In Indian pressurized heavy water reactor (PHWR), loss of coolant accident with simultaneous failure of emergency core cooling system can lead to significant temperature rise in the pressure tube (PT) with the system internal pressure varying from 9 MPa to 0.1 MPa during the event. This high temperature can cause metallurgical and geometrical changes in the PT. PT would deform plastically due to internal pressure and fuel weight. A computer code “PTCREEP” based on physical models was developed to simulate the ballooning deformation expected during the channel heatup condition under internal pressure. This paper presents the assessment of the code PTCREEP against the set of experiments conducted with PT material used in Indian PHWRs.