T2: PFC/Heat Removal

Conveners - R. Mattas (ANL) and M. Ulrickson (SNL)

PFC Charter

Assess PFC systems for candidate burning plasma devices to determine their capabilities with regard to meeting the physics objectives, operating performance and flexibility, and ability to test advanced PFC systems under reactor relevant conditions. These capabilities should be achievable while meeting all safety and reliability goals. The necessary R&D to develop the PFC systems should be identified and completed in a time frame consistent with construction schedules for the burning plasma device.

People

Jeff Brooks — PMI analysis

Richard Nygren — Heat removal, Coolant thermal hydraulics

Saurin Majumdar — Limiter, divertor, first wall structural analysis during static and transient conditions

Rich Mattas — bulk materials, first wall design, lifetime analysis

Ahmed Hassanein — Disruption, ELMs heating and material loss

Mike Ulrickson — Divertor,/limiter plasma facing materials, divertor/limiter design

Dennis Youchison — Disruption eddy current analysis

Dan Driemeyer — Thermal and structural analysis

Chandu Baxi — Thermal analysis and thermal hydraulics

Evaluation Criteria

    1. Does the component meet the physics performance requirements? Is the pulse length capability of the PFC adequate for the proposed experimental sequence? Is the divertor design capable of achieving detached or partially detached plasma operation? Is there a credible impurity control system to limit impurity influx to plasma to achieve the Zeff needed to assure adequate plasma energy confinement to achieve the needed fusion gain? What is the predicted Tritium inventory in PFCs codeposited areas? Is this inventory consistent with tritium supply and safety guidelines? Is there a credible method for controlling or removing tritium inventory if the guidelines are exceeded? Is the proposed tritium control method compatible with the needed availability?
    2. Operating margins and flexibility. Does the peak heat load capability of the PFCs meet or exceed the predicted power flow to the component? Is there adequate margin in the PFC coolant system? Is the critical heat flux sufficiently above the expected maximum heat flux? What provisions have been made for accommodating ELMs, disruptions, and other plasma operating modes that may have short bursts of higher heat flux? Is there sufficient flexibility in the design and change-out methods to permit changing the PFCs to accommodate a range of plasma operating points?
    3. Feasibility of manufacturing and readiness of manufacturing
    4. Have key issues and major R&D needs been identified?
    5. How much more R&D are required? Is there a credible plan to complete the needed R&D prior to construction?
    6. Capital and operating costs (Is it available and credible? - absolute numbers are of lower importance) Has the cost estimate for the PFCs been made using adequate detail, with sufficient manufacturing input, and adequate contingency? Have sound engineering practices been used for the cost estimate? Is it a top down or bottoms up cost estimate?
    7. Relevance to DEMO. Is the proposed PFC design a step along the path to a fusion reactor? Include capability of testing under reactor level conditions and potential to test reactor blanket concepts (done in cooperation with other technology groups).
    8. Relevance to other fusion experiments and applications
    9. Has reliability/maintainability and off-normal conditions been considered. Is the estimated time between PFC change-outs consistent with the proposed experimental program (e.g., will there be so much maintenance that the availability will make the planned experiments take much longer than desired)? Is the analysis of erosion and redeposition adequate to predict the component lifetime? Is neutron damage to the PFC an important consideration? Is the proposed maintenance scheme consistent with the neutron damage levels predicted? At the predicted maximum heat flux are the thermal stresses low enough to assure reliability of the PFCs? Is the mechanical design of the PFCs consistent with disruption induced eddy currents for the most likely disruption scenarios?
    10. Interfaces identified? (Can we see that interfaces have been identified and addressed?)
    11. Maturity of design (pre-conceptual, conceptual, detailed)

 

Rating Methods

In order to keep the ratings method relatively straightforward, the technology group agreed to use three rating levels. After all the assessments have been completed, each criterion will be given one of these three ratings.

Areas to be addressed by PFC group

This outline gives additional information of the items to be considered in the assessment.

  1. Plasma Facing Components (limiters, divertors and first wall)
    1. PMI
      1. Sputtering
      2. Redeposition
      3. Influx into plasma edge and core
      4. Tritium inventory
      5. Transport of eroded particles to other parts of device
    2. Materials
      1. Plasma facing materials
        1. Status of availability and fabrication technology
        2. Property changes during operation
      2. Structural materials
        1. Status of availability and fabrication technology
        2. Property changes during operation
      3. Bond materials
        1. Status of availability and fabrication technology
        2. Property changes during operation
    3. Performance capability
      1. Heat load capability
      2. Response to transients
      3. Design flexibility
      4. Expected service life
      5. Ability to simulate reactor system performance
      6. Ability to test prototype breeding blanket module (Done in cooperation with other groups.)
    4. R&D requirements
  1. System integration
    1. PFC integration with coolant system
    2. PFC integration with other in-vessel components
      1. Heating and CD
      2. Diagnostics
      3. Vacuum vessel
    1. PFC integration with fueling cycle

Overlap and connection to other sub-groups
  1. T5 - Safety/tritium/materials — This group provides operating limits and material properties needed for PFC design
  2. P5 — Boundary physics — This group provides the plasma operating conditions needed to design the PFC
  3. T3 — Heating/Current drive — Antennas, waveguides as PFCs and PFCs needed to protect these items
  4. T4 — Vacuum vessel/Remote Handling — PFC system integration and replacement
  5. T6 — Cost
  6. E1 — Diagnostics — diagnostics for PFCs as well as diagnostics as PFCs

 

Criteria

ITER

FIRE

IGNITOR

Meet Performance Requirements

      

Margins and Adequate flexibility

      

Feasible fabrication

      

Issues and R&D needs identified

      

Credible R&D Plan

      

Credible cost estimate

      

On path to DEMO

      

Relevance to other fusion devices

      

Adequate reliability and maintainability

      

Interfaces identified

      

Maturity of design