Add average effect of ELMS on divertors heat flux

[orso82]

[bclyons12]

You've got better experts than I in that thread, and some of these points got mentioned already, but there are two separate issues.

• The peak heat load from ELMs. This is generally considered to be intolerable in PT anyway, so a reactor will need an ELM mitigation strategy. A PT reactor should then take into account the cost of such a system (e.g., RMP coils, pellet pacing) and the cost for divertor materials that can tolerate expected peak heat fluxes (e.g., pellet pacing, grassy ELMs) from an erosion standpoint. The latter should be higher than what would be required by the time-averaged heat flux. You would also want to account for the risk that ELMs breakthrough your mitigation strategy (e.g., loss of QH-mode or ELM suppression).
• The average divertor heat loads in PT vs NT. Again, I think a PT attached divertor is generally considered intolerable (except with liquid metals, perhaps?).
  • PT you need a detachment strategy. Radiation is still localized to the divertor region, so there's some increased heat flux there. That has cost implications on the materials. Then there are risk considerations from loss of detachment and loss of confinement if there's a pedestal collapse.
  • NT benefits from the potential use of radiated mantle. At the very least, there's TRL risk associated with that for core-edge integration. I'm not sure what the demonstration status is for this.

I would think you'd want an actor making discrete choices between these options, then assess the monetary cost and the quantized risk associated with each. After that, the optimizer can figure out which is best. Here's an example, though there might be other options of course (strike point sweeping?).

[orso82]

I love this way of breaking down the problem @bclyons12 !

The ActorDivertors should capture the expected change in divertor heatflux, while cost and risk should go in the ActorCosting and ActorRisk respectively

Here's a mermaid diagram of your figure ;)

flowchart TD
  FPP("FPP")
  DetachedPT("Detached PT")
  NT("NT")
  RMP("RMP")
  ELMFreeScenario("ELM-free Scenario")
  PelletPacing("Pellet Pacing")
  DetachedDivertor("Detached Divertor")
  RadiativeMantle("Radiative Mantle")
  StrikePointSweeping("Strike Point Sweeping")
  CostRisk("COST AND RISK FOR EACH LEAF")

  FPP --> DetachedPT
  FPP --> NT
  DetachedPT --> RMP
  DetachedPT --> ELMFreeScenario
  DetachedPT --> PelletPacing
  DetachedPT --> StrikePointSweeping
  NT --> DetachedDivertor
  NT --> RadiativeMantle
  RMP --> CostRisk
  StrikePointSweeping --> CostRisk
  ELMFreeScenario --> CostRisk
  PelletPacing --> CostRisk
  DetachedDivertor --> CostRisk
  RadiativeMantle --> CostRisk

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