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Bechtel’s Impact Report

Sellafield Pile Fuel Cladding Silo Retrieval

Sellafield nuclear site

Safely decommissioning a 1950s nuclear waste storage facility

Known as one of the four most hazardous buildings in Western Europe, the Sellafield Pile Fuel Cladding Silo (PFCS) was commissioned in 1952 to safely store radioactive cladding – pieces of metal tubes used for uranium fuel rods in some of the UK’s earliest nuclear reactors. The UK government has partnered with Bechtel Cavendish Nuclear Solutions to deliver a system that will allow Sellafield to retrieve the decades-old waste, package it safely, and dispose of it permanently. 

The project is part of a UK Nuclear Decommissioning Authority program to decommission nuclear storage facilities dating to the early 1950s.

The project entails the detailed design, procurement, manufacture, works testing, delivery to site, installation and commissioning of a complex system for cutting access holes into the silo that include shielded access doors, a robotic waste retrieval arm, waste transporters, and repackaging plants. The team also is utilizing virtual reality and mockup training facilities to enhance operations.

A digital rendering shows the robotic waste retrieval arm installed on the superstructure built onto the Pile Fuel Cladding Silo.

Inside the project

The Pile Fuel Cladding Silo was at capacity by 1964. Since then, the facility has been safely storing radioactive cladding from military projects and later power plants, as well as other hazardous debris.

  • The more than 60-foot-tall silo has six compartments and holds more than 3,200 cubic meters (4,200 cubic yards) of intermediate-level waste.
  • Upgrade work completed in the 1990s made it possible for this silo and other structures to continue storing waste safely.
  • The project team engineered a way to cut openings and install doors at the top of the silo’s storage compartments while maintaining an airtight seal to reduce the threat of a spontaneous fire within.
  • A waste retrieval unit with a remote-operated “grabber” arm will extend and lower into each compartment, retrieving the waste and packaging it in secure containers for final disposal.

Collaboration ensures safe, on-time project delivery

The doors and the retrieval unit were fabricated, assembled, and partially commissioned at a dockyard in Scotland to maximize work offsite rather than at the cramped Sellafield Site. The retrieval modules were then installed on a platform against the side of the silo structure nearly 60 feet above ground level. 

Through our highly collaborative partnership with Sellafield, the first two stages of this Bechtel-led program, which successfully readied the plant to begin retrieving waste, were delivered 15 months early and £120m under the client budget.

Furthermore, the program was a 2019 finalist in the UK Association for Project Management annual awards, received a formal Commendation from the Nuclear Decommissioning Authority for Safety and Innovation, and formed the exemplar case study in a UK Government-sponsored Confederation of British Industry study into excellence in government contract delivery.