Development of Device for Detecting Helium Leak From Canister: Part 1 — Experiment on Temperature Behavior During Gas Leak From Canister of 1/4.5 Scale Cask Model

2018 ◽  
Author(s):  
Hirofumi Takeda ◽  
Masanori Goto
Keyword(s):  
Performance Monitoring ◽  
Temperature Data ◽  
Detection Methods ◽  
Helium Pressure ◽  
Leak Detector ◽  
Long Term Storage ◽  
Sealing Performance ◽  
Gas Leak ◽  
Term Storage

A concrete cask has an advantage in cost and period of manufacturing compared with a metal cask. In the metal cask, monitoring of helium pressure between a primary lid and a secondary lid of the cask is required by regulation. On the other hand, in the concrete cask, the lids of a canister are welded and have high sealing performance, so that the monitoring of helium leak from the canister is not required. However, a loss of the sealing performance of the secondary lid, which is caused by stress corrosion cracking (SCC), is concerned in the case of long-term storage by the concrete cask. In the view of this situation, it would be useful to install a helium leak detector in the concrete cask in order to improve the safety of the long-term storage. Thus, we have been developing the detector. The phenomenon that the temperature at the bottom of the canister (TB) increases and the temperature at the top of the canister (TT) decreases during the helium leak from the canister has been confirmed by the experiments in the previous study. We have proposed the performance monitoring by monitoring the temperature difference ΔTBT (= TB-TT) instead of pressure monitoring. This time, to make the installation and maintenance of the helium leak detector easier in consideration of practical use, we proposed a new detection technique using only the temperature of either the lid or the bottom of the canister. We performed leak tests by using a 1/4.5 scale cask model based on a similarity law of thermal hydraulics. In the experiments, air was used for an inner gas of a canister of the model, and a heat flux of a canister surface had the same value as that of the actual canister surface. In this model, Ra* number can be made to coincide with that of the actual canister. Besides, Gr* number and Bo* number are almost equal to those of the actual canister. Temperature data at respective canister parts were obtained under condition of canister internal pressure from 6 atm to 1 atm (atmosphere pressure). Also, the new and old leak detection methods were evaluated by using the obtained temperature data.

Development of a Device for Detecting Helium Leaks From Canisters: Part 2 — Numerical Analysis of Temperature Behavior During Gas Leaks From a Canister of a 1/4.5 Scale Cask Model

2018 ◽  
Author(s):  
Kosuke Shimizu ◽  
Hirofumi Takeda ◽  
Masanori Goto
Keyword(s):  
Heat Transfer ◽  
Internal Pressure ◽  
Ambient Air ◽  
Ideal Gas ◽  
Helium Pressure ◽  
Leak Detector ◽  
Long Term Storage ◽  
Sealing Performance ◽  
Term Storage

In the concrete cask, the canister is sealed with lids by welding, and has high sealing performance. But considering long-term storage, there is a concern about loss of the sealing performance due to stress corrosion cracking (SCC). In the concrete cask, unlike the metal cask, it is not mandatory to constantly monitor helium pressure between the lids. However, it is useful from the viewpoint of improving safety during the long-term storage to install a helium leak detector in the canister inside the concrete cask. Currently, we are developing the leak detector utilizing the phenomenon that the surface temperature of the canister changes when helium leaks out of the canister. As part of developing the leak detector of the canister, leak tests were performed using a small canister model as a pressurized vessel and a 1/4.5 scale cask model of the actual cask including the canister. This leak detector utilized the phenomenon that canister bottom temperature (TB) increases and canister lid temperature (TT) decreases when the internal pressure of the canister decreases. In computational fluid dynamics (CFD) calculation, focused on this phenomenon, the influence of the internal pressure and physical properties of internal gas in the canister were examined by calculating conditions of three kinds of pressure and two types of gas (air and helium). The main purpose of the CFD calculation was to confirm the results of the experiment, and we grasped the phenomenon occurring in the canister and elucidated its mechanism. For the CFD calculation, a commercial CFD software, STAR-CCM+® (ver.12.06.010) by Siemens PLM Software Company, was used. A CAD file used for the calculation simulated also the shape inside the canister (e.g. basket, fuel rods). A polyhedral mesh was used for a calculation mesh. In the small canister model, a mesh of its ambient air was not generated, and heat transfer between the canister surface and the ambient air was calculated from a heat transfer correlation equation. On the other hand, in the 1 / 4.5 scale cask model, the mesh of its ambient air was generated, so that the heat transfer on the surface of the canister was calculated according to the actual heat transfer phenomenon. The internal gas and the ambient air of the canister were ideal gas, and buoyancy due to density change was taken into consideration. A realizable k-epsilon model was used for a turbulence model, and a DO model was used for a radiation model.

Modelling of Moisture Movement in Wood during Outdoor Storage

2001 ◽  
Vol 6 (2) ◽  
pp. 3-14 ◽  
Author(s):  
R. Baronas ◽  
F. Ivanauskas ◽  
I. Juodeikienė ◽  
A. Kajalavičius
Keyword(s):  
Experimental Data ◽  
Finite Difference ◽  
Climatic Conditions ◽  
Two Dimensional ◽  
Moisture Movement ◽  
Finite Difference Technique ◽  
Long Term Storage ◽  
Space Formulation ◽  
Term Storage

A model of moisture movement in wood is presented in this paper in a two-dimensional-in-space formulation. The finite-difference technique has been used in order to obtain the solution of the problem. The model was applied to predict the moisture content in sawn boards from pine during long term storage under outdoor climatic conditions. The satisfactory agreement between the numerical solution and experimental data was obtained.

Trehalose: a cryoprotectant that enhances recovery and preserves function of human pancreatic islets after long-term storage

Diabetes ◽  
1997 ◽  
Vol 46 (3) ◽  
pp. 519-523 ◽  
Author(s):  
G. M. Beattie ◽  
J. H. Crowe ◽  
A. D. Lopez ◽  
V. Cirulli ◽  
C. Ricordi ◽  
...  
Keyword(s):  
Pancreatic Islets ◽  
Human Pancreatic Islets ◽  
Long Term Storage ◽  
Term Storage

Humidity reliability of commercial flash memories for long-term storage

2020 ◽  
Vol 59 (SL) ◽  
pp. SLLC01 ◽  
Author(s):  
Tomoki Murota ◽  
Toshiki Mimura ◽  
Ploybussara Gomasang ◽  
Shinji Yokogawa ◽  
Kazuyoshi Ueno
Keyword(s):  
Flash Memories ◽  
Long Term Storage ◽  
Term Storage

MODERN PROBLEMATICS AND ANALYSIS OF EFFICIENCY OF APPLICATION OF DIFFERENT APPROACHES TO DESTRUCTION OF INFORMATION ON MAGNETIC MEDIA

2019 ◽  
Vol 2 (12) ◽  
pp. 154-164
Author(s):  
O. Semenenko ◽  
O. Vodchyts ◽  
V. Koverga ◽  
R. Lukash ◽  
O. Lutsenko
Keyword(s):  
Armed Forces ◽  
Information Storage ◽  
Storage Device ◽  
Magnetic Media ◽  
Long Term Storage ◽  
Physical Impact ◽  
And Storage ◽  
Term Storage

The introduction and active use of information transmission and storage systems in the Ministry of Defense (MoD) of Ukraine form the need to develop ways of guaranteed removal of data from media after their use or long-term storage. Such a task is an essential component of the functioning of any information security system. The article analyzes the problems of guaranteed destruction of information on magnetic media. An overview of approaches to the guaranteed destruction of information on magnetic media of different types is presented, and partial estimates of the effectiveness of their application are given by some generally accepted indicators of performance evaluation. The article also describes the classification of methods of destruction of information depending on the influence on its medium. The results of the analysis revealed the main problems of application of software methods and methods of demagnetization of the information carrier. The issue of guaranteed destruction of information from modern SSD devices, which are actively used in the formation of new systems of information accumulation and processing, became particularly relevant in the article. In today's conditions of development of the Armed Forces of Ukraine, methods of mechanical and thermal destruction are more commonly used today. In the medium term, the vector of the use of information elimination methods will change towards the methods of physical impact by the pulsed magnetic field and the software methods that allow to store the information storage device, but this today requires specialists to develop new ways of protecting information in order to avoid its leakage.

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