A method based on laser light scattering is presented for the observation of the condensation of working molecules in a steady-state-flow supersonic Laval nozzle operating in a closed loop. The distribution of scattered light from droplets formed by condensation along the flow direction is measured from photographs to determine the point of condensation onset. The temperature and density at the onset point are obtained from the values of static pressure based on the equations of isentropic flow.

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