Yes, there was an explosion at the Centraco plant in Marcoule, France. It has been described as an "industrial accident."
NO, it was not a nuclear explosion.
NO, it did not involve nuclear materials.
NO, Centraco is not a nuclear reactor. It is a low-level waste processing site.
One person is confirmed dead, and three injured.
Now compare that to the second explosion which took place today:
A leaking gas pipeline in Kenya exploded, killing at least 75 and injuring at least 100.
Was that second incident underreported? ABSOLUTELY. (Google News counts: "Marcoule explosion" in last hour: 1,710; "Kenya explosion" in last hour: 712.)