Sellafield does not have a power plant. All it does is reprocess spent fuel and store it for thousands of years.
If the article is true, then it would be an improvement on what's happening at the moment. It might mean that there would be no reason to transport spent fuel to Sellafield on trains all over the country.
If they could use the stored spent reprocessed fuel at Sellafield so it was only radioactive for 300 years instead of millennia, that would be an improvement, but I still would not want it.
One of the things said in the article was that it would mean small nuclear power stations all over. I'd rather be able to see wind turbines than a nuclear power station.
I presume they would still have to be built at the coast, for the water cooling. Don't fancy half a dozen nuclear power stations along the Northumbrian coastline.