Abstract: The nondestructive examination for the closure weld of the high pressure heater tube side has always been a difficulty, for the radiography technique for the general circumferential weld cannot be implemented. This paper describes an exposure technique that placing a radiation source in the heat exchange tube to achieve the radiography examination for the closure weld of the HP heater tube side. After several tests and improvements, this exposure technique works well. And it was successfully applied in the radiography examination of the closure welds on the HP and LP heater. Other shell and tube heat exchangers can also refer to this exposure technique to achieve the radiography examination of closure welds.