Conceptual study of the cryocascade for pumping, separation and recycling of ITER torus exhaust

Mack, A.; Perinić, D.

doi:10.1016/0920-3796(95)90054-3

Cited by 4 publications

(3 citation statements)

References 4 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Another cryopump variant, often denoted compound or cascaded cryopump [12] provides a distributed pumping by providing cryosurfaces at different temperatures so that they can be released one after the other, if a mechanical mechanism is installed that allows to sample the regenerated gases. By this fore-separation, impurities and helium could be separated relatively sharply from the fusion plasma, what allows to reduce the size of the tritium plant significantly.…”

Section: ) Cryopumpsmentioning

confidence: 99%

Exhaust pumping of DT fusion devices: Current state-of-the-art and a potential roadmap to a fusion power plant

Day

Giegerich

2013

2013 IEEE 25th Symposium on Fusion Engineering (SOFE)

View full text Add to dashboard Cite

The main functions of the exhaust pumping system of a DT fusion device are to pump out the helium ash and to control the divertor neutral gas density. This requires the handling of large gas throughputs at high pumping speeds (but at relatively moderate vacua). The pumped exhaust gas is then usually transported to the tritium plant for cleaning, which involves impurity removal and separation of the pure hydrogenic species for re-injection as fuel.In view of a fusion power plant, a systematic technical review of primary and roughing pump technologies is conducted in order to identify potential exhaust pumping concepts which eliminate some of the disadvantages that eventually result from simple scale-up of the ITER solutions that are based on batchwise operating cryogenic pumps. This paper also illustrates the methodology applied to come to unbiased results and describes the final configuration which is based on a vapor diffusion pump as primary pump together with a metal foil pump for hydrogen separation, and a liquid metal ring pump as roughing pump. All pumps are working continuously and do not require cryogenic temperatures.The new concept will reduce the tritium inventories of a power plant, firstly because of the continuous pumping characteristics of the pumps involved, and secondly because the metal foil pump allows for internal recycling of the unburnt fuel species directly from the divertor to the fuelling systems, bypassing the tritium plant.

show abstract

Section: ) Cryopumpsmentioning

confidence: 99%

Exhaust pumping of DT fusion devices: Current state-of-the-art and a potential roadmap to a fusion power plant

Day

Giegerich

2013

2013 IEEE 25th Symposium on Fusion Engineering (SOFE)

View full text Add to dashboard Cite

show abstract

“…Having said that, all primary pump technologies that do only provide the requested pumping speed and capacity at very low pressures (such as sublimation pumps and ion pumps) are not appropriate. In summary, three pump technologies have been identified as at least partly suitable:  Cryogenic pumping (score of 50%): The standard pump technology used on modern medium-size tokamaks could be an option but require significant R&D to implement a hydrogen isotope separation function for the DIR [48,49] (R&D topic 13).…”

Section: Vacuum Technology Reviewmentioning

confidence: 99%

Consequences of the technology survey and gap analysis on the EU DEMO R&D programme in tritium, matter injection and vacuum

Day

Butler

Giegerich

et al. 2016

Fusion Engineering and Design

View full text Add to dashboard Cite

In the framework of the EUROfusion Programme, EU is preparing the conceptual design of the inner fuel cycle of a pulsed tokamak DEMO. This paper illustrates a quantified process to shape a R&D programme that exploits as much as possible previous R&D. In an initial step, the high-level requirements are collected and a novel DEMO inner fuel cycle architecture with its three subsystems vacuum pumping, matter injection (fuelling and injection of plasma enhancement gases) and tritium systems (tritium plant and breeder coolant purification) is delineated, driven by the DEMO key challenge to reduce tritium inventory. Then, a technology survey is carried out to review potential existing solutions for the required process functions and to assess their maturity and risks. Finally, a decision-making scheme is applied to select the most promising candidates. ITER technology is exploited where possible. As a primary result, a fuel cycle architecture is suggested with an advanced tritium plant that avoids full isotope separation in the main loop and with a Direct Internal Recycling path in the vacuum systems to shorten cycle times. For core fuelling, classical inboard pellet injection technology is selected, in principle similar to that proposed for ITER but aiming for higher launch speeds to achieve deep fuelling of the DEMO plasma. Based on these findings, a tailored R&D programme is shaped that tackles the key questions until 2020.

show abstract

“…(b) Pre-separation of helium has been proposed for ITER [6]. In this scheme all gases would be captured together in the main pump.…”

Section: Introductionmentioning

confidence: 99%

Compound cryopump for fusion reactors

Kovari

Clarke

Shephard

2013

Fusion Engineering and Design

View full text Add to dashboard Cite

We reconsider an old idea: a three-stage compound cryopump for use in fusion reactors such as DEMO. The helium "ash" is adsorbed on a 4.5 K charcoal-coated surface, while deuterium and tritium are adsorbed at 15-22 K on a second charcoal-coated surface. The helium is released by raising the first surface to ~30 K. In a separate regeneration step, deuterium and tritium are released at ~110 K. In this way, the helium can be pre-separated from other species. In the simplest design, all three stages are in the same vessel, with a single valve to close the pump off from the tokamak during regeneration. In an alternative design, the three stages are in separate vessels, connected by valves, allowing the stages to regenerate without interfering with each other. The inclusion of the intermediate stage would not affect the overall pumping speed significantly. The downstream exhaust processing system could be scaled down, as much of the deuterium and tritium could be returned directly to the reactor. This could reduce the required tritium reserve by almost 90%. We used a well-established free Direct Simulation Monte Carlo (DSMC) code, DS2V. At very high upstream densities (~1020 molecules/m3 and above) the flow into the pump is choked. Enlarging the aperture is the only way to increase the pumping speed at high densities. Ninety percent of the deuterium and tritium is successfully trapped at 15 K (assuming that the sticking coefficient is 80-100% on the 15-22 K surface). On the other hand, the remaining 10% still exceeds the small amount of helium in the gas input.Comment: 12 pages, 10 figures. For publication in Fusion Engineering & Desig

show abstract

Conceptual study of the cryocascade for pumping, separation and recycling of ITER torus exhaust

Cited by 4 publications

References 4 publications

Exhaust pumping of DT fusion devices: Current state-of-the-art and a potential roadmap to a fusion power plant

Exhaust pumping of DT fusion devices: Current state-of-the-art and a potential roadmap to a fusion power plant

Consequences of the technology survey and gap analysis on the EU DEMO R&D programme in tritium, matter injection and vacuum

Compound cryopump for fusion reactors

Contact Info

Product

Resources

About