Oxidation rate of nuclear-grade graphite IG-110 in the kinetic regime for VHTR air ingress accident scenarios

Lee, Jo Jo; Ghosh, Tushar K.; Loyalka, Sudarshan K.

doi:10.1016/j.jnucmat.2013.11.032

Cited by 41 publications

(18 citation statements)

References 19 publications

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“…Table 1 compares the results obtained by the method recommended by ASTM D7542 and the proposed method. The obtained activation energy of graphite IG-110 (220 kJ/mol) based on the proposed method is closer to those of other studies (218 kJ/mol 12 and 222 kJ/mol 19 ) with sufficient O 2 supply comparing with 201 kJ/mol 21 and 205 kJ/mol 32 based on experiment conditions recommended by ASTM D7542 standard. In addition, the standard errors of the proposed method are smaller.…”

Section: Resultssupporting

confidence: 82%

“…For the high gas flow rate (10 L/min), we got the related data including surface areas from previous study 32 . The calculation result of activation energy of graphite IG-110, 220 kJ/mol, echoed the results of previous studies with more adequate O 2 supply, 218 kJ/mol 12 and 222 kJ/mol 19 , compared with 201 kJ/mol 21 or 205 kJ/mol 32 under the experiment condition recommended by ASTM D7542. For the low gas flow rate (0.2 L/min), nuclear graphite ET-10, produced by IBIDEN Co. Ltd, was oxidized by a 0.2 L/min mixture gas (helium and O 2 , 10% or 20% O 2 mole fraction) at 650–850 °C.…”

Section: Introductionsupporting

confidence: 82%

“…However, several studies 12 , 19 – 23 on graphite IG-110 got the quite different values of activation energy, whose conditions were close to that recommended by ASTM D7542. A study indicated that recommend condition by ASTM D7542 can not guarantee sufficient O 2 supply for oxidation of graphite IG-110, and therefore the increased insufficiency of O 2 supply resulted in decreased values of activation energy 24 .…”

Section: Introductionsupporting

confidence: 71%

“…And therefore, the interaction between the changes of the adequacy of O 2 supply and the graphite microstructure results in variations of behavior of ORs with temperature, and finally different values of activation energy. This is the main reason why the calculation results of activation energy were quite different 12 , 19 – 22 , 32 for graphite IG-110. Among them, the more adequate O 2 supply increased the surface area of oxidized graphite and the OR at high temperature finally resulting in higher calculated values of activation energy (218 kJ/mol 12 and 222 kJ/mol 19 ).…”

Section: Discussionmentioning

confidence: 98%

See 3 more Smart Citations

Characterizing thermal-oxidation behaviors of nuclear graphite by combining O2 supply and micro surface area of graphite

Zhou

Dong

Hua-qiang

et al. 2018

Sci Rep

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The effects of different parameters on oxidation rate are non-linear, interactive and diversified in which the change of adequacy of O2 supply is an important indicator. The influence of microstructure on oxidation rate became stronger worsening the fitting linearity to calculate the activation energy based on present method with the decreased adequacy of O2 supply due to the increase of temperature, the decrease of gas flow rate, etc. Here, we proposed a method to characterize thermal-oxidation behaviors of nuclear graphite by combining O2 supply and micro surface area of graphite. The proposed method improved the linearity and reduced the standard error of Arrhenius plots of oxidized graphite IG-110 (10 L/min reactant gas) and ET-10 (0.2 L/min reactant gas). The value of activation energy of graphite IG-110 oxidized under ASTM D7542 condition is calculated as 220 kJ/mol by this method echoing the results of previous studies with sufficient O2 supply. For the conditions with less O2 supply at low gas flow rate and/or high temperature, the change of microstructure of oxidized graphite should be obtained as an important factor influencing oxidation rate of graphite.

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Section: Resultssupporting

confidence: 82%

Section: Introductionsupporting

confidence: 82%

Section: Introductionsupporting

confidence: 71%

Section: Discussionmentioning

confidence: 98%

See 2 more Smart Citations

Characterizing thermal-oxidation behaviors of nuclear graphite by combining O2 supply and micro surface area of graphite

Zhou

Dong

Hua-qiang

et al. 2018

Sci Rep

View full text Add to dashboard Cite

show abstract

“…Schematic diagram of the nuclear steam supply system [22] Such pressure vessel configuration is intended to reduce the possibility of water intrusion into the reactor. The intrusion of water and also air from the steam generator into the reactor core can cause corrosion in the reactor structure which consists mainly of graphite [23,24]. The blower or compressor used to circulate helium gas in the primary cooling system loop is installed at the top of the pressure vessel for the steam generator.…”

Section: Nuclear Steam Supply Systemmentioning

confidence: 99%

Performance Analysis of Rde Energy Conversion System in Various Reactor Power Condition

et al. 2019

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Reaktor Daya Eksperimental (RDE) is an experimental power reactor based on High Temperature Gas-cooled Reactor (HTGR) technology with thermal power of 10 MW. As an experimental power reactor, RDE is designed for electricity generation and provides thermal energy for experimental purposes. RDE energy conversion system is designed with cogeneration configuration in the Rankine cycle. To ensure the effectiveness of its cogeneration, the outlet temperature of the RDE is set at 700°C and steam generator outlet temperature is around 530°C. Analysis of the performance of the energy conversion system in various power levels is needed to determine the RDE operating conditions. This research is aimed to study the performance characteristics of RDE energy conversion systems in various reactor power conditions. The analysis was carried out by simulating thermodynamic parameter calculations on the RDE energy conversion system and the overall cooling system using the ChemCad program package. The simulation is carried out by increasing the reactor power from 0 MW to 10 MW at constant pressure and constant mass flow rate. The simulation results show that the steam fraction at the steam generator outlet increases starting from 3 MW reactor power and reaches saturated steam after the thermal power level of 7.5 MW. From the results, it can be concluded that with constant mass flow rate and operating pressure, optimal turbine power is obtained after the reactor thermal power reached 7.5 MW.

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Depth profile analysis of oxidized nuclear graphite microstructures using micro-focused synchrotron X-ray diffraction

Huang

et al. 2022

J Mater Sci

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Oxidation rate of nuclear-grade graphite IG-110 in the kinetic regime for VHTR air ingress accident scenarios

Cited by 41 publications

References 19 publications

Characterizing thermal-oxidation behaviors of nuclear graphite by combining O2 supply and micro surface area of graphite

Characterizing thermal-oxidation behaviors of nuclear graphite by combining O2 supply and micro surface area of graphite

Performance Analysis of Rde Energy Conversion System in Various Reactor Power Condition

Depth profile analysis of oxidized nuclear graphite microstructures using micro-focused synchrotron X-ray diffraction

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