Power station considers dumping sediment off Portishead coastline

Bristol Channel.

Bristol Channel. - Credit: Pixabay

A nuclear power station is considering a Portishead site to deposit hundreds of thousands of tonnes of sediment as part of works taking place in the Bristol Channel. 

EDF Energy Hinkley Point C Power Station is due to resume its second phase of mud dredging later this year and wants to deposit the sediment as part of works to install cooling water intakes under the channel. 

Hinkley Point C is currently making applications to the Marine Management Organisation to commence dredging at either the Portishead licensed disposal site or at Natural Resources Wales for the Cardiff Grounds equivalent.  

Mud dredging first began at the Cardiff Grounds in September 2018 and either the site in Portishead or Cardiff will be used for the entirety of the disposal.  

The maximum volume of mud and sediment dredging being applied for is 469,000 cubic metres (m3). 

One of the dredging vessels used in 2018.

One of the dredging vessels used in 2018. - Credit: EDF Energy

Head of environment at Hinkley Point C, Chris Fayers, said the sediment is typical of any found elsewhere in the Bristol Channel and under UK law it is not radioactive.  

He said: “We are due to resume mud dredging in 2021 as part of works to install cooling water intakes in the Bristol Channel.  

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“The mud is no different from mud elsewhere in the area and comprehensive testing has shown that it poses no harm to people or the environment."

EDF says it has tested the mud ‘beyond internationally recognised best practice’, including tests for pure alpha-emitting particles and tritium - a rare and radioactive isotope of hydrogen. 

Applications will also include a full environmental impact assessment and the results and analysis of the company’s latest testing of the sediment. 

One of the dredging vessels used in 2018.

One of the dredging vessels used in 2018. - Credit: EDF Energy

EDF says the Bristol Channel has ‘very low levels’ of radioactivity identified in the sediment which are ‘predominantly naturally occurring’. 

However, marine pollution consultant Tim Deere-Jones says radioactivity attached to sediments suspended in the water column will ‘tend to’ deposit out in areas of fine sediment deposition along sheltered coastlines and in coastal and estuarine intertidal areas such as mudflats. 

The closest coastline is approximately 150m south of the Portishead disposal site and an EDF spokesman said sediment will move around the area as well as wash back in the with the tide. 

Portishead Town Council chairman, Paul Gardner, said EDF gave a presentation about the organisation's seabed sediment disposal at a town council meeting on January 20. 

He added: “The council feels it is important for EDF to keep the town informed about their plans and thank them for their co-operation thus far.” 

If the Portishead disposal site is chosen, dredging will only start if Hinkley Point C’s application is approved by the Marine Management Organisation.

It is due to make a decision after a compulsory six-week public consultation on the plans.

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