A Single Channel Thermal-Hydraulic Calculation Module for PWR Pin-by-Pin Wise Coupled Calculation System

Abstract Due to the strong feedback effect between neutronics and thermal-hydraulics in the core of pressurized water reactors (PWR), neutronics and thermal-hydraulics coupling calculations are often used in the design and safety evaluation of PWR to provide more accurate results. The coupling calculation of neutronics and thermal-hydraulics at the full core pin-by-pin wise can provide more precise and precise coupling parameters, which is a hot research topic in the industry. How to advance the efficiency and accuracy of neutronics and thermal-hydraulics coupling calculations at the entire core pin by pin wise is a challenge in this research. Multiple digital reactor plans have been proposed worldwide, and one important task is to attempt to use the most advanced numerical simulation methods, high-precision calculation models, and ultra large-scale high-performance computing clusters to develop the new generation of digital reactor technology. In order to improve the efficiency of the pin-by-pin wise neutronics and thermal-hydraulics coupling calculation of the entire reactor core, this paper developed a two-phase thermal-hydraulic calculation module TH1D based on a single channel model, which can achieve thermal conductivity calculation of flat fuel and rod fuel, as well as two-phase thermal-hydraulic calculation of a single channel, and improve parameters such as fuel effective temperature, coolant temperature, moderator density, and void fraction for thermal feedback. And coupled it with the core fine mesh transportation calculation program CORCA-SPn to develop a PWR pin-by-pin wise neutronics and thermal-hydraulics coupling calculation program. The overall performance of TH1D was evaluated by conducting pin-by-pin wish neutronics and thermal-hydraulics coupling calculation on two typical PWR core: Hua-long Pressurized Reactor (HPR1000) and the Coupling benchmark of PWR with High Parameters (COPHP). Compared with the coupling program using the traditional sub-channel/multi-channel thermal-hydraulic calculation program CORTH/CORTH-R, the differences in thermal-hydraulic parameters between calculated by TH1D and the results of sub-channel/multi-channel program, as well as the differences in coupling calculation results, were compared. The following conclusions were drawn: 1) Through thermal-hydraulic simulation of a single channel containing a single plate or rod, TH1D showed good load performance compared to the reference results, with a relative deviation of less than 0.5% for all parameters; 2) the key result parameter deviation of the pin-by-pin wise coupling calculation using CORCA-SPn/TH1D is within an acceptable range, with the maximum keff deviation ≤ 250pcm and the maximum power weight deviation ≤ 1.88%; 2) The average efficiency of pin-by-pin wish coupling calculation is increased by 16 times (compared to CORTH) and 0.86 times (compared to CORTH-R), respectively.