TRAC-BF1/NEM Modeling and results of OECD/NEA BWR core transient benchmarks

TRAC-BF1/NEM is a coupled neutronics-thermal hydraulics code for BWR transient and accident analysis developed at the Penn State University. Research has been carried out at Penn State to further verify this coupled code by using the (OECD/NEA) 3-D BWR core transient benchmarks. These benchmarks provide an opportunity to compare TRAC-BF1/NEM predictions with the results of many other coupled codes as well as to establish a well-defined set of test problems for future TRAC-BF1/NEM modifications and code distributions. The paper gives a description of the developed neutronics and thermal-hydraulic models and presents a comparison and discussion of the obtained steady-state results as well as the transient results for the inlet sub-cooling transient