I have a whole lot of mods that also change sciences. Some of them also add production-science-pack to atomic-bomb and kovarex-enrichment-process. Since your mod loads after them, it breaks factorio since science can't have the same ingredient added twice.
In general it is good practice to check if the ingredient already exists before attempting to add it.

oh yea, same applies to adding technology prerequisites. Those too can't be added twice and should be checked beforehand.

+1

+1

Thank you for the report and suggestions.

Technology prerequisites and ingredients are now checked to avoid duplication in 0.2.5.