Estimation of mitigation effects of sodium nanofluid for SGTR accidents in SFR

Ichikawa, Kenta*; Kanda, Hironori; Yoshioka, Naoki*; Ara, Kuniaki; Saito, Junichi; Nagai, Keiichi

Proceedings of 26th International Conference on Nuclear Engineering (ICONE-26) (Internet), 6 Pages, 2018/07

Studies on the suppression of the reactivity of sodium itself have been performed on the basis of the concept of suspended nanoparticles in liquid sodium (sodium nanofluid). According to the experimental and theoretical results of studies for sodium nanofluid, velocity and heat of sodium nanofluid-water reaction are lower than those of the pure sodium-water reaction. The analytical model for the peak temperature of a sodium nanofluid-water reaction jet has been developed in consideration of these suppression effects by the authors. In this paper, the prediction method for mitigation effects for a damage of adjacent tubes in a steam generator tube rupture (SGTR) accidents is arranged by applying this analytical model for the peak temperature of the reaction jet. On the assumption that the sodium nanofluid is used for the secondary coolant of sodium-cooled fast reactor (SFR), mitigation effects under the design-base accident (DBA) condition and the design-extension condition (DEC) of SGTR are estimated by using this method. As a result, there is a possibility to reduce the number of damaged tubes and to suppress the pressure generated by SGTR accidents by using sodium nanofluid in the secondary coolant.

Study on a suppression of sodium-water reaction in SFR by applying sodium with suspended nanoparticles

Kanda, Hironori; Yoshioka, Naoki*; Ara, Kuniaki; Saito, Junichi; Nagai, Keiichi

no journal, , 

An important safety concern for SFR is the possibility of steam leaking from a tube at high-pressure into surrounding liquid sodium within the steam generator. The steam/liquid sodium pair is very reactive and the steam leak will form a sodium-water reaction jet which may attack and rupture adjacent tubes. A study on the suppression of the reactivity of sodium itself using the concept of suspended nanoparticles in liquid sodium (sodium nanofluid) has carried out. From the experimental results for sodium nanofluid, it was clear that the reaction rate and reaction heat with water were decreased by the atomic interaction of sodium with suspended nanoparticles. Taking the changes of physical and chemical property into account, an analytical model for peak temperature within a sodium nanofluid-water reaction jet has been constructed. The object of this paper is to confirm this analytical model for reaction jet temperature and to predict a mitigation effect on adjacent tube damage in a steam generator by applying sodium nanofluid to the secondary coolant of SFR. Comparing calculation results using the analytical model with the experimental results for a steam injection experiment, we demonstrated that the analytical model for temperature within the reaction jet is appropriate.

A Study on the straight double-walled tube steam generator design against sodium-water reaction in DECs

Kanda, Hironori; Enuma, Yasuhiro; Futagami, Satoshi; Kawamura, Masaya*; Ushiki, Hiroshi*; Ogumo, Shinya*; Ichihara, Takashi*; Nakashima, Takashi*

no journal, , 

Preliminary study of low flow-rate evaluation method by transport time-delay analysis of temperature fluctuation in a sodium circulation loop

Kanda, Hironori; Onojima, Takamitsu; Suzuki, Masashi; Imamura, Hiroaki; Tanaka, Masaaki; Murakami, Satoshi*

no journal, , 

The flow rate of the primary coolant system in natural circulation decay heat removal operation is reduced much lower than that in rated operation in Next generation sodium-cooled fast reactor. The electromagnetic flow meters have uncertainty on the indicated value at low flow rates conditions. Ensuring the measurement accuracy of electromagnetic flow meter is presumed to contribute the promotion of understanding of thermal hydraulics phenomena such as natural circulation in the fast reactor. In this paper, low flow rate evaluation method has been examined preliminarily by transport time-delay analysis of temperature fluctuation in sodium circulation loop. Measured data and evaluation results from temperature fluctuations which have been acquired in sodium-loop in AtheNa, indicate that this evaluation method can be applied to estimate flow rate in natural circulation decay heat removal operation.