Development of design Criteria for ITER In-vessel Components

Analysis and mitigation of backstreaming-electron-induced heat load on the KSTAR NBI E-dump under a cusp magnetic fields

“…Therefore, the E-dump damage observed in figure 3(c) can be considered to result from thermal-creep deformation occurring below the melting temperature. CuCrZr alloys are known to undergo creep deformation at temperatures as low as approximately 30%-40% of their melting point when subjected to sustained stress [19][20][21][22]. Several factors are expected to contribute to stress development in the E-dump, including self-weight and the pressure difference between vacuum and atmospheric conditions.…”

“…For the operation of the KSTAR NBI system, conservative temperature limits for the E-dump are defined based on well-established material criteria reported for CuCrZr heat sinks in fusion-related applications. CuCrZr alloys have been extensively studied as heat sink materials for plasma-facing components such as divertor targets and first-wall structures in magnetic confinement fusion devices, owing to their favorable combination of high thermal conductivity and adequate mechanical strength at elevated temperatures [19][20][21][22]. Several design studies for CuCrZr heat sinks have introduced conservative temperature limits to mitigate excessive deformation associated with thermal and irradiation-induced creep.…”

“…Several design studies for CuCrZr heat sinks have introduced conservative temperature limits to mitigate excessive deformation associated with thermal and irradiation-induced creep. In particular, a local upper temperature limit of 320 • C-350 • C have been applied in highly stressed regions to prevent irradiation creep deformation [20][21][22]. Meanwhile, creep-fatigue studies on CuCrZr heat sinks, including investigations based on EAST divertor operating conditions, have indicated that high-temperature creep of CuCrZr becomes physically activated at temperatures above approximately 0.22 T m (≈230 • C, where T m is the melting temperature of CuCrZr) [19].…”

Analysis and mitigation of backstreaming-electron-induced heat load on the KSTAR NBI E-dump under a cusp magnetic fields

“…Therefore, the E-dump damage observed in figure 3(c) can be considered to result from thermal-creep deformation occurring below the melting temperature. CuCrZr alloys are known to undergo creep deformation at temperatures as low as approximately 30%-40% of their melting point when subjected to sustained stress [19][20][21][22]. Several factors are expected to contribute to stress development in the E-dump, including self-weight and the pressure difference between vacuum and atmospheric conditions.…”

“…For the operation of the KSTAR NBI system, conservative temperature limits for the E-dump are defined based on well-established material criteria reported for CuCrZr heat sinks in fusion-related applications. CuCrZr alloys have been extensively studied as heat sink materials for plasma-facing components such as divertor targets and first-wall structures in magnetic confinement fusion devices, owing to their favorable combination of high thermal conductivity and adequate mechanical strength at elevated temperatures [19][20][21][22]. Several design studies for CuCrZr heat sinks have introduced conservative temperature limits to mitigate excessive deformation associated with thermal and irradiation-induced creep.…”

“…Several design studies for CuCrZr heat sinks have introduced conservative temperature limits to mitigate excessive deformation associated with thermal and irradiation-induced creep. In particular, a local upper temperature limit of 320 • C-350 • C have been applied in highly stressed regions to prevent irradiation creep deformation [20][21][22]. Meanwhile, creep-fatigue studies on CuCrZr heat sinks, including investigations based on EAST divertor operating conditions, have indicated that high-temperature creep of CuCrZr becomes physically activated at temperatures above approximately 0.22 T m (≈230 • C, where T m is the melting temperature of CuCrZr) [19].…”

Towards Virtual Qualification in Nuclear Fusion: Demonstrating Probabilistic Model Validation on a High Heat Flux Component

“…The mode coefficients are therefore suitable for prediction by our Gaussian Process surrogate model. We train our Gaussian Process surrogates using the first 𝑛 mode coefficients computed from (11), σ, for each training field. Our hybrid surrogate models can therefore predict field data by first predicting the mode coefficients for each field type, and then reconstructing the full field by combining with the precomputed mode shapes.…”

“…Much of the past and current focus in fusion component qualification is on development and usage of design codes and standards [11,12]. It is well documented that existing design codes are inadequate for the unique demands on components in future fusion power stations [10,[12][13][14].…”

Analysis and mitigation of backstreaming-electron-induced heat load on the KSTAR NBI E-dump under a cusp magnetic fields

“…Therefore, the E-dump damage observed in figure 3(c) can be considered to result from thermal-creep deformation occurring below the melting temperature. CuCrZr alloys are known to undergo creep deformation at temperatures as low as approximately 30%-40% of their melting point when subjected to sustained stress [19][20][21][22]. Several factors are expected to contribute to stress development in the E-dump, including self-weight and the pressure difference between vacuum and atmospheric conditions.…”

“…For the operation of the KSTAR NBI system, conservative temperature limits for the E-dump are defined based on well-established material criteria reported for CuCrZr heat sinks in fusion-related applications. CuCrZr alloys have been extensively studied as heat sink materials for plasma-facing components such as divertor targets and first-wall structures in magnetic confinement fusion devices, owing to their favorable combination of high thermal conductivity and adequate mechanical strength at elevated temperatures [19][20][21][22]. Several design studies for CuCrZr heat sinks have introduced conservative temperature limits to mitigate excessive deformation associated with thermal and irradiation-induced creep.…”

“…Several design studies for CuCrZr heat sinks have introduced conservative temperature limits to mitigate excessive deformation associated with thermal and irradiation-induced creep. In particular, a local upper temperature limit of 320 • C-350 • C have been applied in highly stressed regions to prevent irradiation creep deformation [20][21][22]. Meanwhile, creep-fatigue studies on CuCrZr heat sinks, including investigations based on EAST divertor operating conditions, have indicated that high-temperature creep of CuCrZr becomes physically activated at temperatures above approximately 0.22 T m (≈230 • C, where T m is the melting temperature of CuCrZr) [19].…”

Towards Virtual Qualification in Nuclear Fusion: Demonstrating Probabilistic Model Validation on a High Heat Flux Component

“…The mode coefficients are therefore suitable for prediction by our Gaussian Process surrogate model. We train our Gaussian Process surrogates using the first 𝑛 mode coefficients computed from (11), σ, for each training field. Our hybrid surrogate models can therefore predict field data by first predicting the mode coefficients for each field type, and then reconstructing the full field by combining with the precomputed mode shapes.…”

“…Much of the past and current focus in fusion component qualification is on development and usage of design codes and standards [11,12]. It is well documented that existing design codes are inadequate for the unique demands on components in future fusion power stations [10,[12][13][14].…”

Analysis and mitigation of backstreaming-electron-induced heat load on the KSTAR NBI E-dump under a cusp magnetic fields

“…Therefore, the E-dump damage observed in figure 3(c) can be considered to result from thermal-creep deformation occurring below the melting temperature. CuCrZr alloys are known to undergo creep deformation at temperatures as low as approximately 30%-40% of their melting point when subjected to sustained stress [19][20][21][22]. Several factors are expected to contribute to stress development in the E-dump, including self-weight and the pressure difference between vacuum and atmospheric conditions.…”

“…For the operation of the KSTAR NBI system, conservative temperature limits for the E-dump are defined based on well-established material criteria reported for CuCrZr heat sinks in fusion-related applications. CuCrZr alloys have been extensively studied as heat sink materials for plasma-facing components such as divertor targets and first-wall structures in magnetic confinement fusion devices, owing to their favorable combination of high thermal conductivity and adequate mechanical strength at elevated temperatures [19][20][21][22]. Several design studies for CuCrZr heat sinks have introduced conservative temperature limits to mitigate excessive deformation associated with thermal and irradiation-induced creep.…”

“…Several design studies for CuCrZr heat sinks have introduced conservative temperature limits to mitigate excessive deformation associated with thermal and irradiation-induced creep. In particular, a local upper temperature limit of 320 • C-350 • C have been applied in highly stressed regions to prevent irradiation creep deformation [20][21][22]. Meanwhile, creep-fatigue studies on CuCrZr heat sinks, including investigations based on EAST divertor operating conditions, have indicated that high-temperature creep of CuCrZr becomes physically activated at temperatures above approximately 0.22 T m (≈230 • C, where T m is the melting temperature of CuCrZr) [19].…”

Towards Virtual Qualification in Nuclear Fusion: Demonstrating Probabilistic Model Validation on a High Heat Flux Component

“…The mode coefficients are therefore suitable for prediction by our Gaussian Process surrogate model. We train our Gaussian Process surrogates using the first 𝑛 mode coefficients computed from (11), σ, for each training field. Our hybrid surrogate models can therefore predict field data by first predicting the mode coefficients for each field type, and then reconstructing the full field by combining with the precomputed mode shapes.…”

“…Much of the past and current focus in fusion component qualification is on development and usage of design codes and standards [11,12]. It is well documented that existing design codes are inadequate for the unique demands on components in future fusion power stations [10,[12][13][14].…”