Sure! This is the report: https://unece.org/sites/default/files/2022-04/LCA_3_FINAL March 2022.pdf

It has a description of the methods and the ISO standards they use to determine life-cycle CO2, from the cradle to the grave numbers. It also includes all the references and sources. I’m sure there’s a lot more info available about the research they did, but this is the high-level report.

The UN seems like a pretty reliable source and the report seems very thorough, but I’m not qualified to say where they went wrong. So I would love to see what other sources say on the subject.

Edit: They even state in their report why the value they give for nuclear is on the low end of most accepted literature:

This value is comparable to the lower range of literature values because of the following assumptions: revised energy inputs for mining and milling, including electricity inputs for ISL, centrifugation-only enrichment, longer lifetime assumed for nuclear power plant (60 years instead of 40).