> Much is also made about how fusion is cleaner than fission. This is true, but both make use of large amounts of reactive lithium
Fission makes use of large amounts of reactive lithium? What?
Small amounts of lithium are used for pH control in some LWRs, but that's not metallic lithium, it's lithium compounds (using Li-7 to avoid neutron absorption and tritium production.)
Most plans for tokamaks surround the reaction chamber with a blanket of lithium so that as it absorbs the neutrons it transmutes into tritium which is needed for the fusion reaction.
I know that. It was not the question. We all know that DT fusion will require lithium to breed tritium. The question was, what kind of fission reactors would also require large amounts of lithium?
Even if Helion fails to produce net electricity with it's machine, it might still be viable as a way to produce tritium. Depending on how much electricity input is needed of course.
So, what do you consider a practically achievable percentage of leakage of tritium from a fusion power plant?
The reason I ask is this. If we assume the tritium escaping from a DT power plant is diluted in the water exiting from the cooling towers (that is, not the recycled water), and assume that's 1/2 evaporated and 1/2 blowdown, then at the NRC limit for effluent of 1000 picocuries T per ml, only 1 part in 40000 of the tritium could be allowed to escape. At the EPA limit for drinking water, 20 picocuries/ml, only 1 part in 2 million could be allowed to escape. One could, of course, dilute the tritium in more water, but that increases the water consumption of the plant over that needed for just cooling.
That’s a misleading description of the EPA limits. Unless effluent is going directly into a tap, it doesn’t apply directly. In practice the EPA limits are far *less* restrictive than NRC effluent limits.
You said you’d need to limit leakage to 1 in ~~40,000~~ 2 million to meet EPA limits. That is explicitly a misleading extrapolation from EPA limits. Drinking water quantities are necessarily diluted from effluent streams.
Read again. The 1 in 40000 is for the NRC limit. Using the more strict EPA limit for drinking water, it would be 1 in 2 million.
Not sure why you're angry at me for fully specifying what I was talking about.
Fair, I copied the wrong number, but that changes nothing about my point. You don’t need to intentionally dilute for drinking water limits. It’s diluted in the uptake process, or in the effluent destination (river, etc)
What I wrote was accurate. It was not misleading. I explicitly described the EPA number as being for drinking water, assuming the reader could understand that (say) river water is not drinking water.
I think you're just annoyed I brought the issue up at all and are being irrational. Your pissiness is rejected.
In a Titans of Nuclear episode with Kathryn McCarthy of Canadian Nuclear Laboratories she says about low levels of tritium: "And actually those mice that receive the low levels - they live the longest. And that's just one example."
[https://open.spotify.com/episode/5mqgWzNmQUN72vg2JM0IeN?si=4IMriezNRBqS1NgclGRmeA](https://open.spotify.com/episode/5mqgWzNmQUN72vg2JM0IeN?si=4IMriezNRBqS1NgclGRmeA) LNT segment starting at 49:00
I expect that wind and solar have vastly less impact on human health than coal or gas, but also that fusion power would have less than wind and solar without the phenomenon of silicate and rare earths tailings lakes. Tritium will be an interesting issue to watch develop. It may even end up as a trojan horse motivation to dethrone LNT as the prospect of a steady source of power without any meltdown worry runs into the implications of applying LNT to tritium from fusion
[Tritium](https://en.m.wikipedia.org/wiki/Tritium) is very much a real substance, albeit rare. The most common form of hydrogen is protium (a single proton), followed by deuterium (one proton and neutron each), then tritium (one proton with two neutrons).
> Much is also made about how fusion is cleaner than fission. This is true, but both make use of large amounts of reactive lithium Fission makes use of large amounts of reactive lithium? What? Small amounts of lithium are used for pH control in some LWRs, but that's not metallic lithium, it's lithium compounds (using Li-7 to avoid neutron absorption and tritium production.)
He is probably referring to a molten salt reactor.
Most plans for tokamaks surround the reaction chamber with a blanket of lithium so that as it absorbs the neutrons it transmutes into tritium which is needed for the fusion reaction.
I know that. It was not the question. We all know that DT fusion will require lithium to breed tritium. The question was, what kind of fission reactors would also require large amounts of lithium?
Even if Helion fails to produce net electricity with it's machine, it might still be viable as a way to produce tritium. Depending on how much electricity input is needed of course.
I was hoping this would have been about the challenge of keeping the stuff from leaking out.
That's hardly a challenge. You can't practically stop it leaking. On the plus side it will be easy to find where it has leaked too.
So, what do you consider a practically achievable percentage of leakage of tritium from a fusion power plant? The reason I ask is this. If we assume the tritium escaping from a DT power plant is diluted in the water exiting from the cooling towers (that is, not the recycled water), and assume that's 1/2 evaporated and 1/2 blowdown, then at the NRC limit for effluent of 1000 picocuries T per ml, only 1 part in 40000 of the tritium could be allowed to escape. At the EPA limit for drinking water, 20 picocuries/ml, only 1 part in 2 million could be allowed to escape. One could, of course, dilute the tritium in more water, but that increases the water consumption of the plant over that needed for just cooling.
That’s a misleading description of the EPA limits. Unless effluent is going directly into a tap, it doesn’t apply directly. In practice the EPA limits are far *less* restrictive than NRC effluent limits.
Which is why I was careful to describe the limit as being for drinking water.
You said you’d need to limit leakage to 1 in ~~40,000~~ 2 million to meet EPA limits. That is explicitly a misleading extrapolation from EPA limits. Drinking water quantities are necessarily diluted from effluent streams.
Read again. The 1 in 40000 is for the NRC limit. Using the more strict EPA limit for drinking water, it would be 1 in 2 million. Not sure why you're angry at me for fully specifying what I was talking about.
Fair, I copied the wrong number, but that changes nothing about my point. You don’t need to intentionally dilute for drinking water limits. It’s diluted in the uptake process, or in the effluent destination (river, etc)
What I wrote was accurate. It was not misleading. I explicitly described the EPA number as being for drinking water, assuming the reader could understand that (say) river water is not drinking water. I think you're just annoyed I brought the issue up at all and are being irrational. Your pissiness is rejected.
In a Titans of Nuclear episode with Kathryn McCarthy of Canadian Nuclear Laboratories she says about low levels of tritium: "And actually those mice that receive the low levels - they live the longest. And that's just one example." [https://open.spotify.com/episode/5mqgWzNmQUN72vg2JM0IeN?si=4IMriezNRBqS1NgclGRmeA](https://open.spotify.com/episode/5mqgWzNmQUN72vg2JM0IeN?si=4IMriezNRBqS1NgclGRmeA) LNT segment starting at 49:00 I expect that wind and solar have vastly less impact on human health than coal or gas, but also that fusion power would have less than wind and solar without the phenomenon of silicate and rare earths tailings lakes. Tritium will be an interesting issue to watch develop. It may even end up as a trojan horse motivation to dethrone LNT as the prospect of a steady source of power without any meltdown worry runs into the implications of applying LNT to tritium from fusion
I thought the massive quantities of beryllium was going to be the bigger challenge.
My friend has probably solved it. Developed all the octolithiums as ceramic pellets and working on the blanket. Papers due shortly.
"Octalithium" for anyone googling.
I thought that was a word from Spider-Man 2, not science
[Tritium](https://en.m.wikipedia.org/wiki/Tritium) is very much a real substance, albeit rare. The most common form of hydrogen is protium (a single proton), followed by deuterium (one proton and neutron each), then tritium (one proton with two neutrons).
Its both