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#51 2022-10-26 05:58:51

tahanson43206
Moderator
Registered: 2018-04-27
Posts: 16,749

Re: Hybrid nuclear fission fusion technologies

This recent post by Calliban is a good fit for this topic:

http://newmars.com/forums/viewtopic.php … 91#p202591

Chinese progress report

(th)

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#52 2023-05-11 05:17:21

Mars_B4_Moon
Member
Registered: 2006-03-23
Posts: 8,892

Re: Hybrid nuclear fission fusion technologies

What if Titan Dragonfly had a Fusion Engine?

https://www.universetoday.com/161270/wh … on-engine/

In a little over four years, NASA’s Dragonfly mission will launch into space and begin its long journey towards Titan, Saturn’s largest moon. As part of the New Frontiers program, this quadcopter will explore Titan’s atmosphere, surface, and methane lakes for possible indications of life (aka. biosignatures). This will commence in 2034, with a science phase lasting for three years and three and a half months. The robotic explorer will rely on a nuclear battery – a Multi-Mission Radioisotope Thermal Generator (MMRTG) – to ensure its longevity.

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#53 2023-05-11 15:47:45

Calliban
Member
From: Northern England, UK
Registered: 2019-08-18
Posts: 3,352

Re: Hybrid nuclear fission fusion technologies

Mars_B4_Moon wrote:

What if Titan Dragonfly had a Fusion Engine?

https://www.universetoday.com/161270/wh … on-engine/

In a little over four years, NASA’s Dragonfly mission will launch into space and begin its long journey towards Titan, Saturn’s largest moon. As part of the New Frontiers program, this quadcopter will explore Titan’s atmosphere, surface, and methane lakes for possible indications of life (aka. biosignatures). This will commence in 2034, with a science phase lasting for three years and three and a half months. The robotic explorer will rely on a nuclear battery – a Multi-Mission Radioisotope Thermal Generator (MMRTG) – to ensure its longevity.

It will be interesting to see how the lattice confinement fusion experiments progress.  This technology could be used to produce very compact fast-fission reactors that could replace RTGs in many applications.


"Plan and prepare for every possibility, and you will never act. It is nobler to have courage as we stumble into half the things we fear than to analyse every possible obstacle and begin nothing. Great things are achieved by embracing great dangers."

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#54 2023-06-21 03:26:49

Calliban
Member
From: Northern England, UK
Registered: 2019-08-18
Posts: 3,352

Re: Hybrid nuclear fission fusion technologies

Nuclear fusion is no panacea for our energy problems.
https://oilprice.com/Alternative-Energy … tmare.html

D-T fusion is by far the easiest to achieve on a commercial scale.  But 80% of the energy is released as neutrons, which smash into the reactor walls making them brittle and radioactive and creating a radioactive waste disposal problem.  A rogue state could use the abundant fast neutrons that a fusion reactor produces to breed plutonium for bombs.  Fusion reactors are energy hungry, consuming a great deal of power to initiate and sustain plasma heating and containment.  In tokamak fusion, the limitations on magnetic field strength also limit power density far beneath what would be achievable with a fission reactor.

In my opinion, these issues make a strong case for pursuing a hybrid approach to nuclear fusion.  This involves either using fission to provide the heat and/or compression to assist initiating inertial confinement fusion or using a tokamak with a DU blanket, breeding plutonium for downstream fission reactors to consume as fuel.  An IC hybrid fusion machine is particularly interesting.  It is energetically much easier to provide the compression conditions needed to initiate fusion than it is to provide the heating.  A few micrograms of fissile material at the heart of a pellet can provide hotspot heating needed for ignition, whilst external drivers provide compression.  This approach wouod allow construction of compact and powerful space drives needed for fast interplanetary travel.  On Earth, an IC hybrid that is triggered by fission, could function as a very compact powerplant.


"Plan and prepare for every possibility, and you will never act. It is nobler to have courage as we stumble into half the things we fear than to analyse every possible obstacle and begin nothing. Great things are achieved by embracing great dangers."

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