Viscosities of molten BC-stainless steel alloys

Nishi, Tsuyoshi*; Sato, Rika*; Ota, Hiromichi*; Kokubo, Hiroki*; Yamano, Hidemasa

Journal of Nuclear Materials, 552, p.153002_1 - 153002_7, 2021/08

https://doi.org/10.1016/j.jnucmat.2021.153002

Determining high precision viscosities of molten BC-stainless steel (BC-SS) alloys is essential for the core disruptive accident analyses of sodium-cooled fast reactors and for analysis of severe accidents in boiling water reactors (BWR) as appeared in Fukushima Daiichi. However, there are no data on the high precision viscosities of molten BC-SS alloys due to experimental difficulties. In this study, the viscosities of molten SS (Type 316L), 2.5mass%BC-SS, 5.0mass%BC-SS, and 7.0mass%BC-SS alloys were measured using the oscillating crucible method in temperature ranges of 1693-1793 K, 1613-1793 K, 1613-1793 K, and 1713-1793 K, respectively. The viscosity was observed to increase as the BC concentration increased from 0 to 7.0 mass%. Using the experimental data of the molten 2.5mass%BC-SS and 5.0mass%BC-SS and 7.0mass%BC-SS in the temperature range of 1713-1793 K, the equation for the viscosity of molten BC-SS alloys was determined, and the measurement error of the viscosity of molten BC-SS alloys is less than 8%.

Viscosity measurement of nickel and stainless steel aiming at systematic viscosity measurement for molten mixture of stainless steel and boron-carbide

Kokubo, Hiroki*; Nishi, Tsuyoshi*; Ota, Hiromichi*; Yamano, Hidemasa

Nihon Kinzoku Gakkai-Shi, 82(10), p.400 - 402, 2018/09

https://doi.org/10.2320/jinstmet.JAW201812

It is important to obtain the viscosity of a mixed alloy consisting of molten stainless steel and boron-carbide (SUS316L + BC alloy) for the improvement of severe accident assessment methodology for sodium-cooled fast reactors. In this study, the viscosities of the molten nickel (Ni) and stainless steel (SUS316L) were measured by the oscillating crucible method to confirm the performance of the viscosity measurement apparatus as a first step. The viscosities of molten Ni and SUS316L melts were measured up to 1823 K. It was found that the measured viscosity values of molten Ni and SUS316L were estimated from the deviation of the experimental data, were 4% and 3%, respectively. It was also found that those of molten Ni and SUS316L were close to those of the literature values of molten Ni and similar composite stainless steels. Moreover, we tentatively measured the viscosity of molten SUS316L-5 mass%BC alloy. The fitted results of the viscosity for molten Ni and SUS316L were obtained.

Measurement of U and Pu concentration by X-ray fluorescence spectrometry using vertical irradiation system.

; ; ; Ikeda, Hisashi ; Jitsukata, Shu*; *

JNC TN8410 2000-022, 55 Pages, 2000/05

JNC-TN8410-2000-022.pdf:1.57MB

Measurement of U and Pu concentrations by wavelength dispersion type X-ray fluorescence spectrometry was studied. Sample holder was installed inside of glove box and other instruments, X-ray tube, monochromator and detectors were set out side of the glove box. X-rays was irradiated to sample though Be window. Fluorescent X-rays form sample were also passing though the same Be window and detected outside. Analytical conditions were optimized as follows. Sample thickness is 8 mm, which is 3ml of sample volume by the sample holder. Voltage and eurrent for X-ray tube is 50kV and 40 mA, respectively. Measurement was done twice, 60 seconds each, and averaged X-ray intensity was used to calculate elemental concentrations. Matrix correction was necessary to measure U and Pu concentration within 10% accuracy. Detection limits were calculated to 0.4 mg/L for U and 0.7mg/L for Pu. Calibration curve was liner up to 9 g/L fbr U and Pu. Two calculation methods, calibration curve method and standard addition method, were studied to measure Pu concentration in organic solution. Detection limit was 5.3 mg/L and 0.2 mg/L, respectively.

Evaluation of Coupled Thermo-Hydro-Mechanical Phenomena in the Near Field for Geological Disposal of High-Level Radioactive waste

Chijimatsu, Masakazu*; Fujita, Tomoo; Sugita, Yutaka; Taniguchi, Wataru

JNC TN8400 2000-008, 339 Pages, 2000/01

JNC-TN8400-2000-008.pdf:30.96MB

Geological disposal of high-level radioactive waste (HLW) in Japan is based on a multibarrier system composed of engineered and natural barriers. The engineered barriers are composed of vitrified waste confined within a canister, overpack and buffer material. Highly compacted bentonite clay is considered one of the most promising candidate buffer material mainly because of its low hydraulic conductivity and high adsorption capacity of radionuclides. In a repository for HLW, complex thermal, hydraulic and mechanical (T-H-M) phenomena will take place, involving the interactive processes between radioactive decay heat from the vitrified waste, infiltration of ground water and stress generation due to the earth pressure, the thermal loading and the swelling pressure of the buffer material. In order to evaluate the performance of the buffer material, the coupled T-H-M behaviors within the compacted bentonite have to be modelled. Before establishing a fully coupled T-H-M model, the mechanism of each single Phenomenon or partially coupled phenomena should be identified. Furthermore, in order to evaluate the coupled T-H-M phenomena, the analysis model was developed physically and numerically and the adequacy and the applicability was tested though the engineered scale laboratory test and in-situ test. In this report, the investigative results for the development of coupled T-H-M model were described. This report consists of eight chapters. In Chapter l, the necessity of coupled T-H-M model in the geological disposal project of the high-level radioactive waste was described. In Chapter 2, the laboratory test results of the rock sample and the buffer material for the coupled T-H-M analysis were shown. The rock samples were obtained from the in-situ experimental site at Kamaishi mine. As the buffer material, bentonite clay (Kunigel V1 and Kunigel OT-9607) and bentonite-sand mixture were used. In Chapter 3, in-situ tests to obtain the rock property were shown. As ...

Simulation of second fire incident in the filling room (R152)

Miura, Akihiko;

JNC TN8410 99-046, 35 Pages, 1999/10

JNC-TN8410-99-046.pdf:7.29MB

Judging from several evidences which are operators' testimony, observation result, and so on, the "Committee for an Investigation into the Fire and Explosion Incident at the BDF of the Reprocessing plant of Tokai Works" concluded another fire incident occurred in the filling room (R152) after the explosion (hereafter called second fire incident). This report explains the simulation result of second fire incident. Calculated air temperature and radiation intensity are used another calculations that indicate the thermal influence from the fire name to the extruder or neighboring drums. About second fire incident, calculated result indicates first fire occurred from the No.30104 drum that was produced in 30B or several drums including No.30104 drum. It is estimated that temperature and thermal runaway reaction was not due to fire of neighboring drum because the drum doesn't receive large influence thermally by radiation from the neighboring fire name. Each result suggests the all burnt 29B and 30B drums were filled at higher temperature than usual.

Analysis of operation records; Evaluation of event sequences in extruder

; Miura, Akihiko; ;

JNC TN8410 99-043, 135 Pages, 1999/10

JNC-TN8410-99-043.pdf:6.44MB

All result of chemical analysis and operators observation suggest non-chemical mechanism raised the filling temperature of the bituminized product at the incident. We, Tokai reprocessing plant safety evaluation and analysis team, performed the experiment using laboratory scale extruder and viscosity measurement to explain the high temperature of mixture. The result of the experiment using laboratory scale extruder showed that the phenomena of salt enrichment and salt accumulation oceured and they raised mixture temperature at the decreased feeed rate. These phenomena depend on the feed rate and they have large contribution of heat transportation and rise of operational torque due to the friction between screw and mixture. Based on the experiment result and all information, we investigated the operation procedure, operational records and machine arrangement to try to explain the behavior of the mixture in the extruder. Judging from each torque and temperature behavior, we succeeded in explaining a sequential behavior in the incident. It is estimated that mixture temperature was raised by physical heat generation in the extruder and this report explains each operation, investigated result and estimated event sequences.

Test on the flowing down of simulated bituminized product

; Aoyama, Makoto; ; Yamanouchi, Takamichi

PNC TN8410 97-319, 143 Pages, 1997/10

PNC-TN8410-97-319.pdf:36.19MB

The fire and explosion incident occurred at Bituminization Demonstration Facility of PNC Tokai Works on March 11, 1997. In order to ascertain the cause of incident, the investigation has been pushed forward. During investigation, we obtained essential information from operators, such as softness of bituminized product, white smoke generated from bituminized product. This condition has never been observed comparing past normal operation. Therefore, we assumed that temperature of bituminized product had increased more than expected. In order to confirm above assumption, we made experiment for obtaining the relationship between temperature and fluidity of bituminized product. Simulated bituminized product was heated up to each temperature (210, 230, 250, 270C) in a pot and poured down into an another pot. We observed the fluidity of bituminized product when it flowing down into a pot. The fluidity of bituminized product increased with high temperature. The fluidity of bituminized product at 270C looked similar to fluidity of bituminized product that had ignited itself at the incident. White smoke generated from bituminized product and amounts of white smoke increased with high temperature. The smoke was considered to be gas that generated through thermal decomposition or volatilization of bitumen.

Preparation of source particles for fabricating pellets through sol-gel microsphere pelletization; Preparation of 50m class microspheres of ThO and (Th,U)O

; Takahashi, Yoshihisa

JAERI-M 93-122, 18 Pages, 1993/06

JAERI-M-93-122.pdf:1.47MB

no abstracts in English

Adsorption of radioactive cobalt by mixture of Manganese oxide and montmorillonite

Onuki, Toshihiko

Journal of Nuclear Science and Technology, 27(11), p.1068 - 1071, 1990/11

https://doi.org/10.3327/jnst.27.1068

no abstracts in English

Studies on the behavior of several elements in the fused bismuth-fused salts system, I; Distribution of several elements between fused bismuth and fused LiCl-KCl (eutectic)

;

Nihon Genshiryoku Gakkai-Shi, 5(3), p.210 - 218, 1963/00

https://doi.org/10.3327/jaesj.5.210

no abstracts in English

Viscosity measurements of molten stainless-steel containing boron-carbide

Nishi, Tsuyoshi*; Ota, Hiromichi*; Kokubo, Hiroki*; Sato, Rika*; Yamano, Hidemasa

no journal, , 

In this study, the viscosities of the molten SS (SUS316L), 2.5mass%BC-SS, 5.0mass%BC-SS, 7.0mass%BC-SS and 10mass%BC-SS alloys were measured by the oscillating crucible method. The viscosity measurements of the molten SS, 2.5mass%BC-SS and 5mass%BC-SS, 7mass%BC-SS and 10mass%BC-SS alloys were performed in the temperature range from 1613 to 1793 K, from 1713 to 1793 K, and from 1793 to 1823 K, respectively. In these results, the viscosity increased with BC components in the BC components range from 0 to 7.0mass%. The equation of viscosity of molten BC-SS alloys was estimated by using the experimental data of the molten 2.5mass%BC-SS and 5.0mass%BC-SS, and 7.0mass%BC-SS in the temperature range from 1713 to 1793 K. The equation of viscosity of molten SS+BC alloys was determined as follows. y=Ax+B, A=0.0302, B=-9.88110T+2.546, where x is the BC component and T is the temperature. The uncertainty of the equation is 2.5%.