5 ms·

Do we know how much tritium is needed for a city's energy generation? What about a state etc? Reason I ask is the only uses I have seen for tritium is on old wa

Do we know how much tritium is needed for a city's energy generation? What about a state etc? Reason I ask is the only uses I have seen for tritium is on old watch dials made in the pre-90's. Curious how much of this resource is out there.

S04dKHzrKT 4y ago
Real Engineering recently made a video that covers fuel needs. https://www.youtube.com/watch?v=BzK0ydOF0oU https://www.youtube.com/watch?v=BzK0ydOF0oU
- phtrivier 4y ago
  And the (otherwise excellent) channel is supposed to soon post an adv... I mean informer... I mean "exclusive documentary" about "repeat after me we're totally not a scam - we just play one on YouTube" fusion startup Helion. Which I'm going to watch, because even though everything I hear about this company gives me insane Theranos vibes... Well, if they pull it off... They might light a bulb with fusion in my lifetime.
  - adaml_623 4y ago
    The Helion approach seems plausible to me. Can you point me towards some of the sources that give you vibes?
    - phtrivier 4y ago
      A recent episode on Matt Ferrel's Undecided [1] (And I though I had seen a similar segment on "Answer with Joe", but I can't find it.) None of those would be opposable source, of course - there won't be any until they open a plant, publish data, etc... In the meantime, I see a hype cycle brewing, and it makes me a bit uncomfortable - but, we'll see. [1] https://youtu.be/yNP8by6V3RA https://youtu.be/yNP8by6V3RA
twic 4y ago
Take spullara's numbers: 2.01410177811 u = 3.34449439340696e-24 g deuterium 3.01604928 u = 5.008267217094e-24 g tritium 17.6 MeV = 7.832863e-19 kWh energy Divide through, and you will see that you need 4.27 ug/kWh of deuterium, and 6.39 ug/kWh of tritium. A random source [1] says that New York will use 50.6 TWh per year by 2027. That would require ~216 kg/yr of deuterium and ~323/yr kg of tritium. This is all assuming 100% efficiency. A quick read suggests 50% efficiency might be practical, so double those quantities. Also, i could easily have messed up that calculation somewhere, so please do check it! [1] https://www.buildingcongress.com/advocacy-and-reports/reports-and-analysis/Electricity-Outlook-2017-Powering-New-York-Citys-Future/The-Electricity-Outlook-to-2027.html https://www.buildingcongress.com/advocacy-and-reports/report...
- BadBadJellyBean 4y ago
  I wonder if that is much or not. I have no idea how hard this is to produce. Do you have an idea about that?
  - davidklemke 4y ago
    The concentration of deuterium in the ocean is about 150-160 parts per million and with 1233.91 quintillion liters covering the earth we have approximately 8.2260667e+12kg worth of it to extract, so we've got a bit to work through! Tritium however is far more rare with only trace amounts of it being available within nature and barely more than a kg produced per year. Producing the 100s of kgs required per year still seems to be an unsolved problem, although my quick searching shows there's a couple viable solutions for it.
    - mlyle 4y ago
      The solution is that fusion power plants can breed tritium and become net producers of it... Though in practice enough will be lost that probably they'll still be somewhat net consumers-- just not nearly to the extent predicted by a simple thermodynamic model. Still, even if fusion becomes a net producer of tritium, the whole tritium-is-hard-to-get problem will likely be a constraint that we'll be fighting as we ramp up use of fusion power in the future.
adgjlsfhk1 4y ago
TLDR is there isn't nearly enough tritium, but fusion reactors can make more (while still generating energy)
- ngcc_hk 4y ago
  Can you collect them easily in the reactor ?
  - elihu 4y ago
    If I understand correctly, tritium is the result of bombarding lithium with neutrons. I'm not sure how tokomaks are expected to work; do you just add lithium and expect the tritium to get where it needs to go to keep the reaction going, or do you actively remove gases from vessel, filter out the tritium, and re-use it as fuel? Either way, I don't imagine it'd be too hard to recapture the stuff. https://en.wikipedia.org/wiki/Breeding_blanket https://en.wikipedia.org/wiki/Breeding_blanket
yonaguska 4y ago
Tritium is very popular on gun sights as well- as it's a glow in the dark sight that doesn't need to be charged. I'm now questioning the practice of appendix carrying with tritium sights.
- ars 4y ago
  Tritium decays by beta-decay (an electron). The electron can not travel very far in air (1/4 inch), and is stopped by even the thinnest piece of metal. It's even stopped by the dead outer layer of your skin. i.e. it's completely harmless unless you eat it.
  - XorNot 4y ago
    Not quite: beta decay will penetrate the skin enough to damage living tissue - beta burns are what caused the fatalities of the Chernobyl first responder fire fighters. They spent a few hours covered in dust on their coats, and did a bunch of subsurface skin damage which manifested as third degree burns. Sepsis, not radiation poisoning, generally killed them.
- dublin 4y ago
  Well, it lasts for several years, but considerably less than even a human lifetime: Tritium's half-life is only about 11 years, so gun sights, dark-proof glow-in-the-dark signage (usually reserved for critical industrial plants, ships and offshore platforms due to expense), etc, will become seriously degraded in just a few years. (Since the glow is directly proportional to the remaining low-level beta radioactivity, which can barely penetrate the glass envelope in the first place - you'd get more radiation (from radium) living in a brick house than carrying 24-7.) FWIW, tritium and a phosphor granule encapsulated in glass microspheres have been developed for self-illuminating runway paint, but again, no one really uses it because tritium is stupid expensive, and again, it' loses half its brightness in only a decade. On the other hand, I've been told that Trijicon will replace their tritium gun sights for the lifetime of the original owner. I plan to live long enough to cost them money...
  - binkHN 4y ago
w0mbat 4y ago
Tritium is also used in gun sights.

S04dKHzrKT 4y ago

Real Engineering recently made a video that covers fuel needs. https://www.youtube.com/watch?v=BzK0ydOF0oU https://www.youtube.com/watch?v=BzK0ydOF0oU

phtrivier 4y ago
And the (otherwise excellent) channel is supposed to soon post an adv... I mean informer... I mean "exclusive documentary" about "repeat after me we're totally not a scam - we just play one on YouTube" fusion startup Helion. Which I'm going to watch, because even though everything I hear about this company gives me insane Theranos vibes... Well, if they pull it off... They might light a bulb with fusion in my lifetime.
- adaml_623 4y ago
  The Helion approach seems plausible to me. Can you point me towards some of the sources that give you vibes?
  - phtrivier 4y ago
    A recent episode on Matt Ferrel's Undecided [1] (And I though I had seen a similar segment on "Answer with Joe", but I can't find it.) None of those would be opposable source, of course - there won't be any until they open a plant, publish data, etc... In the meantime, I see a hype cycle brewing, and it makes me a bit uncomfortable - but, we'll see. [1] https://youtu.be/yNP8by6V3RA https://youtu.be/yNP8by6V3RA

twic 4y ago

Take spullara's numbers: 2.01410177811 u = 3.34449439340696e-24 g deuterium 3.01604928 u = 5.008267217094e-24 g tritium 17.6 MeV = 7.832863e-19 kWh energy Divide through, and you will see that you need 4.27 ug/kWh of deuterium, and 6.39 ug/kWh of tritium. A random source [1] says that New York will use 50.6 TWh per year by 2027. That would require ~216 kg/yr of deuterium and ~323/yr kg of tritium. This is all assuming 100% efficiency. A quick read suggests 50% efficiency might be practical, so double those quantities. Also, i could easily have messed up that calculation somewhere, so please do check it! [1] https://www.buildingcongress.com/advocacy-and-reports/reports-and-analysis/Electricity-Outlook-2017-Powering-New-York-Citys-Future/The-Electricity-Outlook-to-2027.html https://www.buildingcongress.com/advocacy-and-reports/report...

BadBadJellyBean 4y ago
I wonder if that is much or not. I have no idea how hard this is to produce. Do you have an idea about that?
- davidklemke 4y ago
  The concentration of deuterium in the ocean is about 150-160 parts per million and with 1233.91 quintillion liters covering the earth we have approximately 8.2260667e+12kg worth of it to extract, so we've got a bit to work through! Tritium however is far more rare with only trace amounts of it being available within nature and barely more than a kg produced per year. Producing the 100s of kgs required per year still seems to be an unsolved problem, although my quick searching shows there's a couple viable solutions for it.
  - mlyle 4y ago
    The solution is that fusion power plants can breed tritium and become net producers of it... Though in practice enough will be lost that probably they'll still be somewhat net consumers-- just not nearly to the extent predicted by a simple thermodynamic model. Still, even if fusion becomes a net producer of tritium, the whole tritium-is-hard-to-get problem will likely be a constraint that we'll be fighting as we ramp up use of fusion power in the future.

adgjlsfhk1 4y ago

TLDR is there isn't nearly enough tritium, but fusion reactors can make more (while still generating energy)

ngcc_hk 4y ago
Can you collect them easily in the reactor ?
- elihu 4y ago
  If I understand correctly, tritium is the result of bombarding lithium with neutrons. I'm not sure how tokomaks are expected to work; do you just add lithium and expect the tritium to get where it needs to go to keep the reaction going, or do you actively remove gases from vessel, filter out the tritium, and re-use it as fuel? Either way, I don't imagine it'd be too hard to recapture the stuff. https://en.wikipedia.org/wiki/Breeding_blanket https://en.wikipedia.org/wiki/Breeding_blanket

yonaguska 4y ago

Tritium is very popular on gun sights as well- as it's a glow in the dark sight that doesn't need to be charged. I'm now questioning the practice of appendix carrying with tritium sights.

ars 4y ago
Tritium decays by beta-decay (an electron). The electron can not travel very far in air (1/4 inch), and is stopped by even the thinnest piece of metal. It's even stopped by the dead outer layer of your skin. i.e. it's completely harmless unless you eat it.
- XorNot 4y ago
  Not quite: beta decay will penetrate the skin enough to damage living tissue - beta burns are what caused the fatalities of the Chernobyl first responder fire fighters. They spent a few hours covered in dust on their coats, and did a bunch of subsurface skin damage which manifested as third degree burns. Sepsis, not radiation poisoning, generally killed them.
dublin 4y ago
Well, it lasts for several years, but considerably less than even a human lifetime: Tritium's half-life is only about 11 years, so gun sights, dark-proof glow-in-the-dark signage (usually reserved for critical industrial plants, ships and offshore platforms due to expense), etc, will become seriously degraded in just a few years. (Since the glow is directly proportional to the remaining low-level beta radioactivity, which can barely penetrate the glass envelope in the first place - you'd get more radiation (from radium) living in a brick house than carrying 24-7.) FWIW, tritium and a phosphor granule encapsulated in glass microspheres have been developed for self-illuminating runway paint, but again, no one really uses it because tritium is stupid expensive, and again, it' loses half its brightness in only a decade. On the other hand, I've been told that Trijicon will replace their tritium gun sights for the lifetime of the original owner. I plan to live long enough to cost them money...
- binkHN 4y ago

w0mbat 4y ago

Tritium is also used in gun sights.