Effect of hydrogen on the melting temperature of FeS at high pressure: Implications for the core of Ganymede

2011 ◽  
Vol 301 (1-2) ◽  
pp. 153-158 ◽  
Author(s):  
Yuki Shibazaki ◽  
Eiji Ohtani ◽  
Hidenori Terasaki ◽  
Ryuji Tateyama ◽  
Tatsuya Sakamaki ◽  
...  
Keyword(s):  
High Pressure ◽  
Melting Temperature ◽  
The Core

scholarly journals O2volumes at high pressure from KClO4decomposition: D″ as a siderophile element pump instead of a lid on the core

2002 ◽  
Vol 3 (11) ◽  
pp. 1-26 ◽  
Author(s):  
D. Walker ◽  
S. M. Clark ◽  
L. M. D. Cranswick ◽  
M. C. Johnson ◽  
R. L. Jones
Keyword(s):  
High Pressure ◽  
The Core

Investigation of Micro-Sized Capsules at High Pressure by PALS Method

2017 ◽  
Vol 373 ◽  
pp. 284-287
Author(s):  
Bożena Zgardzińska ◽  
Maciej Tydda ◽  
Jan Wawryszczuk
Keyword(s):  
High Pressure ◽  
Solid Phase ◽  
Boundary Region ◽  
Argon Atmosphere ◽  
Phase Changes ◽  
Filling Material ◽  
Polymer Shell ◽  
Positron Annihilation Lifetime ◽  
The Core ◽  
Phase Pressure

The positron annihilation lifetime spectroscopy (PALS) was applied to investigate the properties of capsules composed of n-alkanes (filling material) and polymer (shell) in the broad range of pressures up to 450 MPa. These microcapsules aggregate into the grains having about 200 μm in diameter. Their properties were investigated as a function of pressure (p) at several selected temperatures: when the filling material is in liquid, rotator and solid phase. Pressure experiments were performed without gas access to the sample and in an argon atmosphere. Two o-Ps components were found, the longer-lived correspond to the filler material, and the shorter-lived one – to the shell. These components change with p; even a small pressure (6 MPa) reduces considerably the o-Ps lifetimes (τ). At 303 K the o-Ps lifetime in the core changes non-monotonically, and at 60 MPa τ is higher than at 20 MPa. The increase of pressure induces the phase changes in the filling material, and also produces the deformation of microcapsule aggregates and crash of small capsules at the grain boundary region. Internal structure of the microcapsules was observed by SEM.

The Structure of Cosmic Ray Air Showers

1949 ◽  
Vol 2 (2) ◽  
pp. 184
Author(s):  
CBO Mohr
Keyword(s):  
High Pressure ◽  
Sea Level ◽  
Cosmic Ray ◽  
Low Density ◽  
Air Showers ◽  
Ionization Chambers ◽  
Single Chamber ◽  
Transition Effect ◽  
The Core ◽  
Rate Frequency

The structure of cosmic ray air showers at sea-level has been studied by an investigation of the burst rate frequency and the transition effect in lead, for cosmic ray bursts occurring simultaneously in two high-pressure ionization chambers with varying separation. Although extensive showers were responsible for all the coincidences observed with the larger chamber separations, they accounted for less than 3 per cent, of the bursts observed with a single chamber. Of the remaining 97 per cent., somewhat more than one-half appear to be due to nuclear disintegrations and the rest either to narrow showers of approximate radius 30 cm. or to the core of an extensive shower of low density. The extensive shower frequency was about 10 times that predicted by theory. The bearing of these results on present views of the origin and development of air showers is discussed.

scholarly journals Assessment of Severe Accident Management for Small IPWR under an ESBO Scenario

2019 ◽  
Vol 2019 ◽  
pp. 1-10 ◽  
Author(s):  
Hao Yu ◽  
Minjun Peng
Keyword(s):  
High Pressure ◽  
Low Pressure ◽  
Lower Pressure ◽  
Severe Accident ◽  
Maximum Temperature ◽  
Pressurized Water ◽  
The Core ◽  
Severe Accidents ◽  
Accident Management ◽  
Degradation Studies

Interest in evaluation of severe accidents induced by extended station blackout (ESBO) has significantly increased after Fukushima. In this paper, the severe accident process under the high and low pressure induced by an ESBO for a small integrated pressurized water reactor (IPWR)-IP200 is simulated with the SCDAP/RELAP5 code. For both types of selected scenarios, the IP200 thermal hydraulic behavior and core meltdown are analyzed without operator actions. Core degradation studies firstly focus on the changes in the core water level and temperature. Then, the inhibition of natural circulation in the reactor pressure vessel (RPV) on core temperature rise is studied. In addition, the phenomena of core oxidation and hydrogen generation and the reaction mechanism of zirconium with the water and steam during core degradation are analyzed. The temperature distribution and time point of the core melting process are obtained. And the IP200 severe accident management guideline (SAMG) entry condition is determined. Finally, it is compared with other core degradation studies of large distributed reactors to discuss the influence of the inherent design characteristics of IP200. Furthermore, through the comparison of four sets of scenarios, the effects of the passive safety system (PSS) on the mitigation of severe accidents are evaluated. Detailed results show that, for the quantitative conclusions, the low coolant storage of IP200 makes the core degradation very fast. The duration from core oxidation to corium relocation in the lower-pressure scenario is 53% faster than that of in the high-pressure scenario. The maximum temperature of liquid corium in the lower-pressure scenario is 134 K higher than that of the high-pressure scenario. Besides, the core forms a molten pool 2.8 h earlier in the lower-pressure scenario. The hydrogen generated in the high-pressure scenario is higher when compared to the low-pressure scenario due to the slower degradation of the core. After the reactor reaches the SAMG entry conditions, the PSS input can effectively alleviate the accident and prevent the core from being damaged and melted. There is more time to alleviate the accident. This study is aimed at providing a reference to improve the existing IPWR SAMGs.

High-Temperature Fatigue Properties of Single Crystal Superalloys in Air and Hydrogen

2001 ◽  
Author(s):  
Nagaraj K. Arakere
Keyword(s):  
High Pressure ◽  
Shear Stress ◽  
High Temperature ◽  
Fatigue Life ◽  
Single Crystal ◽  
Room Temperature ◽  
Turbine Blades ◽  
The Core ◽  
Blade Tip ◽  
Pressure Hydrogen

Hot section components in high performance aircraft and rocket engines are increasingly being made of single crystal nickel superalloys such as PWA1480, PWA1484, CMSX-4 and Rene N-4 as these materials provide superior creep, stress rupture, melt resistance and thermomechanical fatigue capabilities over their polycrystalline counterparts. Fatigue failures in PWA1480 single crystal nickel-base superalloy turbine blades used in the Space Shuttle Main Engine (SSME) fuel turbopump are discussed. During testing many turbine blades experienced Stage II non-crystallographic fatigue cracks with multiple origins at the core leading edge radius and extending down the airfoil span along the core surface. The longer cracks transitioned from stage II fatigue to crystallographic stage I fatigue propagation, on octahedral planes. An investigation of crack depths on the population of blades as a function of secondary crystallographic orientation (β) revealed that for β = 45+/- 15 degrees tip cracks arrested after some growth or did not initiate at all. Finite element analysis of stress response at the blade tip, as a function of primary and secondary crystal orientation, revealed that there are preferential β orientations for which crack growth is minimized at the blade tip. To assess blade fatigue life and durability extensive testing of uniaxial single crystal specimens with different orientations has been tested over a wide temperature range in air and hydrogen. A detailed analysis of the experimentally determined Low Cycle Fatigue (LCF) properties for PWA1480 and SC 7-14-6 single crystal materials as a function of specimen crystallographic orientation is presented at high temperature (75 F – 1800 F) in high-pressure hydrogen and air. Fatigue failure parameters are investigated for LCF data of single crystal material based on the shear stress amplitudes on the 24 octahedral and 6 cube slip systems for FCC single crystals. The max shear stress amplitude [Δτmax] on the slip planes reduces the scatter in the LCF data and is found to be a good fatigue damage parameter, especially at elevated temperatures. The parameter Δτmax did not characterize the room temperature LCF data in high-pressure hydrogen well because of the noncrystallographic eutectic failure mechanism activated by hydrogen at room temperature. Fatigue life equations are developed for various temperature ranges and environmental conditions based on power-law curve fits of the failure parameter with LCF test data. These curve fits can be used for assessing blade fatigue life.

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