Considerations and Integration Design of CFETR

Yong Liu

2nd workshop on MFE development strategy in China

Hefei, May 30- June 1, 2012

Southwestern Institute of Physics (SWIP)

Outline

1. Some general considerations

2. Integrated design of CFETR

3. Remarks

1. Some general considerations

Gap Between ITER & DEMO

DIII-D

JET

JT-60U

KSTAR

EAST

HL-2A

DEMO

We are here

We have well understood, even if ITER succeeds, we still need test facilities, to bridge the gap beyond ITER toward DEMO.

ITER ?

Gaps:

• Nuclear S&T issue with a reactor;

• PFC, Structure and functional materials;

• Blanket technology including tritium self-sufficiency;

• Control and stability of high-performance burning plasma, heat exhaust, and helium ash removal;

• Transient events, H&CD systems, Remote Handling;

• ……

Hopefully, ITER can address fully or partly the issues with blue color.

• ITER is to demonstrate the scientific and engineering feasibility of DT burning plasma. However, ITER does not address nuclear technologies relevant to DEMO.

• IFMIF is a neutron irradiation test facility for fusion material development. It can not be used for component tests.

• In this situation, we should have a fusion energy development strategy to play a role as a guideline for domestic fusion program.

• CFETR (China Fusion Engineering Testing Reactor) could be the important part of the strategy.

Motivation of the Strategy

Position of ITER in the strategy

• ITER is the most important reference for the drafting of the China Fusion Strategy

• ITER is the most important part of present China fusion program

• ITER’s Success is extremely important for fusion community both in China and in the world. Thus, ensuring the success of ITER will be most important task for fusion community including Chinese one.

Position of CFETR in roadmap to Fusion Energy

CurrentTokomaks

DEMO

We are here

ITER

IFMIF

CFETR (opt 1)

Option 3 seems more reasonable at this moment

CFETR (opt 2)

CFETR (opt 3)

Mission of CFETR should be defined as:

Address the Nuclear S&T issue for a reactor ;

Test materials and components in integrated fusion nuclear environment;

Demonstrate tritium self-sufficiency;

Demonstrate the physics issue for a reactor.

Mission and Design goal of the first option of CFETR

• A good complement with ITER;• Demonstration of fuel cycle of fusion energy with Pf= 50 ~

400MW；• Long pulse or steady-state operation with duty factor ≥0.3 ~

0.5；• Demonstration of fuel cycle of T self-sustained with TBR

≥1.1 ~ 1.2;• Relay on the existing ITER physical (k<1.8, q>3, H~1) and

technical bases (higher BT , diagnostic, H&CD);• Exploring options for DEMO blanket & diverter with a easy

changeable core by RH；

Importance of an integration design

• An integration design is quite necessary and urgent after the mission is preliminarily fixed. This design would be a good guide for fusion research activities in the following years.

• The specification and even the mission could be adjustable, depending on many factors, most important benefits from the process of the design are knowledge on how to design and experienced talents.

2. Integration design of CFETR

Guidelines for CFETR Design

• Lower risks

• Good accessibility

• Easy maintenance

• Flexibility

• With existing technology

• Plasma operation based on present database or moderate extrapolation

CFETR magnets, supper conducting or copper ?

Needing further validation

It seems that a copper machine probably possesses some potentially good performances, and may probably reduce aspect ratio / increase inductive driving ability.

But, the Joule heat for a copper machine, perhaps up to ~GW level for both Joule heat and its removal, is a big issue.

CFETR magnets, supper conductor or copper ?

Key Technologies

Key technologies required for CFETR:

• Fuel processing & Breeding blanket;

• Avoidance and mitigation of transit event (ELM, disruption)

• Divertor, PFC;

•Diagnostic and control;

•H&CD technologies, Remote Handing, hot cell;

• Maintenance, et al.

Plasma Parameters for CFETRwith SC magnets

Major radius is 5.3m, Minor radius is 1.2m, Elongation is 1.75, Triangularity is 0.40, TF on axis is 6.0T, Plasma current is 5MA~8MA, Beta N is 2.0~3.5 ， Fusion power is 200MW~400MW, Heating power is 90MW, Fusion gain is 2.0~4.0, Neutron wall load is 0.4MW/m2~0.8MW/m2, Energy confinement time enhancement factor is 1.0~1.2, Plasma density is 70%~95% of Greenwald limit, Volt-second is more than 120Vs, Operating times is more than 2000s, Duty factor is 0.3~0.5;

Plasma Parameters for CFETRwith copper magnets

Major radius is 4.9m, Minor radius is 1.3m, Elongation is 1.75, Triangularity is 0.40, TF on axis is 5.0T, Plasma current is 6MA~9MA, Beta N is 2.4~3.5 ， Fusion power is 200MW~400MW, Heating power is 100MW, Fusion gain is 2.0~4.0, Neutron wall load is 0.4MW/m2~0.8MW/m2, Energy confinement time enhancement factor is 1.0~1.2, Plasma density is 70%~95% of Greenwald limit, Volt-second is more than 150Vs, Operating times ~ 1000s, Duty factor is 0.3~0.5;

3. Remarks

3. REMARKS

• It is very difficult to make strategic choice for fusion energy development at this phase of the ITER construction. No choice is perfect and the key is to consider the pros and cons and make the choice with the fewest disadvantage.

• The development trends in other countries (especially ITER partner countries) will certainly have great influence to the drafting of the Chinese fusion strategy.

• The consensus not only from the fusion Community but also from the Science community in China is indispensable for the realization of any strategy of the huge project such as a fusion reactor.

3. REMARKS (cont’d)

• the process of the integration design is as important as results of the integration design. Even the mission can be significantly modified during the process of the integration design.

• The license for a nuclear project with some uncertainty will be extremely difficult, will take quite long time in China (also in anywhere of the world).

Thank You for Your Attention!