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Structural and metallurgical effects in stainless steel for first wall applications in simulated plasma disruptions
DISCUSSION ON CONTRIBUTED
PAPERS
Discussion
Paper on page
on coniribuled papers
1165
Paper on page
270
Structural and meta~urgic~ effects in stainiess steel for first wall applications in simulated plasma disruptions J. G. van der Laan, H. T. Klippel, J. Bakker and R. C. L. van der Stad S. Yamazaki: In our similar study using an e-beam as the heat source, we obtained the same result on the melting thickness of metallic materials. The experimental results were much larger than predictions, and this can be explained as the heat transfer enhancement due to molten metal movement. The prediction with higher liquid metal thermal conductivity (2-5 times) agreed well with experimental data. What is the reason for the difference of the results for 20 ms pulse, from the results for other shorter pulses ? Did you perform only 1-D calculation ? If so, isn’t consideration of lateral heat conduction required ? J. G. van der Laan: The energy-content of the 20 ms pulse is about 8 3 (40% absorption). From 2-D calculations on 316-s&l we estimate the heat losses in the radial direction to reduce the melting depth about 20%. Taking this into account the results for the largest pulse duration are more similar. Still an unknown factor is the exact spatial beam intensity profile. For the shortest pulse durations melt ejection and evaporation are the main phenomena.
in MgO-A1203 under electron and/or
system ion-irradiation
Y. Satoh, C. Kinoshita and K. Nahai E. R. Hodgson: 1) How do you explain the rather low threshold energy for MgO ? 2) Is it necessary to compare with metals, there are many examples of 4”’ dependence in insulators. Y. Satoh: 1) Theoretical studies have indicated that the displacement threshold energy Ed is a minimum along directions. Relatively thick specimens (e.g. 500 pm) necessary for optical measurements spread an electron beam through multiple scattering and give Ed averaged around a crystal direction parallel to the electron beam. In our experiments, the growth rate of loops in thin specimens is used to obtain Ed along the direction. Furthermore., the critical electron energy to nucleate loops dose not correspond to Ed, because it depends on Ioop kinetics. 2) Not always necessary, but the power of 4 tells us about nucleation sites of loops as well as the kinetic behavior of point defects at temperatures where only interstitials are mobile. Our objective is to summarize the nucleation process of loops in terms of characteristics of crystals including metals, oxides and carbides. Paper on page
Pam on page
298
Topographical change of high-temperature copper surface bomberded by Ar ions Y. Talcso, Y. Kanda, 1‘. Yomura, A. Eashiguchi and S. Ku&u R. Behrisch: When you measured the sputtering yield at the temperature of about 1200 K, did you take into account that there is also a considerable material loss due to evaporation ? Did you subtract this in determining the sputtering yield ? Y. Takao: We didn’t subtract the loss due to evaporation from the sputtering yiefd at 1173 K. We want to know the tendency of the temperature dependency of the sputtering yield between 423 K and 573 K. The absolute value in our work is 35% lower than that in earlier work. Therefore more detailed experiments are needed to determine the absolute value of the sputtering yield at high-temperatu~,
399
Kinetic study of defect clusters
425
Charpy impact testing using miniature specimens and its application to the study of irradiation behavior of low-activation ferritic steels H. Kayano, H. Kurishita, A. Kimura, M. Narui, M. Yamazaki and Y. Suzuki M. L. Hamilton: How is the modified stress concentration factor Kt’ calculated ? H. Kurishita: The modified stress concentration factor, Kt’, is defined as the product of elastic stress concentration factor at the notch root, Kt, and the ratio of the maximum plastic stress concentration factor for mini-size specimens to that for full-size specimens.
PAPERS
Discussion
Paper on page
on coniribuled papers
1165
Paper on page
270
Structural and meta~urgic~ effects in stainiess steel for first wall applications in simulated plasma disruptions J. G. van der Laan, H. T. Klippel, J. Bakker and R. C. L. van der Stad S. Yamazaki: In our similar study using an e-beam as the heat source, we obtained the same result on the melting thickness of metallic materials. The experimental results were much larger than predictions, and this can be explained as the heat transfer enhancement due to molten metal movement. The prediction with higher liquid metal thermal conductivity (2-5 times) agreed well with experimental data. What is the reason for the difference of the results for 20 ms pulse, from the results for other shorter pulses ? Did you perform only 1-D calculation ? If so, isn’t consideration of lateral heat conduction required ? J. G. van der Laan: The energy-content of the 20 ms pulse is about 8 3 (40% absorption). From 2-D calculations on 316-s&l we estimate the heat losses in the radial direction to reduce the melting depth about 20%. Taking this into account the results for the largest pulse duration are more similar. Still an unknown factor is the exact spatial beam intensity profile. For the shortest pulse durations melt ejection and evaporation are the main phenomena.
in MgO-A1203 under electron and/or
system ion-irradiation
Y. Satoh, C. Kinoshita and K. Nahai E. R. Hodgson: 1) How do you explain the rather low threshold energy for MgO ? 2) Is it necessary to compare with metals, there are many examples of 4”’ dependence in insulators. Y. Satoh: 1) Theoretical studies have indicated that the displacement threshold energy Ed is a minimum along
Pam on page
298
Topographical change of high-temperature copper surface bomberded by Ar ions Y. Talcso, Y. Kanda, 1‘. Yomura, A. Eashiguchi and S. Ku&u R. Behrisch: When you measured the sputtering yield at the temperature of about 1200 K, did you take into account that there is also a considerable material loss due to evaporation ? Did you subtract this in determining the sputtering yield ? Y. Takao: We didn’t subtract the loss due to evaporation from the sputtering yiefd at 1173 K. We want to know the tendency of the temperature dependency of the sputtering yield between 423 K and 573 K. The absolute value in our work is 35% lower than that in earlier work. Therefore more detailed experiments are needed to determine the absolute value of the sputtering yield at high-temperatu~,
399
Kinetic study of defect clusters
425
Charpy impact testing using miniature specimens and its application to the study of irradiation behavior of low-activation ferritic steels H. Kayano, H. Kurishita, A. Kimura, M. Narui, M. Yamazaki and Y. Suzuki M. L. Hamilton: How is the modified stress concentration factor Kt’ calculated ? H. Kurishita: The modified stress concentration factor, Kt’, is defined as the product of elastic stress concentration factor at the notch root, Kt, and the ratio of the maximum plastic stress concentration factor for mini-size specimens to that for full-size specimens.