Energy From Thorium Discussion Forum

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 Post subject: Re: Tritium risks
PostPosted: Sep 25, 2015 12:54 am 
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Lars wrote:
Tritium production from BWR's are particularly low 10x lower than PWRs

Why is this so? I can see heavy water and light water making a difference, but why should the pressure make such a difference to tritium production?


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 Post subject: Re: Tritium risks
PostPosted: Sep 25, 2015 6:26 am 
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Quote:
Why is this so? I can see heavy water and light water making a difference, but why should the pressure make such a difference to tritium production?


Most of the PWRs use boron to control the reactivity (while the BWRs don't use it). The boron is added in the primary coolant in the form of boric acid. This acidifies the water.

In order to get a a neutral pH they add LiOH to the primary water (LiOH rises the pH), so there are Li atoms in the water. The boron atoms also make 7Li when they capture a neutron. Some of the Li atoms (7Li and 6Li) absorb neutrons and make tritium.


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 Post subject: Re: Tritium risks
PostPosted: Aug 07, 2018 2:04 pm 
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There must be a fairly large amount of tritium on Earth already, naturally occurring or from weapons testing. Can't they just dump the tritiated water into the Ocean?


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 Post subject: Re: Tritium risks
PostPosted: Aug 07, 2018 4:18 pm 
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modifiedgenes wrote:
There must be a fairly large amount of tritium on Earth already, naturally occurring or from weapons testing. Can't they just dump the tritiated water into the Ocean?


Virtually no tritium exists in the environment as a result of weapons testing.
The last significant weapons test programme was in the 90s, which is 25 years or so ago now (the end of NTS use and the French in Polynesia).

That is several half lives, and the large scale nuclear testing in the 50s and 60s is a long time ago now.


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 Post subject: Re: Tritium risks
PostPosted: Aug 07, 2018 6:35 pm 
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Actually, the half life of tritium is 12.32 years, so only about 3/4 of the environmental tritium left after large scale testing stopped has decayed. The Canadians deal with a lot of tritium because they use heavy water as a moderator. So it is possible to deal with.

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 Post subject: Re: Tritium risks
PostPosted: Aug 08, 2018 2:33 am 
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I was sure it had a 12 year half life, so a lot has decayed. Best get on and dump that tritiated water in the Pacific then. I do not see what use storing it will do.


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 Post subject: Re: Tritium risks
PostPosted: Aug 08, 2018 3:38 am 
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modifiedgenes wrote:

I was sure it had a 12 year half life, so a lot has decayed. Best get on and dump that tritiated water in the Pacific then. I do not see what use storing it will do.


Tritium is not waste. Think about glowing tritium luminaires for example.
Quote:

During manufacture, a length of borosilicate glass tube that has had the inside surface coated with a phosphor-containing material is filled with radioactive tritium. The tube is then sealed at the desired length using a carbon dioxide laser. Borosilicate is preferred for its strength and resistance to breakage.

I would prefer a refillable bottle instead of a welded bottle – or I guess so. Although the glowing bottle should be recyclable, refilling at home could not be allowed, because inhaling tritium is a health risk.

Quote:

Tritium is an isotope of hydrogen, which allows it to readily bind to hydroxyl radicals, forming tritiated water (HTO), and to carbon atoms. Since tritium is a low energy beta emitter, it is not dangerous externally (its beta particles are unable to penetrate the skin), but it can be a radiation hazard when inhaled, ingested via food or water, or absorbed through the skin.


To improve logistics of tritium consumer products container deposit legislation could be extended to cover tritium products.

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 Post subject: Re: Tritium risks
PostPosted: Aug 08, 2018 1:14 pm 
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Sorry, I did realise that tritium had a substantial market value, and always has, however, I understood that separating it, isotopically, was impossible?

Dump it in the Pacific ocean.


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 Post subject: Re: Tritium risks
PostPosted: Aug 08, 2018 1:22 pm 
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The Canadians have become extremely adept at separating tritium, and operate a facility adjacent to the Darlington plant, who's purpose is to produce near pure tritium from moderator heavy water


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 Post subject: Re: Tritium risks
PostPosted: Aug 08, 2018 6:51 pm 
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If it is so easy, why did the Japanese ever begin to store tritiated water in endless numbers of tanks? Seperate it, sell the tritium and get the water put into the sea.


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 Post subject: Re: Tritium risks
PostPosted: Aug 08, 2018 6:58 pm 
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Probably because the water they are collecting isn't moderator heavy water, and also probably has other stuff in it, which makes the canadian techniques difficult to apply?


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 Post subject: Re: Tritium risks
PostPosted: Aug 08, 2018 7:34 pm 
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modifiedgenes wrote:
If it is so easy, why did the Japanese ever begin to store tritiated water in endless numbers of tanks? Seperate it, sell the tritium and get the water put into the sea.

Moderator heavy water costs $300-600/kg

The costs are orders of magnitude apart.

I suspect the ALARA alternative is to release the oldest water first and continue like that.


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 Post subject: Re: Tritium risks
PostPosted: Aug 09, 2018 1:43 pm 
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So dump it into the Ocean then? Storing it in tanks is a nonsense.

I did read an article that had a graphic that showed all the sources of radioactivity in the Oceans and basically, man made sources were totally insignificant compared to those that were there already.


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