Integrity assessment of the high temperature engineering test reactor (HTTR) control rod at very high temperatures

1997 ◽  
Vol 172 (1-2) ◽  
pp. 93-102 ◽  
Author(s):  
Y. Tachibana ◽  
S. Shiozawa ◽  
J. Fukakura ◽  
F. Matsumoto ◽  
T. Araki
Keyword(s):  
High Temperature ◽  
High Temperatures ◽  
Control Rod ◽  
Integrity Assessment ◽  
Test Reactor ◽  
Very High

Characteristics and aging of SiC MOSFETs operated at very high temperatures

2014 ◽  
Vol 1693 ◽  
Author(s):  
Dean P. Hamilton ◽  
Michael R. Jennings ◽  
Craig A. Fisher ◽  
Yogesh K. Sharma ◽  
Stephen J. York ◽  
...  
Keyword(s):  
High Temperature ◽  
High Temperatures ◽  
Threshold Voltage ◽  
Thermal Aging ◽  
Ohmic Contacts ◽  
Stress Tests ◽  
Temperature Capability ◽  
Temperature Constant ◽  
Voltage Management ◽  
Very High

ABSTRACTSilicon carbide power devices are purported to be capable of operating at very high temperatures. Current commercially available SiC MOSFETs from a number of manufacturers have been evaluated to understand and quantify the aging processes and temperature dependencies that occur when operated up to 350°C. High temperature constant positive bias stress tests demonstrated a two times increase in threshold voltage from the original value for some device types, which was maintained indefinitely but could be corrected with a long negative gate bias. The threshold voltages were found to decrease close to zero and the on-state resistances increased quite linearly to approximately five or six times their room temperature values. Long term thermal aging of the dies appears to demonstrate possible degradation of the ohmic contacts. This appears as a rectifying response in the I-V curves at low drain-source bias. The high temperature capability of the latest generations of these devices has been proven independently; provided that threshold voltage management is implemented, the devices are capable of being operated and are free from the effects of thermal aging for at least 70 hours cumulative at 300°C.

scholarly journals Forging, textures, and deformation systems in a B2 FeAl alloy

1999 ◽  
Vol 14 (3) ◽  
pp. 715-728 ◽  
Author(s):  
P. Zhao ◽  
D. G. Morris ◽  
M. A. Morris Munoz
Keyword(s):  
High Temperature ◽  
Flow Stress ◽  
Slip System ◽  
High Temperatures ◽  
Low Temperatures ◽  
High Speed ◽  
Deformation Texture ◽  
Slip Systems ◽  
Feal Alloy ◽  
Very High

High-temperature forging experiments have been carried out by axial compression testing on a Fe–41Al–2Cr alloy in order to determine the deformation systems operating under such high-speed, high-temperature conditions, and to examine the textures produced by such deformation and during subsequent annealing to recrystallize. Deformation is deduced to take place by the operation of 〈111〉 {110} and 〈111〉{112} slip systems at low temperatures and by 〈100〉{001} and 〈100〉{011} slip systems at high temperatures, with the formation of the expected strong 〈111〉 textures. The examination of the weak 〈100〉 texture component is critical to distinguishing the operating slip system. Both texture and dislocation analyses are consistent with the operation of these deformation systems. Recrystallization takes place extremely quickly at high temperatures (above 800 °C), that is within seconds after deformation and also dynamically during deformation itself. Recrystallization changes the texture such that 〈100〉 textures superimpose on the deformation texture. The flow stress peak observed during forging is found at a very high temperature. Possible origins of the peak are examined in terms of the operating slip systems.

Applications: Light My Fire

1982 ◽  
Vol 75 (1) ◽  
pp. 53-55
Author(s):  
George Knill ◽  
George Fawceti
Keyword(s):  
High Temperature ◽  
High Temperatures ◽  
Low Temperatures ◽  
Chemical Process ◽  
Room Temperature ◽  
Very High

Everyone knows that wood bums at a very high temperature. This burning is a chemical process that combines oxygen and carbon. The process occurs at very low temperatures as well as at very high ones. At high temperatures the process is spectacular-fire. At low temperatures (room temperature) you won’t even notice it, although it is still going on. Wood is always burning.

Characteristic Tests on Transition Core of HTR-10

2018 ◽  
Author(s):  
Liqiang Wei ◽  
Dongmei Ding ◽  
Ling Liu ◽  
Yucheng Wang ◽  
Xiaoming Chen ◽  
...  
Keyword(s):  
High Temperature ◽  
Control Rod ◽  
Safety Requirements ◽  
Operation Characteristic ◽  
Power Operation ◽  
Test Reactor ◽  
High Temperature Gas

After a long-term shutdown, the 10MW high temperature gas-cooled test reactor (HTR-10) was restarted, and the operation & safety characteristics of the HTR-10 transition core are tested and verified. A series of the characteristic tests have been implemented, such as the value calibrating test of the control rod and boron absorber ball, the disturbance characteristic of helium circulator, the start-stop characteristic and the stable power operation characteristic, which indicated the characteristics of the reactor transition core meet the design and safety requirements.

In-situ Hrem Heating Experiments at Very High Temperatures

1995 ◽  
Vol 404 ◽  
Author(s):  
T. Kamino ◽  
H. Saka
Keyword(s):  
High Temperature ◽  
High Temperatures ◽  
Atomic Resolution ◽  
Very High

AbstractA specimen-heating holder which allows an observation of reactions of more than one materials, in a controlled manner, at such a high temperature as 1723K has been developed. Facet-unfacet transformation and reconstruction of Au-deposited Si surfaces have been observed at very high temperatures at near-atomic resolution.

Development of high temperature creep resistance in Fe-Al alloys

2004 ◽  
Vol 842 ◽  
Author(s):  
D. G. Morris ◽  
M. A. Muñoz-Morris ◽  
C. Baudin
Keyword(s):  
High Temperature ◽  
High Temperatures ◽  
Creep Resistance ◽  
Good Strength ◽  
Thermally Activated ◽  
Intermediate Temperature Range ◽  
Deformation Processes ◽  
Good Creep Resistance ◽  
Oxidation And Corrosion ◽  
Very High

ABSTRACTMost of the studies aimed at the development of creep-resisting Fe-Al intermetallics have been oriented at application temperatures of the order of 500–650°C, where these materials may compete with conventional stainless steels. The Fe-Al intermetallics are, however, particularly excellent in their oxidation and corrosion resistances at temperatures of the order of 1000°C, where Chromium-Nickel steels are no longer able to withstand the aggressive environments. This presentation is part of a study aimed at the development of good creep resistance at such high temperatures.Studies of a variety of cast Fe3Al-base alloys, strengthened by solution or precipitate/dispersoid-forming alloying additions, are reported. The alloys show good strength from room temperature to about 500°C, but thereafter strength falls rapidly as thermally-activated deformation processes become operative. Solution additions are capable of producing good low temperature strength, but do not contribute significantly to creep strength at very high temperatures (above 700°C). Precipitation hardening has been examined in Nb-containing alloys, where Fe2Nb Laves precipitates form at intermediate temperatures. These materials show good strength up to about 700°C, but at higher temperatures the fine precipitates coarsen excessively. Strengthening in the intermediate temperature range varies depending on whether the solute is precipitated prior to high temperature testing or concurrent with this.

COLUMBIUM D-31

Alloy Digest ◽  
1963 ◽  
Vol 12 (3) ◽  
Keyword(s):  
High Temperature ◽  
Physical Properties ◽  
Surface Treatment ◽  
Tensile Properties ◽  
High Temperatures ◽  
Base Alloy ◽  
Density Ratio ◽  
Heat Treating ◽  
Temperature Performance ◽  
Very High

Abstract COLUMBIUM D-31 is a columbium-base alloy that maintains its stability at very high temperatures. It is 5 times as resistant to oxidation as pure columbium and about 100 times as resistant as molybdenum. Its strength to density ratio at 2000 F (stress relieved) is 77400. This datasheet provides information on composition, physical properties, elasticity, and tensile properties as well as creep. It also includes information on high temperature performance as well as forming, heat treating, machining, joining, and surface treatment. Filing Code: Cb-4. Producer or source: E. I. Dupont de Nemours & Company Inc..

Burn-Up Dependency of Control Rod Position at Zero-Power Criticality in the High-Temperature Engineering Test Reactor

2016 ◽  
Vol 3 (1) ◽  
Author(s):  
Yuki Honda ◽  
Nozomu Fujimoto ◽  
Hiroaki Sawahata ◽  
Shoji Takada ◽  
Kazuhiro Sawa
Keyword(s):  
High Temperature ◽  
Temperature Distribution ◽  
Core Temperature ◽  
Measured Data ◽  
Block Type ◽  
Control Rod ◽  
The Core ◽  
Burnable Absorber ◽  
Test Reactor ◽  
Operation Cycle

The high-temperature engineering test reactor (HTTR) is a block-type high-temperature gas-cooled reactor (HTGR), which was constructed in Japan. The operating data of HTTR with burn-up to about 370 EFPD (effective full-power days), which are very important for the development of HTGRs, have been collected in both zero-power and powered operations. In the aspects of code validation, the detailed prediction of temperature distribution in the core makes it difficult to validate the calculation code because of difficulty in measuring the core temperature directly in powered operation of the HTTR. In this study, the measured data of the control rod position, while keeping the temperature distribution in the core uniform at criticality in zero-power operation at the beginning of each operation cycle were compared with the calculated results by core physics design code of the HTTR. The measured data of the control rod position were modified based on the core temperature correlation. At the beginning of burn-up, the trends of burn-up characteristics are slightly different between experimental and calculation data. However, the calculated result shows less than 50 mm of small difference (total length of control rod is 4060 mm) to the measured one, which indicates that the calculated results appropriately reproduced burn-up characteristics, such as a decrease in uranium-235, accumulation in plutonium, and decrease in burnable absorber.

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