MANTA, Heat Transfer Fuel Elements Cluster to Single-Phase Steady-State Fluid Flow

1 - Description of problem or function: MANTA is a program which provides a thermal-hydraulic nodal analysis in the steady state. It was designed to analyze fuel element configuration in the superheat development program. MANTA analyzes mixing between coolant channels, allows for temperature variant conductivity in admittance calculations, and multiple stacked segments through the fuel region for a 7-element cluster analysis over a length of up to 8 feet. MANTA is designed for single-pass steam flow. The flow direction in the coolant channels may be either up or down, thereby permitting the analysis of two-pass as well as single-pass fuel elements. MANTA accounts for the heat transfer and pressure drop that may occur between coolant channels due to mixing as well as to the conventional heat transfer and pressure drop relationships due to friction, discontinuities, acceleration, convection, conduction, and radiation. MANTA allows for the calculation at each node of the material properties viscosity, specific heat, conductivity, and specific volume to correspond to the actual node temperature being solved for. The CDC6600 version uses sodium for the working fluid rather than steam. 2 - Method of solution: The program embodies two independent analytical solutions. The solution proceeds by solving for the node temperatures of the first segment, evaluating the change in coolant temperature, and proceeding to calculate the temperatures of the second segment. This process continues until all segment temperatures have been evaluated. A pressure drop check on each coolant channel is then made which requires that all channel pressure drops be within specified input values. If these values are not converged, a new flow rate for each channel is derived and the solution repeated until convergence is achieved. 3 - Restrictions on the complexity of the problem: Maxima of - 200 nodes; 1 to 100 internal nodes; 101 to 150 surface nodes; 48 coolant nodes; 24 coolant channels; 20 segments; 6 connections per node except for the coolant nodes which have 5