Calculation of Radioactivity and Dose Rate of Activated Corrosion Products in Water-Cooled Fusion Reactor

Jingyu Zhang,Lu Li,Yixue Chen,Shuxiang He

doi:10.1155/2016/6051834

Abstract

In water-cooled reactor, the dominant radioactive source term under normal operation is activated corrosion products (ACPs), which have an important impact on reactor inspection and maintenance. A three-node transport model of ACPs was introduced into the new version of ACPs source term code CATE in this paper, which makes CATE capable of theoretically simulating the variation and the distribution of ACPs in a water-cooled reactor and suitable for more operating conditions. For code testing, MIT PWR coolant chemistry loop was simulated, and the calculation results from CATE are close to the experimental results from MIT, which means CATE is available and credible on ACPs analysis of water-cooled reactor. Then ACPs in the blanket cooling loop of water-cooled fusion reactor ITER under construction were analyzed using CATE and the results showed that the major contributors are the short-life nuclides, especially Mn-56. At last a point kernel integration code ARShield was coupled with CATE, and the dose rate around ITER blanket cooling loop was calculated. Results showed that after shutting down the reactor only for 8 days, the dose rate decreased nearly one order of magnitude, which was caused by the rapid decay of the short-life ACPs.

Highlights

In the cooling loop of water-cooled reactor, the oxidation and corrosion of the metal material by water are inevitable, and part of the corrosion products will be activated under neutron irradiation and become radioactive, which are called activated corrosion products (ACPs)
A three-node transport model was introduced into the ACPs source term code CATE, making CATE capable of theoretically simulating the variation and the distribution of ACPs in a water-cooled reactor and suitable for more operating conditions
MIT PWR Coolant Chemistry Loop (PCCL) was chosen to test the new version of CATE, and the calculation results from CATE are close to the experimental results from MIT, which means CATE is available and credible on ACPs analysis of water-cooled reactor

Summary

Introduction

In the cooling loop of water-cooled reactor, the oxidation and corrosion of the metal material by water are inevitable, and part of the corrosion products will be activated under neutron irradiation and become radioactive, which are called activated corrosion products (ACPs). For the water-cooled fusion reactor, it is necessary to research the formation mechanism and transport process of ACPs and to predict the variation and distribution of radioactivity and dose rate of ACPs, which is important to radiation shielding design, inspection, and maintenance as well as accident analysis of the reactor. The basic theory and equations of the three-node transport model were described in the second section of this paper, and ACPs in MIT PWR coolant chemistry loop and ITER blanket cooling loop were calculated using the code CATE, respectively, in the third section and the fourth section. The dose rate around ITER blanket cooling loop caused by ACPs was calculated using the point kernel integration code ARShield in the fifth section.

Description of the Three-Node Transport Model

Calculation of Dose Rate Caused by ACPs Using ARShield Code

Conclusions