RSICC CODE PACKAGE PSR-387
1. NAME AND TITLE
CONTEMPT-LT/028: Code System to Predict Containment Pressure-Temperature Response to a LOCA.
Previous Versions Available: CONTEMPT-LT/026
Idaho National Engineering Laboratory, Idaho Falls, Idaho.
3. CODING LANGUAGE AND COMPUTER
FORTRAN IV and COMPASS; CDC 7600 (P00387/C7600/00).
4. NATURE OF PROBLEM SOLVED
CONTEMPT-LT was developed to predict the long-term behavior of water-cooled nuclear reactor containment systems subjected to postulated loss-of-coolant accident (LOCA) conditions. CONTEMPT-LT calculates the time variation of compartment pressures, temperatures, mass and energy inventories, heat structure temperature distributions, and energy exchange with adjacent compartments. The program is capable of describing the effects of leakage on containment response. Models are provided for fan cooler and cooling spray engineered safety systems. One to four compartments can be modeled, and any compartment except the reactor system may have both a liquid pool region and an air-vapor atmosphere region above the pool. Each region is assumed to have a uniform temperature, but the temperatures of the two regions may be different. The user determines the compartments to be used, specifies input mass and energy additions, defines heat structure and leakage systems, and prescribes the time advancement and output control.
5. METHOD OF SOLUTION
The initial conditions of the containment atmosphere are calculated from input values, and the initial temperature distributions through the containment structures are determined from the steady-state solution of the heat conduction equations. A time advancement proceeds as follows. The input water and energy rates are evaluated at the midpoint of a time interval and added to the containment system. Pressure suppression, spray system effects, and fan cooler effects are calculated using conditions at the beginning of a time-step. Leakage and heat losses or gains, extrapolated from the last time-step, are added to the containment system. Containment volume pressure and temperatures are estimated by solving the mass, volume, and energy balance equations. Using these results as boundary conditions, the heat conduction equations describing structure behavior are advanced using an implicit technique. The resulting heat transfer rates are used to correct the previous estimates of the water and energy storage in the containment volume, and the containment conditions are obtained by solving for the second time the containment balance equations. The pressure suppression routines use the conditions at the beginning of a time-step to calculate both the initial expulsion of water from the vents and the flow through the vents. From the calculated flow rates, mass and energy are removed from the dry well and added to the wet well.
6. RESTRICTIONS OR LIMITATIONS
Maxima of 20 heat conducting structures, 101 mesh points for each structure, 20 regions for each structure, 50 flow elements in one segment of the horizontal vent pressure suppression system, and 10 horizontal vents (or branches) in a segment, and 50 reductions within an input time step. CONTEMPT-LT can be used for analyzing the transient containment behavior of boiling water reactors (BWRs) including Mark I, Mark II, and Mark III systems; pressurized water reactors (PRWs), and experimental water reactor simulator or related experiments.
7. TYPICAL RUNNING TIME
On the CDC7600, CONTEMPT-LT/028 requires less than 30 seconds to run the two sample problems.
8. COMPUTER HARDWARE REQUIREMENTS
CDC7600, 58K (octal) bytes and a CalComp or microfilm plotter IBM 360.
9. COMPUTER SOFTWARE REQUIREMENTS
FORTRAN IV compiler and SCOPE 2.1.
a. Included in the document:
D. W. Hargroves and L. J. Metcalfe, "CONTEMPT-LT/028 - A Computer Program for Predicting Containment Pressure-Temperature Response to a Loss-of-Coolant Accident," NUREG/CR-0255 (TREE-1279) (March 1979).
b. Background information:
W. J. Mings, "Version 26 modifications to the CONTEMPT-LT program," SRD-83-76 (APRIL 1976).
L. L. Wheat, et al, "Contempt-LT - A Computer Program for Predicting Containment Pressure-Temperature Response to a Loss-of-Coolant Accident," UC-78b; ANCR-1219 (June 1975).
11. CONTENTS OF CODE PACKAGE
Included are the reference document and one 3.5" DOS diskette with a self-extracting file containing source, libraries, sample input and output.
12. DATE OF ABSTRACT
KEYWORDS: LOCA; CONTAINMENT; THERMAL HYDRAULICS