Standard Guide for Investigating the Effects of Helium in Irradiated Metals
NORMA vydaná dňa 1.12.2016
Označenie normy: ASTM E942-16
Dátum vydania normy: 1.12.2016
Počet strán: 12
Približná hmotnosť: 36 g (0.08 libier)
Krajina: Americká technická norma
Kategória: Technické normy ASTM
This guide presents the simulation procedure which would provide advice for conducting experiments to investigate the effects of helium on the properties of irradiated metals where the technique for introducing the helium differs in someway from the actual mechanism of introduction of helium in service. Simulation techniques considered for introducing helium shall include charged particle implantation, exposure to alfa-emitting radioisotopes, and tritium decay techniques. Procedures for the analysis of helium content and helium distribution within the specimen are also recommended. The two other methods for introducing helium into irradiated materials namely, the enhancement of helium production in nickel-bearing alloys by spectral tailoring in mixed-spectrum fission reactors, and the isotopic tailoring in both fast and mixed-spectrum fission reactors, are not covered in this guide. Dual ion beam techniques for simultaneously implanting helium and generating displacement damage are also not included here.
helium analysis, helium effects, ion irradiation, radiation damage, tritium trick ,, ICS Number Code 77.040.99 (Other methods of testing metals)
|Significance and Use|
4.1 Helium is introduced into metals as a consequence of nuclear reactions, such as (n, α), or by the injection of helium into metals from the plasma in fusion reactors. The characterization of the effect of helium on the properties of metals using direct irradiation methods may be impractical because of the time required to perform the irradiation or the lack of a radiation facility, as in the case of the fusion reactor. Simulation techniques can accelerate the research by identifying and isolating major effects caused by the presence of helium. The word ‘simulation’ is used here in a broad sense to imply an approximation of the relevant irradiation environment. There are many complex interactions between the helium produced during irradiation and other irradiation effects, so care must be exercised to ensure that the effects being studied are a suitable approximation of the real effect. By way of illustration, details of helium introduction, especially the implantation temperature, may determine the subsequent distribution of the helium (that is, dispersed atomistically, in small clusters in bubbles, etc.).
1.1 This guide provides advice for conducting experiments to investigate the effects of helium on the properties of metals where the technique for introducing the helium differs in some way from the actual mechanism of introduction of helium in service. Techniques considered for introducing helium may include charged particle implantation, exposure to α-emitting radioisotopes, and tritium decay techniques. Procedures for the analysis of helium content and helium distribution within the specimen are also recommended.
1.2 Three other methods for introducing helium into irradiated materials are not covered in this guide. They are: (1.3 In addition to helium, hydrogen is also produced in many materials by nuclear transmutation. In some cases it appears to act synergistically with helium 1.4 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.
1.5 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.
|2. Referenced Documents|
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