Effects of Hydrogen Peroxide on Cobalt Deposition Rate on Primary Cooling System of Boiling Water Reactors

Experimental data of radioactivity deposition rates on stainless steel specimensexposed to high-temperature water including hydrogen peroxide (H2O2) and oxygen (O2) were applied to the evaluation of Co-60 accumulation rates in oxide films on the stainless steel piping of a boiling water reactor (BWR) primary cooling system and then an empirical formula of Co-60 deposition rate coefficient was proposed as a function of exposure time. The empirical formula was applied to the evaluationof the amount of Co-60 deposition on the stainless steel piping of BWR primary cooling systems under normal water chemistry (NWC) and hydrogen water chemistry (HWC) conditions. The results are summarized as follows. 1) The Co-60 deposition rate coefficient was almost independent of O2 concentration ([O2]), while it decreased as H2O2 concentration ([H2O2]) decreased. 2) The proposed empirical formula determined on the basis of experiments under H2O2 conditions could give a much better estimation of the Co-60 deposition rate coe...