technology - Earliest story about civil nuclear power

Does anybody know which is the earliest SF story about the civil uses of nuclear power (possibly, power generation)?
The best I can find is a 1940 short story by Robert A. Heinlein, “Blowups Happen” (Astounding Science Fiction, September 1940), modified and updated for a 1946 anthology, and later restored (“I now see, as a result of the enormous increase in the art in 33 years, more errors in the ’46 version than I spotted in the ’40 version when I checked it in ’46”). Now it appears in the collection Expanded Universe.

Answer

Wikipedia's article on the Atomic Age contains a timeline of popular culture references to nuclear power.

The earliest item on the timeline is:

1913 — C.W. Leadbeater published Man: How, Whence, and Whither? . This book describes the future society of the world in the 28th century (which, as a clairvoyant, Leadbeater claimed to have gotten information about from consulting the akashic records) as being powered by what he called atomic energy.

Now, I know very little about C.W. Leadbeater, but as a clairvoyant, he probably doesn't count as a sci-fi writer.

The next item on the timeline is much more promising:

1914 — H. G. Wells publishes science fiction novel The World Set Free, describing how scientists discover potentially limitless energy locked inside of atoms, and describes the deployment of atomic bombs.

I have not read the story in question, so I don't know how much detail it goes into about nuclear power, but from wikipedia, it is evident that he theorised about power generation based on atomic energy.

After this in the timeline, there is a huge gap, and no further entries until 1939. I'm not sure if that means that the timeline on wikipedia is incomplete, or if there actually were no further references to nuclear power in that time in popular culture.

However, the following entry is as follows:

October 1939 — Amazing Stories published a painting of an atomic power plant by science fiction artist Howard M. Duffin on its back cover.

Again not an actual science fiction story, but perhaps the beginnings of nuclear technology entering the science fiction world.

After that, the next entry is the Heinlein story the OP mentioned.

So, if H.G. Wells' novel The World Set Free does in fact describe nuclear power to a satisfactory level, then it can probably be considered the first story to mention it. Otherwise, Heinlein's Blowups Happen as mentioned by the OP probably can, unless someone can dig out a more obscure reference.