Abstract
The analysis of the Simplified Boiling Water Reactor (SBVVR) is carried out through the use of the reactor analysis code RAMONA-4B in a scenario of an operational transient, a turbine trip with failure of all the bypass valves. This study is divided in three parts. As an introduction, a brief description of the code RAMONA-4B. Later, the implemented SBWR model, based on the General Electric Standard Safety Analysis Report (SSAR), is described and discussed. Finally, the reactor behavior during a turbine trip transient is numerically simulated through the description of nuclear and thermal hydraulic parameters and under the scenario conditions suggested by General Electric. The SBWR model consists of the representation of the vessel internal components through parameters such as areas, diameters and volumes, and the one-quarter-core neutron parameters which were obtained using the transport theory lattice physics code CASMO-3. The thermohydraulic equations are solved by RAMONA-4B in a closed-contour inside the vessel and in a hundred eighty four parallel channels (including bypass) in the core. The tridimensional representation of the reactor core is accomplished through a proposed fuel load which was obtained from a selection of out of three fuel loads and using some standard fuel design parameters. The cross sections are represented using a polynomial as a function of the bumup, void fraction, fuel and moderator temperatures. The six-group delayed neutron equation and the one-and-a-half neutron diffusion equation are solved and the power distribution in the reactor core is obtained.Also, RAMONA-4B has implemented a (adiabatic) steam line model to represent the acoustic effects of the turbine stop valve closure during the transient. Finally, the two-phase coolant and neutronic parameters are calculated in steady state and during the turbine trip transient. The results are discussed and compared against the ones shown in the chapter XV of the SSAR.
Cuevas Vivas, Gabriel Francisco (1995). Analysis of the Simplified Boiling Water Reactor using the code Ramona-4B. Master's thesis, Texas A&M University. Available electronically from
https : / /hdl .handle .net /1969 .1 /ETD -TAMU -1995 -THESIS -C84.