Validation Study of MATRA Code for PNL 7 by 7 Flow Blockage Test

Concern on the hydraulic design on DNB estimation under abnormal operating condition is slightly different. The abnormal operating condition may occur at postulating an isolated flow blockage in the hot channel which may enhance or deteriorate critical heat flux(CHF) at the unblocked condition. As clad temperatures increases during an accident, internal fuel rod pressure may cause clad swelling or ballooning which could lead to coolant blockage. Most of experiments on flow blockage is focused on the heat transfer and flow distribution under these accident condition. The objective of this study is to evaluate the local flow distribution prediction of MATRA code on flow blockage condition as a prerequisite study to conduct the DNB estimation under an isolated flow blockage condition. The PNL 7x7 experiment is selected as a validation data of subchannel code because this experiment provides the local flow distribution averaged on subchannel area. Sequential validation works of MATRA code on PNL 7x7 experiments were performed by same author groups.