UNCERTAINTY ANALYSIS OF TOXIC GAS LEAKAGE ACCIDENT IN COGENERATION HIGH TEMPERATURE GAS-COOLED REACTOR

2019 ◽  
Vol 2019.27 (0) ◽  
pp. 1038
Author(s):  
Hiroyuki Sato ◽  
Hirofumi Ohashi
Keyword(s):  
High Temperature ◽  
Uncertainty Analysis ◽  
Gas Leakage ◽  
Toxic Gas ◽  
High Temperature Gas

scholarly journals Viscoelastic behavior of a casing material and its utilization in premium connections in high-temperature gas wells

2018 ◽  
Vol 10 (12) ◽  
pp. 168781401881745 ◽  
Author(s):  
Ying Zhang ◽  
Zhanghua Lian ◽  
Mi Zhou ◽  
Tiejun Lin
Keyword(s):  
High Temperature ◽  
Contact Pressure ◽  
Viscoelastic Model ◽  
Viscoelastic Behavior ◽  
Element Model ◽  
Gas Production ◽  
Prony Series ◽  
Gas Well ◽  
Gas Leakage ◽  
High Temperature Gas

At the high or extra-high temperatures in a natural gas oilfield, where the premium connection is employed by casing, gas leakage in the wellbore is always detected after several years of gas production. As the viscoelastic material’s mechanical properties change with time and temperature, the relaxation of the contact pressure on the connection sealing surface is the main reason for the gas leakage in the high-temperature gas well. In this article, tension-creep experiments were conducted. Furthermore, a constitutive model of the casing material was established by the Prony series method. Moreover, the Prony series’ shift factor was calculated to study the thermo-rheological behavior of the casing material ranging from 120°C to 300°C. A linear viscoelastic model was implemented in ABAQUS, and the simulation results are compared to our experimental data to validate the methodology. Finally, the viscoelastic finite element model is applied to predict the relaxation of contact pressure on the premium connections’ sealing surface versus time under different temperatures. And, the ratio of the design contact pressure and the intending gas sealing pressure is recommended for avoiding the premium connections failure in the high-temperature gas well.

scholarly journals Prediction calculations for the first criticality of the HTR-PM using the PANGU code

2021 ◽  
Vol 32 (9) ◽  
Author(s):  
Ding She ◽  
Bing Xia ◽  
Jiong Guo ◽  
Chun-Lin Wei ◽  
Jian Zhang ◽  
...  
Keyword(s):  
Monte Carlo ◽  
High Temperature ◽  
Power Plant ◽  
Uncertainty Analysis ◽  
Nuclear Data ◽  
High Fidelity ◽  
Pebble Bed ◽  
Input Model ◽  
High Temperature Reactor ◽  
High Temperature Gas

AbstractThe high-temperature reactor pebble-bed module (HTR-PM) is a modular high-temperature gas-cooled reactor demonstration power plant. Its first criticality experiment is scheduled for the latter half of 2021. Before performing the first criticality experiment, a prediction calculation was performed using PANGU code. This paper presents the calculation details for predicting the HTR-PM first criticality using PANGU, including the input model and parameters, numerical results, and uncertainty analysis. The accuracy of the PANGU code was demonstrated by comparing it with the high-fidelity Monte Carlo solution, using the same input configurations. It should be noted that keff can be significantly affected by uncertainties in nuclear data and certain input parameters, making the criticality calculation challenge. Finally, the PANGU is used to predict the critical loading height of the HTR-PM first criticality under design conditions, which will be evaluated in the upcoming experiment later this year.

Uncertainty Analysis for Source Term Evaluation of High Temperature Gas-Cooled Reactor Under Accident Conditions: Identification of Influencing Factors in Loss-of-Forced Circulation Accidents

2017 ◽  
Author(s):  
Yuki Honda ◽  
Hiroyuki Sato ◽  
Shigeaki Nakagawa ◽  
Hirofumi Ohashi
Keyword(s):  
High Temperature ◽  
Uncertainty Analysis ◽  
Influencing Factors ◽  
Source Term ◽  
Input Parameter ◽  
Forced Circulation ◽  
Variable Parameters ◽  
Term Evaluation ◽  
High Temperature Gas

One of the key elements in probabilistic risk assessment is identification and characterization of uncertainties. This paper aims to suggest a procedure to identify influencing factors for uncertainty in source term evaluation, which are important to risk of public dose. We propose the following five steps for the identification: (1) derivation of variable parameters by expansion of dynamic equation for the system and scenario to be investigated, (2) extraction of uncertainties in variable factors, (3) selection of influencing factors for uncertainty among variable parameters by analysis of existing knowledge and sensitivity study, (4) identification of influencing factors for uncertainty using expert judgement, and (5) integration of selected factors in the aforementioned steps and determination of input parameters in the uncertainty evaluation of the source term evaluation tools relevant to selected factors. The approach is applied to select factors for a risk dominant accident scenario in direct cycle High Temperature Gas-cooled Reactor (HTGR) plant. As a first step, this approach is tested to evaluation of fuel temperature in a depressurized loss-of-forced circulation (DLOFC) accident and failure of mitigation systems such as control rod systems in a representative HTGR plant from the view point of reactor dynamics and thermal hydraulic characteristics. The procedures (1) and (2) are trial to investigate in this paper. As a result, the variable parameters and the relevant uncertainties are successfully extracted in accordance with the suggested procedure. The result will be used for determination of input parameter and uncertainty distribution of these parameters in the uncertainty analysis of source term evaluation.

An Environmental Wet Cell For High Voltage Electron Microscopy

1973 ◽  
Vol 31 ◽  
pp. 18-19
Author(s):  
N.J. Tighe ◽  
H.M. Flower ◽  
P.R. Swann
Keyword(s):  
Electron Microscopy ◽  
High Temperature ◽  
Image Quality ◽  
Inelastic Scattering ◽  
High Voltage ◽  
High Voltage Electron Microscopy ◽  
Voltage Electron ◽  
Environmental Cell ◽  
Water Saturated ◽  
High Temperature Gas

A differentially pumped environmental cell has been developed for use in the AEI EM7 million volt microscope. In the initial version the column of gas traversed by the beam was 5.5mm. This permited inclusion of a tilting hot stage in the cell for investigating high temperature gas-specimen reactions. In order to examine specimens in the wet state it was found that a pressure of approximately 400 torr of water saturated helium was needed around the specimen to prevent dehydration. Inelastic scattering by the water resulted in a sharp loss of image quality. Therefore a modified cell with an ‘airgap’ of only 1.5mm has been constructed. The shorter electron path through the gas permits examination of specimens at the necessary pressure of moist helium; the specimen can still be tilted about the side entry rod axis by ±7°C to obtain stereopairs.

DISPERSED PHASE VELOCITY IN A HIGH-TEMPERATURE GAS FLOW

2019 ◽  
Vol 23 (4) ◽  
pp. 319-328
Author(s):  
Dmitry V. Nesterovich ◽  
Oleg G. Penyazkov ◽  
Yu. A. Stankevich ◽  
M. S. Tretyak ◽  
Vladimir V. Chuprasov ◽  
...  
Keyword(s):  
High Temperature ◽  
Phase Velocity ◽  
Gas Flow ◽  
Dispersed Phase ◽  
High Temperature Gas
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