Thermophysical properties of molten stainless steel containing 5mass%BC

Fukuyama, Hiroyuki*; Higashi, Hideo*; Yamano, Hidemasa

Nuclear Technology, 205(9), p.1154 - 1163, 2019/09

https://doi.org/10.1080/00295450.2019.1578572

An electromagnetic-levitation technique performed in a static magnetic field was used to measure the density, surface tension, normal spectral emissivity, heat capacity, and thermal conductivity of molten 316L stainless steel (SS316L) and SS316L that contained 5mass%BC. The addition of 5mass%BC to SS316L yielded reductions of 111 K, 6%, 19%, and 6% in the liquidus temperature, density, normal spectral emissivity, and thermal conductivity at the liquidus temperature of SS316L, respectively. The heat capacity increased by 5% with this addition. Although the 5mass%BC addition had no clear effect on the surface tension, sulfur dissolved in the SS316L resulted in a significant decrease in the surface tension.

The Effects of plutonium content and self-irradiation on thermal conductivity of mixed oxide fuel

Ikusawa, Yoshihisa; Morimoto, Kyoichi; Kato, Masato; Saito, Kosuke; Uno, Masayoshi*

Nuclear Technology, 205(3), p.474 - 485, 2019/03

https://doi.org/10.1080/00295450.2018.1494999

This study evaluated the effects of plutonium content and self-irradiation on the thermal conductivity of mixed-oxide (MOX) fuel. Samples of UO fuel and various MOX fuels were tested. The MOX fuels had a range of plutonium contents, and some samples were stored for 20 years. The thermal conductivity of these samples was determined from thermal diffusivity measurements taken via laser flash analysis. Although the thermal conductivity decreased with increasing plutonium content, this effect was slight. The effect of self-irradiation was investigated using the stored samples. The reduction in thermal conductivity caused by self-irradiation depended on the plutonium content, its isotopic composition, and storage time. The reduction in thermal conductivity over 20 years' storage can be predicted from the change of lattice parameter. In addition, the decrease in thermal conductivity caused by self-irradiation was recovered with heat treatment, and recovered almost completely at temperatures over 1200 K. From these evaluation results, we formulated an equation for thermal conductivity that is based on the classical phonon-transport model. This equation can predict the thermal conductivity of MOX fuel thermal conductivity by accounting for the influences of plutonium content and self-irradiation.

Thermal property measurements on LiTiO added with TiO

Hoshino, Tsuyoshi; Kobayashi, Takeshi*; Nashimoto, Makoto*; Kawamura, Hiroshi; Dokiya, Masayuki*; Terai, Takayuki*; Yamawaki, Michio*; Takahashi, Yoichi*

JAERI-Conf 2004-012, p.140 - 147, 2004/07

https://jopss.jaea.go.jp/pdfdata/JAERI-Conf-2004-012.pdf

no abstracts in English

Thermal conductivity of neutron irradiated BeTi

Uchida, Munenori*; Ishitsuka, Etsuo; Kawamura, Hiroshi

Fusion Engineering and Design, 69(1-4), p.499 - 503, 2003/09

https://doi.org/10.1016/S0920-3796(03)00395-8

no abstracts in English

Study on effect of effective thermal conductivities on melting characteristics of latent heat storage capsules

Shiina, Yasuaki; Inagaki, Terumi*

Nihon Kikai Gakkai Rombunshu, B, 69(681), p.1233 - 1241, 2003/05

https://doi.org/10.1299/kikaib.69.1233

In order to reduce phase change time in latent heat technology, improvement of effective thermal conductivity of heat storage unit would be one of the techniques. Effect of effective thermal conductivity on melting time are studied analytically of circular composite heat storage capsules made by immersing phase change materials (PCM) into porous metals. Numerical and approximate analysis were made with the consideration of uniform and non-uniform heat transfer coefficients around the cylindrical surface. Four PCMs (HO,Octadecane, LiCO, NaCl) and three metals (copper, aluminum and carbon steel) were selected specific materials. Porosity of the metals were restricted larger than 0.9 in order to lessen decrease in latent heat. Results show that reduction in melting time was obtained for the above PCMs, especially for low conductivity PCMs. Melting time obtained by approximate analysis agrees well with numerical analysis. High Nusselt number and high thermal conductivity of heat transfer fluid would be more effective to reduce phase change time.

Thermal properties of pellet

Nakamura, Jinichi

Saishin Kaku Nenryo Kogaku; Kodoka No Genjo To Tembo, p.93 - 98, 2001/06

no abstracts in English

CompalisonoFnlermohydraulicCharacteristicsintheuseofvariousCoolants

; ; *; Yamaguchi, Akira

JNC TN9400 2000-109, 96 Pages, 2000/11

JNC-TN9400-2000-109.pdf:9.56MB

Numerical calculations were carried out for a free surface sloshing, a thermal stratification, a thermal striping, and a natural convection as key phenomena of in-vessel thermohydraulics in future fast reactor systems with various fluids as coolants. This numerical work was initiaied based on a recognition that the fundamental characteristics of the phenomena have been unsolved quantitatively in the use of various coolants. From the analysis for the phenomena, the following results were obtained. [Free Surface Sloshing phenomena] (1)Ther is no remarkable difference betweeen liquid sodium and luquid Pb-Bi in characteristics of internal flows and free surface charatristics based on Fr number. (2)the AQUA-VOF code has a potentiall enough to evaluate gas entrainment behavior from the free surface including the internal flow characteristics. [thermal Stratification Phenomena] (1)On-set position of thermal entainment process due to dynamic vortex flows was moved to downstream direction with decreasing of Ri number. 0n the other hand, the position in the case of C0 gas was shifted to upstream side with decreasing of Ri number. (2)Destruction speed of the thermal stratyification interface was dependent on thermal diffusivity as fluid properties. therefor it was concluded that an elimination method is necessary for the interface generated in C0 gas. [thermal Striping Phenomena] (1)Large amplitudes of fluid temperature fluctuations was reached to down stream area in the use of CO gas, due to larger fluid viscosity and smaller thermal diffusivity, compared with liquid sodium and liquid Pb-Bi cases. (2)To simulate thermal striping conditions such as amplitude and frequency of the fluid temperature fluctuations, it isnecessary for coincidences of Re number for the amplitude and of velocity value for the frequency, in various coolants. [Natural Convection Phenomena] (1)Fundamental behavior of the natural convection in various coolant follows buoyant jet ....

The evaluation of material base standard of ODS ferritic stainless steel core component for fast breeder reactors

Mizuta, Shunji; ;

JNC TN9400 2000-048, 28 Pages, 2000/04

JNC-TN9400-2000-048.pdf:0.64MB

ODS (Oxide Dispersion Strengthened) ferritic-martainsitic steels are one of the most prospective cladding materials for advanced fast breeder reactors, since they are expected to have excellent swelling resistance and superior high temperature strength due to the finely distributed stable oxide particles(YO). Properties and the tentative strength equations for ODS ferritic-martainsitic were proposed on the basis of the latest data to apply to the feasibility study of the sodium coolant MOX fuel plant. The items of equations are follows. (1)creep rupture strength (2)correction factor of creep rupture strength (in Na and in reactor) (3)outer surface eorrosion (Na) (4)inner surface corrosion (in MOX fuel pin) (5)thermal conductivity

None

Yamanaka, Shinsuke*; Uno, Masayoshi*; Kurosaki, Ken*; ; Namekawa, Takashi

JNC TY9400 2000-011, 41 Pages, 2000/03

JNC-TY9400-2000-011.pdf:1.28MB

no abstracts in English

Current status and future plan for thermaI striping investigations at JNC

; kasahara, Naoto; ; ; Kamide, Hideki

JNC TN9400 2000-010, 168 Pages, 2000/02

JNC-TN9400-2000-010.pdf:8.78MB

Thermal striping is significant issue of the structural integrity, where the hot and cold fluids give high cycle fatigue to the structure through the thermal stress resulted from the time change of temperatur distibution in the structure. In the sodium cooled fast reactor, temperature change in fluid easily transfers to the structure because of the high thermal conductivity of the sodium. It means that we have to take care of thermal striping, The thermal striping is complex phenomena between the fluid and structure engineering fields. The investigations of thermal striping are not enough to evaluate the integrity directly. That is the fluctuation intensity at the structure surface is assumed to be temperature difference between source fluids (upstream to the mixing region) as the maximum value in the design. 0therwise, the design conditions are defined by using a mockup experiment and large margin of temperature fluctuation intensity. Furthermore, such evaluation manners have not yet been considered as a design rule. Transfer mechanism of temperature fluctuation from fluid to structure has been investigated by the authors on the view points of the fluid and structure. Attenuation of temperature fluctuation was recognized as a dominant factor of thermal fatigue. We have devdoped a numerical analysis system which can evaluate thermal fatigue and crack growth with consideration of the attenuation of temperature fluctuation in fluid, heat transfer, and structure. This system was applied to a real reactor and the applicability was confirmed. Further verification is planned to generalize the system. For the higher cost performance of the fast reactor, an evaluation rule is needed, which can estimate thermal loading with attenuation and can be applied to the design. An idea of the rule is proposed here. Two methods should be prepared; one is a precise evaluation method where mechanism of attenuation is modeled, and the other is simple evaluation method where ...