Neutron Flux in ITER: Benefits & Containment Challenges

In summary, the ITER experiment will utilize energetic neutron flux to breed tritium for fuel by using lithium 6 and lithium 7, and will also utilize heat exchangers to capture their energy. However, the main concern with the neutrons is their damaging effect on the containment walls, reducing their strength and thermal conductivity. This can also lead to other issues such as material getting knocked off and becoming radioactive, requiring shielding and disposal. Therefore, careful consideration must be given to the materials used in construction to avoid further problems.
  • #1
99
2
I was reading that the ITER will take advantage of the energetic neutron flux by using them and lithium 6 to breed tritium for more fuel, and to use multiple heat exchangers to grab their energy. And just to make sure that I'm reading it right, the main problem with the neutrons will be their effect on the containment walls that are between the fusion reaction and the lithium, with them knocking atoms out of place (thus lessening the integrity of the walls)?
 
Physics news on Phys.org
  • #2
A D-T fusion power plant will have to breed tritium using the neutron lithium reaction. The reaction works with both Li-6 and Li-7. And in theory we can adjust the relative concentration of the two lithium isotope to fine tune the breeding ratio.

ITER however is not a power plant. It is a physics experiment. ITER will have some test blanket modules where scientist will perform tritium breeding experiments. Also while it has cooling lines that remove the heat from the reactor. They are there to prevent things from melting. ITER will not use this heat to produce electricity.

The neutron interaction with the walls and other structures will cause material damage which has a number of negative consequences. For example in addition to decreasing the strength of the materials, neutron damage can reduce the thermal conductivity of a material. In ITER this will make it harder to cool the first wall.
 
  • #3
Additional problems with neutrons hitting the walls include such things as material of the wall getting knocked off by the neutrons. That means you get atoms of the wall floating into the plasma, which strongly tends to slow down the reaction.

Then there are a variety of radiation protection issues. The neutrons must be shielded, which requires some meters of whatever you are going to use. And that shielding has to be an efficient neutron absorber that won't produce a lot of secondary radiation. Or that will absorb the secondary radiation itself. It probably should not be lead, for example, because lead has the annoying habit of producing (n,2n) reactions. That is, you start with one neutron and end up with two lower energy neutrons.

And anything that gets exposed to neutrons tends to become radioactive itself. In addition to affecting the structural characteristics of the material, you wind up with radioactive material that must be itself shielded. And possibly disposed of. And that frequently means you have hard choices as to material you might use in constructing components of the reactor. Just as one example, you probably have to keep cobalt out of the mix, since activated cobalt is particularly nasty. So many grades of steel are probably off your list because they can contain cobalt. But there are many other potential problem materials in a neutron flux.
 

What is neutron flux?

Neutron flux refers to the number of neutrons passing through a unit area per unit time, typically measured in neutrons per square centimeter per second. In the context of ITER, neutron flux is important because it is a measure of the nuclear reactions and energy produced within the reactor.

Why is neutron flux important in ITER?

Neutron flux is important in ITER because it is an indicator of the amount of energy being produced through nuclear reactions. This energy is used to heat the plasma and sustain the fusion reaction, making it a crucial factor in achieving a self-sustaining fusion reaction.

What are the benefits of neutron flux in ITER?

The main benefit of neutron flux in ITER is that it is the primary source of energy for the fusion reaction. It also provides valuable information about the characteristics and behavior of the plasma and the efficiency of the reactor. Additionally, neutron flux can be used to produce medical isotopes for cancer treatment and other applications.

What are the containment challenges associated with neutron flux in ITER?

The high neutron flux in ITER poses several containment challenges. The neutrons can cause damage to the structural materials of the reactor, leading to material degradation and potential safety hazards. Additionally, the high energy neutrons can produce radioactive isotopes, which must be safely contained and disposed of.

How is neutron flux controlled in ITER?

Neutron flux is controlled in ITER through various methods, including the use of shielding materials to prevent damage to the reactor and surrounding structures. The plasma is also carefully controlled to maintain a stable and efficient fusion reaction. Additionally, advanced diagnostics and monitoring techniques are used to measure and analyze the neutron flux to ensure safe and efficient operation of the reactor.

Suggested for: Neutron Flux in ITER: Benefits & Containment Challenges

Replies
11
Views
1K
Replies
15
Views
1K
Replies
2
Views
1K
Replies
17
Views
1K
Replies
2
Views
980
Replies
5
Views
2K
Replies
20
Views
2K
Back
Top