Computational Methodology of Sodium-Water Reaction Phenomenon in Steam Generator of Sodium-Cooled Fast Reactor

Abstract

A new computational methodology of sodium-water reaction (SWR), which occurs in a steam generator of a liquid-sodium-cooled fast reactor when a heat transfer tube in the steam generator fails, has been developed considering multidimensional and multiphysics thermal hydraulics. Two kinds of reaction models are proposed in accordance with a phase of sodium as a reactant. One is the surface reaction model in which water vapor reacts directly with liquid sodium at the interface between the liquid sodium and the water vapor. The reaction heat will lead to a vigorous evaporation of liquid sodium, resulting in a reaction of gas-phase sodium. This is designated as the gas-phase reaction model. These two models are coupled with a multidimensional, multicomponent gas, and multiphase thermal hydraulics simulation method with compressibility (named the 'SERAPHIM' code). Using the present methodology, a numerical investigation of the SWR under a pin-bundle configuration (a benchmark analysis of the SWAT-1R experiment) has been carried out. As a result, the maximum gas temperature of approximately 1,300 C is predicted stably, which lies within the range of previous experimental observations. It is also demonstrated that the maximum temperature of the mass weighted average in the analysis agrees reasonably well with the experimental result measured by thermocouples. The present methodology will be promising to establish a theoretical and mechanical modeling of secondary failure propagation of heat transfer tubes due to such as an overheating rupture and a wastage.

A numerical model for the CO2–sodium chemical interactions in Sodium Fast nuclear Reactors

“…Epstein et al did not take into account the chemical reaction inside the bubbly flow regime. Takata et al (2009) modeled the SWR inside a steam-into-liquid-sodium jet employing an analogy between heat and mass transfer: the reaction rate is a function of the Lewis number, the heat transfer coefficient between the phases, the specific heat of the gas phase, the steam mass fraction and the interfacial area. The interfacial area was evaluated through the Nigmatulin model (Rivard and Torrey, 1976) which is based on purely bubbly flow.…”

A theoretical study of Ti nanoparticle effect on sodium water reaction: Using ab initio calculation

“…This goal can be attained by suspending 2 at% of 10-nm Ti nanoparticles (NPs) in liquid Na (Ara et al, 2010a,b;Nishimura et al, 2012;Ara, 2010, 2012;Saito et al, 2012b,c;Takata et al, 2009). Addition of 10-nm Ti NPs reduced the heat of the SWR, and its estimated rate of hydrogen production (Saito and Ara, 2010).…”

Applicability of a mechanistic numerical method for sodium-water reaction phenomena in steam generators of sodium-cooled fast reactors

“…The second-order central difference scheme was applied to the viscous, heat conduction and diffusion terms. The governing equations are solved by the HSMAC (Highly Simplified Marker And Cell) method modified for compressible multiphase flows (Takata et al 2009;Uchibori et al, 2009). The HSMAC method for incompressible single-phase flow was developed by Hirt and Cook (1972).…”

“…The system consists of the multiple computer codes. As one component of the system, there is a computer code called SERAPHIM (Sodium-watEr Reaction Analysis : PHysics of Interdisciplinary Multi-phase flow) calculating compressible multicomponent multiphase flow with sodium-water chemical reaction Takata et al, 2005;Takata et al 2009;Uchibori et al, 2009;Uchibori et al, 2012;Uchibori and Ohshima, 2014 Figure 2 shows phenomena to be evaluated by the SERAPHIM code. The SERAPHIM code is based on the mechanistic numerical models and predicts profiles of the velocity, temperature and concentration as an environment of a material damage.…”