OPERATORS at Hinkley Point C have decided to carry out a full environmental impact assessment (EIA) as part of its licence application to dispose of mud dredged in the Bristol Channel for a second time.

The decision has been taken following heavy pressure from politicians and campaign groups who believe the sediment disposed in 2018 at the Cardiff Grounds was contaminated and dangerous.

EDF Energy wants to again deposit up to 780,000 tonnes of sediment dredged as part of building work for the Hinkley Point C plant.

Hinkley Point C says this time it has decided to carry out the EIA to provide "reassurance for the public".

Why has it caused controversy?

The seabed alongside Hinkley Point C is being dredged so that the power station's water cooling system can be installed.

EDF Energy, which operates the plant, says this will involve tunnelling more than 3km into the Bristol Channel.

But many campaigners are worried this could be churning up contamination from the old Hinkley A and B reactors, which used to be on the site.

EDF says previous testing has shown the mud is no different to mud found elsewhere in the Bristol Channel, and is not classed as radioactive under UK law.

What is happening now?

A licence is required for the planned second phase of dredging off in 2021 at the Somerset site and disposal of mud at the Cardiff Grounds disposal site.

Further dredging is needed before placing of the Low Velocity Intake Heads, drilling of shafts for the cooling water system, the installation of a fish recovery and return system and maintenance dredging at the jetty.

The plant has commissioned CEFAS, the UK Government's marine science experts, to undertake analysis on further sediment samples following approval of the sampling plan, which was subject to a six-week public consultation process in the spring.

What have Hinkley Point C said?

Chris Fayers, head of environment at Hinkley Point C, said: "For this second phase of dredging, we intend to go further than normal regulatory requirements in order to provide the public with additional reassurance.

"We have proposed a testing plan that goes above and beyond internationally recognised best practice, with more samples at greater depth and with a greater range of analysis - including tests for pure alpha emitting particles and tritium. 

"We also intend to conduct a full Environmental Impact Assessment as part of our disposal licence application. We believe it is right to go beyond technical arguments to provide the necessary public confidence that all concerns have been addressed." 

No dredging activity is planned until 2021, which will require approval of the testing plan, analysis of the results, an application being made, and a licence issued.