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Kurihara, Akikazu; Umeda, Ryota; Shimoyama, Kazuhito; Kikuchi, Shin
Nihon Kikai Gakkai Rombunshu (Internet), 84(859), p.17-00382_1 - 17-00382_11, 2018/03
Wastage on adjacent tubes (target-wastage) arise from water/steam leak in steam generators of sodium-cooled fast reactors (sodium-water reaction). Target-wastage is likely to be caused by liquid droplet impingement erosion (LDI) and Na-Fe composite oxidation type corrosion with flow (COCF) in an environment marked by high temperature and high-alkali (reaction jet) due to sodium-water reaction. In the previous study, the authors quantitatively evaluated the effect of material temperature and fluid velocity on COCF rate, and revealed that COCF was sodium-iron composite oxidation type corrosion from metallographic observation and element assay. In this study, the applicability of new wastage correlations was confirmed for each tube in sodium-water reaction test with straight vertical tube bundle under practical steam generator operation condition. The authors established that the new wastage correlations were applicable to each tube of tube bundle in the above test, and the time progress of wastage was qualitatively investigated for the two penetrated tubes in the period including the water and/or steam blowdown.
Umeda, Ryota; Shimoyama, Kazuhito; Kurihara, Akikazu
JAEA-Technology 2017-018, 70 Pages, 2017/08
JAEA-Technology-2017-018.pdf:9.67MB
In case of the water leak into sodium in a SG of SFRs due to tube failure, reaction jet is formed by sodium-water reaction with exothermic heat. The reaction jet forms highly alkaline environment with high temperature and high pressure, which cause local thinning of adjacent heat transfer tubes (target wastage). In this report, for the purpose of elucidation of target wastage, the authors developed the experimental apparatus and experimental technique which enable the separate evaluation of wastage influence factors, including temperature, impingement velocity, reagent ratio and so on by using high temperature sodium hydroxide as major reaction product and sodium monoxide as secondary reaction product. In addition, the impingement corrosion experiments have been conducted by using high temperature reagents (NaOH and Na
O). Based on the corrosive data, authors quantitatively evaluated the influence factors of wastage and formulated the average corrosive equations.
Akabane, Masaaki*; Horiki, Sachiyo*; Osakabe, Masahiro*; Koizumi, Yasuo; Uchibori, Akihiro; Ohno, Shuji; Ohshima, Hiroyuki
Proceedings of 23rd International Conference on Nuclear Engineering (ICONE-23) (DVD-ROM), 7 Pages, 2015/05
Behavior of liquid droplets in a high-velocity gaseous jet was experimentally investigated to provide validation data for the evaluation method of sodium-water reaction phenomenon. The visualization experiment on the entrained liquid droplets in the air jet submerged in a water pool was carried out. Filament-like wisps from the wavy gas-liquid interface were observed. The wisps were broken off and entrained into the air jet. The velocity of the entrained liquid droplets was estimated from an image processing. The axial velocity of the liquid droplets increased as the air inlet velocity increased. Acceleration behavior of the liquid droplets was also confirmed quantitatively.
Uchibori, Akihiro; Ohshima, Hiroyuki
Proceedings of 9th Korea-Japan Symposium on Nuclear Thermal Hydraulics and Safety (NTHAS-9) (CD-ROM), 6 Pages, 2014/11
A computer code called SERAPHIM calculating compressible multicomponent multiphase flow with sodium-water chemical reaction has been developed to evaluate wastage environment under tube failure accident in a steam generator of sodium-cooled fast reactors. In this study, the numerical model for liquid droplet entrainment and its transport was developed. The applicability of the model was investigated through the analysis of the basic experiment. It was demonstrated that our numerical model could reproduce the time to end of entrainment and the pressure variation during the occurrence of entrainment.
Jang, S.*; Takata, Takashi; Yamaguchi, Akira*; Uchibori, Akihiro; Kurihara, Akikazu; Ohshima, Hiroyuki
Proceedings of 9th Korea-Japan Symposium on Nuclear Thermal Hydraulics and Safety (NTHAS-9) (CD-ROM), 8 Pages, 2014/11
Numerical quantification of the self-wastage phenomenon has been carried out using a multi-dimensional computational code: SERAPHIM. The width of the completely enlarged crack was investigated in this study. Several steps of numerical calculations were devised to reproduce transient self-wastage phenomenon caused by Sodium Water Reaction (SWR). In the analyses, 2-dimensional calculation was carried out to obtained thermal hydraulic properties in the reaction zone. The wastage amount was evaluated based on hypothetical Arrhenius equation by using the temperature and molar concentration of Sodium hydroxide. New analytical grid was created by exchanging the solid cells to fluid cells in the reaction based on the wastage amount evaluation. These series of procedure have been repeated. The width and the shape of the enlarged crack showed good agreement with the experimental results.
*; *; Kuroha, Mitsuo
PNC TN9410 86-023, 112 Pages, 1986/03
It is essential to clarify wastage behavior of a heat transfer tube in a sodium-water reaction in order to analyze a water leakage incident in a steam generator of LMFBR Monju. There fore wastage tests in small and intermediate leak ranges were conducted for austenitic stainless steel JIS 
SUS321 of a Monju superheater tube material by use of Small Leak Sodium-Water Reaction Test Loop (SWAT-2) and Large Leak Sodiam-Water Reaction Test Rig (SWAT-1). In the tests, a water leak rate, a distance from a leak nozzle to a target tube, and a sodium temperature were varied as empirical parameters. Test Results are as follows: (1)In the small 1eak range (0.1
10g/sec), the wastage rate of SUS321 depends on L/D and has maximum value at L/D of 20 to 30 ; where L ls distance from the nozzle to the target and D is a nozzle diameter. Since the maximun wastage rate of SUS321 is about half as high as that of SUS304, SUS321 is more resistive against wastage than SUS304. (2)In the intermediate leak range (30 and 150 g/sec), the wastage rate depends on L/D and has a peak at L/D of 2050. The maximum wastage rate is quarter as high as that of 2%Cr-1Mo Steel. (3)Empirical formulas were derived from these test results concerning the relation between the wastage rate and the parameters.
Shimoyama, Kazuhito; Kurihara, Akikazu; Kikuchi, Shin; Umeda, Ryota; Ohshima, Hiroyuki
no journal, ,
Corrosion may proceed on the tube surface due to chemical reaction between sodium and water (self-wastage), in case of water/steam leak though the penetrating crack caused in the steam generator tube of sodium-cooled fast reactor. We performed the self-wastage experiments under high sodium temperature condition to evaluate the effect of wastage dimension and water leak rate on self-wastage rate in the fine crack in this report.
Umeda, Ryota; Kurihara, Akikazu; Shimoyama, Kazuhito; Kikuchi, Shin; Ohshima, Hiroyuki
no journal, ,
no abstracts in English
Shimoyama, Kazuhito; Kurihara, Akikazu; Kikuchi, Shin; Umeda, Ryota
no journal, ,
Self-wastage comes from water/steam leak through the penetrating crack caused in the steam generator tube of sodium-cooled fast reactor. When the self-wastage proceeds to inside wall of tube, breach area and water leak rate will be larger, then, it will be likely to spread the affected area caused by sodium-water reaction. It is very important to clarify the self-wastage behavior for locally affected region and detection of the water leak in real plant. In the 1st report, the authors have performed the self-wastage experiments for the pinhole type micro crack. In this report, fatigue crack type self-wastage experiments were carried out to evaluate the effect of wastage form/geometry and water leak rate, it was confirmed that initial defect geometry, such as pinhole and fatigue crack, does not strongly influence to self-wastage rate.
Kojima, Saori*; Uchibori, Akihiro; Takata, Takashi; Ohno, Shuji; Fukuda, Takeshi*; Yamaguchi, Akira*
no journal, ,
Analytical evaluation on a self-wastage phenomenon at heat transfer tubes in the steam generator of sodium cooled fast reactors has been performed by using the sodium-water reaction analysis code SERAPHIM. In this study, a fluid-structure thermal coupling model was developed and incorporated in the SERAPHIM code to evaluate heat transfer between the sodium-side reacting flow and the outer surface of the heat transfer tube. The effect of the fluid-structure thermal coupling model on the temperature field was demonstrated through the numerical analyses.
Jang, S.*; Yamaguchi, Akira*; Takata, Takashi; Ohshima, Hiroyuki
no journal, ,
In a self-wastage phenomenon, which occurs when a quite small leak of water or water vapor occurs in a steam generator of sodium cooled fast reactor, many parameters such as a shape and rate of leakage and sodium temperature are related mutually. In the present study, DEMATEL (Decision Making Trial and Evaluation Laboratory) method is applied to choose dominant parameters in the self-wastage phenomenon.
Umeda, Ryota; Shimoyama, Kazuhito; Kurihara, Akikazu
no journal, ,
For the purpose of making a contribution to the rational safety design of a steam generator in sodium-cooled fast reactor, in order to utilize as the verification data of the new wastage evaluation method in consideration of the local wear environment around adjacent tubes in case of sodium-water reaction, the sodium-water reaction experiments have been carried out in the vertical tube bundle, the basic data such as temperature around the target tube, the wastage conditions, and so on were obtained.
Kurihara, Akikazu; Umeda, Ryota; Shimoyama, Kazuhito
no journal, ,
The authors analyzed the wastage environment around the neighboring tubes acquired in the sodium-water reaction experiment that simulated the vertical tube bundle, and qualitatively evaluated the applicability of new wastage evaluating method taken into account of the local wastage environment.
Umeda, Ryota
no journal, ,
As for the wastage behavior caused on tubes in steam generator of sodium-cooled fast reactor, the author has developed the new experimental procedure, such as the phenomenological separation effect experiment and the new isolation mechanism to avoid the measurement error.
Kurihara, Akikazu; Umeda, Ryota; Shimoyama, Kazuhito; Kikuchi, Shin
no journal, ,
Wastage phenomena on adjacent tubes (target-wastage) arise from water/steam leak in steam generators of sodium-cooled fast reactors. Target-wastage is likely to be caused by liquid droplet impingement erosion (LDI) and Na-Fe composite oxidation type corrosion with flow (COCF) in an environment marked by high temperature and high-alkali (reaction jet) due to sodium-water reaction. The authors derived new wastage correlations from COCF and LDI data based on influencing factors which were formed on the periphery of an adjacent tube. In this report, the authors established that the new wastage correlations were applicable to each tube of tube bundle in sodium-water reaction test with straight vertical tube bundle under practical steam generator operation condition, and the time progress of wastage was qualitatively investigated for the two penetrated tubes in the period including the blowdown.
Kurihara, Akikazu; Umeda, Ryota
no journal, ,
When the heat transfer tube failed in steam generator of sodium-cooled fast reactor, failure propagation is caused by secondary accident of adjacent tubes, it has possibility that the affected area will be expanded. In this report, the authors reported the result of investigating the applicability of local wastage influencing factors based on the existing data, for the conventional wastage correlations arranged by the boundary conditions.
