Low Level Waste Disposal IP-2 Package Containing Plutonium Contaminated Slag Pots

Croft Associates were approached by PC Richardson to carry out the licensing of an IP2 package containing Plutonium contaminated slag pots. This project provided several unique challenges for all those involved.

The slag pots belonged to Outokumpu steel company based in Sheffield. During use, sampling indicated a high level of plutonium in the form of Pu 238 was present in a slag pot. Further sampling identified that 4 slag pots were contaminated with Pu 238 and required disposal. The source of the Pu-238 contamination was believed to be a single heart pacemaker present in scrap that was melted down for reuse.

All four slag pots weighed between 50t to 60t and three had large patched cracks. The size and nature of the contamination prevented the slag pots being broken up therefore they had to be packaged and transported intact.

REMAC designed a steel box to package the slag pots. It was the responsibility of Croft to license this package. Several challenges were faced when licensing: firstly the weight, size and contents prevented any physical drop testing of the package. Secondly the box was to be assembled around the slag pot, limiting the leak testing that could be carried out.

All drop testing was therefore carried out by finite element analysis by AMEC NNC. This approach was also used to check the tie down and lifting systems. Leak testing was carried out on the assembled box prior to grouting. The transportation box, once assembled and licensed, was transported to Drigg from Sheffield by road.