Nprim Computer Code of Neutron Dose Calculation for Radiation Damage Estimation

Shimakawa, Satoshi; Nojiri, Naoki; Sekimura, Naoto

doi:10.1142/9789812705563_0011

Cited by 6 publications

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“…The displacement damages (dpa) and irradiation temperatures were 0.44 dpa at 531°C and 0.47 dpa at 583°C for pure W and WRe alloys, respectively. The dpa was calculated according to the NPRIM-1.3 code 18) using 90 eV as the displacement threshold energy of W. 19) …”

Section: Methodsmentioning

confidence: 99%

Effects of Re Content and Fabrication Process on Microstructural Changes and Hardening in Neutron Irradiated Tungsten

et al. 2012

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The effects of the material fabrication process and rhenium (Re) content on the irradiation-induced changes in the microstructure and hardness of pure tungsten (W) and WRe alloys were investigated. Neutron irradiation of pure W and WRe alloys (Re concentration 326%) was carried out in the experimental fast reactor JOYO. The irradiation conditions were 0.44 displacement per atom (dpa) at 531°C and 0.47 dpa at 583°C for pure W and WRe alloys, respectively. After irradiation, microstructural observations using a transmission electron microscope (TEM) and Vickers microhardness tests were performed.Voids and dislocation loops were observed in both pure W and WRe alloys after irradiation. The number density of voids in pure W was higher than that in W3%Re, W5%Re and W10%Re. Only in the case of W26%Re irradiated to 0.47 dpa at 583°C were there no voids observed, but irradiation-induced fine precipitates and a few dislocation loops were observed. The irradiation hardening of pure W was greater than that of the WRe alloys. It was considered that irradiation hardening of pure W was caused mainly by the higher number density of voids. The addition of Re suppressed void formation and irradiation hardening of the WRe alloys. Irradiation hardening of W was also suppressed in hot-rolled W compared with arc-melted as-cast W.

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Section: Methodsmentioning

confidence: 99%

Effects of Re Content and Fabrication Process on Microstructural Changes and Hardening in Neutron Irradiated Tungsten

et al. 2012

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“…The irradiation conditions are shown in Table 1. Displacement damage (dpa) was calculated using the NPRIM-1.3 code 11) with a displacement threshold energy of 90 eV. 12) In this calculation, fluence of 8 Â 10 25 n/m 2 (E n > 0:1 MeV) corresponds to 1 dpa approximately.…”

Section: Methodsmentioning

confidence: 99%

Microstructure Development in Neutron Irradiated Tungsten Alloys

et al. 2011

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The aim of this work is to investigate the influence of neutron irradiation condition, especially temperature, on irradiation hardening and microstructure development in irradiated tungsten-rhenium (W-Re) alloys. Neutron irradiations were carried out in JOYO at the range of 400 to 750 C, up to 1.54 dpa. Micro Vickers hardness tests and micro structural observations using a TEM were performed. Irradiation hardening of WRe alloys irradiated at 538 C were clearly larger than those irradiated at other temperatures. Fine voids and fine needle-or plate-like precipitates were observed in pure W and W-Re alloys irradiated at 538 C, respectively, with high number density. The fine complex microstructure seems to be the cause of the characteristic irradiation hardening.

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“…Irradiation conditions are shown in Table 2 (fluences of fast neutron (En > 0:1 Mev) are shown). Displacement damages (dpa) were calculated by NPRIM-1.3 code 8) using 90 eV as the displacement threshold energy. 9) With these fluences, composition changes during irradiation can be almost disregarded because the cross section of transmutation of W with the neutron spectrum in JOYO is small.…”

Section: Methodsmentioning

confidence: 99%

Effects of Transmutation Elements on Neutron Irradiation Hardening of Tungsten

et al. 2007

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Tungsten (W) is a candidate material for Plasma facing materials of fusion reactors. During fusion reactor operation, not only irradiation damages but also transmutation elements such as rhenium (Re) and osmium (Os) are produced by neutron irradiation. As a result, the original pure tungsten changes to W-Re or W-Re-Os alloys. Thus, the mechanical and physical properties are expected to change. The aim of this study is to investigate the effects of transmutation elements on neutron irradiation hardening and microstructure changes of tungsten.To simulate the effects of transmutation elements, tungsten base model alloys were used in this study. The examined compositions of the alloys were selected from the calculated changes in solid solution area of W-Re-Os alloy. Neutron irradiation was performed in fast test reactor JOYO in JAEA. The irradiation damages and temperature ranges were 0.17-1.54 dpa and 400-750 C respectively. After the irradiation, Vickers hardness test and TEM observation were performed.There were clear differences between Re and Os in effects on irradiation hardening. In the case of W-Re alloys, when damages were less than 0.40 dpa, the irradiation hardenings were nearly equal to those of pure tungsten independent of Re addition. But when the damage was 1.54 dpa, the irradiation hardenings increased lineally with Re content. Microstructural observations showed that precipitations mainly formed in W-Re alloys. In the case of W-Os alloys, the irradiation hardenings (ÁHv) of W-3Os alloys were larger than those of pure tungsten. And the differences were about 400 independent of dpa and irradiation temperature. Effects of Re and Os on irradiation hardening based on the microstructural observations were discussed.

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Nprim Computer Code of Neutron Dose Calculation for Radiation Damage Estimation

Cited by 6 publications

References 0 publications

Effects of Re Content and Fabrication Process on Microstructural Changes and Hardening in Neutron Irradiated Tungsten

Effects of Re Content and Fabrication Process on Microstructural Changes and Hardening in Neutron Irradiated Tungsten

Microstructure Development in Neutron Irradiated Tungsten Alloys

Effects of Transmutation Elements on Neutron Irradiation Hardening of Tungsten

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