Consultation outcome

Summary of decision: Hinkley Point C water discharge activity permit variation: EPR/HP3228XT/V005

Updated 31 July 2023

Introduction

The Environment Agency is the independent environmental regulator for the nuclear industry in England. We make sure that nuclear power stations meet high standards of environmental protection.

Any company that wants to operate a nuclear power station must show that it can do the following safely and securely, while also protecting the environment:

• build, commission, operate and decommission the power station
• manage the wastes it produces

NNB Generation Company (Hinkley Point C) Limited applied to the Environment Agency to change its water discharge activity permit in December 2022.

The water discharge activity permit is a permit to discharge returned abstracted seawater from the cooling water system, fish recovery and return system, and other liquid trade effluents (including treated sewage effluent) to the Bristol Channel.

The application asked the Environment Agency to make these changes to the permit:

• remove all references to the acoustic fish deterrent (AFD)
• remove all references to the effects of abstracting cooling water because the Environment Agency does not regulate this from the open sea
• add the discharge of seawater and biomass from the fish recovery and return system

We consulted on the application from 24 January to 2 March 2023 and on our proposed decision and draft permit from 25 April to 25 May 2023.

We are grateful to everyone who took the time to respond to our consultation and attend our online consultation meetings.

We have assessed the permit application and considered the responses we received from both consultations. We have now made a final decision about whether we should grant the permit, and if so, what conditions it should include.

Our final decision is that we should grant the permit variation the operator has requested. We have added new limits and conditions in the permit to protect people and the environment.

This document covers the final stage of our process to determine the variation to the environmental permit application for water discharge activities at Hinkley C nuclear power station. It provides a summary of our decisions. You can find more detailed explanations in the decision document.

New nuclear power stations – the government’s view

Energy policy, including the use of nuclear power, is a matter for government. Government published an Energy white paper: Powering our net zero future in 2020 that set out the need for nuclear power, among other measures, to help the UK achieve net zero by 2050.

In 2022, the government published the British energy security strategy and, in 2023, its plan for implementing this strategy in the Powering up Britain documents. These confirm government’s aim for 24GWe (gigawatt electrical) of new nuclear to be deployed in the UK by 2050, providing about a quarter of our electricity demand.

To help achieve this aim government has created Great British Nuclear (GBN) to be the delivery body for new nuclear in the UK. GBN’s initial tasks are to develop a plan for the 2050 aim and to select the technologies to be deployed to enable two decisions (final investment decisions) on nuclear developments in the next parliament.

We have published our own plan, EA2025 creating a better place to guide our activities.

Our 5-year action plan (EA2025) sets out 3 goals:

• a nation resilient to climate change
• healthy air, land and water
• green growth and a sustainable future

We will continue to work with the government, regulatory partners, industry and others to enable nuclear energy production. Whilst doing this, we will make sure that people and the environment are properly protected. Nuclear is a low carbon energy source that could contribute significantly towards net zero goals and implementing the British energy security strategy.

Our processes align with the goals in EA2025 because they help make sure that nuclear power stations are designed and operated in ways which minimise waste, consider sustainability and protect the environment.

Regulating nuclear power stations

The process for assessing and permitting new nuclear power stations is normally split into 2 stages.

Generic Design Assessment

The first stage is the generic design assessment (GDA) , where we assess the environmental aspects of a power station design that would be relevant to any site. We carry out the GDA of a new design at the request of government. GDA allows us to begin scrutinising new nuclear power station designs well in advance of construction starting. This means that we can identify any potential design issues at an early stage and ask the applicant to address them. At the end of GDA, we provide a statement about the acceptability of the design.

We have previously carried out GDA on the design under construction at Hinkley Point C, known as EDF-Areva’s UK EPR.

Environmental permits

In order to build and operate a new power station at a specific site, a company must also apply for environmental permits from the Environment Agency. These permits cover:

• site investigation and preparation
• construction works and relevant ‘associated developments’ – such as workers’ accommodation
• operating and decommissioning the power station

In deciding whether to grant the permits, we will take into account matters relevant to the specific site as well as the GDA for the design proposed for the site.

We also work closely with the Office for Nuclear Regulation (ONR), which regulates the safety and security aspects of nuclear sites.

Read about our role as a regulator on nuclear sites.

About Hinkley

The Hinkley Point nuclear power stations are on the north Somerset coast. Hinkley Point A was Hinkley Point’s first nuclear power station. It operated from 1965 to 2000 and is being decommissioned.

Hinkley Point B began operation in 1976. It stopped generating electricity on 1 August 2022.

EDF’s company NNB Generation Company (Hinkley Point C) Ltd is building a new, twin reactor nuclear power station at the site. Operation of the first reactor is expected in 2027.

Read about our regulation of Hinkley Point C power station.

The image below shows an illustration of the Hinkley Point C development.

Image from NNB Generation Company (Hinkley Point C) Limited

The UK EPR design

There are various types of nuclear reactors around the world. One of the most common types is the pressurised water reactor (PWR), including the UK EPR. This design is currently under construction at Hinkley Point C in Somerset.

In the reactor core, some of the uranium atoms that make up the fuel split in a process called nuclear fission. These fissions produce heat in a continuous process called a chain reaction. The heat created by the nuclear fission is used to heat water inside the reactor, which is circulated by pumps in the primary circuit to a steam generator. In the steam generator, the very hot primary circuit water is used to heat water in the separate secondary circuit. This produces steam which is fed to a turbine. This makes the turbine spin and drives a generator that produces electricity.

This image shows a simplified schematic of the EPR reactor.

Image from NNB Generation Company (Hinkley Point C) Limited

For each reactor, the main nuclear support facilities include a water filled pool for storing used (spent) nuclear fuel and water treatment systems for maintaining the chemistry of the primary and secondary water circuits. There are also some facilities shared by the 2 reactors, including an interim spent fuel store and an intermediate level radioactive waste store.

There are 12 stand-by diesel generators that would provide power if there was a loss of electricity from the National Grid.

Find out more on EDF’s website.

The cooling water system

In UK nuclear power stations, seawater is usually used in the third water circuit to cool the condenser of the turbine, converting the steam of the secondary circuit back to water.

For Hinkley Point C, this will require a continuous supply of water taken from the Bristol Channel by 2 intake tunnels 3.3km offshore, one for each reactor unit. Each intake tunnel includes 2 low velocity side entry (LVSE) intake heads.

After being used within the plant, the seawater would then be discharged back to the Bristol Channel at a higher temperature through a single outfall cooling water tunnel (serving both reactor units), approximately 1.8km long.

A small proportion of the seawater will be discharged back to the Bristol Channel using a fish recovery and return system through a separate outfall tunnel, approximately 0.5km long.

The company has produced this diagram showing its proposal for a fish protection system.

Image from NNB Generation Company (Hinkley Point C) Limited

The cooling system is considered by these 3 regulators with different regulatory powers:

• Environment Agency in relation to the water discharge activity permit
• Secretary of State for Energy Security and Net Zero (formerly Business, Energy and Industrial Strategy) in relation to the Development Consent Order
• Marine Management Organisation in relation to the marine licence

The Environment Agency does not regulate the intake of cooling water from the sea at Hinkley Point C. This is because under the Water Resources Act you only need an abstraction licence to take water from lakes, rivers, estuaries or streams, or from groundwater. This intake is considered to be open sea.

The existing water discharge activity permit

The original water discharge activity permit application (in 2011) included an AFD in the design of the cooling water system. This uses sound to encourage fish to move away from the water intake, thereby aiming to reduce the number of fish which could be drawn into the pipe. The AFD was proposed as 1 of 3 fish protection mechanisms with a low velocity side intake and fish recovery and return system.

The original water discharge activity permit, granted in 2013, allows the cooling water system to operate as described in the application. We included conditions in that permit that required the operator to submit reports to the Environment Agency describing how its proposed AFD will operate and minimise any effects on fish.

The operator is now asking us to remove these conditions from the permit as it no longer proposes to use an AFD in the station design.  

There is a similar requirement in the Development Consent Order and in the marine licence, which were issued at the same time as the permit, for the AFD. We have concluded that the most appropriate way to regulate the cooling water intake is through the Development Consent Order. This decision was made in consultation with Natural England and the Marine Management Organisation, who agree with this approach.

When considering this permit variation application, we assessed the effects of removing the AFD on the:

• potential for water pollution
• habitat and species directly affected by the discharge from the fish recovery and return outfall

Our final decision

Our final decision is that we should grant the permit variation for the water discharge activity. The limits and conditions attached to the permit will make sure that people and the environment are protected from the water discharges under normal operation.

To reach our final decision, we have considered:

• the relevant legislation
• government policy and guidance
• our own guidance
• the relevant responses to our consultations on both the application and our proposed decision and draft permit

In reaching our decision, we completed these assessments and published the findings:

• Habitats Regulations assessment (HRA)
• Site of Special Scientific Interest (SSSI) assessment
• Water Framework Directive (WFD) compliance assessment

Assessing impacts on designated wildlife sites

Before making decisions about permit applications, we must carry out assessments to check whether the activities carried out under an environmental permit could have an effect on designated nature conservation sites. This includes carrying out an HRA on European designated sites and an assessment of operations that are likely to damage SSSIs.

Habitats Regulations assessment

An HRA is an assessment that we must carry out when we determine a permit application for an activity that could have a significant effect on a European designated site. The activity does not need to take place within a European designated site to have an effect, but there must be a link or pathway to a site, and the features within that site must be sensitive to the risks.

European designated sites include:

• Special Areas of Conservation (SAC) – designated for important high quality habitat sites and rare species
• Special Protection Areas (SPAs) – for the protection of rare and vulnerable birds
• Ramsar sites – for the protection of wetlands

Ramsar sites are wetlands of international importance designated under the Ramsar Convention, but it is government policy that they are given the same protection as SACs and SPAs.

The habitats and species protected by these European designated sites are collectively known as ‘designated features’.

The assessment must be carried out alone or in combination with other permissions, plans and projects on the designated features of the sites.

SSSI assessment

An SSSI assessment is a test that we must carry out when we determine a permit application to assess if an activity is likely to damage a site’s features.

SSSIs are the finest sites for wildlife and natural features in England, supporting many rare and endangered species, habitats and natural features.

What we looked at in our ecological assessments

We considered the likely effect of dead and damaged fish and invertebrates (collectively referred to as a biomass) being discharged from the fish recovery and return system outlet on both ecology and water quality. This includes:

• any potential smothering effects from this biomass on species and habitats
• changes to water quality from the release of chemicals and nutrients from the decay of this biomass
• the subsequent effect this change in water quality may have on species and habitats
• any habitat loss or change in local species composition from these potential effects

We only considered this discharge as it is the only one that would be affected by this permit variation for a water discharge activity. For our HRA, we assessed all these potential risks on their own and combined with the risks from other ongoing activities and planned projects in the area.

The following European designated sites were identified as having the potential to be adversely affected by the risks set out above:

• Severn Estuary SAC
• Severn Estuary SPA
• Severn Estuary Ramsar
• River Usk SAC
• River Wye SAC
• Somerset Levels and Moors SPA
• Somerset Levels and Moors Ramsar
• Bristol Channel Approaches SAC

The potential risk would be from toxic contamination, nutrient enrichment and smothering from the release of dead and damaged fish and invertebrates, with the potential to also cause habitat loss and changes in community composition.

Our HRA demonstrates that the release of dead and damaged fish and invertebrates from the fish recovery and return system will not result in an adverse effect on the integrity of the European designated sites.

SSSIs

The following 8 SSSIs were identified as being potentially at risk from the fish recovery and return system discharge from Hinkley Point C:

• Bridgwater Bay SSSI
• Blue Anchor to Lilstock Coast SSSI
• Steep Holm SSSI
• Brean Down SSSI
• Severn Estuary SSSI
• Flat Holm SSSI
• River Usk SSSI
• River Wye SSSI

The potential risk would be from toxic contamination, nutrient enrichment and smothering from the release of dead and damaged fish and invertebrates, with the potential to cause habitat loss and change in community composition.

Our SSSI assessment demonstrates that the release of dead and damaged fish and invertebrates from the fish recovery and return system will not result in the condition of the sites deteriorating, nor will it prevent them from improving or recovering where necessary.

Complying with the Water Framework Directive (WFD)

When we assessed the risk of pollution from dead and damaged fish and invertebrates, we found that the water quality changes would not compromise water body environmental objectives. We looked at how the discharges might affect the environment, together with the available data on other activities, and found no case for significant effects.

We therefore propose that there is minimal risk of these water bodies being unable to meet their environmental objectives because of these discharges.

The final permit with its conditions and limits

This section provides information about what the final permit variation allows, and any changes to limits and conditions.

The original permit, which is subject to this variation, regulated the operational water discharge activities from Hinkley Point C – they are discharges of these non-radioactive liquid effluents:

• returned cooling water from the turbine condensers
• trade process effluents from the various plant systems (including those that maintain water purity and chemistry to keep the best operating conditions and maximise efficiency)
• treated sewage effluent (from staff welfare facilities)

The final varied permit will also now regulate the discharge of seawater through a fish recovery and return system.

As a result of our assessment on the impact of the fish recovery and return system discharge, we have included limits on volume, rate and the total biomass discharged from the fish recovery and return system outlet.

We have removed all conditions (or parts of conditions) relating to the AFD.

We have concluded that there would be no adverse effect on the integrity of the relevant European designated sites (in relation to pollution from regulated discharges to waters) if there is no AFD in place. This includes those sites functionally linked to the Severn Estuary. The discharges will not result in the condition of relevant SSSIs deteriorating or prevent them from improving or recovering.

We have also concluded that the permit variation will not cause the current status of the water bodies to deteriorate or prevent them from achieving their objectives.

The final varied permit includes the requirement to use an additional operating technique and an improvement condition. It also includes 2 pre-operational conditions which need Environment Agency approval before the proposed power station can be commissioned or begin to operate. These are included to make sure that NNB Generation Company (Hinkley Point C) Limited builds and operates the proposed power station according to the commitments made in its permit variation application.

Our consultations

We aim to build and maintain confidence in our decision-making processes through our public engagement and consultation. It is our responsibility to make decisions about the environmental permit applications for Hinkley Point C, but we consider that our decisions are better informed through consultation.

We can all help to protect and improve the environment by being actively involved. Our public participation statement shows how our process is open, transparent and consultative. We would like people to understand our role, what we are doing and why it’s important.

When we consulted, we explained that the consultations were not about the need for nuclear power, UK energy policy or policy relating to the siting of nuclear power stations.

During the consultations we shared information with people, explained our proposed decision and considered the feedback we received.

We emphasised that we would not make any final decision until we had considered all relevant responses to the consultation.

Our approach to consultation is in line with the government’s published consultation principles and our public participation statement.

Our consultations were open to everyone and, in particular, we invited the following groups to take part:

• the public (including local interest and action groups) in west Somerset and south Wales near to the Hinkley site
• elected representatives, including local councillors and MPs
• angling and environmental groups
• academics, scientists and consultants with an interest in nuclear power, energy or the environment
• non-governmental organisations (NGOs) and campaign groups
• other organisations and public bodies

We publicly consulted on:

• NNB Generation Company (Hinkley Point C) Limited’s application to change the water discharge activity permit from 24 January to 2 March 2023
• our proposed decision and draft permit from 25 April to 25 May 2023

For our consultation on the permit applications, we received 50 consultation responses from members of the public, local councils, environmental groups, public bodies and departments, and other interested parties. All responses to this consultation (if the respondent gave permission) are published on the application consultation website.

For our consultation on the proposed decision and draft permit, we received 193 consultation responses. These were from members of the public, environmental groups, local councils and other interested parties. All responses to this consultation (if the respondent gave permission) are published on the proposed decision consultation website.

Information about which organisations responded and how we considered all relevant issues raised is included in our final decision document.

We used the relevant responses to help inform our decision on whether to grant the permit variation and what conditions it should include. We are grateful to everyone who took the time to respond to our consultations and attend our consultation events.

You can find more detailed information about our consultation activities in the document ‘Summary of our consultation activities’.

Evaluating our consultations helps us to learn lessons and share our experiences with others. We will use the findings from these evaluations to improve our work on future nuclear projects and other relevant consultations that we carry out.

Publishing our final decision

You can read a detailed explanation of our decision in our decision document. It explains how we have considered the permit application and the relevant consultation responses, and why we have included the specific conditions in the permit we are issuing. It is our record of our decision-making process, to show how we have considered all relevant factors in reaching our decision.

You can find our decision document on GOV.UK and the Environment Agency’s consultation website.

We have published the following documents:

• permit for water discharge activity
• decision document for water discharge activity

We have republished the following documents:

• Habitats Regulations assessment report
• SSSI assessment report
• WFD compliance assessment report

Next steps

Future opportunities to have your say

It is likely that there will be further opportunities to input into our decision-making for other environmental permits for this site.

NNB Generation Company (Hinkley Point C) Limited could apply for a range of environmental permits relating to site investigation, construction works and for relevant ‘associated developments’ such as workers’ accommodation.

Where appropriate, we will consult on the applications for these permits. We will make our decision once we have considered the comments we receive in the consultation. Construction activities are not unique to nuclear developments and are time limited, so we will deal with these permit applications as we would for other types of construction sites. This is a proportionate approach that will help us exercise the best regulatory control on rapidly changing construction activities.

We may also receive further applications for changes (variations) to the 3 operational permits and for other environmental permits related to work at the site. Where appropriate, we will consult on these.

Future engagement

We will continue our programme of communications and stakeholder engagement for Hinkley Point C and other nuclear developments and projects. This includes holding events with communities and stakeholders.

Find out more about our work at Hinkley Point C.

Read our Hinkley engagement plan.

Contact us

You can feed back on this document or our work in regulating Hinkley Point C. Email your questions and comments to nuclear@environment-agency.gov.uk.