scholarly journals The Effect of Low Dose-Rate Irradiation on the Microstructure of 304 Stainless Steel

1998 ◽  
Vol 540 ◽  
Author(s):  
J. I. Cole ◽  
T. R. Allen
Keyword(s):  
Stainless Steel ◽  
Dose Rate ◽  
Low Dose ◽  
Rate Effect ◽  
304 Stainless Steel ◽  
Microstructural Development ◽  
Dose Rates ◽  
Low Dose Rate ◽  
Radiation Induced ◽  
Dose Rate Effect

AbstractChanges in mechanical and corrosion properties caused by the development of radiation-induced microstructures have relevance to the aging and lifetime extension of light water reactors (LWR‘s). However, much of the current data related to microstructural development in irradiated metals are generated from studies carried out at much higher dose-rates than encountered in LWR‘s. An opportunity exists to study the influence of low dose-rate irradiation on microstructural development for a variety of structural and surveillance materials extracted from the experimental breeder reactor EBR-lI. In this study, irradiated 304 stainless steel hexagonal “hex” duct material is examined in order to compare microstructures in the dose-rate range of 10−7 - 10−9 dpa/sec. The samples, taken from the reflector locations in EBR-II, experienced a total dose between 10 and 12 dpa at a temperature of ∼375 °C. Transmission electron microscopy (TEM) analysis reveals that there is a moderate dose-rate effect on microstructural development for samples irradiated in the range of 2 × 10−8 to 4 × 10−8. dpa/sec, however a substantial dose-rate effect exists between dose-rates of 2 × 10−8 and 1 × 10−9 dpa/sec Results detail the development of the microstructure in terms of radiation-induced cavities, dislocations, and precipitates.

The Effect of Low Dose Rate Radiation on the Microchemistry of 304 Stainless Steel

1998 ◽  
Vol 540 ◽  
Author(s):  
T. R. Allen ◽  
J. I. Cole ◽  
E. A. Kenik
Keyword(s):  
Stainless Steel ◽  
Grain Boundary ◽  
Dose Rate ◽  
Low Dose ◽  
304 Stainless Steel ◽  
Pressurized Water ◽  
Dose Rates ◽  
Low Dose Rate ◽  
Radiation Induced ◽  
Water Reactors

AbstractAs part of the shutdown of the EBR-II reactor, structural materials were retrieved to analyze the effect of long term, low dose rate irradiation. In this work, the effect of low dose rate (10 to 10−9 dpa/s) irradiation on grain boundary and void surface chemistry is analyzed. These dose rates are comparable to those in light water reactor structural components. The components were irradiated at 375-379°C, temperatures near the highest temperatures experienced in pressurized water reactors. Radiation-induced segregation (RIS) was measured on samples taken from 304 stainless steel hex ducts irradiated to doses between 10 and 12 dpa. Radiation-induced segregation is shown to vary with dose rate, with measured grain boundary chromium concentrations reaching as low as 5 at. % and nickel concentrations reaching as high as 33 at. %. For some radiation conditions, significant grain boundary precipitation occurs, possibly leaving components susceptible to environmental attack.

Radiation-Induced Segregation in 316 and 304 Stainless Steels Irradiated at Low Dose Rate

2000 ◽  
Vol 650 ◽  
Author(s):  
T. R. Allen ◽  
J. I. Cole ◽  
J. Ohta ◽  
K. Dohi ◽  
H. Kusanagi ◽  
...  
Keyword(s):  
Stainless Steel ◽  
Grain Boundary ◽  
Dose Rate ◽  
Stainless Steels ◽  
Low Dose ◽  
Bulk Composition ◽  
304 Stainless Steel ◽  
316 Stainless Steel ◽  
Low Dose Rate ◽  
Radiation Induced

ABSTRACTAs part of the shutdown of the EBR-II reactor, structural materials were retrieved to analyze the effects of long-term irradiation on mechanical properties and microstructure. In this work, the effect of low dose rate irradiation (10−7 to 10−8 dpa/s) on grain boundary composition in 316 and 304 stainless steels was analyzed. Samples were taken from surveillance specimens and subassemblies irradiated in the reflector region of EBR-II at temperatures from 371-390°C to maximum doses of 30 dpa. The effects of dose, dose rate, and bulk composition on radiation- induced segregation are analyzed. In 316 stainless steel, changes in grain boundary chromium and nickel concentrations occur faster than changes in iron and molybdenum concentrations. In 304 stainless steel, decreasing the dose rate increases the amount of grain boundary segregation. For a dose of 20 dpa, chromium depletion and nickel enrichment are greater in 304 stainless steel than in 316 stainless steel, the difference most likely due to dose rate. In both 304 and 316 stainless steels, the presence of a grain boundary precipitate significantly changes the composition of the adjacent grain boundary.

The conversion model of low dose rate effect in bipolar transistors

2009 ◽  
Author(s):  
V. S. Pershenkov ◽  
D. V. Savchenkov ◽  
A. S. Bakerenkov ◽  
V. N. Ulimov ◽  
A. Y. Nikiforov ◽  
...  
Keyword(s):  
Dose Rate ◽  
Low Dose ◽  
Bipolar Transistors ◽  
Rate Effect ◽  
Conversion Model ◽  
Low Dose Rate ◽  
Dose Rate Effect

scholarly journals Mechanical Properties of 20% Cold-Worked 316 Stainless Steel Irradiated at Low Dose Rate

2002 ◽  
Author(s):  
Todd R. Allen ◽  
Hanchung Tsai ◽  
James I. Cole ◽  
Joji Ohta ◽  
Kenji Dohi ◽  
...  
Keyword(s):  
Stainless Steel ◽  
Dose Rate ◽  
Work Hardening ◽  
Low Dose ◽  
Dose Range ◽  
Total Elongation ◽  
316 Stainless Steel ◽  
Dose Rates ◽  
Low Dose Rate ◽  
Cold Worked

To assess the effects of long-term, low-dose-rate neutron exposure on mechanical strength and ductility, tensile properties were measured on irradiated 20% cold-worked Type 316 stainless steel. Samples were prepared from reactor core components retrieved from the EBR-II reactor following final shutdown. Sample locations were chosen to cover a dose range of 1–47 dpa at temperatures from 371–385°C and dose rates from 0.8–2.8 × 10−7 dpa/s. These dose rates are about one order of magnitude lower than those of typical EBR-II in-core experiments. Irradiation cuased hardening, with the yield strength (YS) following approximately the same trend as the ultimate tensile strength (UTS). At higher dose, the difference between the UTS and YS decreases, suggesting the work-hardening capability of the material is decreasing with increasing dose. Both the uniform elongation and total elongation decrease up to the largest dose. Unlike the strength data, the ductility reduction showed no signs of saturating at 20 dpa. While the material retained respectable ductility at 20 dpa, the uniform and total elongation decreased to <1 and <3%, respectively, at 47 dpa. Fracture in the 30 dpa specimen is mainly ductile but with local regions of mixed-mode failure consisting of dimples and microvoids. The fracture surface of the higher-exposure 47 dpa specimen displays significantly more brittle features. The fracture consists of maily small facets and slip bands that suggest channel fracture. The hardening in these low-dose-rate components differs from that measured in test samples irradiated in EBR-II at higher-dose-rate. The material irradiated at higher dose rate loses work hardening capactiy faster than the lower dose rate material, although this effect could be due to compositional differences.

scholarly journals Enhanced low dose rate sensitivity (ELDRS) and reduced low dose rate sensitivity (RLDRS) in bipolar devices

2020 ◽  
Vol 33 (2) ◽  
pp. 303-316
Author(s):  
Vyacheslav Pershenkov ◽  
Alexander Bakerenkov ◽  
Alexander Rodin ◽  
Vladislav Felitsyn ◽  
Alexander Zhukov ◽  
...  
Keyword(s):  
Dose Rate ◽  
Low Dose ◽  
Rate Sensitivity ◽  
Interface Traps ◽  
Oxide Charge ◽  
Conversion Model ◽  
Low Dose Rate ◽  
Bipolar Devices ◽  
Radiation Induced ◽  
Dose Rate Effect

Possible physical mechanism of enhanced low dose rate sensitivity (ELDRS) and reduced low dose rate sensitivity (RLDRS) in bipolar devices is described. Modification of the low dose rate conversion model is presented. The enhanced or reduced sensitivity can be connected with a specific position of the effective Fermi level relatively acceptor and donor radiation-induced interface traps. The qualitative and quantitative analysis of the low dose rate effects is presented. The effect of the oxide trapped charge on the value of the oxide electric field and the yield of the oxide charge were taken into account. It leads to dependence of the accumulation of radiation induced oxide charge and interface traps on the dose rate. In enhancement version the ELDRS and RLDRS conversion model describes the low dose rate effect in as ?true? dose rate effect.

Physical Model for the Low-Dose-Rate Effect in Bipolar Devices

2006 ◽  
Vol 53 (6) ◽  
pp. 3655-3660 ◽  
Author(s):  
J. Boch ◽  
F. Saigne ◽  
R. D. Schrimpf ◽  
J.-R. Vaille ◽  
L. Dusseau ◽  
...  
Keyword(s):  
Dose Rate ◽  
Physical Model ◽  
Low Dose ◽  
Rate Effect ◽  
Low Dose Rate ◽  
Bipolar Devices ◽  
Dose Rate Effect
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