The Analysis of SBWR Critical Power Bundle Using Cobrag Code

The coolant mechanism of SBWR is similar with the Dodewaard Nuclear Power Plant (NPP) in the Netherlands that first went critical in 1968. The similarity of both NPP is cooled by natural convection system. These coolant concept is very related with same parameters on fuel bundle design especially fuel bundle length, core pressure drop and core flow rate as well as critical power bundle. The analysis was carried out by using COBRAG computer code. COBRAG computer code is GE Company proprietary. Basically COBRAG computer code is a tool to solve compressible three-dimensional, two fluid, three field equations for two phase flow. The three fields are the vapor field, the continuous liquid field, and the liquid drop field. This code has been applied to analyses model flow and heat transfer within the reactor core. This volume describes the finitevolume equations and the numerical solution methods used to solve these equations. This analysis of same parameters has been done i.e.; inlet sub cooling 20 BTU/lbm and 40 BTU/lbm, 1000 psi pressure and R-factor is 1.038, mass flux are 0.5 Mlb/hr.ft2, 0.75 Mlb/hr.ft2, 1.00 Mlb/hr.ft2 and 1.25 Mlb/hr.ft2. Those conditions based on history operation of some type of the cell fuel bundle line at GE Nuclear Energy. According to the results, it can be concluded that SBWR critical power bundle is 10.5 % less than current BWR critical power bundle with length reduction of 12 ft to 9 ft

vitamin e as a functional and biocompatibility modifier of synthetic hemodialyzer membranes an overview of the literature on vitamin e modified hemodialyzer membranes

Along with one century of history, research has provided many solutions for hemodialysis (HD) biomaterials, encompassing several generations of copolymers that have found wide application in the deve

Dynamic film thickness between bubbles and wall in a narrow channel

The present paper describes a novel technique to characterize the behavior of the liquid film between gas bubbles and the wall in a narrow channel. The method is based on the electrical conductance. Two liquid film sensors are installed on both opposite walls in a narrow rectangular channel. The liquid film thickness underneath the gas bubbles is recorded by the first sensor, while the void fraction information is obtained by measuring the conductance between the pair of opposite sensors. Both measurements are taken on a large two-dimensional domain and with a high speed. This makes it possible to obtain the two-dimensional distribution of the dynamic liquid film between the bubbles and the wall. In this study, this method was applied to an air-water flow ranging from bubbly to churn regimes in the narrow channel with a gap width of 1.5m

Distal radius fracture after proximal row carpectomy

AbstractIntroductionWe encountered a patient with distal radius fracture (DRF) after proximal row carpectomy (PRC). The mechanism of the DRF after PRC is discussed in this report.Presentation of caseThe patient was a 73-year-old female who had undergone PRC due to Kienböck disease before. The wrist range of motion was: 45° on dorsiflexion and 20° on flexion. DRF has occurred at 3 years after PRC. The fracture type was extra-articular fracture. Osteosynthesis was performed using a volar locking plate. No postoperative complication developed, the Mayo score was excellent at 6 months after surgery, and the daily living activity level recovered to that before injury.DiscussionSince the wrist range of motion decreased and the lunate fitted into the joint surface after PRC, making the forearm join with the hand like a single structure, pressure may have been loaded on the weak distal end of the radius from the dorsal side, causing volar displacement and fracture.ConclusionThe pressure distribution and range of motion of the radiocarpal joint after PRC are different from those of a normal joint, and the mechanism of fracture also changes due to PRC

DESIGN AND TEST PLAN OF THE SUPERCRITICAL CO 2 COMPRESSOR TEST LOOP

ABSTRACT Supercritical carbon dioxide (CO 2 ) gas turbine systems can generate power at a high cycle thermal efficiency, even at modest temperatures of 500-550°C. That high thermal efficiency is attributed to a markedly reduced compressor work in the vicinity of critical point. In addition, the reaction between sodium (Na) and CO 2 is milder than that between H 2 O and Na. Consequently, a more reliable and economically advantageous power generation system can be created by coupling with a Na-cooled fast breeder reactor. In a supercritical CO 2 turbine system, a partial cooling cycle is employed to compensate a difference in heat capacity for the high-temperature -low-pressure side and low-temperaturehigh-pressure side of the recuperators to achieve high cycle thermal efficiency. In our previous work, a conceptual design of the system was produced for conditions of reactor thermal power of 600 MW, turbine inlet condition of 20 MPa/527°C, recuperators 1 and 2 effectiveness of 98%/95%, Intermediate Heat Exchanger (IHX) pressure loss of 8.65%, a turbine adiabatic efficiency of 93%, and a compressor adiabatic efficiency of 88%. Results revealed that high cycle thermal efficiency of 43% can be achieved. In this cycle, three different compressors, i.e., a low-pressure compressor, a high-pressure compressor, and a bypass compressor are included. In the compressor regime, the values of properties such as specific heat and density vary sharply and nonlinearly, dependent upon the pressure and temperature. Therefore, the influences of such property changes on compressor design should be clarified. To obtain experimental data for the compressor performance in the field near the critical point, a supercritical CO 2 compressor test project was started at the Tokyo Institute of Technology on June 2007 with funding from MEXT, Japan. In this project, a small centrifugal CO 2 compressor will be fabricated and tested