Improvement of efficiency on ball-cleaning method for JRR-3 heat exchanger

Ota, Kazunori  ; Ikekame, Yoshinori; Owada, Minoru; Fukushima, Manabu; Oba, Toshinobu ; Takeuchi, Masaki; Imahashi, Masaki; Murayama, Yoji

JRR-3 uses shell and tube heat exchangers. The secondary coolant flushes into the tubes and the primary coolant flows outside of the tubes. The heat exchangers are cleaned with the ball-cleaning method, which is a method to clean inside of the tubes by passing the sponge balls with secondary coolant. Decline in the performance of heat exchanger could rise temperature of the primary coolant and then influence the safe and stable reactor operation. The effective way of ball-cleaning for JRR-3 heat exchangers is examined based on past cleaning data. The results show the optimal ball size and the way to determine the cleaning time.