Primary coolant activity of 54Mn, 59Fe, 58Co, 60Co, and 51Cr in system integrated small and modular reactor

Abstract

The corrosion results in not only material degradation but also causes CRUD generation in the primary coolant. The axial offset anomaly (AOA) or CRUD Induce Power Shift (CIPS) is caused by CRUD accumulation on the fuel assemblies. It also causes an increase in Occupational Radiation Exposure (ORE). Therefore, in this work, activated CRUD behavior due to 54Mn, 59Fe, 58Co, 60Co, and 51Cr has been studied under primary coolant flow transient and power perturbations in a System Integrated Advanced and Modular Reactor (SMART). The “Activated CRUD particles” ACP-SMART code is used to study the primary coolant activity under parabolic corrosion rate. The SMART reactor core has been modeled in OpenMC, and respective group fluxes have been generated. The ACP-SMART, coupled with OpenMC, is modeled and implemented in MATLAB. A dynamic grid load following model and a kinetic coastdown model is implemented in ACP-SMART in terms of the ratio of the coolant kinetic energy and the kinetic energy stored in the rotating parts of a pump (β). The response of 54Mn, 59Fe, 58Co, 60Co, and 51Cr activity in primary coolant due to linear, monotonically, and asymptotically coastdown has been investigated. The 59Fe and 54Mn showed higher sensitivity relative to the 58Co, in primary coolant activity corresponding to the dynamic grid load following. However, the 59Fe and 58Co activities are more sensitive to coastdown. Nearly all the radioisotopes showed similar behavior under monotonic flow perturbation. 58Co and 54Mn have shown a catastrophic behavior in the primary coolant activity under asymptotically coastdown.