scholarly journals Density Changes in Plutonium Observed from Accelerated Aging using Pu-238 Enrichment

2003 ◽  
Vol 802 ◽  
Author(s):  
B. W. Chung ◽  
S. R. Thompson ◽  
C. H. Woods ◽  
D. J. Hopkins ◽  
W. H. Gourdin ◽  
...  
Keyword(s):  
Accelerated Aging ◽  
Physical Property ◽  
Recoil Nucleus ◽  
Irradiation Damage ◽  
Volume Changes ◽  
Defect Clusters ◽  
Particle Decay ◽  
Lattice Damage ◽  
Property Changes ◽  
Inside Out

Plutonium, because of its radioactive nature, ages from the “inside out” by means of self-irradiation damage and thus produces Frankel-type defects (vacancies and self-interstitial atoms) and defect clusters. The self-irradiation damage in Plutonium-239 occurs mainly by α-particle decay, where most of the damage comes from the U-235 recoil nucleus. The defects resulting from the residual lattice damage and helium in-growth could result in microstructural and physical property changes. Because these self-irradiation effects would normally require decades to measure, with a fraction (7.5 wt%) of Pu-238 is added to the reference plutonium alloy thus accelerating the aging process by approximately 18 times the normal rate. By monitoring the properties of the Pu-238 spiked alloy over a period of about 3.5 years, the properties of plutonium in storage can be projected for periods up to about 60 years. This paper presents density and volume changes observed from the immersion density and dilatometry measurements equivalent to aging the reference plutonium alloys to nine years.

scholarly journals Physical Property Changes in Plutonium Observed from Accelerated Aging using Pu-238 Enrichment

2006 ◽  
Vol 986 ◽  
Author(s):  
Brandon W. Chung ◽  
Bill Choi ◽  
Cheng Saw ◽  
Stephen Thompson ◽  
Conrad Woods ◽  
...  
Keyword(s):  
Ultimate Strength ◽  
Tensile Property ◽  
Aging Process ◽  
Accelerated Aging ◽  
Physical Property ◽  
Tensile Tests ◽  
Weight Percent ◽  
Volume Increase ◽  
Property Changes ◽  
Weapons Grade Plutonium

AbstractWe present changes in volume, immersion density, and tensile property observed from accelerated aged plutonium alloys. Accelerated alloys (or spiked alloys) are plutonium alloys enriched with approximately 7.5 weight percent of the faster-decaying 238Pu to accelerate the aging process by approximately 17 times the rate of unaged weapons-grade plutonium. After sixty equivalent years of aging on spiked alloys, the dilatometry shows the samples at 35°C have swelled in volume by 0.15 to 0.17 % and now exhibit a near linear volume increase due to helium in-growth. The immersion density of spiked alloys shows decrease in density, similar normalized volumetric changes (expansion) for spiked alloys. Tensile tests show increasing yield and engineering ultimate strength as spiked alloys are aged.

scholarly journals Physical Property Changes in Aging Plutonium Alloys

2008 ◽  
Vol 1104 ◽  
Author(s):  
Brandon W. Chung ◽  
Stephen R. Thompson ◽  
David S. Hiromoto
Keyword(s):  
Aging Process ◽  
Specific Activity ◽  
Physical Property ◽  
Alpha Decay ◽  
Mechanical Tests ◽  
Aging Effects ◽  
Extended Aging ◽  
Lattice Damage ◽  
Property Changes ◽  
Weapons Grade Plutonium

AbstractPlutonium, because of its self-irradiation by alpha decay, ages by means of lattice damage and helium in-growth. These integrated aging effects will result in microstructural and physical property changes. Because these effects would normally require decades to measure, studies are underway to asses the effects of extended aging on the physical properties of plutonium alloys by incorporating roughly 7.5 wt% of highly specific activity isotope 238Pu into the weapons-grade plutonium to accelerate the aging process. This paper presents updated results of self-irradiation effects on enriched and reference alloys measured from the immersion density, dilatometry, and mechanical tests. After nearly 90 equivalent years of aging, both the immersion density and dilatometry show that the enriched alloys at 35°C have decreased in density by ∼0.19 % and now exhibit a near linear density decrease, without void swelling. Both tensile and compression measurements show that the aging process continues to increase the strength of plutonium alloys.

scholarly journals Study on Metakaolin Impact on Concrete Performance of Resisting Complex Ions Corrosion

2021 ◽  
Vol 8 ◽  
Author(s):  
Chen Xupeng ◽  
Sun Zhuowen ◽  
Pang Jianyong
Keyword(s):  
Physical Property ◽  
Similar Amount ◽  
Concrete Durability ◽  
Test Results ◽  
Micro Structure ◽  
Complex Ions ◽  
Cyclic Corrosion ◽  
Property Changes ◽  
Micro Morphology ◽  
Composition Changes

The main purpose of this study is to determine the metakaolin (MK) impacts on the concrete durability when the concrete is subjected to joint corrosion of SO42−,Mg2+ and, Cl−. Four groups of concrete test samples, which contained different MK contents, were designed and tested in order to see their physical property changes and macro-morphology differences during the cyclic corrosion process. And a series of approaches, including XRD, FTIR, SEM, and EDS, were applied to study the concrete phase composition changes and the micro-morphology features of all groups. According to the test results, when reaching 20 cycles, the concrete sample with 10% MK showed the best concrete physical properties; when reaching 120 cycles, the concrete with 5% MK content showed the best durability, produced similar amount of corrosion products to ordinary concrete, and presented relatively compacted micro-structure and small internal porosity. Mg2+ actually has a great impact on metakaolin. The corrosion product quantity increased significantly when MK admixture reached 15%. Due to the great number of produced M-S-H, the corrosive ions damaged the concrete for a second time, leading to serious aggregate peeling-off, powder surface of test samples, and porous micro-structure.

scholarly journals Technical Evaluation Method for Physical Property Changes due to Environmental Degradation of Grout-Injection Repair Materials for Water-Leakage Cracks

2019 ◽  
Vol 9 (9) ◽  
pp. 1740 ◽  
Author(s):  
Jiang ◽  
Oh ◽  
Kim ◽  
He ◽  
Oh
Keyword(s):  
Environmental Degradation ◽  
Evaluation Method ◽  
Physical Property ◽  
Performance Comparison ◽  
Test Method ◽  
Grout Injection ◽  
Chemical Corrosion ◽  
Technical Evaluation ◽  
Injection Materials ◽  
Property Changes

Leakage in below-grade concrete structures are repaired using various types of grout-injection materials, but the selection of optimal material types with a consideration of the environmental degradation factors are not conducted. Different degradation factors can act on the waterproofing membranes or grout-injection materials simultaneously. Especially in the early stages of installation, the injected grout materials in the cracks for leakage repair or for reforming damaged waterproofing layers are subject to complex forms of degradation factors. In such cases, physical property changes to the materials can reduce the waterproofing performance of the grout-injection materials. In this study, a technical evaluation regime is proposed for selecting the optimal repair material to be used in underground concrete structure leakage cracks. In this study, six environmental degradation factors (thermal stress, chemical corrosion, erosion due to ground water flow, hydrostatic pressure, substrate movement, and humidity on concrete surface) are identified. Corresponding evaluation methods based on the ISO TS 16774 test method series were used for each factor to assess the performance evaluation of four different types of grout-injection materials (acrylic resin, epoxy resin, polyurethane foam, and synthetic polymerized rubber gel). Based on the test results, a new comprehensive evaluation regime is presented that allows a quantitative performance comparison between each type of grout-injection material.

Polymorphic Amino Acid Variations in HLA-DQ Are Associated With Systematic Physical Property Changes and Occurrence of IDDM

Diabetes ◽  
1995 ◽  
Vol 44 (1) ◽  
pp. 125-131 ◽  
Author(s):  
C. B. Sanjeevi ◽  
T. P. Lybrand ◽  
C. DeWeese ◽  
M. Landin-Olsson ◽  
I. Kockum ◽  
...  
Keyword(s):  
Amino Acid ◽  
Physical Property ◽  
Hla Dq ◽  
Property Changes

scholarly journals A time-dependent atomistic reconstruction of severe irradiation damage and associated property changes in nuclear graphite

Carbon ◽  
2017 ◽  
Vol 120 ◽  
pp. 111-120 ◽  
Author(s):  
Baptiste Farbos ◽  
Helen Freeman ◽  
Trevor Hardcastle ◽  
Jean-Pierre Da Costa ◽  
Rik Brydson ◽  
...  
Keyword(s):  
Time Dependent ◽  
Irradiation Damage ◽  
Nuclear Graphite ◽  
Property Changes

Effect of Storage Temperature on Self-Irradiation Damage of 238PU-Substituted Zirconolite

1982 ◽  
Vol 15 ◽  
Author(s):  
F. W. Clinard ◽  
D. E. Peterson ◽  
D. L. Rohr ◽  
R. B. Roof ◽  
L. W. Hobbs
Keyword(s):  
Ambient Temperature ◽  
Crystalline Structure ◽  
Amorphous Matrix ◽  
Storage Temperature ◽  
Alpha Decay ◽  
Irradiation Damage ◽  
Partial Recovery ◽  
Defect Clusters

ABSTRACT238Pu-substituted cubic zirconolite (CaPuTi2 O7) was stored at ambient temperature, 575 K and 875 K until alpha decay doses of 2.4 to 3.6 × 1025/m3 had been accumulated. The ambient temperature material swelled to a saturation value of 5.5 vol%, and the originally crystalline structure was transformed to one with an amorphous matrix and small domains that had retained their crystallinity. At 575 K lesser amounts of swelling (4.1 vol%) and transformation were observed, reflecting concurrent partial recovery. The material held at 875 K remained crystalline, swelled only 0.4 vol%, and exhibited formation of isolated defect clusters.

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