Modification and Final Alignment of the TFTR Bumper Limiter

The tritium surface distribution on graphite tiles used in the TFTR bumper limiter and exposed to TFTR D-T discharges from 1993 to 1997 was measured by the Tritium Imaging Plate Technique (TIPT). The TFTR bumper limiter shows both re-/co-deposition and erosion. The tritium images for all tiles measured are strongly correlated with erosion and deposition patterns, and long-term tritium retention was found in the re-/co-depositions and flakes.The CFC tiles located at erosion dominated areas clearly showed their woven structure in their tritium images owing to different erosion yields between fibers and matrix. Significantly high tritium retention was observed on all sides of the erosion tiles, indicating carbon transport via repetition of local erosion/deposition cycles.

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“…4. The two neighboring tiles were near the bottom surrounding a diagnostic port and were heavily eroded due to the high particle flux [10].…”

Section: Resultsmentioning

confidence: 99%

Measurement of Tritium Surface Distribution on TFTR Bumper Limiter Tiles

Sugiyama

Tanabe

Skinner

et al. 2004

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“…For example, it was found that retention in gaps was about 1/3 that on plasma facing surface even though the area of gaps was ≈30 times less. However, in the period 1992-1993 TFTR conducted an extensive re-alignment campaign for the inner bumper limiter, and the leading edge exposure between tiles was greatly reduced [23]. Thus, for the first approximation, gap deposition has not been included in the present estimates of tritium retention due to codeposition and is the subject of ongoing work.…”

Section: Bbq Resultsmentioning

confidence: 99%

“…The latter is a feature of the 'attached' condition of these limiter plasmas, and differs from detached divertor plasmas, for which thermal conduction (by definition) plays a marginal role. To treat the first effect, the code uses detailed measurements of in-vessel components compiled in a computer aided design (CAD) file [ 23 ]. Using the exact geometry is important for large-area limiters since the near alignment of flux surfaces with the inner bumper limiter results in particle and heat fluxes which depend critically on the small angle of incidence of field lines with respect to this edge structure.…”

Section: Codeposition Rates For Tritium Operation (Modeling Studies Wmentioning

confidence: 99%

“…We focus on the effect of neutral beam injection by considering the period from November 1993 to August 1995, when nearly all of the tritium (3.8x10 23 tritons) was injected into the torus via the neutral beams (including 6% cold gas) and only a trace amount (4.2x10 21 ) was injected by gas puff. By comparing the tritium injected with that recovered, the tritium inventory in the torus was estimated to be 1.3x10 23 tritons. According to earlier tile measurements 44% of the deuterium retained in the torus was in a codeposited layer on plasma facing tile surfaces.…”

Section: Comparison Of Tritium Retention Predicted By Modeling To Thamentioning

confidence: 99%

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Modeling of Tritium Retention in TFTR

Blanchard¹,

Brooks²,

Budny³

et al. 1998

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Abstract:The Tokamak Fusion Test Reactor tritium retention experience is reviewed and the data related to models of plasma surface interactions. Over 3.5 years of TFTR DT operations, approximately 51% of the tritium injected into TFTR was retained in the torus. Most of this was subsequently recovered by glow discharges and air ventilation. Co-deposition rates for representative conditions in tritium operation were modeled with the BBQ code. The calculations indicate that known erosion mechanisms and subsequent co-deposition are sufficient to account for the order of magnitude of retention.

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“…Tile material was initially 100% Union Carbide AXF-5Q isotropic graphite. In 1993 some damage was noted on the top and bottom rows of tiles [15]. In areas of heavy damage, the tiles were replaced with Fiber Materials Inc. 4D coarse weave carbon fiber composite (CFC) tiles and Hercules 3-D fine weave CFC tiles.…”

Section: Introductionmentioning

confidence: 99%

Observations of Flaking of Co-deposited Layers in TFTR

Gentile¹,

Skinner²,

Young³

1999

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Abstract-Flaking of co-deposited layers in the Tokamak Fusion Test Reactor (TFTR) has been observed after the termination of plasma operations. This unexpected flaking affects approximately 15% of the tiles and appears o n isotropic graphite tiles but not on carbon fiber composite tiles. Samples of tiles, flakes and dust were recently collected from the inside of the vacuum vessel and will be analyzed to better characterize the behavior of tritium o n plasma facing components in DT fusion devices.

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Modification and Final Alignment of the TFTR Bumper Limiter

Cited by 12 publications

References 1 publication

Measurement of Tritium Surface Distribution on TFTR Bumper Limiter Tiles

Measurement of Tritium Surface Distribution on TFTR Bumper Limiter Tiles

Modeling of Tritium Retention in TFTR

Observations of Flaking of Co-deposited Layers in TFTR

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