Deuterium bombarded with Neutrons from tritium?

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Discussion Overview

The discussion revolves around the interaction of neutrons with deuterium, specifically whether bombarding deuterium with neutrons can lead to the formation of tritium. The scope includes theoretical considerations and potential experimental implications.

Discussion Character

  • Exploratory
  • Technical explanation
  • Debate/contested

Main Points Raised

  • One participant questions if bombarding a gas or plasma of deuterium with neutrons would result in tritium formation.
  • Another participant argues that the probability of this reaction is effectively zero, referencing heavy water reactors.
  • Some participants note that while some neutrons may interact with deuterium, the majority will be lost through other reactions, emphasizing the role of D2O as a moderator in CANDU reactors.
  • Data is presented regarding the absorption cross section for thermal neutrons and high-energy neutron capture cross sections, suggesting low probabilities for the reaction.
  • A participant hypothesizes that increasing the density of the deuterium target could enhance the chances of neutron capture due to reduced space between nuclei.
  • Further exploration of increasing density by factors of 10 or 100 is proposed, with calculations provided for liquid deuterium versus gaseous deuterium.
  • Another participant confirms that higher density could increase the likelihood of neutron interactions with deuterium nuclei.

Areas of Agreement / Disagreement

Participants express differing views on the likelihood of neutron capture by deuterium, with some asserting it is highly improbable while others suggest that increasing density could improve chances, indicating ongoing debate and uncertainty.

Contextual Notes

The discussion includes references to specific cross-section values and the physical state of deuterium, but does not resolve the implications of these factors on neutron capture probabilities.

Who May Find This Useful

Readers interested in nuclear physics, fusion research, and neutron interactions may find this discussion relevant.

BrianConlee
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If we bombard a gas or plasma of Deuterium with Neutrons will they "stick" and from Tritium?
 
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Not too likely. Heavy water reactors use the fact that the probability of this reaction is 0.
 
Some will, but you need lots of neutrons (thermalized)... The vast majority will be lost by other paths, which is why the CANDU reactors use D2O as a moderator.

Deuterium's absorption cross section for thermal neutrons is .52 millibarns

from: http://en.wikipedia.org/wiki/Heavy_water
 
Here is a plot of the high energy deuterium (neutron,gamma) tritium cross section from the "Barn Book" series data sets at

http://www.nndc.bnl.gov/atlas/.

Looks like about 10 to 20 microbarns high energy neutron capture cross section at 14.1 MeV neutron energy from D-T reaction.

Bob S
 

Attachments

  • Deuterium (n,gamma).jpg
    Deuterium (n,gamma).jpg
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I see.

It appears our target it just to small, making the probability infinitesimal.

I understand why the tritium breeding methods using lithium 6 and 7 is preferred now.

Let's add another factor into the mix. This may not be researched, but it may require you to "best guess" or hypothesize as we say.

What if we increased the density of our Deuterium target from standard atmosphere 10 fold. Now there's less space between the nuclei of the different atoms.

Does that increase the chances somewhat?

Take it another order of magnitude even. If we could somehow increase density 100 fold, that would surely give more of a target for the neutrons to hit... less empty space. At least somewhat.

Thoughts?
 
BrianConlee said:
What if we increased the density of our Deuterium target from standard atmosphere 10 fold. Now there's less space between the nuclei of the different atoms.

Does that increase the chances somewhat?

Take it another order of magnitude even. If we could somehow increase density 100 fold, that would surely give more of a target for the neutrons to hit... less empty space. At least somewhat.
If you substitute liquid deuterium (density 162 mg/cm3) for gasseus deuterium at 1 atm (0.168 mg/cm3), you can increase the concentration of deuterium by a factor of about 960:1. However, the boiling point of liquid deuterium is about 23 kelvin.

Bob S
 
so with that higher density, does it increase the chances the neutron would hit and stick to a nucleus?
 
BrianConlee said:
so with that higher density, does it increase the chances the neutron would hit and stick to a nucleus?
Yes.

Bob S
 

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