A major consideration when nuclear waste is being stored is the contamination which occurs on the submerged surfaces of the containment vessel – be it a silo or pond. In either case, the water in the silo or pond acts as a radiation barrier and hence its level needs to be maintained to ensure storage integrity.

Removal of the radioactive contaminant from the submerged concrete surface of silo or pond is obviously made more difficult because of this water barrier. If the water is removed to facilitate removal of deposits then airborne contamination can occur. Conversely, leaving the
water shielding in place renders the use of standard concrete scarification systems or chemical leaching products totally impractical.

Through its work for British Nuclear Group in the design, manufacture, assembly and test of waste retrieval machines for use in Silo Emptying Plant at Sellafield, PJS sister company NESL has considerable experience of the factors to be considered when handling wet or solid radioactive waste.

Working in partnership with NESL, PJS has now developed a bespoke range of water jet cleaning equipment for these particularly hazardous duties.

The latest generation of equipment utilises high pressure water jetting techniques together with a rotating epicyclic cleaning head to remove the waste build up, which can then be removed using vacuum techniques. This complete process is known as ‘scabbling’.