Soon, in nuclear usage, means maybe in the next ten years. Anyway, they are called small modular reactors (SMRs). Supposedly safer design that doesn't require back-up power for pumps, etc. Trade-off is that they are may lose some economies of scale on fuel efficiency. Article may be paywalled. If so, my apologies
Link: http://science.sciencemag.org/content/363/6429/806