Study on the aerosol generation of plutonium metal due to oxidation

Abstract Transuranic metals such as plutonium usually need to be protected in inert gases to inhibit oxidation and produce aerosols. In the paper, the oxidation reaction process of plutonium was depicted based on the point defect model. The aerosol generation rate was approximated to the oxidation rate of plutonium when the oxidation layer keeps constant. The results show that the rate is strongly dependent on the vacancy diffusivity and reaction rate constant of the vacancy generation and consumption. The aerosol generation rate at the temperature of 298 K is in the order of 108 particles/cm2/s.

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Determination of exothermic batch reactor specific model parameters

MATEC Web of Conferences ◽

10.1051/matecconf/201929201063 ◽

2019 ◽

Vol 292 ◽

pp. 01063

Author(s):

Lubomír Macků

Keyword(s):

Rate Constant ◽

Reaction Rate ◽

Batch Reactor ◽

Specific Model ◽

Reaction Rate Constant ◽

Order Reaction ◽

First Order Reaction ◽

Model Parameters ◽

Reactor Model ◽

First Order

An alternative method of determining exothermic reactor model parameters which include first order reaction rate constant is described in this paper. The method is based on known in reactor temperature development and is suitable for processes with changing quality of input substances. This method allows us to evaluate the reaction substances composition change and is also capable of the reaction rate constant (parameters of the Arrhenius equation) determination. Method can be used in exothermic batch or semi- batch reactors running processes based on the first order reaction. An example of such process is given here and the problem is shown on its mathematical model with the help of simulations.

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Performance of Photocatalytic Microfiltration with Hollow Fiber Membrane

Materials Science Forum ◽

10.4028/www.scientific.net/msf.544-545.95 ◽

2007 ◽

Vol 544-545 ◽

pp. 95-98 ◽

Cited By ~ 8

Author(s):

Jong Tae Jung ◽

Jong Oh Kim ◽

Won Youl Choi

Keyword(s):

Heavy Metals ◽

Humic Acid ◽

Rate Constant ◽

Hollow Fiber ◽

Reaction Rate ◽

Hollow Fiber Membrane ◽

Membrane Surface ◽

Reaction Rate Constant ◽

Operational Parameters ◽

Tio2 Particles

The purpose of this study is to investigate the effect of the operational parameters of the UV intensity and TiO2 dosage for the removal of humic acid and heavy metals. It also evaluated the applicability of hollow fiber microfiltration for the separation of TiO2 particles in photocatalytic microfiltration systems. TiO2 powder P-25 Degussa and hollow fiber microfiltration with a 0.4 μm nominal pore size were used for experiments. Under the conditions of pH 7 and a TiO2 dosage 0.3 g/L, the reaction rate constant (k) for humic acid and heavy metals increased with an increase of the UV intensity in each process. For the UV/TiO2/MF process, the reaction rate constant (k) for humic acid and Cu, with the exception of Cr in a low range of UV intensity, was higher compared to that of UV/TiO2 due to the adsorption of the membrane surface. The reaction rate constant (k) increased as the TiO2 dosage increased in the range of 0.1~0.3 g/L. However it decreased for a concentration over 0.3 g/L of TiO2. For the UV/TiO2/MF process, TiO2 particles could be effectively separated from treated water via membrane rejection. The average removal efficiency for humic acid and heavy metals during the operational time was over 90 %. Therefore, photocatalysis with a membrane is believed to be a viable process for humic acid and heavy metals removal.

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Reaction rate constant of SO3+ NH3in the gas phase

Journal of Geophysical Research Atmospheres ◽

10.1029/jd095id09p13981 ◽

1990 ◽

Vol 95 (D9) ◽

pp. 13981 ◽

Cited By ~ 15

Author(s):

Gaunlin Shen ◽

Masako Suto ◽

L. C. Lee

Keyword(s):

Gas Phase ◽

Rate Constant ◽

Reaction Rate ◽

Reaction Rate Constant

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Photocatalytic Degradation of Methyl Orange by TiO2/Schorl Photocatalyst: Kinetics and Thermodynamics

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.713-715.2789 ◽

2015 ◽

Vol 713-715 ◽

pp. 2789-2792

Author(s):

Huan Yan Xu ◽

Xue Li ◽

Yan Li ◽

Ping Li ◽

Wei Chao Liu

Keyword(s):

Methyl Orange ◽

Reaction Rate ◽

Reaction Kinetic ◽

Kinetic Studies ◽

Reaction Rate Constant ◽

Order Reaction ◽

Solution Ph ◽

Kinetics And Thermodynamics ◽

Hoff Equation ◽

Degradation Of Methyl Orange

An active dye, Methyl Orange (MO) was employed as the target pollutant to evaluate the photocatalytic activity of TiO2/schorl composite and the kinetics and thermodynamics of this process was emphasized in this work. Langmuir–Hinshelwood kinetic model was employed for the kinetic studies and the results revealed that the process of MO photocatalytic discoloration by TiO2/schorl composite followed one order reaction kinetic equation under different conditions. The reaction rate constant (k) increased with initial MO concentration decreasing. When the catalyst dosage or solution pH increased,kvalues increased and then decreased. The possible reasons for these phenomena were discussed. Finally, the thermodynamic parameters ΔG, ΔH, ΔSwere obtained by the classical Van't Hoff equation.

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Reduction Kinetics of Mill Scale Briquettes by Using A3 Fine Coal as a Reductant

Journal of Nanoscience and Nanotechnology ◽

10.1166/jnn.2021.19101 ◽

2021 ◽

Vol 21 (4) ◽

pp. 2563-2567

Author(s):

Nguyen Hoang Viet ◽

Pham Ngoc Dieu Quynh ◽

Nguyen Thi Hoang Oanh

Keyword(s):

Reaction Rate ◽

Reduction Process ◽

Reduction Reaction ◽

Reaction Rate Constant ◽

Reduction Degree ◽

Furnace Temperature ◽

Time Duration ◽

Mill Scale ◽

Fine Coal ◽

Kinetics Of

In this work, a mixture of mill scale with 5 wt% molasses as binder was pressed under pressure of 200 MPa to prepare briquettes. The reduction process was performed at the temperature of 1000, 1050, 1100, 1150 and 1200 °C in the bed of A3 fine coal as the reductant. The degree of reduction was evaluated at time duration of 15, 30, 45, 60, 90 and 150 minutes, after the furnace temperature reached the predetermined reduction temperature. The highest reduction degree is 94.7% at the reduction process temperature of 1200 °C. Reaction rate constant (k) increased from 4.63×10-4 to 5.03×10-3 min-1 when the temperature increased from 1000 to 1200 °C. The apparent activation energy of the reduction reaction (Ea) is about 95.6 kJ/mole.

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Prediction of Chemical Reaction Yield in a Microreactor and Development of a Pilot Plant Using the Numbering-Up of Microreactors

ASME 2010 8th International Conference on Nanochannels, Microchannels, and Minichannels: Parts A and B ◽

10.1115/fedsm-icnmm2010-30532 ◽

2010 ◽

Author(s):

Shigenori Togashi ◽

Yukako Asano ◽

Yoshishige Endo

Keyword(s):

Monte Carlo Simulation ◽

Monte Carlo ◽

Chemical Reaction ◽

Rate Constant ◽

Pilot Plant ◽

Reaction Rate ◽

Main Product ◽

Reaction Rate Constant ◽

Reaction Yield ◽

Production Scale

The chemical reaction yield was predicted by using Monte Carlo simulation. The targeted chemical reaction of a performance evaluation using the microreactor is the consecutive reaction. The main product P1 is formed in the first stage with the reaction rate constant k1. Moreover, the byproduct P2 is formed in the second stage with the reaction rate constant k2. It was found that the yield of main product P1 was improved by using a microreactor when the ratio of the reaction rate constants became k1/k2 >1. To evaluate the Monte Carlo simulation result, the yields of the main products obtained in three consecutive reactions. It was found that the yield of the main product in cased of k1/k2 >1 increased when the microreactor was uesd. Next, a pilot plant involving the numbering-up of 20 microreactors was developed. The 20 microreactor units were stacked in four sets, each containing five microreactor units arranged. The maximum flow rate when 20 microreactors were used was 1 × 104 mm3/s, which corresponds to 72 t/year. Evaluation of the chemical performance of the pilot plant was conducted using a nitration reaction. The pilot plant was found to capable of increasing the production scale without decreasing the yield of the products.

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Estimation of Effective Moisture Diffusivity in Starchy Materials Following Hydrothermal Treatments

Defect and Diffusion Forum ◽

10.4028/www.scientific.net/ddf.312-315.364 ◽

2011 ◽

Vol 312-315 ◽

pp. 364-369 ◽

Cited By ~ 4

Author(s):

Seyed Amir Bahrani ◽

Catherine Loisel ◽

Jean Yves Monteau ◽

Sid Ahmed Rezzoug ◽

Zoulikha Maache-Rezzoug

Keyword(s):

Reaction Rate ◽

Effective Diffusivity ◽

Moisture Diffusivity ◽

Reaction Model ◽

Reaction Rate Constant ◽

Diffusivity Coefficient ◽

Maize Starch ◽

First Order ◽

Melting Phenomenon ◽

Treatment Processes

Two hydrothermal treatment processes (DV-HMT and DIC treatment) were investigated on standard maize starch for three processing temperatures; 100, 110 and 120°C. The gravimetric change of starch powder during the treatment was analyzed by a simultaneous water diffusion and starch reaction model. The effective diffusivity coefficient (Deff) and reaction rate constant (k) were estimated by minimizing the error between experimental and analytical results. The values of Deff and k clearly increased with temperature. The degree of starch melting was evaluated for the two treatments using the first-order reaction model as a function of processing time. The results suggest that the absorption process is controlled by water–starch reactivity that induces melting phenomenon of starch crystallites, which progresses when temperature increases. The two hydrothermal treatments considerably differ: DIC being more prone to water absorption as demonstrated by the values of Deff and k.

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