FUNDAMENTAL SAFETY OVERVIEW VOLUME 3: ENVIRONMENTAL IMPACT CHAPTER C: GENERIC SITE DESCRIPTION

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1 : GENERIC SITE DESCRIPTION PAGE : 1 / 10 PART C GENERIC SITE DESCRIPTION 1. INTRODUCTION The requirements for building a new reactor are dictated by both technical and environmental characteristics. A detailed assessment will be completed for the selected UK site prior to construction. A generic site envelope which should encompass a specific site for the construction of an European Light Water Pressurised Reactor (EPR) in the UK was discussed in Volume 1. The generic site envelope determined was based on the requirements set up by the European Utility Requirements for LWR nuclear power plants (EUR) which formed the basis for the Flamanville EPR (Flamanville 3) design, and, more specifically, the site parameters and conditions assumed for the Flamanville 3 plant, obtained from the public version of the Flamanville 3 Preliminary Safety Analysis Report. It includes requirements on: Heat sink Grid connection Demography and siting criteria Malicious activity External hazards, including: natural and manmade external hazards; seismic; flooding; meteorological; biological and geological. This section develops the characteristics of a generic site which need to be considered when assessing environmental impact of a reactor design. This will only be used for initial submission and the site specific assessment in a number of areas will be required at a later stage. The areas developed in this document are as follows: reference state of the marine ecosystem, reference state of the terrestrial ecosystem, landscape and demographics. The reference states for both the marine and terrestrial ecosystems were defined for the Flamanville site, and therefore similar observations will need to be made in the UK after the decision is made on the location of the UK EPR.

2 : GENERIC SITE DESCRIPTION PAGE : 2 / MARINE SITE ENVELOPE REQUIREMENTS 2.1. MARINE HYDROLOGY Marine hydrology will involve site specific studies on tidal level bathymetry, currents, swell and sedimentology. The generic site envelope as developed in Volume 1 has not established site requirements for any of the above topics and therefore site specific assessments will be required at a later stage. This is in particular to comply with the UK requirement of 1 in 10,000 year external flood protection, as discussed in the European Utility Requirements for LWR nuclear power plants. However, in order to address potential tidal effects on flooding, the generic site envelope specifies the maximum and minimum still seawater levels at the site during specified return periods for nonsafety and safety functions, including a margin for a storm surgeinduced wave levels. In the case of the Flamanville site, average tide levels including average spring and neaptides levels have been considered, along with exceptional spring tide levels, for both high and low water conditions. A similar approach will be undertaken in the UK on a site specific basis. For the study of currents, swell and sedimentology, models following the methodology used at Flamanville will be developed for the site specific assessment MARINE PHYSICALCHEMISTRY Although only briefly mentioned in the generic site envelope, the marine physicalchemical reference status has been studied over a period of time at Flamanville. Monthly readings of salinity, ammonium, nitrate and nitrite concentrations, phosphates, silicates and, more recently, suspended matter, trihalomethanes and boron have been recorded. Although no specific requirement has been detailed in the site generic envelope for these parameters, similar data will be obtained for the selected UK site and modelling of the physicalchemical environment, including temporal and spatial variations of coastal deep sea gradient, may be completed if necessary. The only requirement described in the site generic envelope regarding the physicalchemical environment of a UK site concerns sea water temperature, and is linked to the temperature of cooling waters. The water temperature envelope defined for the design of newbuild light water reactor (LWR) ranges from 0.5 C for seawater cooling (0 C if cooling is derived from rivers or cooling towers) to 30 C. These temperatures are met at most UK sites. No requirements concerning potential impacts of the EPR on marine physicalchemistry have been developed in the site generic envelope. However, sitespecific data, including temporal and spatial variations will need to be collected in order to assess the impact of the EPR on sea water temperatures. A similar approach to the Flamanville study will be adopted including thermal modelling using TELEMAC 3D (computer software 3D modelling) or similar Environment Agency Approved model.

3 : GENERIC SITE DESCRIPTION PAGE : 3 / MARINE BIOLOGY The generic site envelope considers biological fouling risk. Specifically this concerns the potential for cooling water intakes to become completely or partially blocked by debris or marine organisms (fish, jellyfish, algae, seaweed or other marine growth). Another possible concern is the loss of equipment performance due to oil or other suspensions/emulsions entering the cooling water system, for example from oil spills. At Flamanville, ecological monitoring studies of the marine environment have included studies of phytoplankton, zooplankton, microbiology, and the benthic and halieutic (species of commercial interest) environments. Assessment of marine transport of hazardous materials (i.e. crude oil) has also been undertaken. These areas will be addressed on a site specific basis for the designated UK site, following a similar approach to the one developed at Flamanville, and impact of the construction of EPR on marine ecosystems will also be assessed MARINE RADIOECOLOGY No specific requirements for marine radioecology assessment have been developed for the site generic envelope. However, it is expected that sampling will be carried out for sediments, seaweed, molluscs and fish, in order to assess the occurrence of natural and artificial radionuclides in the locality and to determine baseline conditions of the site prior to construction of EPR. A similar approach to the one developed at Flamanville will be adopted, involving recording the levels of activity at selected locations and over a period of one year prior to construction of the new reactor. Monitoring of these sampling points will also be carried out throughout the construction phase, as well as after commissioning of the reactor ENVIRONMENTAL CHANGES / FLOODING AND EROSION The EPR design process includes facilities to adapt the design for possible realistic climate developments that are larger than those initially planned'. These developments include increases in ambient temperatures and sea water levels although, in general, margins of safety will have been built in at the preliminary design stage. The nuclear island of Flamanville site is located at 12.4 m above the French sealevel reference (NGF), compared with the maximum design flood level of 7.79 m NGF. In the UK, especially for coastal sites, flooding, due to sea level rise and coastal erosion, may be a potential problem and therefore further site specific assessments will be required.

4 : GENERIC SITE DESCRIPTION PAGE : 4 / TERRESTRIAL SITE ENVELOPE REQUIREMENTS 3.1. SEISMIC AND LIQUEFACTION It has been determined in Volume 1 that the ground conditions in the UK generic site envelope can be defined as hard, medium or soft. Three different types of soils are associated with each of the three ground conditions, typically giving a combination of nine sets of soil properties. For the construction of the EPR, only six soil conditions have been assessed. These include one soft, three medium and two hard site conditions. The typical values for a hard generic site are as follows: Shear Modulus: 20 GPa Density: 2700 kg/m 3 Poisson's Ratio: 0.23 Assumed damping: (as EPR condition for building BLNC [EF}) Young's Modulus: 70 GPa. Outside of this envelope, site specific data will need to be collected in order to obtain additional seismic analysis. In addition, and in the case of the seismic design assessment of EPR, liquefaction would need to be considered for any site defined as soft according to the European Utility Requirements (EUR) specification. Liquefaction is a phenomenon encountered at soft sites, when watersaturated soil can rearrange itself under the influence of repeated shock of earthquake waves. Flamanville has been identified as a hard site and therefore liquefaction is not a significant issue. However, extensive sitespecific studies have been carried out in order to determine the seismological characteristics of the site, and similar studies will be carried out at the UK EPR location to assess the impact of earthquake potential TOPOGRAPHY AND GEOLOGY / HYDROGEOLOGY Local topography plays an important part in the choice of the location for a new reactor. At Flamanville, the general location and local topography have been studied, along with the terrestrial and submarine geology. The Flamanville granite and Diélette synclinorium (rock at Flamanville site) in particular have been studied in order to determine the general geological structure, faults and fracturing and chemical and physical weathering. Although geological conditions play an important part in nuclear site design, no specific criteria have been set for the geological conditions of a potential nuclear site in the generic site envelope, apart from the fact that foundation conditions applicable to the site shall be investigated and analysed at the site specific design stage. Similarly, the envelope requires that hydrogeological data shall be taken into consideration.

5 : GENERIC SITE DESCRIPTION PAGE : 5 / 10 At a site specific assessment stage, detailed study of the site geology will be carried out, as has been the case at Flamanville, and the impact of the layout of the site and potential future effects of the geology on the stability of the site will be assessed. The hydrogeological context of the Flamanville site has also been extensively studied, and potential effects on the foundation integrity have been assessed. A similar sitespecific approach will be used for the UK EPR location HYDROLOGY At Flamanville, extensive studies of the hydrology of the site have been carried out. As the study of the hydrographic network and conditions is very sitespecific, the site generic envelope does not include a designated hydrological element. However, the hydrologic context, and in particular the hydrographic network will be studied on a sitespecific basis for the designated UK site. This will also be the case for existing water use, whether it is for human consumption, irrigation water or for industrial use CLIMATE Climate may influence design with respect to the potential effects that flooding or extreme rainfall, high winds or snow storms could have on the EPR reactor. The site generic envelope as presented in Volume 1 developed a number of climatic criteria for the potential EPR site, including: Rainfall: a designbasis maximum rainfall of 100 mm in one hour, and of 400 mm in 24 hours at the site; Wind speed: basic wind speed of 43 m/s and an extreme wind speed of 70 m/s, assumed to occur 10 m above ground level; Air temperatures: ambient air temperatures (recorded at distance between 2 and 4 m above ground surface) shall be in the range of 25ºC to 32 ºC for an extended period (over seven days), 30ºC to 37ºC for a short term period (between six hours and seven days), and 35ºC to 42ºC for up to six hours (extreme temperature period). The UK requirement to design against a 1 in 10,000 year extreme temperature event will require sitespecific assessment; Lightning: electrical equipment shall include protection against surges resulting from lightning strikes on electrical transmission lines (First stroke: 200 ka; 10/350 µs; Second stroke: 50 ka; 0.25/100 µs, consistent with EU standard EN V 61024); Snow fall: building design shall consider a level of snow loading of 0.9 kn/m 2, which should be increased by 0.75 kn/m 2 if manaccess is possible, but no requirements are given in the site generic envelope regarding volume or depth of snow which may accumulate on site; Humidity: maximum external relative humidity of 60% at 37ºC in summer and of 100% at 25ºC in winter is required. No requirements on ground temperatures (temperatures recorded close to the ground surface, as opposed to air temperatures) or drought conditions are specified in the site generic envelope, and therefore site specific assessment will be carried out for these criteria.

6 : GENERIC SITE DESCRIPTION PAGE : 6 / 10 Extensive site and regionspecific studies have been carried out at Flamanville for a number of years, recording direction and characterisation of winds, air temperature, precipitation, air humidity, sunshine and snow/frost/fog, to demonstrate compliance with the site generic requirements. A similar approach will be required at the UK location AIR QUALITY Requirements on air quality have not been addressed in the generic site envelope, however, a sitespecific air quality reference report is required before, during and after construction of the new reactor, in order to assess the potential impact of the EPR on local air quality (see Volume III Chapter D for the impact assessment). At Flamanville, the regional monitoring station, located about 20 km away from the site, records daily levels of air pollutants such as carbon monoxide, nitrogen monoxide and dioxide, sulphur dioxide, ozone and suspended particulates. Levels of a number of radioactive elements such as tritium, carbon 14, iodine, noble gases and artificial alpha, beta and gamma emitters are also monitored, and will need to be monitored at the UK location. A similar approach will be used in the UK on a sitespecific basis in order to comply with the requirements needed for the environmental impact assessment as described Volume 3 Section D NOISE Again, no requirements on noise have been addressed in the site generic envelope. However, a sitespecific noise reference state will need to be established before and during the construction of a new reactor. At Flamanville, the noise reference state relates to measurements of residual noise and noise emissions in a 2 kmradius perimeter around the site. At the chosen UK location, similar studies will be carried out in order to assess the potential impact of the new plant on the noise environment (see Volume 3 Section D for the specific noise impact assessment) TERRESTRIAL ECOLOGY The generic site envelope considers biological fouling risk as main potential biological risk to the EPR, but does not include an envelope for terrestrial ecology. Therefore, site specific assessment will be undertaken. At Flamanville, ecological monitoring studies in a perimeter of 5 km around the site have included studies of flora (specifically coastal cliff vegetation, dune vegetation, cultivated land, forested land, countryside with small fields and hedges, and meadows), and fauna (specifically, amphibians and reptiles, birds, and land and marine mammals). Due to the sitespecific character of ecological impacts, they will be addressed on a site specific basis for the designated UK site, following a similar approach to the one developed at Flamanville.

7 : GENERIC SITE DESCRIPTION PAGE : 7 / TERRESTRIAL RADIOECOLOGY No specific requirements on terrestrial radioecology have been developed in the site generic envelope. However, it is expected that analysis of samples collected in the terrestrial environment of the chosen UK site will be carried out in order to assess the occurrence of natural and artificial radionuclides in the locality of the site prior to construction. A similar approach to the one used at Flamanville will be developed, involving records of levels of activity at a number of locations and over a period of one year prior to construction of the new reactor. Monitoring of these sampling points will also be carried out throughout the construction phase, as well as after commissioning of the reactor. At Flamanville, the measurements conducted within the French regulatory framework do not specifically identify radionuclides present, but rather give an indication of the global activity of a certain type of emitter (i.e. alpha, beta or gamma emitter). The environmental compartments monitoring are ambient air, aerosols, rainwater, milk and vegetation. The periodicity of these measurements permits the detection of operating anomalies over the short term, thus performing a control and alert function. A similar approach will be undertaken at the designated UK site.

8 : GENERIC SITE DESCRIPTION PAGE : 8 / LANDSCAPE/VISUAL IMPACT AND SOCIOECONOMICS SITE ENVELOPE REQUIREMENTS 4.1. LANDSCAPE AND VISUAL IMPACT There is no generic site envelope for landscape and visual impact as these are very sitespecific and will require detailed assessment at a later stage DEMOGRAPHICS The site generic envelope only addresses requirements on demography. As developed in Volume 1, demographic constraints on plant siting are derived from national regulations. In the UK, the current requirements on demography are given by the 2006 edition of the HSE's Safety Assessment Principles. This document notes that siting policy '... includes the consideration of demographics to constrain the number of people who might be affected in the event of an emergency'. The most recent demographic criteria for the UK were published in 1988, and set out cumulative population limits for distance radii around power station sites and in any 30 degree sector. Different criteria were applied for Magnox power stations which, for the most part, had steel pressure vessels, and for the advanced gas reactora (AGR) which have reinforced concrete pressure vessels. However, it is not possible to determine whether future siting criteria will follow the Magnox or the AGR criteria. Although the EPR has a steel pressure vessel, it is located inside a doublewalled concrete containment building and might therefore be considered as equivalent to an AGR (until new regulations provide clarification later in 2007). The different population criteria for both AGR and Magnox power stations have been given Volume 1, and have been reproduced in Table C.4a. Distance from site (km) Cumulative population (Magnox) Cumulative population (AGR) Population around site in all directions Population in 30 degree sector Table C.4a: Limiting population criteria (1988)

9 : GENERIC SITE DESCRIPTION PAGE : 9 / 10 Until new regulations are in force, the limiting population criteria are assured to be those displayed in Table C.4a. Therefore, the demographic requirements of the site generic envelope for the construction of an EPR need to comply with these values. Site specific assessment will consequently be needed in order to demonstrate compliance with the regulations HEALTH IMPACTS The generic site envelope defined for radiological health impacts under normal operating conditions is set by the Basic Safety Standards (BSS) Directive, 96/29/Euratom, as implemented in the UK via The Radioactive Substances (Basic Safety Standards) (England and Wales) Direction This sets the following limits: All public radiation exposures from radioactive waste disposal are kept as low as reasonably achievable (ALARA); The sum of such exposures does not exceed the dose limit of 1 msv/y; The dose received from any new source does not exceed 0.3 msv/y; The dose received from any single site does not exceed 0.5 msv/y. Concerning the impacts of nonradiological emissions, the World Health Organisation (WHO) limit is 1 x 10 5 for liquids and gaseous emissions. In order to comply with these regulations and assess the radiological and nonradiological health impact, studies have been carried out at the Flamanville site, including surveys on population, tourism, schools, agriculture, fishing (both professional and amateur), hunting and leisure activities, and the diet of the local population. The health impact assessment, both radiological and non radiological, is dealt with in more detail in Volume 3 Chapter D. In the UK, similar sitespecific studies will be undertaken once the location of the UK EPR has been determined. Assessment of the impact of the construction and commissioning of the EPR on local permanent and visiting population as well as on both the marine and terrestrial ecosystems will be carried out.

10 : GENERIC SITE DESCRIPTION PAGE : 10 / CONCLUSION A number of criteria have been established in order to produce a generic envelope setting the requirements for the site prior to the construction of a new EPR in the UK. These include requirements on: marine hydrology and physicalchemistry, flooding and erosion, seismic and geology, climate and demography. There are also a number of aspects, such as radioecology, both on a marine and terrestrial ecology, air quality, noise, landscape, health impact etc, which are very sitespecific in nature and can only be addressed on a sitespecific basis. Therefore, further impact assessment will be required at a later stage in order to address these issues once the location for the EPR has been identified.