Tritium!! We make it, sure, but can't use an atom of it!

If you wonder how/why fusion works, or how/why the Fusor works, look here first.
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Richard Hull
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Tritium!! We make it, sure, but can't use an atom of it!

Post by Richard Hull » Tue Aug 31, 2021 7:10 pm

So many who are just starting to understand D-D fusion and its by products after reading my FAQ...

https://www.fusor.net/board/viewtopic.php?f=42&t=13284

....Get the idea that for every neutron we detect, we create an atom of fusible tritium in our D-D fusors. This is, of course, a fact. Know full well that D-T fusion is over a thousand fold more easy to do. Many wrongfully think that the fusor is a breeder reactor for tritium that will slowly fill with enough tritium to augment and boost our fusion output due to D-T fusion.

Let us do some math.........

The ideal!

Let us go crazy an assume the never obtainable Ideal situations in physics at every turn.

Operating conditions:
1. We have a perfect vacuum in our fusor.
2. Our fusor has a volume of 1000 cubic centimeters (one liter)
3. We are producing 2 million neutrons/second at a deuterium pressure of 15 millitorr. (2X10e6 tritons/sec)

Question: How many atoms of deuterium are in our chamber?
We have Avagadros number of deuterium molecules in a liter volume at STP. 2.69 × 10e22
A deuterium molecule has two D atoms in it 5.4 X 10e22 atoms of deuterium in a liter at STP
We are not at STP but are at .000015 ATM or 1.5 X 10e-5 ATM
Thus, (1.5 x10e-5) X (5.4 x 10e22) = 8.1 x 10e17 atoms of deuterium in our running fusor.

At the end of one hour of continuous running of our fusor making 2 millions tritons/sec, we have 3600, (3.6 x 10e2) X (2 x10e 6) = 7.2 X 10e8 or 720 million tritium atoms in our fusor (assuming none of them fuse). What is the ratio of generated tritium atoms to deuterium atoms in our fusor?
(7.2 x 10e8) / (8.1 x 10e17) = .88 x 10e11 or... for every tritium atom in the mix, there are 880 Billion deuterium atoms ready to do D-D or D-T fusion.

The ideal is done!

Flies in the ideal ointment

1. Due to the huge overburden of Deuterium atoms (deuterons) during operation and the rate of production of tritons, coupled with the thousand fold more likelihood that D-T fusion will take place, no tritium build up will occur as they will be effectively burned in D-T fusion long before they can accumulate. as in the ideal computations above.
2. The energy of this "as produced" D-T fusion and its associated sub-microscopic amount of added energy will never be seen or become measurable in any amatuer device under any circumstances, ever!!!!
3. D-D fusion will prevail as the effective sole energy product in any amateur fusion effort for all time.
4. As noted in the FAQ URL and PDF above, the D-D energy, itself, is not measurable from an amateur fusor at 4 million fusions/second!
5. The only way we have of knowing the fusion energy is by the calcs presented in the PDF due to the measured neutron output of the fusor, itself.

Leave behind all hope of tritium values achieved in D-D fusion or in any n-Li6 blanket production within an amateur fusor.

Richard (the wet blanket), Hull
Progress may have been a good thing once, but it just went on too long. - Yogi Berra
Fusion is the energy of the future....and it always will be
Retired now...Doing only what I want and not what I should...every day is a saturday.

Chris Seyfert
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Re: Tritium!! We make it, sure, but can't use an atom of it!

Post by Chris Seyfert » Sat Sep 04, 2021 4:11 pm

As Richard has pointed out, the atomic fractions of tritium produced in even a high-class amateur fusor are vanishingly small. They're still vanishingly small even from a radiological perspective. What's the radioactivity of 7.2x10e8 tritium atoms?

The formula is A = λ*N, where A is activity, λ is the decay constant, and N is the number of atoms present.

The decay constant is equal to ln(2)/half-life, and for the units to work out, the half-life has to be in seconds. For tritium, 12.3 years, the decay constant is ln(2)/[12.3y*3.16x10e7 s/y] = 1.8x10e-9 s-1

We then get A = (1.8x10-9 s-1)*(7.2x10e8 atoms) = 1.3 decays/second = 1.3 becquerel = 35 pCi.

It's hard to convey how ridiculously small this amount of tritium is. Environmental scientists speak of "tritium units" or TU, where 1 TU = 1 tritium atom per 10e18 H atoms. Water at 1 TU = 8.5 Bq/L. Normal rain usually has between 3 - 10 TU!

Yep, you make it, but can't use it, probably can't detect it, and dancing in the rain exposes you to more tritium than licking the inside of the fusor chamber!


https://www.eawag.ch/en/department/wut/ ... ritium-h3/

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Richard Hull
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Re: Tritium!! We make it, sure, but can't use an atom of it!

Post by Richard Hull » Sun Sep 05, 2021 12:01 am

Thanks, Your radiological notation added to the value of this FAQ and put another fine point aspect on how little T is there. This is the kind of add on to a FAQ that is welcomed. It extends it.

Richard Hull
Progress may have been a good thing once, but it just went on too long. - Yogi Berra
Fusion is the energy of the future....and it always will be
Retired now...Doing only what I want and not what I should...every day is a saturday.

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Bob Reite
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Re: Tritium!! We make it, sure, but can't use an atom of it!

Post by Bob Reite » Tue Sep 07, 2021 11:11 pm

It is a good thing that we can't make detectible amounts of tritium in our amateur fusors. One is not allowed to possess tritium in the United States without the appropriate license from the NRC.
The more reactive the materials, the more spectacular the failures.
The testing isn't over until the prototype is destroyed.

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Re: Tritium!! We make it, sure, but can't use an atom of it!

Post by Richard Hull » Wed Oct 13, 2021 11:04 pm

Most of the tritium that is not fused in my system finds its way to the great outdoors. (vent/exhaust of the mechanical pump is piped outside). With a gentle breeze towards my side porch, our cats will get a bit of the oil mist/tritium vapor wafting over them. Otherwise, the tritium rises, as hydrogen does, and goes into outer space or becomes HTO or T2O in rain. The oil mist falls onto the grass at the rear of the lab.

Richard Hull
Progress may have been a good thing once, but it just went on too long. - Yogi Berra
Fusion is the energy of the future....and it always will be
Retired now...Doing only what I want and not what I should...every day is a saturday.

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