Which factors are important for plutonium production?

[vifteovn]

As far as I understand plutonium production is mainly a function of the spesific burn-up. A low burn-up of under 1000 MWd/tU is preferred to produce weapongs-grade plutonium. The higher the burn-up the more pu-240 and other plutonium isotopes that makes production of weapons a bit more difficult and increases the risk of a fizzle.

How does the enrichment level play into this? A reactor fueled with natural uranium will have more u-238 available for neutron capture than a reactor fueled with LEU. Will a LEU reactor produce a better/worse composition of plutonium isotopes compared to a NU reactor if their burn-up levels were equal?

 

[Kritmiss]

A reactor fuelled with natural uranium would be your choice to make weapons grade plutonium. The design of fuel and moderator (which needs to be heavy water or graphite) is such that it maximises the production of plutonium, the irradiation time will determine the isotopic composition of your plutonium.

 

[raining Pete]

Yes, the enrichment level does play a role in the production of plutonium. A reactor fueled with natural uranium will have more U-238 available for neutron capture, which will result in a higher percentage of Pu-240 being produced. This is because U-238 has a higher neutron capture cross-section compared to U-235, which is the main fissile isotope used in nuclear reactors.

On the other hand, a reactor fueled with low-enriched uranium (LEU) will have a higher percentage of U-235, resulting in a lower amount of Pu-240 being produced. This is because U-235 has a lower neutron capture cross-section compared to U-238.

In terms of the composition of plutonium isotopes, a LEU reactor and a natural uranium (NU) reactor with the same burn-up levels will produce different amounts of Pu-240. The NU reactor will have a higher percentage of Pu-240, which can make it more difficult to extract weapons-grade plutonium. However, the overall yield of weapons-grade plutonium will also depend on the specific burn-up level, as mentioned in the original post.

In summary, the enrichment level does play a role in the production of plutonium and can affect the composition of plutonium isotopes. However, the specific burn-up level is also an important factor in determining the yield of weapons-grade plutonium.