Plasma-Material Interactions in a Controlled Fusion Reactor

This book is a primer on the interplay between plasma and materials in a fusion reactor, so-called plasma-materials interactions (PMIs), highlighting materials and their influence on plasma through PMI. It aims to demonstrate that a plasma-facing surface (PFS) responds actively to fusion plasma and that the clarifying nature of PFS is indispensable to understanding the influence of PFS on plasma. It describes the modern insight into PMI, namely, relevant feedback to plasma performance from plasma-facing material (PFM) on changes in a material surface by plasma power load by radiation and particles, contrary to a conventional view that unilateral influence from plasma on PFM is dominant in PMI.There are many books and reviews on PMI in the context of plasma physics, that is, how plasma or plasma confinement works in PMI. By contrast, this book features a materials aspect in PMI focusing on changes caused by heat and particle load from plasma: how PFMs are changed by plasma exposure and then, accordingly, how the changed PFM interacts with plasma.

Autorentext

Tetsuo Tanabe is a special-appointment professor at the Research Center for Artificial Photosynthesis (ReCAP), Osaka City University. His work is mainly concerned with nuclear materials, fusion engineering, and tritium science. He received his Doctor of Engineering from Osaka University in 1977. He has been a professor at Nagoya University and Kyushu University, and has served in his current position since 2017. He is now an emeritus professor at Nagoya University and Kyushu University.

Inhalt

0.Preface (3 pages)

1.Introduction (10 pages, 1 table, 5 figures)
1-1. Energy conversion from nuclear to thermal for electric power generation
1-2. Brief history of development of plasma facing materials

2.Discharges in current tokamaks (11 pages, 16 figures)
2-1. Views of the inside of current tokamaks with and without plasma
2-2. Diagnostics for PSI research
2-2-1 Optical spectroscopy
2-2-2 Probe measurements
2-3. Plasma wall interactions observed by prove and limiter experiments

3. Power load on plasma facing materials (11 pages, 1 table, 4 figures)
   3-1 Estimation of power load and its distribution in a fusion reactor
   3-2 Steady state power load
   3-3 Transient power load
   3-4 Power load by neutrons
   3-5 Mitigation of power load (Power Exhaust)

4. Responses of plasma facing surfaces to heat and particle loads (17 pages, 21 figures)
   4-1 Energy loss processes of energetic particles in solid target
   4-2 Emission of ions and neutrals
   4-2-1 Reflection
   4-2-2 Physical sputtering
   4-2-3 Chemical sputtering
   4-2-4 Ion induced desorption and radiation enhance sublimation
   4-3 Electron and photon emissions
   4-3-1 Electron emission
   4-3-2 Photon emission
   4-4 Energy reflection
   4-5 Remission of incident ions
   4-5-1 Reemission of hydrogen (fuel)
   4-5-2 Reemission of inert gas/molecules
   4-6 Interaction of released particles with photons and electrons in boundary plasmas
   4-7 Summary

5. Erosion and deposition & their influence on plasma behavior (Material transport in tokamak) (7 pages, 9 figures)
   5-1 Erosion, transport and deposition
   5-2 Formation of deposited layers made of eroded materials
   5-2-1 Carbon wall
   5-2-1-1 Deposition on plasma facing surface
   5-2-1-2 Modification of deposited materials
   5-2-1-3 Deposition at non-plasma facing surfaces
   5-2-2 Metallic wall
   5-3 Summary

   6 Material modification by high power load and its influence on plasma (16 pages, 11 figures)
   6-1 Power load to PFM
   6-2 Material response to heat loads and its influence on boundary plasmas (PMI)
   6-2-1 Spontaneous response to plasma heat load
   6-2-2 Melting and evaporation
   6-2-3 Hydrogen recycling
   6-3 Damaging and degradation of PFM
   6-3-1 Carbon
   6-3-2 W
   6-3-2-1 Surface damage by high power load (melting, recrystallization and cracking
   6-3-2-3 Surface damage by fuel particle load below melting threshold
   6-3-3 Other PFM candidates (Be and Li)
   6-3-4 Structure materials

6. Fundamentals of hydrogen recycling and retention (12 pages, 5 figures)
   7-1 Overall fuel flow at steady state burning
   7-2 Injection of energetic hydrogen
   7-3 Reflection, remission and retention
   7-4 Permeation
   7-5 Isotope effects
   7-6 Retention and trapping
   7-7 Simulation and modeling

7. PMI in large Tokamaks (24 pages, 2 table, 14 figures)
   8-1. Power load in tokamaks
   8-1-1 Power load in JET
   8-1-2 Exchange of PFM from Carbon to high Z metals
   8-1-3 ITER like wall (ILW) in JET
   8-1-4 Power load by charged particles from fusion
   8-2. Erosion and deposition
   8-2-1 Carbon wall
   8-2-2 Metallic wall
   8-3 Dust
   8-4 Recycling and retention of fuels
   8.4.1 Consideration of fuel retention rate
   8-4-2 Recycling
   8-4-2-1 Changes recycling coefficient with discharge time
   8-4-2-2 Isotopic replacement and appearance of H (the lightest hydrogen isotope) as an impurity
   8-4-2-3 Recycling at steady state
   8-4-3 Long term fuel retention
   8-4-3-1 Fuel retention in Carbon materials
   8-4-3-2 Summary of deuterium retention in present tokamaks using D discharges
   8.5 Fuel (H and D) retention in present large tokamaks
   8-6 T related issues on the in-vessel T inventory
8. Estimatio...