Now I left plasma physics for other areas of physics and engineering 50 years ago, but my concern with fusion reactors is neutron damage and (for DT fusion) Tritium breeding efficiency. In implosion fusion the optics or forward beam components are going to be exposed to the hot neutron flux. In magnetic confinement fusion the first wall is going to be exposed to the hot neutron flux. This suggests to me a rather short component lifetime driving a lower duty cycle and correspondingly high capital costs. At least in fission most of the radiation damage is confined to the fuel and cladding, which are consumables. How do you see this being managed.
There are many challenges to building and operating a fusion reactor - a main concern with DT burning reactors is neutron damage to the first wall facing the fusion reaction - promising candidate materials have been developed that can survive the expected atomic displacements that are tested in fission reactors - but we need to test with the higher energy DT fusion neutrons - hence the need for a pilot fusion reactor to test and advance such materials. Similarly, we have developed neutron damage resistant final optics that have been tested using neutrons from fission reactors. Again, there is the critical need for a high-power DT fusion source to test our designs. These and other technical challenges to laser fusion were addressed in the so called Congressionally supported "high average power laser" program. http://qedfusion.org/HAPL/ Potential solutions to the above and other challenges (low-cost target production, target injection, precise target engagement by the laser beams) were identified by this program. To build practical laser fusion reactor there needs to be a concerted public-private research effort. The deep UV Argon Fluoride (ArF) laser technology being advanced by LaserFusionX and the U.S. Naval Research Laboratory looks very promising towards helping us reach the goal of economical laser fusion power plants Steve Obenschain
I know that the atoms in fission fuel cladding are typically displaced large numbers of times within the fuel burn time. I could easily see how glassy metals could survive intense neutron bombardment, particularily if they are hot enough to be in an annealing regeime. Transmission optics stike me as more problematic as neutron irradiation is likely to create optically active defects. If you can restrict the neutron exposed surfaces to reflective optics and have the beam compensation components out of the neutron flux, it may well work. But I don't know how high a reflectivity you will have under the neutron damage regieme.
My Ph.D. was actually in Mechanical Engineering - Materials Science.
We do indeed plan to use mirrors for the final optic that faces the DT fusion reaction. Both grazing incidence metal mirrors (aluminum) and neutron resistant dielectric mirrors have sufficient reflectivity. We plan to protect them from ions by deflecting magnetic fields.
Now I left plasma physics for other areas of physics and engineering 50 years ago, but my concern with fusion reactors is neutron damage and (for DT fusion) Tritium breeding efficiency. In implosion fusion the optics or forward beam components are going to be exposed to the hot neutron flux. In magnetic confinement fusion the first wall is going to be exposed to the hot neutron flux. This suggests to me a rather short component lifetime driving a lower duty cycle and correspondingly high capital costs. At least in fission most of the radiation damage is confined to the fuel and cladding, which are consumables. How do you see this being managed.
Hello John
There are many challenges to building and operating a fusion reactor - a main concern with DT burning reactors is neutron damage to the first wall facing the fusion reaction - promising candidate materials have been developed that can survive the expected atomic displacements that are tested in fission reactors - but we need to test with the higher energy DT fusion neutrons - hence the need for a pilot fusion reactor to test and advance such materials. Similarly, we have developed neutron damage resistant final optics that have been tested using neutrons from fission reactors. Again, there is the critical need for a high-power DT fusion source to test our designs. These and other technical challenges to laser fusion were addressed in the so called Congressionally supported "high average power laser" program. http://qedfusion.org/HAPL/ Potential solutions to the above and other challenges (low-cost target production, target injection, precise target engagement by the laser beams) were identified by this program. To build practical laser fusion reactor there needs to be a concerted public-private research effort. The deep UV Argon Fluoride (ArF) laser technology being advanced by LaserFusionX and the U.S. Naval Research Laboratory looks very promising towards helping us reach the goal of economical laser fusion power plants Steve Obenschain
I know that the atoms in fission fuel cladding are typically displaced large numbers of times within the fuel burn time. I could easily see how glassy metals could survive intense neutron bombardment, particularily if they are hot enough to be in an annealing regeime. Transmission optics stike me as more problematic as neutron irradiation is likely to create optically active defects. If you can restrict the neutron exposed surfaces to reflective optics and have the beam compensation components out of the neutron flux, it may well work. But I don't know how high a reflectivity you will have under the neutron damage regieme.
My Ph.D. was actually in Mechanical Engineering - Materials Science.
We do indeed plan to use mirrors for the final optic that faces the DT fusion reaction. Both grazing incidence metal mirrors (aluminum) and neutron resistant dielectric mirrors have sufficient reflectivity. We plan to protect them from ions by deflecting magnetic fields.