Temperature Jump Measurement at Stainless Steel and Helium Interface: Application to Used Nuclear Fuel Vacuum Drying Process

2018 ◽  
Author(s):  
Cody Zampella ◽  
Mustafa Hadj-Nacer ◽  
Miles Greiner
Keyword(s):  
Stainless Steel ◽  
Nuclear Fuel ◽  
Temperature Jump ◽  
Rarefied Gas ◽  
Maximum Temperature ◽  
Vacuum Drying ◽  
Stainless Steel Surface ◽  
Concentric Cylinders ◽  
Experimental Apparatus ◽  
Fuel Assemblies

Vacuum drying of nuclear fuel canisters may cause the temperature of fuel assemblies to considerably increase due to the effect of gas rarefaction at low pressures. This effect may induce a temperature-jump at the gas-solid interfaces. It is important to predict the temperature-jump at these interfaces to accurately estimate the maximum temperature of the fuel assemblies during vacuum drying. The objective of this work is to setup a concentric cylinders experimental apparatus that can acquire data to benchmark rarefied gas heat transfer simulations, and determine the temperature-jump coefficient at the interface between stainless steel surface and helium gas. The temperature-jump is determined by measuring the temperature difference and heat flux across a 2-mm gap between the concentric cylinders that contains rarefied helium and compare the results to analytical calculations in the slip rarefaction regime.

Temperature Measurement of an Array of Heated Rods Subjected to Vacuum Drying Conditions

2017 ◽  
Author(s):  
Dilesh Maharjan ◽  
Mustafa Hadj-Nacer ◽  
Miles Greiner
Keyword(s):  
Temperature Jump ◽  
Maximum Temperature ◽  
Vacuum Drying ◽  
Helium Pressure ◽  
Used Nuclear Fuel ◽  
Experimental Apparatus ◽  
Computational Fluid Dynamics Simulations ◽  
Dynamics Simulations ◽  
Drying Conditions ◽  
Low Pressures

During vacuum drying of used nuclear fuel canister, helium pressure is decreased to as low as 67 Pa to promote evaporation and removal of water remaining in the canister following draining operation. At low pressures associated with vacuum drying, there is a temperature jump (thermal resistance) between the solid surfaces and helium in contact with them. This temperature jump increases as the pressure decreases (rarefied condition), which contributes to the fuel assembly’s temperature increase. It is important to keep the temperature of the fuel assemblies below 400°C during vacuum drying to ensure their safety for transport and storage. In this work, an experimental apparatus consisting of a 7×7 array of electrically heated rods maintained between two spacer plates and enclosed inside a square cross-section stainless steel pressure vessel is constructed to evaluate the temperature of the heater rods at different pressures. This geometry is relevant to a BWR fuel assembly between two consecutive spacer plates. Thermocouples are installed in each of the 49 heater rods, spacer plates and enclosure walls. They provide a complete temperature profile of the experiment. Different pressures and heat generation relevant to vacuum drying conditions are tested. The results showed that the maximum temperature of the heater rods increases as the pressure decreases. The results from these experiments will be compared to computational fluid dynamics simulations in a separate work.

Design of an Experiment to Measure the Thermal Accommodation Coefficient Between Helium and Stainless-Steel in Concentric Cylinders

2015 ◽  
Author(s):  
Rachel Green ◽  
Mustafa-Hadj Nacer ◽  
Miles Greiner
Keyword(s):  
Heat Transfer ◽  
Heat Flux ◽  
Stainless Steel ◽  
Temperature Difference ◽  
Rarefied Gas ◽  
Accommodation Coefficient ◽  
Theoretical Expression ◽  
Thermal Accommodation ◽  
Concentric Cylinders ◽  
Thermal Accommodation Coefficient

Heat transfer through a 1 mm gap between two concentric cylinders representing the gap between a fuel support basket and a canister is experimentally and numerically investigated. The objective of this work is to study rarefied gas heat transfer in a simple geometry, and to measure the thermal accommodation coefficient at the interface between stainless steel and rarefied helium. The thermal accommodation coefficient is used to characterize the interaction between gas molecules and wall at the molecular level. It is important to determine its value with precision for better determination of heat transfer at low pressure. The experimental procedure consists of measuring the temperature difference between the inner and outer cylinders as the pressure is decreased in the gap. By knowing the heat flux across the gap the thermal accommodation coefficient can be extracted from the theoretical expression relating the temperature difference to the radial heat flux. Three-dimensional simulations using the ANSYS/Fluent commercial code are conducted to assess on the design of the experimental apparatus. These simulations confirmed that the apparatus design is effective to study the heat transfer across rarefied gas and to determine the thermal accommodation coefficient for helium on stainless steel surface.

A Global Model for Predicting Vacuum Drying of Used Nuclear Fuel Assemblies

2021 ◽  
pp. 1-14
Author(s):  
Sudipta Saha ◽  
Jamil Khan ◽  
Travis Knight ◽  
Tanvir Farouk
Keyword(s):  
Nuclear Fuel ◽  
Global Model ◽  
Vacuum Drying ◽  
Used Nuclear Fuel ◽  
Fuel Assemblies

Design of an Experimental Apparatus to Measure the Thermal Accommodation Coefficient Between Stainless Steel Surfaces and Rarefied Helium

2014 ◽  
Author(s):  
Rachel Green ◽  
Ernesto T. Manzo ◽  
Mustafa Hadj Nacer ◽  
Miles Greiner
Keyword(s):  
Heat Transfer ◽  
Stainless Steel ◽  
Rarefied Gas ◽  
Accommodation Coefficient ◽  
Electric Heater ◽  
Cross Sectional ◽  
Thermal Accommodation ◽  
Experimental Apparatus ◽  
Thermal Accommodation Coefficient ◽  
Aluminum Cylinder

The objective of this work is to design an experimental apparatus that can acquire data to benchmark rarefied gas heat transfer simulations, and determine the thermal accommodation coefficient at the interface between the solid surfaces and the gas. The design consists of an aluminum cylinder with an electric heater at its centerline, and within a stainless-steel sheath, centered inside a cylindrical pressure vessel whose temperature is controlled using an external water jacket. There is 0.47-cm-wide helium-filled gap between the inner cylinder and vessel wall. For a given heat generation rate, the temperature difference across this gap will increase as the gas pressure decreases due to ratification. Thermocouples will be bonded to the vessel’s outer surface, and the inner surface of the sheath that surrounds the heated aluminum cylinder. Two, two-dimensional computational meshes of the apparatus (one cross sectional and the other cross sectional is offset) and one three-dimensional computational mesh are constructed. These models include heat generation within the electric heater, conduction within the solid and gas-filled regions, and radiation heat transfer across the gas, and rarefied gas thermal resistances at the solid/gas interfaces. These simulations show that the difference between the thermocouple temperatures and the surfaces of the helium filled gap are small compared to the temperature across the gap. This will allow this apparatus design to be used to effectively benchmark the ANSYS/Fluent simulations, and determine the thermal accommodation coefficient.

Novel Electro Polymerization Method to Synthesized Anti-corrosion Coated Layer on Stainless Steel Surface from (N-Benzothiazolyl Maleamic Acid) and Study its Biological Activity

2018 ◽  
Vol 9 (3) ◽  
Author(s):  
Muna I Khalaf ◽  
Khulood A Saleh ◽  
Khalil S Khalil
Keyword(s):  
Stainless Steel ◽  
Chemical Structure ◽  
Inhibition Efficiency ◽  
Steel Plate ◽  
Polymeric Coating ◽  
Stainless Steel Surface ◽  
Plate Electrode ◽  
Before And After ◽  
Maleamic Acid ◽  
Polymerization Method

Electro polymerization of N-benzothiazolyl maleamic acid (NBM) was carried out on stainless steel plate electrode in a protic medium of monomer aqueous solution using electrochemical oxidation procedure in electrochemical cell.Spectroscopic characterization techniques were investigated to obtain information about the chemical structure of polymer. The anti-corrosion action of polymer was investigated on stainless steel by electrochemical polarization method. In addition, the effect of adding nanomaterial (TiO2, ZnO (bulk-nano)) to monomer solution on the corrosion behavior of stainless steel was investigated. The results obtained showed that the corrosion rate of S-steel increased with temperature increase from 293K to 323K and the values of inhibition efficiency by coating polymer increase with nanomaterial addition. Apparent energies of activation have been calculated for the corrosion process of S-steel in acidic medium before and after polymeric coating. Furthermore were studied the effect of the preparing polymer on some strain of bacteria.

Comparison of DSMC and CFD Models of Heat Transfer in a Rarefied Two-Dimensional Geometry

2018 ◽  
Author(s):  
Dilesh Maharjan ◽  
Mustafa Hadj-Nacer ◽  
Miles Greiner ◽  
Stefan K. Stefanov
Keyword(s):  
Heat Transfer ◽  
Rarefied Gas ◽  
Complex Geometry ◽  
Direct Simulation Monte Carlo ◽  
Accurate Method ◽  
Vacuum Drying ◽  
Helium Pressure ◽  
Two Dimensional ◽  
Dsmc Method ◽  
Cfd Simulations

During vacuum drying of used nuclear fuel (UNF) canisters, helium pressure is reduced to as low as 67 Pa to promote evaporation and removal of remaining water after draining process. At such low pressure, and considering the dimensions of the system, helium is mildly rarefied, which induces a thermal-resistance temperature-jump at gas–solid interfaces that contributes to the increase of cladding temperature. It is important to maintain the temperature of the cladding below roughly 400 °C to avoid radial hydride formation, which may cause cladding embrittlement during transportation and long-term storage. Direct Simulation Monte Carlo (DSMC) method is an accurate method to predict heat transfer and temperature under rarefied condition. However, it is not convenient for complex geometry like a UNF canister. Computational Fluid Dynamics (CFD) simulations are more convenient to apply but their accuracy for rarefied condition are not well established. This work seeks to validate the use of CFD simulations to model heat transfer through rarefied gas in simple two-dimensional geometry by comparing the results to the more accurate DSMC method. The geometry consists of a circular fuel rod centered inside a square cross-section enclosure filled with rarefied helium. The validated CFD model will be used later to accurately estimate the temperature of an UNF canister subjected to vacuum drying condition.

scholarly journals Analysis of the Accelerator-Driven System Fuel Assembly during the Steam Generator Tube Rupture Accident

Materials ◽  
2021 ◽  
Vol 14 (8) ◽  
pp. 1818
Author(s):  
Di-Si Wang ◽  
Bo Liu ◽  
Sheng Yang ◽  
Bin Xi ◽  
Long Gu ◽  
...  
Keyword(s):  
Fuel Assembly ◽  
Steam Generator ◽  
Metal Flow ◽  
Maximum Temperature ◽  
Steam Generator Tube ◽  
Driven System ◽  
Fuel Assemblies ◽  
Accelerator Driven System ◽  
The Impact ◽  
Steam Bubble

China is developing an ADS (Accelerator-Driven System) research device named the China initiative accelerator-driven system (CiADS). When performing a safety analysis of this new proposed design, the core behavior during the steam generator tube rupture (SGTR) accident has to be investigated. The purpose of our research in this paper is to investigate the impact from different heating conditions and inlet steam contents on steam bubble and coolant temperature distributions in ADS fuel assemblies during a postulated SGTR accident by performing necessary computational fluid dynamics (CFD) simulations. In this research, the open source CFD calculation software OpenFOAM, together with the two-phase VOF (Volume of Fluid) model were used to simulate the steam bubble behavior in heavy liquid metal flow. The model was validated with experimental results published in the open literature. Based on our simulation results, it can be noticed that steam bubbles will accumulate at the periphery region of fuel assemblies, and the maximum temperature in fuel assembly will not overwhelm its working limit during the postulated SGTR accident when the steam content at assembly inlet is less than 15%.

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