Recovery in neutron irradiated tungsten

Anand, M. S.; Pande, B.M.; Agarwala, R.P.

doi:10.1080/00337577808234468

Cited by 26 publications

(13 citation statements)

References 25 publications

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“…The maximum temperature in the TDS measurements (900°C) corresponds to stage V of recovery processes in which disappearance of some defect clusters or formation of voids are possible. 20) It is therefore necessary to improve computer program such as TMAP to simulate desorption under variations of trap density and E det,i with time and temperature. Figure 5 shows a result of simulation with TMAP4 program together with desorption spectrum obtained after plasma exposure at 500°C.…”

Section: Resultsmentioning

confidence: 99%

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Retention of Hydrogen Isotopes in Neutron Irradiated Tungsten

et al. 2013

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To investigate the effects of neutron irradiation on hydrogen isotope retention in tungsten, disk-type specimens of pure tungsten were irradiated in the High Flux Isotope Reactor in Oak Ridge National Laboratory followed by exposure to high flux deuterium (D) plasma in Idaho National Laboratory. The results obtained for low dose n-irradiated specimens (0.025 dpa for tungsten) are reviewed in this paper. Irradiation at coolant temperature of the reactor (around 50°C) resulted in the formation of strong trapping sites for D atoms. The concentrations of D in nirradiated specimens were ranging from 0.1 to 0.4 mol% after exposure to D plasma at 200 and 500°C and significantly higher than those in nonirradiated specimens because of D-trapping by radiation defects. Deep penetration of D up to a depth of 50100 µm was observed at 500°C. Release of D in subsequent thermal desorption measurements continued up to 900°C. These results were compared with the behaviour of D in ion-irradiated tungsten, and distinctive features of n-irradiation were discussed.

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Section: Resultsmentioning

confidence: 99%

“…210) In those studies, W specimens were irradiated with various types of high-energy ions (³ MeV) to moderate damage levels (³ a few dpa) and exposed to relatively low energy, high-flux (eVkeV, 10 20 …”

Section: Introductionmentioning

confidence: 99%

Retention of Hydrogen Isotopes in Neutron Irradiated Tungsten

et al. 2013

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“…Numerous studies have also been undertaken with regard to the recovery of irradiation-induced defects post-irradiation. However, these have mostly centred around resistivity measurements [12][13][14][15][16][17][18][19], with some early field ion microscopy work [20,21] and a single early TEM study on single crystal tungsten [22]. A similar TEM work has also been done in molybdenum [23].…”

Section: Previous Recovery Studiesmentioning

confidence: 96%

“…Stage V recovery, starting at 0:31T m , 1 was initially explained as being due to vacancy migration, based on early field-ion microscopy studies [20,21], but later attributed to the disappearance of "defect clusters" or formation of voids [19]. It is still unclear what is the cause of this recovery stage.…”

Section: Previous Recovery Studiesmentioning

confidence: 98%

High temperature annealing of ion irradiated tungsten

et al. 2015

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Transmission electron microscopy of high temperature annealing of pure tungsten irradiated by self-ions was conducted to elucidate microstructural and defect evolution in temperature ranges relevant to fusion reactor applications (500-1200°C). Bulk isochronal and isothermal annealing of ion irradiated pure tungsten (2 MeV W + ions, 500°C, 10 14 W + /cm 2 ) with temperatures of 800, 950, 1100 and 1400°C, from 0.5 to 8 h, was followed by ex situ characterisation of defect size, number density, Burgers vector and nature. Loops with diameters larger than 2-3 nm were considered for detailed analysis, among which all loops had b ¼ 1 2 h1 1 1i and were predominantly of interstitial nature. In situ annealing experiments from 300 up to 1200°C were also carried out, including dynamic temperature ramp-ups. These confirmed an acceleration of loop loss above 900°C. At different temperatures within this range, dislocations exhibited behaviour such as initial isolated loop hopping followed by large-scale rearrangements into loop chains, coalescence and finally line-loop interactions and widespread absorption by free-surfaces at increasing temperatures. An activation energy for the annealing of dislocation length was derived, finding E a ¼ 1:34 AE 0:2 eV for the 700-1100°C range.

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“…These observations can be interpreted on the basis of literature data on the recovery of defects in n-irradiated W. According to Keys and Moteff [16] and Anand et al [17] who examined damage annealing over a wide range of temperature after fast neutron irradiation, a large extent of defect recovery in W takes place in two temperature regions: 473-773K (stage III) and 1073-1273K (stage V). Both Keys and Moteff [16] and Anand et al [17] reported that the recovery of defects in stage III was a second-order reaction with an activation energy of ≈1.7 eV.…”

Section: Thermal Stability Of Defects Formed By Ion Irradiationmentioning

confidence: 99%

Deuterium trapping at defects created with neutron and ion irradiations in tungsten

et al. 2013

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The effects of neutron and ion irradiations on deuterium (D) retention in tungsten (W) were investigated. Specimens of pure W were irradiated with neutrons to 0.3 dpa at around 323 K and then exposed to high-flux D plasma at 473 and 773 K. The concentration of D significantly increased by neutron irradiation and reached 0.8 at% at 473K and 0.4 at% at 773 K. Annealing tests for the specimens irradiated with 20 MeV W ions showed that the defects which play a dominant role in the trapping at high temperature were stable at least up to 973 K, while the density decreased at temperatures equal to or above 1123 K. These observations of the thermal stability of traps and the activation energy for D detrapping examined in a previous study (≈1.8 eV) indicated that the defects which contribute predominantly to trapping at 773 K were small voids. The higher concentration of trapped D at 473 K was explained by additional contributions of weaker traps. The release of trapped D was clearly enhanced by the exposure to atomic hydrogen at 473 K, though higher temperatures are more effective for using this effect for tritium removal in fusion reactors.2

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Recovery in neutron irradiated tungsten

Cited by 26 publications

References 25 publications

Retention of Hydrogen Isotopes in Neutron Irradiated Tungsten

Retention of Hydrogen Isotopes in Neutron Irradiated Tungsten

High temperature annealing of ion irradiated tungsten

Deuterium trapping at defects created with neutron and ion irradiations in tungsten

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