Tritium fuel cycle modeling and tritium breeding analysis for CFETR

Chen, Hongli; Pan, Lei; Lv, Zhongliang; Li, Wei; Zeng, Qin

doi:10.1016/j.fusengdes.2016.02.100

Cited by 24 publications

(8 citation statements)

References 8 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…However, the blanket structures such as the FW, cooling plate (CP), stiffening plate (SP), cap and some other design parameters in detailed 3-D model would have significant impacts on the tritium breeding performance. The tritium self-sufficiency studies have shown that the required minimum tritium breeding ratio is 1.05 for CFETR [11]. Thus for meeting the tritium self-sufficiency target, the sensitivity analyses of the blanket structure modifications on TBR are carried out.…”

Section: Tbr Of the Current Blanket Schemementioning

confidence: 99%

“…It reveals that as the thickness of CP increases from 5 to 8 mm, the global TBR decreases from 1.091 to 1.029. If the steel content of CP reduced from 69 to 60 %, the thickness of CP should not be thicken than 8 mm in order to meet the tritium self-sufficiency target (TBR C 1.05 [11,15]). Moreover, the affection of the thickness of CP on the TBR performance shows that the global TBR decreases with the rate of *-1.9 % DTBR/mm for the CP.…”

Section: Impact Of Different Thickness Of Cooling Plate On Tbrmentioning

confidence: 99%

See 1 more Smart Citation

Impact Analysis of Helium Cooled Solid Blanket Structures on the Tritium Breeding Performance in CFETR

Zeng

et al. 2016

J Fusion Energ

Self Cite

View full text Add to dashboard Cite

Chinese Fusion Engineering Test Reactor (CFETR) is a test tokamak reactor to bridge the gap between ITER and future fusion power plant. As its objectives are to demonstrate generation of fusion power and to realize tritium self-sufficiency, the tritium breeding ratio (TBR) is a key design parameter. In the blanket design and optimization, the structures such as the first wall (FW), cooling plate (CP), stiffening plate (SP), cap and some other design parameters in detailed 3-D model have significant impacts on the tritium breeding performance. Based on a helium cooled solid breeder blanket option for CFETR, the impact analysis of the helium cooled solid blanket structures on tritium breeding performance was performed in this paper. Firstly, the detailed 3D neutronics model was built by using of a CAD to Monte Carlo Geometry conversion tool McCad. Then based on the detailed 3D neutronics model, the impact analyses of the blanket structures on tritium breeding performance were carried out, which include the FW, CP, SP, cap and side wall. By the sensitivity study of the blanket structures on the TBR, it gave the TBR variation trend and references for the blanket design and optimization.

show abstract

Section: Tbr Of the Current Blanket Schemementioning

confidence: 99%

Section: Impact Of Different Thickness Of Cooling Plate On Tbrmentioning

confidence: 99%

Impact Analysis of Helium Cooled Solid Blanket Structures on the Tritium Breeding Performance in CFETR

Zeng

et al. 2016

J Fusion Energ

Self Cite

View full text Add to dashboard Cite

show abstract

“…Of particular concern is that detailed analysis shows that extrapolation of the state-of-the-art in plasma physics and fusion technology to future DEMO and power plants require extensive programs of R & D whose outcome cannot be assured. These serious issues were addressed in a number of publications over the past three decades (see for example, references [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15]). Although progress has been made in some areas, there are persistent challenges for which no solutions have yet been found.…”

Section: Introductionmentioning

confidence: 99%

Physics and technology considerations for the deuterium–tritium fuel cycle and conditions for tritium fuel self sufficiency

et al. 2020

View full text Add to dashboard Cite

The tritium aspects of the DT fuel cycle embody some of the most challenging feasibility and attractiveness issues in the development of fusion systems. The review and analyses in this paper provide important information to understand and quantify these challenges and to define the phase space of plasma physics and fusion technology parameters and features that must guide a serious R&D in the world fusion program. We focus in particular on components, issues and R&D necessary to satisfy three ‘principal requirements’: (1) achieving tritium self-sufficiency within the fusion system, (2) providing a tritium inventory for the initial start-up of a fusion facility, and (3) managing the safety and biological hazards of tritium. A primary conclusion is that the physics and technology state-of-the-art will not enable DEMO and future power plants to satisfy these principal requirements. We quantify goals and define specific areas and ideas for physics and technology R&D to meet these requirements. A powerful fuel cycle dynamics model was developed to calculate time-dependent tritium inventories and flow rates in all parts and components of the fuel cycle for different ranges of parameters and physics and technology conditions. Dynamics modeling analyses show that the key parameters affecting tritium inventories, tritium start-up inventory, and tritium self-sufficiency are the tritium burn fraction in the plasma (f b), fueling efficiency (η f), processing time of plasma exhaust in the inner fuel cycle (t p), reactor availability factor (AF), reserve time (t r) which determines the reserve tritium inventory needed in the storage system in order to keep the plant operational for time t r in case of any malfunction of any part of the tritium processing system, and the doubling time (t d). Results show that η f f b > 2% and processing time of 1–4 h are required to achieve tritium self-sufficiency with reasonable confidence. For η f f b = 2% and processing time of 4 h, the tritium start-up inventory required for a 3 GW fusion reactor is ∼11 kg, while it is <5 kg if η f f b = 5% and the processing time is 1 h. To achieve these stringent requirements, a serious R&D program in physics and technology is necessary. The EU-DEMO direct internal recycling concept that carries fuel directly from the plasma exhaust gas to the fueling systems without going through the isotope separation system reduces the overall processing time and tritium inventories and has positive effects on the required tritium breeding ratio (TBRR). A significant finding is the strong dependence of tritium self-sufficiency on the reactor availability factor. Simulations show that tritium self-sufficiency is: impossible if AF < 10% for any η f f b, possible if AF > 30% and 1% ⩽ η f f b ⩽ 2%, and achievable with reasonable confidence if AF > 50% and η f f b > 2%. These results are of particular concern in light of the low availability factor predicted for the near-term plasma-based experimental facilities (e.g. FNSF, VNS, CTF), and can have repercussions on tritium economy in DEMO reactors as well, unless significant advancements in RAMI are made. There is a linear dependency between the tritium start-up inventory and the fusion power. The required tritium start-up inventory for a fusion facility of 100 MW fusion power is as small as 1 kg. Since fusion power plants will have large powers for better economics, it is important to maintain a ‘reserve’ tritium inventory in the tritium storage system to continue to fuel the plasma and avoid plant shutdown in case of malfunctions of some parts of the tritium processing lines. But our results show that a reserve time as short as 24 h leads to unacceptable reserve and start-up inventory requirements. Therefore, high reliability and fast maintainability of all components in the fuel cycle are necessary in order to avoid the need for storing reserve tritium inventory sufficient for continued fusion facility operation for more than a few hours. The physics aspects of plasma fueling, tritium burn fraction, and particle and power exhaust are highly interrelated and complex, and predictions for DEMO and power reactors are highly uncertain because of lack of experiments with burning plasma. Fueling by pellet injection on the high field side of tokamak has evolved to be the preferred method to fuel a burning plasma. Extrapolation from the DIII-D penetration scaling shows fueling efficiency expected in DEMO to be <25%, but such extrapolations are highly uncertain. The fueling efficiency of gas in a reactor relevant regime is expected to be extremely poor and not very useful for getting tritium into the core plasma efficiently. Gas fueling will nonetheless be useful for feedback control of the divertor operating parameters. Extensive modeling has been carried out to predict burn fraction, fueling requirements, and fueling efficiency for ITER, DEMO, and beyond. The fueling rate required to operate Q = 10 ITER plasmas in order to provide the required core fueling, helium exhaust and radiative divertor plasma conditions for acceptable divertor power loads was calculated. If this fueling is performed with a 50–50 DT mix, the tritium burn fraction in ITER would be ∼0.36%, which is too low to satisfy the self-sufficiency conditions derived from the dynamics modeling for fusion reactors. Extrapolation to DEMO using this approach would also yield similarly low burn fraction. Extensive analysis presented shows that specific features of edge neutral dynamics in ITER and fusion reactors, which are different from present experiments, open possibilities for optimization of tritium fueling and thus to improve the burn fraction. Using only tritium in pellet fueling of the plasma core, and only deuterium for edge density, divertor power load and ELM control results in significant increase of the burn fraction to 1.8–3.6%. These estimates are performed with physics models whose results cannot be fully validated for ITER and DEMO plasma conditions since these cannot be achieved in present tokamak experiments. Thus, several uncertainties remain regarding particle transport and scenario requirements in ITER and DEMO. The safety standard requirements for protection of the public and release guidelines for tritium have been reviewed. General safety approaches including minimizing tritium inventories, reducing tritium permeation through materials, and decontaminating material for waste disposal have been suggested.

show abstract

“…18,19 Tritium self-sufficiency cannot be fully validated just through the construction of ITER device. 9,20,21 The objectives of this work are as follows: (a) to introduce the preliminary fuel cycle concept and available tritium resources for CFETR, (b) to evaluate and discuss the tritium demand for CFETR start-up (phase I: 200 MW) and the feasibility of DD start-up, (c) to identify the possible pathways to tritium self-sufficiency through sensitivity analysis based on the design baseline of CFETR, (d) to evaluate the consequences in case of failing tritium self-sufficiency, and (e) to identify the future R&D needed for tritium self-sufficiency. Both of the fusion engineering test reactors and fusion demonstration reactors are being designed to achieve the target of tritium self-sufficiency.…”

mentioning

confidence: 99%

“…The reactor start-up and tritium self-sufficiency issues should be discussed for CFETR during its engineering design phase considering the uncertainties of tritium resources available and existing risk of failing tritium self-sufficiency. 9,20,21 The objectives of this work are as follows: (a) to introduce the preliminary fuel cycle concept and available tritium resources for CFETR, (b) to evaluate and discuss the tritium demand for CFETR start-up (phase I: 200 MW) and the feasibility of DD start-up, (c) to identify the possible pathways to tritium self-sufficiency through sensitivity analysis based on the design baseline of CFETR, (d) to evaluate the consequences in case of failing tritium self-sufficiency, and (e) to identify the future R&D needed for tritium self-sufficiency. It is expected to give insights into the question on how to start the reactor in a more economical way, into the feasibility of tritium selfsufficiency, and what will happen in case of failing tritium self-sufficiency.…”

mentioning

confidence: 99%

Insights into fuel start‐up and self‐sufficiency for fusion energy: The case of CFETR

Nie¹,

Ran

Zeng

et al. 2019

Energy Science & Engineering

Self Cite

View full text Add to dashboard Cite

Commercial tritium resources available are too scarce to fully supply the future fusion reactors after International Thermonuclear Experimental Reactor (ITER). Tritium self‐sufficiency, ITER fails to fully validate, was regarded as one of the most important issues needed to be solved in the pathway of achieving fusion energy. After ITER, several concepts of fusion engineering test reactors and fusion demonstration reactors have been proposed worldwide, for example, Chinese Fusion Engineering Test Reactor (CFETR), Fusion Nuclear Science Facility (FNSF), DEMOnstration fusion reactor (DEMO) in European Union and Korea. CFETR is in the engineering design phase and would be hopefully completed around 2020. Tritium resources for the reactor start‐up and tritium self‐sufficiency are two primary issues besides the steady‐state operation for CFETR. The objectives of this work are as follows: (a) to introduce the preliminary fuel cycle concept and available tritium resources for CFETR, (b) to evaluate and discuss the tritium demand for CFETR start‐up (phase I: 200 MW) and the feasibility of DD start‐up, (c) to identify the possible pathways to tritium self‐sufficiency through sensitivity analysis based on the design baseline of CFETR, (d) to evaluate the consequences in case of failing tritium self‐sufficiency, and (e) to identify future R&D needed for tritium self‐sufficiency. It is expected to give insights into the question on how to start the reactor in a more economical way, into the feasibility of tritium self‐sufficiency, and into the question on what will happen in case of failing tritium self‐sufficiency.

show abstract

Tritium fuel cycle modeling and tritium breeding analysis for CFETR

Cited by 24 publications

References 8 publications

Impact Analysis of Helium Cooled Solid Blanket Structures on the Tritium Breeding Performance in CFETR

Impact Analysis of Helium Cooled Solid Blanket Structures on the Tritium Breeding Performance in CFETR

Physics and technology considerations for the deuterium–tritium fuel cycle and conditions for tritium fuel self sufficiency

Insights into fuel start‐up and self‐sufficiency for fusion energy: The case of CFETR

Contact Info

Product

Resources

About