Experimental study on thermo-chemical behavior of PHWR fuel channel under slumped fuel pin condition

•The thermal-chemical response of the fuel channel with a slumped fuel bundle is analyzed.•A particular configuration of the slumped bundle is conceptualized in which all the pins are in the maximum stable state.•A notable temperature variation is seen in the outer pitch fuel element simulators along the radial direction.•The slumping of fuel pins on the PT has led to local heating of the PT in the contact area.•With the increase in the fuel bundle's average temperature, the values of axial and circumferential temperature gradient increased in FBS, PT and CT.•A substantial increase in oxidation rate was observed as the average temperature of FBS increases.