Cavendish awarded graphite inspection contract

03 January 2018

EDF Energy has awarded nuclear services company Cavendish Nuclear a five-year contract to support the continued operation of its UK fleet of advanced gas-cooled reactors (AGRs). The contract is worth some GBP7.5 million ($10.2 million).

Under the contract, Cavendish Nuclear - a subsidiary of Babcock International Group - will provide specialists and equipment to carry out inspections of the graphite blocks in the reactor cores. This service was previously delivered on an outage-by-outage basis under contracts with individual plants, which, however, "deterred long-term investment in skills, planning and equipment", according to Cavendish Nuclear.

The new contract will include 12-month equipment and resource plans for the fleet. This will lead to "optimisation of resource and reduction in re-work due to short timescale planning". It will also deliver "reduced overhead to cover planned work and emergent repairs, compared to managing multiple small complex contracts across the fleet".

AGR reactors feature a graphite moderator and are cooled using carbon dioxide. The graphite blocks cannot be replaced or repaired during the operating life of the reactors. However, radiation damage changes the shape and size of the crystallites that comprise graphite, a process known as dimensional change, which in turn degrades the mechanical properties of the graphite. For continued operation, it is therefore necessary to demonstrate that the graphite can still perform its intended role irrespective of the degradation.

Sue Walker, manager of EDF Energy's graphite team, said: "Establishing this long-term contract has secured a more efficient, sustainable, flexible and resilient service for graphite inspections across the AGR fleet. Long-term partnerships like this are an essential part of ensuring that EDF Energy's nuclear stations continue to provide secure, affordable low-carbon electricity for the UK."

EDF Energy operates 14 AGRs at six plant sites in the UK, which provide about 18% of the country's electricity.

Researched and written
by World Nuclear News