Implicit Solution of the Point Kinetics Equations Using TRACE

open_access
Open Access
Author:
Malencia, Austin James
Area of Honors:
Nuclear Engineering
Degree:
Bachelor of Science
Document Type:
Thesis
Thesis Supervisors:
Justin Kyle Watson, Thesis Supervisor
Marek Flaska, Thesis Honors Advisor
Keywords:
TRACE
Implicit
Point Kinetic Equations
Nuclear Engineering
Nuclear Simulation
Abstract:
Nuclear engineers constantly use nuclear safety analysis codes to prevent design basis and beyond design basis accidents. In the past, nuclear engineers have used analysis codes such as TRAC and RELAP to predict and prevent fatal accident design scenarios. Now, the NRC uses its flagship thermal-hydraulic safety analysis code called TRAC/RELAP Advanced Computational Engine, or TRACE. TRACE - which performs analysis through heat transfer equations, thermal hydraulics equations, and point reactor kinetic equations – models transients in pressurized water reactors and boiling water reactors. The code performs analysis using standard finite volume method – a numerical method that discretizes the problem and solves for the physical parameters in small parts in order to develop a solution. The neutron population, found through the solution of the point kinetics equations, determines the power of the reactor. The purpose of this project is to develop and check the accuracy of an implicit implementation of the point kinetics model in TRACE. TRACE, which solves the point kinetics equations explicitly, could produce more accurate and stable solutions without the need for time steps of approximately 10-4 seconds. This project takes the modified version of the TRACE code that solves the point-kinetics equations implicitly, and compares the results of both the explicit and implicit solutions in terms of the neutronics feedback parameters, and searches for scenarios where analysis would benefit from using the implicit model. This project shows the potential benefit of using fully implicit models in nuclear reactor safety analysis, especially in accident scenarios.