A coupled neutronic/thermal–hydraulic module for the transient analysis of VVER-1000 reactor during reactivity insertion accidents. (March 2020)

• Record Type: Journal Article
• Authors: Ajami, Mona; Zangian, Mahdi; Minuchehr, Abdolhamid; Zolfaghari, Ahmadreza
• Is Part Of: Progress in nuclear energy. Volume 121(2020)
• Publication Date: 2020-03
• Subjects: Nuclear reactor core modular simulator -- Point kinetics -- Time-dependent single heated channel -- Two-phase homogeneous model -- Reactivity insertion accidents -- VVER-1000; CMS Nuclear reactor core modular simulator -- FSAR Final safety analysis report -- BNPP Bushehr nuclear power plant -- CPS Control and protection system -- CPS AR Absorber rod of the control and protection system -- APC Automatic power controller -- CRA Control rod assembly -- FA Fuel assembly -- BA Burnable absorber; Nuclear energy -- Periodicals; Nuclear engineering -- Periodicals; 333.7924
• DOI: 10.1016/j.pnucene.2020.103249
• Languages: English
• ISSNs: 0149-1970

Abstract

Abstract: For the safety analysis of nuclear power plants, it is essential to provide a simple and fast model to investigate the time-dependent behavior of reactor cores. Most research papers in this field have generally been limited to use coupling techniques between existing codes. In this paper, an integrated module called CMS (nuclear reactor Core Modular Simulator) is proposed to simulate the transient thermo-neutronic behavior of a VVER-1000 reactor core during reactivity insertion accidents. CMS contains three modules: a neutronic module based on the point kinetic equations, a thermal-hydraulic module based on the time-dependent single heated channel approximation and a reactivity calculation one. A two-stage fourth order implicit Runge-Kutta method was used for solving the point kinetics equations and the homogeneous two-phase flow model was considered for the thermal-hydraulic part. To verify the proposed module, two reactivity insertion accidents of the Bushehr VVER-1000 reactor, a design basis accident and an anticipated operational occurrence, have been simulated and the obtained results have been compared with its final safety analysis report showing a good agreement. Highlights: An integrated time-dependent module has been proposed for simulating the reactivity insertion analysis of the VVER-1000. An implicit Runge-Kutta method was used for solving the point kinetics equations. The thermal-hydraulic part is based on a time-dependent two-phase flow model with the single-channel approximation. A solver based on the COBRA-3C model has been developed for heat transfer calculations in the fuel rod with a central hole.