Add chain parameter to Material.get_activity for half-life data#3957

EdenRochmanSharabi wants to merge 7 commits into

openmc-dev:developopenmc-dev/openmc:developfrom

EdenRochmanSharabi:feature/get-activity-chain-halflifeEdenRochmanSharabi/openmc:feature/get-activity-chain-halflifeCopy head branch name to clipboard