| 1. |
- Rudakov, D. L., et al.
(författare)
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Dust measurements in tokamaks (invited)
- 2008
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Ingår i: Review of Scientific Instruments. - : AIP Publishing. - 0034-6748 .- 1089-7623. ; 79:10, s. 10F303-
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Tidskriftsartikel (refereegranskat)abstract
- Dust production and accumulation present potential safety and operational issues for the ITER. Dust diagnostics can be divided into two groups: diagnostics of dust on surfaces and diagnostics of dust in plasma. Diagnostics from both groups are employed in contemporary tokamaks; new diagnostics suitable for ITER are also being developed and tested. Dust accumulation in ITER is likely to occur in hidden areas, e.g., between tiles and under divertor baffles. A novel electrostatic dust detector for monitoring dust in these regions has been developed and tested at PPPL. In the DIII-D tokamak dust diagnostics include Mie scattering from Nd:YAG lasers, visible imaging, and spectroscopy. Laser scattering is able to resolve particles between 0.16 and 1.6 mu m in diameter; using these data the total dust content in the edge plasmas and trends in the dust production rates within this size range have been established. Individual dust particles are observed by visible imaging using fast framing cameras, detecting dust particles of a few microns in diameter and larger. Dust velocities and trajectories can be determined in two-dimension with a single camera or three-dimension using multiple cameras, but determination of particle size is challenging. In order to calibrate diagnostics and benchmark dust dynamics modeling, precharacterized carbon dust has been injected into the lower divertor of DIII-D. Injected dust is seen by cameras, and spectroscopic diagnostics observe an increase in carbon line (CI, CII, C(2) dimer) and thermal continuum emissions from the injected dust. The latter observation can be used in the design of novel dust survey diagnostics.
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| 2. |
- Cui, Daqing, et al.
(författare)
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Immobilization of radionuclides on iron canister material at simulated near-field conditions
- 2009
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Ingår i: Scientific Basis for Nuclear Waste Management XXXII. - Warrendale, Pa : Materials Research Society. - 9781605110967 ; 1124
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Konferensbidrag (refereegranskat)abstract
- This work is a continuation of a long-term spent fuel leaching and radionuclides immobilization (by iron canister) experiment under simulated near-field conditions, in deoxygenated 2 mM NaHCO3 solution with 1 Gy/h γ irradiation. The corrosion of iron canister material was investigated by electrochemical and microanalytical methods. Significant amounts of radionuclides (U, Np, Tc, Sr) were found to be immobilized on the corrosion layer of iron canister material by using SEM-WDS and SIMS methods. The observation is useful for bettering our understanding of near-field chemical processes at earlier canister failure conditions.
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