Muddying the Waters?

There is a continuing fuss about the plan to 'dump' around 300,000 tons of mud from around the old ands newer nuclear power stations at Hinckley Point, in Somerset, into the sea near Penarth close to Cardiff (https://www.walesonline.co.uk/news/wales-news/radioactive-mud-dumped-coast-cardiff-14464416). Apparently, tests have shown that the mud is not (as was feared) radioactive but one has to ask why the mud has to be dumped in this location (and the benefit to Wales of receiving Somerset mud)?