Research on the influence of fabrication methods on the performance of fusion reactor divertors

Key findings from this study

This research indicates that:

• The brazing fabrication approach for Cu-ODS-Cu interfaces outperforms Hot Isostatic Pressing in thermal fatigue resistance and heat transfer under high heat flux conditions.
• Divertor components sustained 20 MW/m² thermal loads across 1000 cycles, validating the baseline heat removal capacity of the tested geometry.
• Interface bonding method selection substantially influences divertor operational performance despite identical constituent materials and overall component structure.

Overview

Flat-type fusion reactor divertors employ sandwich-like layered structures requiring specialized interlayer bonding methods. The Cu-to-ODS-Cu interface bonding quality directly affects operational performance and component lifespan. This study systematically compared two fabrication approaches—Hot Isostatic Pressing (HIPping) and brazing—applied to divertor mock-ups otherwise identical in materials and geometry. The comparison addresses the scarcity of direct, controlled evaluations of fabrication method effects on divertor reliability.

Methods and approach

Two divertor mock-ups were fabricated with identical copper and oxide dispersion strengthened copper constituent materials. The first employed Hot Isostatic Pressing for Cu-to-ODS-Cu interface bonding. The second utilized brazing at the same interface. High heat flux testing systematically evaluated both specimens, assessing heat transfer performance, thermal fatigue resistance, and overall reliability across multiple operational cycles.

Results

The divertor specimens successfully sustained thermal loads of 20 MW/m² across 1000 operational cycles, demonstrating adequate heat removal capacity for the component design. High heat flux test results indicate that the brazing-fabricated mock-up exhibited superior performance compared to the HIP-bonded specimen. Performance differences emerged in thermal fatigue resistance and heat transfer characteristics at the Cu-ODS-Cu interface, with brazing producing more favorable outcomes under the imposed operational conditions.

Implications

The identification of brazing as a superior bonding method has direct applicability to divertor design and manufacturing for current and future fusion reactors. Enhanced thermal fatigue resistance and heat transfer performance at interlayer interfaces contribute to extended component operational lifespan and improved reactor reliability. Standardization of the brazing approach for Cu-ODS-Cu interfaces may facilitate more consistent performance predictions in divertor engineering and reduce manufacturing variability across reactor programs.

Scope and limitations

This summary is based on the study abstract and available metadata. It does not include a full analysis of the complete paper, supplementary materials, or underlying datasets unless explicitly stated. Findings should be interpreted in the context of the original publication.