Feasibility analysis of ⁶⁰Co production in pressurized water reactors

The radioactive isotope ⁶⁰Co is used in many applications and is typically produced in heavy water reactors. As most of the commercial reactors in operation are pressurized light water reactors (PWRs), the world supply of high level radioactive cobalt would be greatly increased if ⁶⁰Co could be produced in them. Currently, ⁶⁰Co production in PWRs has not been extensively studied; for the ⁵⁹Co (n, γ) ⁶⁰Co reaction, the positioning of ⁵⁹Co rods in the reactor determines the rate of production. This article primarily uses the models of ⁶⁰Co production in Canadian CANDU power reactors and American boiling water reactors; based on relevant data from the pressurized water Daya Bay nuclear power plant, a PWR core model is constructed with the Monte Carlo N-Particle Transport Code; this model suggests changes to existing fuel assemblies to enhance ⁶⁰Co production. In addition, the plug rods are replaced with ⁵⁹Co rods in the improved fuel assemblies in the simulation model to calculate critical parameters including the effective multiplication factor, neutron flux density, and distribution of energy deposition. By considering different numbers of ⁵⁹Co rods, the simulation indicates that different layout schemes have different impact levels, but the impact is not large. As a whole, the components with four ⁵⁹Co rods have a small impact, and the parameters of the reactor remain almost unchanged when four ⁵⁹Co rods replace the secondary neutron source. Therefore, in theory, the use of a PWR to produce ⁶⁰Co is feasible.