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Recrystallization, melting, and erosion of dispersoid-strengthened tungsten materials during exposure to DIII-D plasmas

Kolasinski, Robert; Coburn, Jonathan D.; Truong, Dinh D.; Watkins, Jonathan; Abrams, Tyler; Fang, Z.Z.; Nygren, Richard; Leonard, Anthony; Ren, Jun; Wang, Huiqian; Whaley, Josh; Bykov, Igor; Glass, Fenton; Herfindal, Jeffrey; Hood, Ryan T.; Lasnier, Charles; Marini, Claudio; Mclean, Adam; Moser, Auna; Nishimoto, Ryan K.; Sugar, Joshua D.; Wilcox, Robert; York, Warren

Abstract not provided.

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TYPE Conference Presentation YEAR 2022
DOIOSTI

Failure of a lithium-filled target and some implications for fusion components

Fusion Engineering and Design

Nygren, Richard; Youchison, D.L.; Michael, Joseph R.; Puskar, J.D.; Lutz, Thomas J.

In preparation for testing a lithium-helium heat exchanger at Sandia, unexpected rapid failure of the mild steel lithium preheater due to liquid metal embrittlement occurred when lithium at ~400 °C flowed into the preheater then at ~200 °C. This happened before the helium system was pressurized or heating with electron beams began. The paper presents an analysis of the preheater plus a discussion of some implications for fusion.

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TYPE Journal Article YEAR 2021
DOIOSTIScopus

Post-test examination of a Li-Ta heat pipe exposed to H plasma in Magnum PSI

Fusion Engineering and Design

Nygren, Richard; Matthews, G.F.; Morgan, T.W.; Silburn, S.A.; Rosenfeld, J.H.; North, M.T.; Tallarigo, A.; Stavila, Vitalie

The authors exposed a radiatively cooled, Li-filled tantalum (Ta) heat pipe (HP) to a H plasma in Magnum PSI continuously for ˜2 h. We kept the overall heat load on the inclined HP constant and varied the tilt to give peak heat fluxes of ˜7.5–13 MW/m2. The peak temperature reached ˜1250 °C. This paper describes the post-test analysis and discusses Li HPs with materials other than Ta for fusion. A companion paper describes the experiment.

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TYPE Conference Poster YEAR 2019
DOIOSTIScopus

Liquid surfaces for fusion plasma facing components—A critical review. Part I: Physics and PSI

Nuclear Materials and Energy

Nygren, Richard; Tabares, F.L.

This review of the potential of robust plasma facing components (PFCs) with liquid surfaces for applications in future D/T fusion device summarizes the critical issues for liquid surfaces and research being done worldwide in confinement facilities, and supporting R&D in plasma surface interactions. In the paper are a set of questions and related criteria by which we will judge the progress and readiness of liquid surface PFCs. Part-II (separate paper) will cover R&D on the technology-oriented aspects of liquid surfaces including the liquid surfaces as integrated first walls in tritium breeding blankets, tritium retention and recovery, and safety.

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TYPE Journal Article YEAR 2016
DOIOSTIScopus

Developing and validating advanced divertor solutions on DIII-D for next-step fusion devices

Nuclear Fusion

Wampler, William R.; Guo, H.Y.; Buchenauer, D.A.; Nygren, Richard; Watkins, Jonathan

A major challenge facing the design and operation of next-step high-power steady-state fusion devices is to develop a viable divertor solution with order-of-magnitude increases in power handling capability relative to present experience, while having acceptable divertor target plate erosion and being compatible with maintaining good core plasma confinement. A new initiative has been launched on DIII-D to develop the scientific basis for design, installation, and operation of an advanced divertor to evaluate boundary plasma solutions applicable to next step fusion experiments beyond ITER. Developing the scientific basis for fusion reactor divertor solutions must necessarily follow three lines of research, which we plan to pursue in DIII-D: (1) Advance scientific understanding and predictive capability through development and comparison between state-of-the art computational models and enhanced measurements using targeted parametric scans; (2) Develop and validate key divertor design concepts and codes through innovative variations in physical structure and magnetic geometry; (3) Assess candidate materials, determining the implications for core plasma operation and control, and develop mitigation techniques for any deleterious effects, incorporating development of plasma-material interaction models. These efforts will lead to design, installation, and evaluation of an advanced divertor for DIII-D to enable highly dissipative divertor operation at core density (n e/n GW), neutral fueling and impurity influx most compatible with high performance plasma scenarios and reactor relevant plasma facing components (PFCs). This paper highlights the current progress and near-term strategies of boundary/PMI research on DIII-D.

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TYPE Journal Article YEAR 2016
DOIOSTIScopus

Integration of liquid surface PFCs into DEMO or FNSF

Physica Scripta

Nygren, Richard

Many ideas for liquid surface PFCs are for divertors. First walls are likely to be more challenging technologically because long flow paths are necessary for fast flowing systems and the first wall must be an integral structure with the blanket. Maximum tolerable heat loads are a critical concern. This paper describes several processes at work in walls with fast-flowing or slow-flowing liquid plasma-facing surfaces, and the considerations imposed by heat transfer and the power balance for the PFC as well as the structure needed for an integrated first wall and blanket, and uses thermal modeling of a generic PFC structure to illustrate the issues and support the conclusions.

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TYPE Conference Poster YEAR 2016
DOIOSTIScopus

Sandia non-fusion R&D supported by FES

Nygren, Richard

Until 2012, Sandia participated regularly in non-fusion R&D that was supported primarily through our collaborations with companies in the DOE program for Small Business Innovative Research but also in some work-for-others contracts. In this work, funds were recovered from collaborating institutions for the staff time and materials used, but FES had supported the facility itself and in doing so enabled the contributions to the non-fusion R&D below.

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TYPE Other Report YEAR 2015
DOIOSTI
Results 1–50 of 98
Results 1–50 of 98