Deuterium: Where does it come from, where does it go?

[vampares]

Deuterium is a stable isotope of hydrogen.

 

If hydrogen (protium, thats hydrogen-1) is bombarded with neutrons, why does this not create deuterium?

 

If I am correct fission occurs (do correct me) because particles conjoin with isotopes that were previously stable. Now the isotope has an extremely short half-life and decays.

 

Well what if the particles are not intrinsically repelled by classical physics and the particles collide?

[swansont]

Deuterium is a stable isotope of hydrogen.

 

If hydrogen (protium, thats hydrogen-1) is bombarded with neutrons, why does this not create deuterium?

 

 

I have a vague recollection that H-2 doesn't have a real excited state — the proton and neutron will split at a lower energy. That makes it difficult to form, since the binding energy must be emitted immediately. So it has a very small cross section for formation.

[mathematic]

Almost all of the deuterons in the universe were formed immediately after the big bang. They are also formed in the interior of stars, but are consumed as part of the process converting H1 to He4.

[Enthalpy]

Protium does form deuterium when absorbing a neutron. It's the reason to prefer heavy water when neutrons are scarce. For instance a reactor can work with natural uranium, but only using heavy water as deuterium absorbs neutrons very little and oxygen almost doesn't it anyway.

 

You have the neutron cross-sections there, many thanks to Nist:

http://www.nndc.bnl.gov/sigma/index.jsp?as=1&lib=endfb7.1⊄=10

a click on "(n, gamma) plot" gives you the absorption versus neutron energy

http://www.nndc.bnl.gov/sigma/getPlot.jsp?evalid=14960&mf=3&mt=102⊄=10 like 0.3 barn at 25meV=300K

then you may choose rather Z=2 for deuterium and see 0.4 millibarn at 25meV

(or take 600K=50meV in a reactor)

 

That same reasons tells you that deuterium isn't very good to produce tritium. Lithium is easier - but deuterium is already there in a Candu reactor.

 

They have the (n, inelastic) graphs for O-16 and O-17, showing negligible cross-sections at 25meV.