Showing papers by "Yu Maruyama published in 1996"

Scoping test and analysis on CsI aerosol behavior in a straight pipe in WIND project

Abstract: In WIND (Wide range piping INtegrity Demonstration) project at Japan Atomic Energy Research Institute (JAERI), a scoping test was performed to investigate aerosol behavior in reactor piping under severe accident conditions. In the experiment, CsI aerosol was injected into a stainless steel straight pipe of 2 m in length and 0.1 m in diameter. The experiment showed that aerosol deposition mass was larger at downstream than that at upstream and aerosol was mostly deposited as chemical form of CsI. VICTORIA code well reproduced these trends of experiment. However, the calculated thermochemical equilibrium at upstream did not well explain the observed difference in deposited mass between cesium and iodine. The code also overpredicted aerosol diameter which depends on aerosol agglomeration rate and on condensation or evaporation of species at aerosol surface. These models in VICTORIA were found to be further improved through the WIND experiment analyses.

Coupling analysis of thermohydraulics and aerosol behavior in WIND experiments

Abstract: In a severe accident of a light water reactor, fission products such as radioactive iodine or cesium will be released from fuel rods or fuel debris. Some of them will be transported to the reactor coolant system (RCS) as gas or aerosol forms and will be partly deposited on the inner surface of piping. The deposited fission products could be a source of thermal load to the piping and also become one of the dominant contributors to source term because of revaporization. Therefore, it is important for source-term evaluation to precisely predict the fission product aerosol behavior in the RCS. However, it is recognized that large uncertainties still remain in this phenomenon. The WIND (Wide range piping INtegrity Demonstration) project is being performed by the Japan Atomic Energy Research Institute (JAERI) under a contract between the Atomic Energy Bureau in Science and Technology Agency of Japan and JAERI to investigate the fission product aerosol behavior in reactor piping and the integrity of piping due to decay heat of deposited fission products under severe-accident conditions. A scoping test on cesium iodide aerosol behavior in piping was recently performed. In the test, argon was injected as a carrier gas into a stainlessmore » steel straight pipe 2 m long and 0.1 m diameter under simulated conditions at a pressurizer water reactor hot-leg inlet.« less

Study of premixing phase of steam explosion with JASMINE code in ALPHA program

Abstract: Premixing phase of steam explosion has been studied in ALPHA Program at Japan Atomic Energy Research Institute (JAERI). An analytical model to simulate the premixing phase, JASMINE (JAERI Simulator for Multiphase Interaction and Explosion), has been developed based on a multi-dimensional multi-phase thermal hydraulics code MISTRAL (by Fuji Research Institute Co.). The original code was extended to simulate the physics in the premixing phenomena. The first stage of the code validation was performed by analyzing two mixing experiments with solid particles and water: the isothermal experiment by Gilbertson et al. (1992) and the hot particle experiment by Angelini et al. (1993) (MAGICO). The code predicted reasonably well the experiments. Effectiveness of the TVD scheme employed in the code was also demonstrated.

Experimental study on aerosol deposition in horizontal straight piping

Abstract: In a severe light water reactor accident, aerosol deposition within a reactor coolant piping system could significantly influence the source term because of the reduction of released fission products and the piping structural integrity due to the decay heat emission from the deposited fission products. Aerosol deposition tests have been performed in the Wide Range Piping Integrity Demonstration (WIND) project at the Japan Atomic Energy Research Institute under a contract with the Atomic Energy Bureau in Science and Technology Agency of Japan. In addition to a scoping test, three tests have been conducted to clarify the deposition characteristics of cesium iodide (CsI) aerosols in horizontal straight piping.