Hybrid fusion fission reactor prospects

In summary, the hybrid fusion-fission reactor would depend on how much energy is generated (more importantly recovered) from the fusion process. If the majority of thermal energy originates from fission, there is not much point adding a fusion process to the system. Fusion would only add to the complexity and capital cost.
  • #1
ensabah6
695
0
since fusion is not commericially feasible, does hybrid fusion fission reactor change that?

http://www.nature.com/nphys/journal/v5/n6/full/nphys1288.html

With the increasingly urgent need to find solutions to the impending energy crisis, there is growing interest within the fusion community in revisiting the concept of the fusion–fission hybrid reactor. But how soon could such reactors be realized, and could they meet the challenges of the coming century?

http://www.newscientist.com/article/mg20527505.900-hybrid-fusion-the-third-nuclear-option.html

Hybrid fusion: the third nuclear option
 
Last edited by a moderator:
Engineering news on Phys.org
  • #2
It would depend on how much energy is generated (more importantly recovered) from the fusion process. If the majority of thermal energy originates from fission, there is not much point adding a fusion process to the system. Fusion would only add to the complexity and capital cost.

We can already build fast or thermal breeders for utilizing fissile/fertile resources, which themselves are finite.
 
  • #3
In 2006 we published an article on this topic in the Lect. Notes. Phys. 694 (Springer, Berlin Heidelberg 2006). The book is entitled: Lasers and Nuclei: Applications of Ultrahigh Intensity Lasers in Nuclear Science. The full contents of this book are online at...
http://www.springerlink.com/content/v31121251rh7/

The title of the article is "Potential Role of Lasers for Sustainable Fission Energy Production and Transmutation of Nuclear Waste" http://www.springerlink.com/content/9803n15542276654/fulltext.pdf.

The basic idea here was to use very high power lasers (which are currently being developed in Europe and the US) to produce large numbers of neutrons through laser induced fusion of D-T. The neutrons could then be pumped into a nuclear reactor to produce power or transmute nuclear waste. The big advantage of the approach is that long before "engineering breakeven" can be obtained in fusion reactors, one will have "scientific breakeven". This scientific breakeven is enough to generate large neutron fluxes which can then be used in fission reactors. More information can be found at http://www.nucleonica.net.
 
  • #4
HotCells said:
In 2006 we published an article on this topic in the Lect. Notes. Phys. 694 (Springer, Berlin Heidelberg 2006). The book is entitled: Lasers and Nuclei: Applications of Ultrahigh Intensity Lasers in Nuclear Science. The full contents of this book are online at...
http://www.springerlink.com/content/v31121251rh7/

The title of the article is "Potential Role of Lasers for Sustainable Fission Energy Production and Transmutation of Nuclear Waste" http://www.springerlink.com/content/9803n15542276654/fulltext.pdf.

The basic idea here was to use very high power lasers (which are currently being developed in Europe and the US) to produce large numbers of neutrons through laser induced fusion of D-T. The neutrons could then be pumped into a nuclear reactor to produce power or transmute nuclear waste. The big advantage of the approach is that long before "engineering breakeven" can be obtained in fusion reactors, one will have "scientific breakeven". This scientific breakeven is enough to generate large neutron fluxes which can then be used in fission reactors. More information can be found at http://www.nucleonica.net.

I don't see the point of a hybrid that expects little or no energy from the fusion side. Why are fission reactors in need of an external/additional neutron flux? If the fuel is fissionable, sufficient neutrons are produced via fission. If the fuel is merely fertile (e.g. U238), then breeders answer.
 
  • #5
mheslep said:
I don't see the point of a hybrid that expects little or no energy from the fusion side. Why are fission reactors in need of an external/additional neutron flux? If the fuel is fissionable, sufficient neutrons are produced via fission. If the fuel is merely fertile (e.g. U238), then breeders answer.

It's a question of timing. Maybe in the long-term we will have pure fusion systems working.

...but pure fusion is still some way off. Before a fusion reactor becomes available (at engineering breakeven) powerful neutron sources will become available based on the inertial laser fusion systems with D-T fuel.

A major problem with fission reactors is the so-called neutron economy. There are just not enough neutrons available due to neutron poisoning by fission products. This is why the fuel must be periodically removed from the reactor and be replaced by fresh fuel or reprocessed to remove fission products.

The basic idea of the hybrid system proposed is to take the best properties of each system and combine them. Thus inertial fusion systems are good at producing neutrons - and fission reactors have already been built and are in use.

hope this helps.
 
  • #6
HotCells said:
A major problem with fission reactors is the so-called neutron economy. There are just not enough neutrons available due to neutron poisoning by fission products. This is why the fuel must be periodically removed from the reactor and be replaced by fresh fuel or reprocessed to remove fission products.
Well there are several reasons why fuel must be removed periodically. Given these reasons, you contend that an additional neutron source could extend the life of existing fuel rods and burnup percentage?
 
  • #7
mheslep said:
Well there are several reasons why fuel must be removed periodically. Given these reasons, you contend that an additional neutron source could extend the life of existing fuel rods and burnup percentage?

Yes. Fission reactors need to be critical. As soon as they go sub-critical, the reactor will switch off. Before this happens, new fuel must be intoduced into the system. Alternatively, one could use an external source of neutrons. Then one has a has a neutron driven sub-critical system. This is the basic idea behind accelerator driven systems (ADS). The so-called keff (neutron multipication factor) of the system (which should be 1 for a critical system) can be significantly less than 1. In accelerator driven system, the extra neutrons come from spallation using high energy protons. In the laser driven system (used in the fusion-fission hybrid proposal mentioned earlier), the neutrons come from laser dirven fusion of D-T. In such an LDS, values of the keff of 0.7 and lower are conceivable.
 
  • #8
HotCells said:
Yes. Fission reactors need to be critical. As soon as they go sub-critical, the reactor will switch off. Before this happens, new fuel must be intoduced into the system. Alternatively, one could use an external source of neutrons. Then one has a has a neutron driven sub-critical system. This is the basic idea behind accelerator driven systems (ADS). The so-called keff (neutron multipication factor) of the system (which should be 1 for a critical system) can be significantly less than 1. In accelerator driven system, the extra neutrons come from spallation using high energy protons. In the laser driven system (used in the fusion-fission hybrid proposal mentioned earlier), the neutrons come from laser dirven fusion of D-T. In such an LDS, values of the keff of 0.7 and lower are conceivable.
Yes it is clear how in isolation from other issues external neutrons can burn fuel what otherwise be a sub-critical system. It is not clear to me that there is an advantage to external neutrons in an actual light water reactor, as advantage depends on what limits the burn. Does fission product poisoning dominate the neutron absorbing control rods? Do other concerns drive the fuel rod replacement time, such as material fatigue and accumulation of fission product-volume?

Edit: To further illustrate, see this high burnup cladding research at Argonne, making the point that cladding material limits fuel rod life in these designs, not burnup.
http://www.ne.anl.gov/capabilities/ip/highlights/light_water_reactor.html
 
Last edited:

1. What is a hybrid fusion fission reactor?

A hybrid fusion fission reactor is a type of nuclear reactor that combines elements from both fusion and fission reactions. It uses a combination of nuclear fusion, which releases energy by combining atoms, and nuclear fission, which releases energy by splitting atoms. This allows for a more efficient and controlled production of energy.

2. What are the benefits of a hybrid fusion fission reactor?

One of the main benefits of a hybrid fusion fission reactor is that it produces less radioactive waste compared to traditional fission reactors. It also has the potential to produce more energy and is not dependent on rare and expensive fuel sources. Additionally, the fusion process is much safer and does not pose the same risk of a meltdown as fission reactors.

3. What are the challenges in developing a hybrid fusion fission reactor?

The main challenge in developing a hybrid fusion fission reactor is the complexity of the technology involved. Scientists are still working on ways to control and sustain nuclear fusion reactions, as well as finding suitable materials to withstand the extreme temperatures and radiation produced by these reactions. Cost is also a significant challenge, as the development and construction of these reactors require a large investment.

4. What is the current status of hybrid fusion fission reactor technology?

Currently, there are several experimental hybrid fusion fission reactors being developed around the world. However, these are still in the early stages, and it may be several years before a fully functional and commercially viable reactor is operational. Additionally, there are ongoing research and testing to improve the efficiency and safety of these reactors.

5. Are there any environmental concerns with hybrid fusion fission reactors?

One of the main environmental concerns with nuclear reactors, in general, is the potential for accidents and radioactive waste. However, with the use of advanced technology and safety measures, hybrid fusion fission reactors have the potential to mitigate these concerns. Additionally, nuclear energy is a low-carbon energy source, making it a potential solution for reducing carbon emissions and addressing climate change.

Similar threads

Replies
16
Views
6K
  • Nuclear Engineering
Replies
11
Views
9K
  • Nuclear Engineering
Replies
14
Views
4K
Replies
2
Views
3K
  • High Energy, Nuclear, Particle Physics
Replies
1
Views
2K
  • Nuclear Engineering
Replies
2
Views
4K
Replies
4
Views
8K
Back
Top