Are vegetables and kimchi from korea still safe to eat, even if they might have tested an h-bomb?

Safe from radiation: Tests were done under ground in North Korea , no fear exposure in south Korea as products are from South . FDA is very vigilant in monitoring any food products that enter USA . Like any stored processed food one has to worry more about bacterial contamination than radiation exposure .

North or South: It is highly unlikely that you are getting any food from North Korea. It is North that claims to have detonated an H-bomb. Any food from South Korea would as safe now as it was before the North's claim of testing H-bomb.

Underground test: Virtually no atmospheric spread of radiation per international agreements.