Development of a three-zone transport model for activated corrosion products analysis of Tokamak Cooling Water System

Highlights: • A three-zone transport model for activated corrosion products analysis of Tokamak Cooling Water System was developed. • The model was used in the ACPs evaluation code CATE, giving CATE the capability to calculate spatial distribution of ACPs. • Under normal operation, the major contributors to radioactivity came from the short-life ACPs, especially Mn-56. - Abstract: In the Tokamak Cooling Water System (TCWS), the activated corrosion products (ACPs) play as an important radioactive source, which have impact on reactor inspection and maintenance. A three-zone transport model of ACPs was elaborated in this paper, which is based on the theory that the main driving force for ACPs transport is the temperature change of the coolant throughout the loop and the resulting change in metal ion solubility in the coolant. The three-zone transport model was used to replace the loop-homogenization model in the ACPs evaluation code CATE 1.0, developing CATE to give the capability to calculate spatial distribution of ACPs. As a result, CATE was upgraded to version 2.0. For code testing, a FW/BLK cooling loop of ITER was simulated using CATE 2.0, and the composition and radioactivity of ACPs were calculated. The results showed that the major contributors came from the short-life nuclides, especially Mn-56, which can influence material choice in reactor design and shutdown time before reactor maintenance.