|
|
|
|
|
|
by mlindner
1424 days ago
|
|
|
> I read recently that fusion reactor will also generate decay heat from all the activated components and this is comparable to a fission reactor. I'd like to know where you read that as the entire idea is to build a reactor out of things that don't activate or are very hard to activate. i.e. things that thermalize or reflect neutrons. Fission reactors produce tons of neutrons too (they kind of have to to work more so than fusion even) and that doesn't leave the containment vessel anywhere near as radioactive as the nuclear waste itself. |
|
|
Here's two papers about decay heat in ITER: https://www.sciencedirect.com/science/article/abs/pii/092037..., and https://www.sciencedirect.com/science/article/pii/S092037961...
I used their data to find power density and compared it the micro modular fission (MMR) fission reactors.
“MMR has a lower decay heat power density than fusion systems like SPARC or ARC, DEMO, or ITER and orders of magnitude lower than other advanced fission reactors as show in the figure below. UNSC's MMR has the lowest decay heat power density at 0.075 W/cm3, less than DEMO's 0.083 W/cm3 in the blanket and divertor. A lower decay heat is more manageable by passive cooling systems, allowing the reactor to dissipate heat more easily and without damaging the reactor. The other aspect to consider is the maximum temperatures that can be safely maintained in the reactor. Gas-cooled reactors like the MMR have all-ceramic cores that can withstand much higher temperatures than a fusion's reactors metals, molten salts, and magnets. MMR's low power density is a paradigm shift in nuclear safety, more foundational than fusion, for it can be accomplished cost effectively today.”