Comparison of Simulated Radioiodine Ratios With Measured Values for Three CANDU Stations

Abstract

A Matlab model was used to predict steady state radioiodine concentrations for ¹³²I, ¹³³I, ¹³⁴I and ¹³⁵I relative to ¹³¹I in the coolant of three CANDU® stations. The radioiodines originated as fission products from tramp uranium that were directly injected to the coolant where they were subject to radioactive decay, plate out and purification. The results of simulations were compared to long-term measured values and plate-out and purification parameters were adjusted until measured and model values agreed. The purification flow rate is the critical variable and operating purification flow rates were deduced for the three stations.