Depends where, here in France, of the 4 left-wing parties (PS, PCF, Les Verts and PG) two (PS and PCF) are mostly in favor of nuclear energy, the two others (Les Verts and PG) mostly against it, while all but Les Verts are internally split.

But that may also be because France has a strong nuclear industry, and the left-wing parties tend to be friendly with the unions, and the unions defend nuclear energy because it creates jobs (both for our own energy and because we export nuclear technology).