FIRE Design: FY03 PFC Tasks

1
FIRE Design FY03 PFC Tasks
NSO PAC Meeting San Diego, February 27-28, 2003

• Mike Ulrickson (FIRE Divertor Design Team)
• presented by
• Richard Nygren (new member, NSO PAC)
• Sandia National Laboratories

Sandia is a multiprogram laboratory operated by
Sandia Corporation, a Lockheed Martin
Company,for the United States Department of
Energy under contract DE-AC04-94AL85000.
2
Introduction

• Best guess for readiness for PVR is late
  August or early September 2003.
• Continuing resolution in FY03 has constrained the
  initial schedule.
• In the following slides
• green text indicates completed tasks,
• blue text indicates tasks in progress,
• black text indicates planned tasks that can be
  done with the FY03 budget.

3
Plasma Equilibrium
green (completed)

• Define baseline plasma shape for 2.14 m.
• Use TSC to compute vertical and radial disruption
  cases.
• Define the range of ?, li, ?, and Paux that
  should be accommodated and provide magnetic data.

black text (can be done with FY03 )
4
Edge modeling

• Use UEDGE to reestablish edge plasma conditions
  with the proper fusion power and heating
• Determine heat flux profiles
• Determine boundaries for partial detachment

blue (in progress) black text (can be done with
FY03 )
Note for high density plasma in ARIES-RS/CLIFF
for APEX, Rognlien found steady state solution
for strongly radiating regions near X-point.
5
Disruption Forces

• Rebuild OPERA model of vessel and PFCs including
  copper (input from design at Boeing)
• Use TSC data as input to Opera to find eddy
  currents and forces
• Use Opera to determine the effect of the copper
  shell on magnetic diagnostics
• Run a vertical disruption case to compare to
  vertical disruption on 2.0 m machine and use
  results to scale radial disruption forces to 2.14
  m

6
Design

• Revise baseline divertor design (input to Opera)
• Revise the divertor hardware to accommodate the
  new plasmas and check shape variations
• Compute stresses in the revised design for both
  thermal and disruption loads (input from Opera)
• Revise design as needed to accommodate stresses

green (completed) black text (can be done with
FY03 )
7
Heat flux testing

• Investigate new concept for W rod attachment to
  improve reliability
• (PFC base program but input from FIRE design)
• New design completed
• Negotiating with vendor for production

green (completed) black text (can be done with
FY03 )
8
W-rod Armor

• Mockups have survived high heat flux tests to
  24MW/m2 and thermal cycling for 500 cycles.
• We recommend two design improvements.
• - Creep resistant Cu alloy as the rod bed.
• - Positive mechanical lock of rod to bed
  (grooved rod tip). Vendor bids have been
  received.

PW-8 rods reached 3300oC at 24MW/m2. Some
erosion of rods occurred but no cracking or
melting. PW-8 was then subjected to thermal
fatigue cycles After 370 cycles (10s-ON10s-OFF)
at 20MW/m2, one rod began to melt. The affected
area grew to 9 rods we terminated testing at 500
cycles.
9
ELMs on FIRE
ELMS are not a problem if no surface melting
occurs. We must reduce the magnitude of ELMS.

• Assumptions for ELM energy deposited on FIRE
  divertor plates.
• Either (a) 2 or (b) 5 of stored energy is lost.
• Footprint for deposition is either (a) same as
  normal operation or (b) up to three times larger
• Duration of ELM is 0.1

• Most of the 2 cases and a few 5 cases are
  acceptable.
• Limit for 0.1ms ELM is 0.3 MJ/m2 (partially
  detached, 12 MW/m2)
• Limit for 1.0ms ELM is 1.0 MJ/m2 (partially
  detached, 12 MW/m2)

10
ELMs Melting LIMIT
Melting will not occur when the deposited energy
density is less than the value at the
intersection of (a) T-rise curve and (b)
TLIMIT,normalHF.
T-rise (1ms ELM) 5 (loss Estored) 6MW/m2
qnormal
Energy Density 1.25MJ/m2 to avoid melting.
11
PFC Task Progress
12
Reporting

• Provide data needed for Physics Validation Review
• Revise divertor section of engineering report to
  include new design

13
Summary

• A redesign of the PFC components can be completed
  in time for the PVR, but the effort must start
  immediately.
• Funding is not adequate for iterating the
  divertor design.
• We can only scale the design to the new size and
  analyze the forces
• Local areas of excessive stress are likely to
  exist on the supports or vacuum vessel