Sellafield – Magnox Skip Size Reduction Facility

Background

The Nuclear Decommissioning Authority (NDA) Lifetime Plan 10 has the requirement to move fuel from the First Generation Magnox Storage Pond (FGMSP) to the Fuel Handling Plant (FHP) as an early hazard reduction opportunity.

Objectives

With limited space for storing the FGMSP fuel in FHP and in order to free up storage space for between 300-450 FGMSP fuel skips, existing empty skips in FHP ponds need to be removed. lt was decided to go directly to size reduction and storage as a means of meeting the FGMSP fuel transfer timescales.

The location for skip size reduction, cutting technique, cutting pattern, off cut handling techniques and packing density are all interlinked and impact upon each other.

Challenges

The skips requiring size reduction are stored below water in a (nuclear) pond and must be size reduced in that environment. The following were requirements:

  • Minimum disturbance of the pond environment.
  • Limited space available for the proposed solution
  • Proposed system should be remotely controlled.
  • Proposed system should be easy to install and require minimal maintenance.
  • A minimum packing density of 2.7:1 of cut skips into clean was required.

Solution

Oxford technologies created a ‘requirements register’ against which proposed design concepts were measured. A review of historical solutions was performed together with an analysis of all potential cutting technologies relevant to this application. This included reviewing a laser based cutting technology developed by The Welding Institute (TWI) that had been investigated but had been deemed unsuitable for use under water. The stringent technical requirements suggested that the laser based solution could be the most appropriate technology if made to work within the pond environment. Oxford technologies solution was to perform this operation within a ‘diving bell’.

Outcome

The team has successfully delivered the detailed requirements, concept design, preliminary design and risk analysis for this innovative equipment. Since then, the project has been suspended by Sellafield Ltd.