Development and Research of New Media Jet Aeration Scheme in a Loop Bioreactor Producing Microbiological Products

Jet aeration loop reactors are widely used in the chemical industry due to their high mixing intensity, possibility of significant saturation of medium with gases, and simplicity of scaling the processes when passing from laboratory equipment to industrial designs. However, to ensure the necessary amount of air in standard jet aeration schemes with ejectors, high pressure of the medium (up to 6 bars) is required in the reactor loop. This paper presents a newly developed scheme of jet aeration, based on mixing the pressure flows of medium and air supplied to the ejector by individual blowers. Experiment results of the new water aeration scheme showed that, for the formation of suspended matter in the ejector with an air content of 2–20 l per 1 l of water, a pressure of 0.3 bar in the reactor loop at an air pressure of 1 bar is sufficient. This allows usage of low-pressure pump and compressor, which form the basis for the energy consumption reduction and creates prerequisites for lowering the shear loads on a crop. The medium aeration rate during experiments was 0.220–0.266 vvm. It was found that, for each mode of joint operation of pump and compressor, it is possible to maintain a constant aeration rate, which is not significantly affected by the flowrate regulation of medium in loop.

MATRIX EXPONENTIAL METHODS FOR PARALLEL COMPUTING OF ISOTOPIC DEPLETION AND SPECIES TRANSPORT FOR MOLTEN SALT REACTOR ANALYSIS

Matrix exponential methods have long been utilized for isotopic depletion in nuclear fuel calculations. In this paper we discuss the development of such methods in addition to species transport for liquid fueled molten salt reactors (MSRs). Conventional nuclear reactors work with fixed fuel assemblies in which fission products and fissile material do not transport throughout the core. Liquid fueled molten salt reactors work in a much different way, allowing for material to transport throughout the primary reactor loop. Because of this, fission product transport must be taken into account. The set of partial differential equations that apply are discretized into systems of first order ordinary differential equations (ODEs). The exact solution to the set of ODEs is herein being estimated using the matrix exponential method known as the Chebychev Rational Approximation Method (CRAM).

Probabilistic Fracture Mechanics Analyses Comparison to LBB Assessments

Analysis of a generic dissimilar metal weld (DMW) susceptible to primary water stress corrosion cracking (PWSCC) in a pressurized water reactor (PWR) is used to compare the newly developed probabilistic models (xLPR code) to the previously performed deterministic leak before break (LBB) analyses. The objective of this scoping analysis is to develop a generic reactor loop composed of representative welds and to investigate the safety margins in the presence of PWSCC at the Alloy 82/182 locations. These locations have been previously studied and approved for LBB, however not in the presence of active degradation such as PWSCC. The purpose of this study is to investigate potential increase in risk due to this mechanism. Comparisons of the individual weld probabilistic results to the deterministic LBB analysis are made as the first results of this study. Additionally the individual welds are combined into a configuration representative of the primary loop. This configuration is then tested against the criterion recommended by the xLPR acceptance group. This xLPR criterion is then compared to the existing LBB criterion to assess the change, if any, in risk due to PWSCC.

Simulated Temperature Profiles for Corrosion Products Deposited in ITER Experimental Loop

An experimental setup was designed to find out behavior of deposition thickness of corrosion products. This experimental setup is designed on the bases of ITER (International Thermonuclear Experimental Reactor) loop. The experiment was done for different values of pH to study its effect on the deposition thickness. System pressure was kept at 0.5 MPa with maximum limit of temperature at 150°C. The pH value was kept in the range of 7.00–10.50. Artificial corrosion particles (Fe3O4) were introduced manually in the loop, which was allowed to stabilize. Four test tubes were used to determine the thickness of deposition, and the temperature at these points were measured by thermocouples. It is also very important to determine the temperature distribution around such points, in order to establish its relationship with pH and deposition thickness. Results show that the change of temperature and pH (of coolant) have a strong effect on deposition thickness. The temperature distribution, found in the various components of the experimental loop, will be used to correlate its relation with the deposition thickness and the coolant pH in future studies.

Experimental Study of the Temperature Field in Fire Caused by Sodium Leakage in Sodium-Cooled Fast Reactor Loop

In order to explore the characteristics of fire caused by sodium leakage in sodium-cooled fast reactor loop, an experiment on the sodium fire in form of columnar flow has been conducted. Temperature field characteristics were analyzed by measured results. Near the axis of the combustion container, the high-temperature region of the sodium fire in form of the columnar flow is located in the bottom and the temperatures are all less than 100°C at height from 0.5m to 2.0m under natural ventilation. The temperatures of the space reach the maximum values after forced ventilation and the highest temperature is up to 950°C at height 0.8m above the ground. Once the lateral distance to the sodium flow is more than 0.4m, the temperature field is affected less by the sodium fire in form of columnar flow.