Meeting 1 Action Items

(1) Date for Next Meeting

The next meeting is scheduled to be held at UCLA during the period January 12 – 14, 1998. It will start at 1:00 PM, Monday, January 12, and adjourn at Noon, January 14.

(2) Eight (8) groups have been formed.

The relationship between APEX Tasks and these groups is outlined in Table I. Proposed organizations/individuals lead and support to undertake APEX Tasks is outlined in Appendix III.

(3) Several questions were raised at the meeting for which acting responses were issued. They are:

A. Failure modes/rates and maintainability considerations should be incorporated early

Response

1) Add availability (reliability and maintainability) as an additional important role for the mechanical design group

• come up with general guidelines/suggestions to designers to reduce failure rates and to enhance maintainability (and fault-tolerant designs).
• re-think the mechanical configuration from the edge of the plasma to the interior of the magnet (including vacuum boundary). “Invent” new configuration(s) for enhancing maintainability.

2) Encourage designers to account for failure rate & maintainability (but they must satisfy high power density requirements). Interact and listen to mechanical design/availability group.

B. Stronger coupling with Physicists and Greater Accounting for plasma interface

Response

1) Strengthen Group 5 Physics Interface

• Invite PPPL and key individuals (e.g. Dale Meade) to take the lead
• design concepts that are more tolerant of a wider range of plasma operating conditions (e.g. accommodating a number of disruptions) should get credit in evaluation

2)Utilize the ALPS physics boundary conditions. (Rich Mattas will ensure data base from ALPS is accessible to APEX).
3) Remember: It is still very useful to find out what the technology limits are. These provide boundary conditions for physics research (It is a two-way street)

C. Alternate confinement concepts may have different requirements on FPT concept

Response

1) Form a new group (Group 7: Alternate confinement concepts) to summarize the main configuration features and general range of parameters (wall load, surface heat flux, etc.) for alternate confinement concepts and to contrast them to Tokamaks

• Chair: Ralph Moir
• Invite Dale Meade (PPPL) to co-chair/help/advise

2) Plan a workshop concerning alternate confinement concepts to promote understanding of the main features and agree on general requirements for FPT designs (Group 7 will have the responsibility for organiz ing the workshop) Time Frame: about late February 1998
D. Thickness of first wall: people have different viewpoints regarding minimum thickness

Comment

Avoid the temptation to solve the problem by simply hypothesizing a very thin wall. This is not consistent with the APEX spirit of providing large design margin. If the feasibility of a concept depends on whether the thickness is 2 mm instead of 3 mm, this concept has to be questioned.

Response

1) The Mechanical Design/Availability Group is requested to examine the issue of minimum thickness consideration. Report findings ASAP and present them during the next meeting.

2) Designers (concepts advocates) have the burden of making and reporting sufficiently detailed analysis to justify their choice of first wall thickness

• concepts that use thinner walls, and where feasibility is crucially dependent on the thinness of the first wall, are required to have more detailed stress, failure rate, etc. analysis.

3) All concepts should assume 1 mm erosion over a nominal irradiation period of 15 MW. y/m2. Concepts that have renewable liquid on the first wall are exempt from this requirement.

(4) The Design Conceptualization and Analysis Group has the core effort of APEX: For concepts proposed in the kick-off meeting the proposed/assigned organizations/individuals will pursue and present by next meeting (January 12) the following:

a) description of the basic features of the concepts (materials, novel features)
b) basic layout/configuration of the concept
c) self-consistent performance parameters based on Actual ANALYSIS (not all guesses)
• neutronics (simple 1-D OK)
• thermal-hydraulics analysis (temperature distribution)
• fluid mechanics analysis
• electromagnetic analysis where essential
• other key parameters
d) a set of issues related to difficulties in modeling, unknown phenomena, lack of database
Note: Design Groups can call on Mechanical Design Group for support

(5) Pursuing Additional Innovative Concepts: The Group still encourages exploring new concepts. Those who have any truly new concepts are encouraged to present it during the next meeting and they do not have to present items required in 4 above.