Tritium removal

The final fate of the tritium removed from palmitate is its appearance in water, as reduced carriers (FADH2, NADH) are reoxidized by the mitochondria. 

Techniques of tritium removal from co-deposited layers in next-generation tokamaks, such as ITER, have an important impact on machine operation. Attempts are being made to develop in-situ co-deposit removal techniques that would not overly constrain machine operation, both in terms of T removal and plasma performance recovery after cleanup. In addition to machine operation considerations, the tritium in the co-deposited layers will also have safety implications. During a severe accident, the vacuum vessel of an operating tokamak can be breached. If a significant inventory of tritium in the form of a saturated layer is present, much of this tritium can be released as tritium oxide as the film reacts with oxygen. 

D. Mueller et al., Tritium removal from TFTR, J. Nucl. Mater. 241-243 (1997) 897-901... 

To address the tritium-co-deposition concern, primarily associated with the use of carbon, ITER will maintain the option to switch from CFC to W armour on the divertor targets prior to D-T operation. This change will depend on both the frequency and severity of ELMs and disruptions in the initial H/D plasmas, and the success of mitigating by design the occurrence of tritium co-deposition and/or on the availability of effective in-situ tritium removal techniques. 

A demonstration of a promising flash-lamp detritiation method has been carried out for the JET 2004 shutdown. Without established fast and efficient tritium removal method a satisfactory schedule of burning plasma operations in a machine with carbon PFCs appears impractical. 

ITER. This will remain a major difficulty unless experimentally validated in tokamaks with impurities and relevant wall materials to provide a realistic test-bed which would closely mirror options proposed for the next-step device (e.g., beryllium walls and carbon and/or tungsten divertor proposed for ITER). Such experiments would indeed help answer questions including the magnitudes of erosion and tritium co-deposition, dust formation in the vessel, the ease of tritium removal from mixed-materials, as well as operational aspects (e.g., of using beryllium on the first wall). 

If pure Li is used as the breeder-moderator, -Ti and a number of other materials can be used, as discussed for the Cauldron Blanket Module. However, the tritium activity in Li drops markedly in the absence of Pb, and the blanket temperature will need to be raised to alleviate the tritium removal problem. 

Natesan, K. Smith, D. "Effectiveness of Tritium Removal From a Lithium Blanket by Cold Trapping Secondary Liquids, Na, K, and NaK" Nucl. Tech. 1974, n. 

Hayashi, T. et al.. Gas separation performance of hollow-filament type polyimide membrane module for a compact tritium removal system, Fus. Technol, 28, 1503, 1995. 

Naflon, DuPont, membranes were applied for separation of hydrogen isotopes in installations for tritium removal from heavy reactor water and from nuclear reactor atmosphere. The monitor for HTO and HT control was constructed in Chalk River Laboratories in Canada [197]. At High-Energy Accelerators Research Organization (KEK), Japan, the work on apparatus for measurement of tritium emitted from high-energy accelerators, equipped with hollow-filament membranes for GS, is carried out [198]. 

Zakrzewska-Trznadel, G., Tritium removal from water solutions, Desalination 1-3, 737, 2006. 

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