100232385 Revision 02

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Sizewell C Project

Water Discharge Activity Permit Application Submission Sizewell C

UNCONTROLLED WHEN PRINTED NOT PROTECTIVELY MARKED WATER DISCHARGE ACTIVITY PERMIT APPLICATION 100232385 SUBMISSION SIZEWELL C Revision 02 NON-TECHNICAL SUMMARY NOT PROTECTIVELY MARKED

Non-Technical Summary

Purpose of this report

This report supports the application for a water discharge activity environmental permit associated with a new nuclear power station to be situated directly to the north of the existing Sizewell B power station. The new power station will be referred to as Sizewell C. The power station will typically discharge 132m3/s of cooling water to the Greater Sizewell Bay (GSB) and requires an environmental permit under the Environmental Permitting Regulations [1]. Discharges from other processes and facilities at Sizewell C will be disposed of with the cooling water. The Operator of the water discharge activity will be NNB Generation Company (SZC) Limited, hereafter referred to as SZC Co., which is a wholly owned subsidiary of NNB Holding Company (SZC) Limited which in turn is 80% owned by EDF Energy Holdings Limited and 20% owned by General Nuclear International Limited.

This submission presents details of the source of emissions, anticipated discharges and potential impacts on the environment. It demonstrates environmental optimisation of the design through the implementation of good practices to ensure an appropriate balance between costs to the operator and benefits to the environment. It also describes the commitments to implement Best Available Techniques (BAT), where appropriate, and good practices in areas where information and approach is yet to be fully developed. A Forward Action Plan (FAP) is proposed in Section 7 to address these areas as the overall programme of work progresses and delivers more detailed information.

The scope of this submission relates to discharges from the cooling water system and its associated effluent streams during the hot functional testing phase of commissioning and the subsequent operation of Sizewell C. Activities related to construction and initial cold flush testing will be the subject of a separate environmental permit application. Proposed activities

Each of the two UK European Pressurised Reactors (EPRTM) units proposed for Sizewell C will require large volumes of cooling water to condense steam used in the turbines that generate electricity for export to the National Grid. This cooling water will be drawn from the GSB, passed through the condensers and then returned to the GSB approximately 3km out to sea from the site. In addition to the cooling water discharge, trade effluents will be produced as a result of normal operation of Sizewell C (e.g. process effluents and sanitary effluents). The volume and characteristics of the discharge will depend on the operational state of the each of the UK EPRTM units. Normal operation includes the scenarios described below, which are routine and anticipated:

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WATER DISCHARGE ACTIVITY PERMIT APPLICATION 100232385 SUBMISSION SIZEWELL C Revision 02 NON-TECHNICAL SUMMARY NOT PROTECTIVELY MARKED

• Standard Operation. Electricity generation based on nuclear fission with both of the UK EPRTM units operating at their full capacity with power changes in line with operational requirements;

• Outage. One reactor on outage and not operating due to scheduled maintenance activities and refuelling.

• Maintenance. Includes planned outages of a circulating water system [CRF] pump for maintenance with both reactors continuing to operate. Emissions and monitoring

Emissions

The main potential impacts on the environment from discharge of the cooling water are associated with thermal load and chlorination for biofouling control. When the reactors are operating at full pow