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United Kingdom Atomic Energy Authority

Culham Science Centre - Phase 1 Ground Condition and Contamination Review

53526-00

Issue 2 | 3 December 2012

This report takes into account the particular instructions and requirements of our client.

It is not intended for and should not be relied upon by any third party and no responsibility is undertaken to any third party.

Job number 53526-00

Ove Arup & Partners Ltd 13 Fitzroy Street London W1T 4BQ United Kingdom www.arup.com

53526-00 | Issue 2 | 3 December 2012

R:\CORRESPONDENCE\PLANNING\CULHAM, CULHAM SCIENCE CENTRE\REDEVELOPMENT PHASE 1\APPLICATION DOCUMENTS DEC 2012\GROUND CONDITIONS DEC 12.DOCX

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Job number Job title Culham Science Centre - Phase 1

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Revision Date Filename Ground Conditions and Contamination Review

Description Issue 1 - Issue as part of the outline planning application

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Filename Ground Conditions and Contamination Review Description Issue 2 – Update to planning guidance


NameLouise Taffel-Andureau

Richard Owen Mike Carter

Issue 2 3 Dec 2012

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Appendix C - page 1

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Appendix C

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United Kingdom Atomic Energy Authority Culham Science Centre - Phase 1 Ground Condition and Contamination Review

53526-00 | Issue 2 | 3 December 2012


Contents

Page

1 Introduction 1

2 Geology 2

3 Site History and Potential for Contamination 2

3.1 Former WW2 Airfield Use 23.2 Culham West and JET Site 3

4 Contamination Ground Investigations 3

4.1 Scope of Investigations 34.2 Results of Investigation 44.3 Investigation Recommendations 4

5 Remediation Works 4

6 Conclusion 5

United Kingdom Atomic Energy Authority Culham Science Centre - Phase 1Ground Condition and Contamination Review

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1 Introduction

This report has been compiled to provide detail of the ground condition of the Phase 1 development plot and also considers any issues associated with any potential contamination of the plot. The report summarises a desk top study review carried out on behalf of the United Kingdom Atomic Energy Authority (UKAEA) for the Culham Science Centre.

The UKAEA previously commissioned several desk studies and carried out soil sampling investigations and contamination remediation works at the Culham Science Centre site over the period 2002 to 2005.

The desk studies and investigations were undertaken to research the site’s history of potentially contaminated uses, to evaluate potential contaminated land liabilities, and to assess the site’s suitability for redevelopment. The following reports were produced and have been reviewed by Arup.

Report Title Author Date1 The History of the

Culham Site, 1944-2002UKAEA FusionDecommissioning Group 18 September

2002

2 The Geological andHydrogeological Environment of theCulham Site

SERCO AssuranceJDEC 131T(03)5371

May 2003

3 Historic Spills Report UKAEA FusionDecommissioning Group 24 November

2003

4 Results of the PreliminarySite Investigation, Invasive Soil sampling Programme

JDEC 131R(05)5767

February 2005

5 Remediation Survey ofthe Contractor’s CabinArea - JET

Jill Gardiner,Environment Section August 2005

An overview of all data reviewed as part of the desk study is included for information, even where the areas are clearly not directly linked to the Phase 1 area. Detailed summaries of each of the 5 No reports are also appended to this report.

All of the reports noted above were carried out in relation to the entire Culham Science Centre site and the extent of the site where trial pits and sample points were located is appended to this report for reference. It should be noted that all trial pit and sample point locations occur outside of the proposed Phase 1 development land. This is due to the proposed Phase 1 area lying outside of the parts of the Culham Science Centre that have been used both historically as a WW2 airfield and currently for research activities.

Appendix C - page 2


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The Culham Science Centre Phase 1 development site currently comprises predominantly of grassed recreation area.

2 Geology

The geology at the UKAEA Culham Science Centre site, based on published geological maps and the results of borehole investigations in 1959 and 1978, is as follows, from ground surface downwards:

River Terrace Deposits (RTD), which comprise sand, gravel, silt and clay, occur across most of the site. These are typically 1.5m to 4m thick, but were found to be up to 9m thick.

Lower Greensand, which comprises beds of red sand, with rounded quartz gravel and clay. This stratum was found to be typically 1m to 6m thick.

Kimmeridge Clay, which comprises grey mudstones and siltstones. This stratum was 41.6m thick where fully penetrated by a borehole.

Corallian Beds, which comprise limestone, sandstone with coral rock, siltstone, clays. These beds occur at approximately 50m depth below ground level (10m AOD).

The RTD and Lower Greensand are considered as a combined ‘near-surface aquifer’. The Kimmeridge Clay is a non-aquifer and the Corallian Beds are a confined aquifer with a potentiometric surface at approximately 50m AOD.

The groundwater depths in the near-surface aquifer, measured in 1978, were in the range of 0.6m to 1.7m below ground level. Groundwater flow across the site in the near-surface aquifer has been interpreted as towards the south-east. This flow will discharge to surface water ditches or be part of the base flow to the River Thames. It was assessed that there is an upward flux of groundwater from the Corallian Beds through the Kimmeridge Clay as a result of the artesian pressures in the lower deposit.

3 Site History and Potential for Contamination

3.1 Former WW2 Airfield UseThe UKAEA Culham Science Centre site was agricultural land until it was requisitioned, together with some additional land beyond the UKAEA property boundary, by the Admiralty in 1942. A World War II airfield (HMS Hornbill) was then constructed on the site and became operational in 1944. The airfield comprised three runways, a perimeter taxiway, associated airfield buildings, and support facilities beyond the perimeter taxiway. The layout of the WW2 airfield is illustrated on Figure 1. The original WW2 runways and taxiways are now largely evident as existing roads at the Culham Science Centre (see Figure 2). The limits of the Culham Science Centre site are the same as the original WW2 perimeter taxiway.

It is assessed as unlikely that there is any significant contamination of the ground or groundwater at the Culham Science Centre site arising from its former airfield


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use. There was no aviation fuel storage, maintenance or other such activities carried out within the limits of the site and although there were a few incidents involving aircraft crash landings, these are very unlikely to have resulted in any significant metal, hydrocarbon or radon contamination. Localised contamination from spilt fuels and oils are possible, as well as residual asbestos fragments.

3.2 Culham West and JET Site The construction of the Culham laboratory buildings began in 1960 and the site was developed through the 1960s and 1970s carrying out research into fusion physics, notably controlled thermonuclear research, plasma wave studies and plasma fusion. In 1979, it was recognised as an ideal location for the Joint European Torus (JET) project.

The activities carried out on Culham West and the JET site, potential contaminants and past incidents are described in the UKAEA Decommissioning Group ‘Historic Spills Report’ (2003). As a result of the desk studies carried out for that report, only one significant environmental incident was identified at Culham Science Centre. This was the release of 790 gallons (3,600L) of transformer oil into the surface water drainage system, which escaped into the environment but did not cause any significant damage.

The Historic Spills desk study report concludes that there are possible localised areas of residual contamination in the form of aviation fuels, lubricants, degreasers and potentially asbestos cement bound fragments in the areas of fuelling aprons, runways and hard standings, and near HMS Hornbill buildings.

Three specific areas of potential contamination sources were identified, namely:

The Shot Blasting Facility (SBF);

The Contractor’s Cabin Area (CCA); and

A small area (2m2) adjacent to the B8 boiler house. No potential wide scale significant contamination was identified.

4 Contamination Ground Investigations

4.1 Scope of InvestigationsA contamination ground investigation was carried out on the East Culham (JET) site (only) in 2004. The investigation comprised shallow soil sampling on an approximate 50m grid spacing across the whole of the JET site. The location of the sampling points is shown on Figure 3.

Scoping of the investigation took into account that the radiological and chemical presence on the site was and is limited. There was no known disposal of waste to land on or near the site. Tritium and beryllium were identified as the most significant risks, however at a very low risk of ground contamination, due to strict control of activities.

Soil samples were taken using a hand auger at a total of 128 locations (including 8 composite sample locations). Fourteen samples were taken from ground level to

Appendix C - page 3


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0.2m depth; 87 samples were taken from 0.2m to 0.5m depth; and eight samples were taken from 0.5m to 1.8m depth.

The samples were chemically analysed for the following determinants:

Metals (11 number including beryllium on 209 samples).

Hydrocarbons (TPH and DRO on random samples located in high risk areas, e.g. adjacent to transformers, roads or in made ground. TPH: 45 samples; DRO: 31 samples).

Tritium (leachable on 35% of samples (81 number) only – as groundwater monitoring for tritium showed only minor concentrations present. Also 22 samples total tritium.).

PCBs (two samples).

4.2 Results of InvestigationThe investigation chemical test results were considered against screening concentrations for two scenarios (a) the current land use (commercial/industrial) and (b) a future land use (assumed to be residential with private gardens). These screening levels were for metals only.

Localised contamination by lead, copper and beryllium above commercial/ industrial screening levels were found in the CCA and SBF areas, and the area around building B8. A very high level of hydrocarbons was also found in the CCA. Contamination levels outside the CCA, SBF and B8 areas were within acceptable levels for commercial/industrial use.

Excluding the results for the CCA, SBF and B8 areas, the 95th percentile of all the results were below residential end–use screening criteria, except for arsenic and cadmium; however the concentrations of these two metals were not elevated by comparison to background levels beyond the site area.

4.3 Investigation Recommendations The report recommended that the soils in the CCA and SBF areas, and the contaminated near surface soils near B8, are remediated (removed) and validation surveys carried out. Elsewhere the report concludes that the survey identified a few minor areas of ground contamination but no significant contamination was identified.

5 Remediation Works

Contaminated near surface soils in the former Contractors Cabin Area were removed in 2005. The remediation was undertaken to a maximum depth of 100mm and validation samples were taken at the reduced level and tested, to confirm that the level of metal contamination had been sufficiently reduced for commercial/ industrial end use.

It is anticipated that similar remediation works were undertaken in the Shot Blasting Facility Area and in the vicinity of Building B8, although Arup has not seen the results for those areas.


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6 Conclusion

6.1 BackgroundThe relevant sections of the National Planning Policy Framework have been reviewed in relation to the ground condition review and this report has been generated as a response to this guidance. Local guidance, issued by the Oxfordshire Contaminated Land Group consortium (January 2010) is in agreement with this, even though it mentions the now withdrawn Planning Policy Statement 23. Indeed, PPS23 continues to represent good practice guidance with respect to the development of land affected by contamination.

6.2 General conclusions Detailed contamination desk studies have been undertaken by various parties at the instruction of the UKAEA. In addition, a ground contamination soil sampling and testing investigation has been undertaken on the East Culham (JET) site. Neither the desk studies nor the ground investigation have indicated any significant residual chemical or radiological contamination of the soils or groundwater at the site. Localised remediation works have been undertaken to shallow depth where elevated levels of metals were found, all of these being outside of the Phase 1 development area.

Based on the information reviewed as part of the ground condition/ contamination desk study, the proposed development of the Phase 1 site area has not been subject to any known contaminative land use during the wider site’s former use as a WW2 airfield or the more recent/ current research facility use. It is therefore assessed that there are no significant ground contamination constraints to the development of the Phase 1 plot at the Culham Science Centre site.

6.3 RecommendationsAdditional soil sampling and contamination testing will be required as part of a detailed assessment for the Phase 1 plot and will be included as part of a detailed planning application. Soil sampling carried out to date across the JET site in 2005 was at a wide (50m grid) spacing. Some localised contamination may be revealed by further investigations, or during subsequent development, however, if found, are only expected to be no more onerous that at many other previously used sites.

Appendix C - page 4


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A1 Plan of site as WW2 airfield


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Figure 1 : Plan of site as WW2 airfield

Appendix C - page 5


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A2 Recent aerial view of Culham Site (from Google maps)


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Figure 2: Recent aerial view of Culham site (from Google maps)

Appendix C - page 6


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A3 Plan of contamination ground investigation sampling points, JET site (2004)


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Figure 3: Plan of contamination ground investigation sampling points, JET site (2004)

Appendix C - page 7


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A4 Locations Plan of historic boreholes (refer to Appendix 7)


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Figure 5: Location of boreholes on the Culham site

Appendix C - page 8


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A5 Groundwater Contour Plan (refer toAppendix 7)


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Figure7: Hydraulic head and groundwater flow directions beneath the Culham site (based on historical rest water level data)

Appendix C - page 9


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A6 Report 1 – History

Report 1 – History (2002)

This report provides a summary history of the Culham site, firstly during its occupation by the Admiralty and secondly as the Culham Science Centre.

6.3.1 HMS Hornbill

In 1942 the Admiralty requisitioned the site (which was in agricultural use) and built the airfield (HMS Hornbill). It was first commissioned in 1944 and a plan of the layout of the airfield is attached as Figure 1. The airfield’s main use was as an Aircraft Receipts and Despatch Unit and as a centre for training naval reservists. HMS Hornbill was closed in 1956 but part of the site remained in use as Admiralty storage until 1966.

There was bulk storage of aviation fuel and kerosene at the airfield - location not known but in Report 3 suggested to be to the south east, and beyond, the United Kingdom Atomic Energy Authority property boundary. It is reported that there is no longer any trace of the bulk fuel store and the area has been returned to agricultural use.

Four aircraft incidents involving crash landings or overshooting of runways are reported. It is advised that there is only a “very small chance of finding any residual oil, metal or radon contamination at any of the crash sites, which have since been reworked by farming methods or landscaping.

6.3.2 Culham Laboratory The Culham Site Development Committee was formed in 1959 and construction of the Culham laboratory buildings began in 1960. A geotechnical soil investigation is reported to have been commissioned by the AEC prior to development and to have shown, from surface to depth:

Sandy clay or gravel, 4ft to 34ft (1.2m to 10m);

Cemented greensands, 2ft to 20ft (0.6m to 6m);

Kimmeridge Clay, not penetrated to below 130ft (40m).

The site developed through the 1960s and 1970s carrying out research into fusion physics, notably controlled thermonuclear research, plasma wave studies and plasma fusion. In 1979 it was recognised as an ideal location for the Joint European Torus (JET) project, expected to run till 2006, with decommissioning due to be complete by 2022.

In 1999 the JET Joint Undertaking was handed over to the United Kingdom Atomic Energy Authority and EFDA close support unit.

The report notes that a full site evaluation will be completed as part of the site’s future decommissioning and will consider all historical ground contamination. It notes that “This information is available titled the Historic Land Contamination of Culham”.


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More detailed information about the site’s research use is given in Report 3.

Appendix C - page 10


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A7 Report 2 – Geological and Hydrogeological Environment of the Culham site (May 2003)

Report 2 - Geological and Hydrogeological Environment of the Culham Site (May 2003)

This report, prepared by Serco Assurance for United Kingdom Atomic Energy Authority, was intended for use as input in the evaluation of potential contaminated land liabilities. The report contains a description of:

Site topography (natural topography was modified in 1942 when earthworks for the HMS Hornbill airfield were carried out).

Site hydrology, including estimated rainfall infiltration per year (200mm) and locations of local water courses on and near the site.

Underlying geology, based on published geological maps and the results of two borehole investigations: by Cementation (1959); and by Soil Mechanics (1978) – see Appendix 4, figure 4 for locations of boreholes. These investigations indicated the following sequence from the ground surface downwards:

- River Terrace Deposits (sand, gravel, silt and clay), occurs across most of the site, approximately 1m to 9m thick, typically 1.5m to 4m thick.

- Lower Greensand (beds of red sand, with rounded quartz gravel and clay), typically 1m to 6m thick. Local Head Deposits noted to be locally present between RTD and Lower Greensand in some locations.

- Kimmeridge Clay (grey mudstones and siltstones), 41.6m thick where fully penetrated by a borehole.

- Corallian Beds (limestone, sandstone with coral rock, siltstone, clays) occurs at approximately 50m depth below ground level (10m AOD), up to 24.7m thick.

The hydraulic properties, water levels and estimated flows in the underlying aquifers.

A description of groundwater receptors and contaminant transport issues.

Recommendations for the review and extension of existing groundwater sampling and analysis, and for the installation of new borehole standpipes.

The RTD and Lower Greensand are considered as a combined ‘near- surface aquifer’. The Kimmeridge Clay is a non-aquifer and the Corallian Beds are a confined aquifer with a potentiometric surface at approximately 50mAOD.

The report provides the hydrogeological properties of the near-surface aquifer, based on pumping tests in 1978.

The groundwater depths measured in 1978 in the near-surface aquifer were in the range 0.6m to 1.7m below ground level (bgl), corresponding to 55.7AOD to 58.0m AOD.


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Groundwater flow across the site in the near-surface aquifer was interpreted as towards the south-east (see Appendix 5, figure 5) at 0.1- 2.4 m/day, based on historical borehole records in the area obtained from the British Geological Survey (BGS). The hydraulic gradient was evaluated as 0.007. This flow will discharge to surface water ditches or a base flow to the River Thames. The lateral migration distance of the shallow groundwater was estimated to be 40m – 880m per year.

It was assessed that there is an upward flux of groundwater from the Corallian Beds through the Kimmeridge Clay as a result of the artesian pressures in the lower deposit. This vertical flux across the site area was estimated to be 1.8m3/day.

Groundwater monitoring at the site was limited to quarterly sampling of water from four boreholes (JA, JB, JC and JD) and analysis for tritium. It was recommended that the method of sampling be reviewed. The monitoring was considered inadequate and it was recommended that additional monitoring boreholes be installed after a desk study was carried out to identify “potential contaminants of concern and potential locations of contaminants loss to ground”.

It was assessed that the key pathway for contaminant migration at the site is the groundwater pathway and that the key receptors would be groundwater abstractions. Enquiries were made to the Environment Agency and South Oxfordshire District Council and Tables 1 and 2 of the report provide details of licensed abstractions.

Appendices to the report contain rainfall data, Thames flow data, borehole logs and receptor (water abstraction) information.



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A8 Report 3 – Historic Spills Report (Nov 2003)

Report 3 – Historic Spills Report (Nov. 2003)

The objective of this report was to collate information about potential ground contamination across the whole Culham site to aid the design of a planned ‘invasive site survey’.

The study was undertaken for the JET Decommissioning Programme and to meet the requirements of the Culham Division Environmental Objective E06.

The site is described in three areas: the JET site; Culham North; and Culham West.

It is reported that the JET Facility had an authorised discharge route for active aqueous wastes to the River Thames and authorised discharges of HT and HTO via the stacks on site. Radioactive authorised discharges were being monitored and there were no chemical authorised discharges in place for the site.

It is reported that there had been only one significant environmental incident at Culham (release of 790 gallons of transformer oil into the surface water drainage system) which escaped into the environment but did not cause any significant damage.

Two groundwater aquifers are identified for the site, after the studies undertaken by SERCO (2003). There is a near surface aquifer comprising River Terrace Gravels overlain by Lower Greensand (sands), with groundwater level at 0.6m to 1.7m below ground level and groundwater flow in a south easterly direction. The lower Corallian Limestone aquifer occurs below the Kimmeridge Clay, which effectively isolates it from near surface activities.

The report concludes that the desk studies have not identified areas of the site where there is the potential for large scale ground contamination, but there are possible areas of residual contamination in the form of aviation fuels, lubricants, degreasers and potentially ACM fragments in the areas of: fuelling aprons; runways and hardstanding; and near HMS Hornbill buildings.

Potential sources of contamination (e.g. fuel and waste tanks), activities in different areas of the site and the incident record for the site are reviewed and a number of locations are identified for further investigation.


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A9 Report 4 – Results of the Preliminary site investigation invasive soil sampling programme (2005)

Report 4 - Results of the Preliminary Site Investigation, Invasive Soil Sampling Programme (2005)

This report concerns the East Culham (JET) site only. The report presents a summary of the site’s environmental setting (potential contaminative sources and geological environment) and the results of a shallow soil sampling investigation carried out on an approximate 50m grid spacing across the whole of the JET site in February 2005.

Contamination Sources

It is stated that the JET site is not believed to have any ground contamination legacy issues from its former use as a WW2 airfield and that prior to construction of JET in the 1970s the only buildings present were part of the Trade Waste Facility (belonging to Culham West) to the east of the site.

Reference is made to the specific areas of potential contamination sources described in Report 3, namely:

The Shot Blasting Facility (SBF);

The Contractor’s Cabin Area (CCA); and

A small area (2m2) adjacent to the B8 boiler house.

It is noted that the radiological and chemical presence on the site was and is limited. Tritium and beryllium most significant risks, however very low risk of ground contamination due to strict control of activities.

Possibility of localised PCB and hydrocarbon contamination locally from around 120 transformers.

It is stated that no major environmental incidents have occurred on site and no known disposal of waste to land on or near the site.

Intrusive soil sampling investigation

Samples were taken using a hand auger at a total of 128 locations (including 8 composite sample locations). 14 samples were taken from ground level to 0.2m depth; 87 samples were taken from 0.2m to 0.5m depth; and 8 samples taken from 0.5m to 1.8m depth. Figure 4 shows the sampling locations. A recent aerial view of the Culham site is also included as Figure 5, for reference.

The samples were chemically analysed for the following determinands:

Metals (11 number including beryllium on 209 samples).

Hydrocarbons (TPH and DRO on random samples located in high risk areas, e.g. adjacent to transformers, roads or in made ground. TPH 45 samples; DRO 31 samples).



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Tritium (Leachable on 35% of samples (81 number) only – as groundwater monitoring for tritium showed only minor concentrations present. Also 22 samples total tritium.).

PCBs (2 samples).

Results of investigation

The chemical test results were considered against screening concentrations for two scenarios (a) the Current land use (commercial/industrial) and (b) a Future land use (assumed to be residential with private gardens). These screening levels were for metals only.

Localised contamination by lead, copper and beryllium above commercial/industrial screening levels were found in the CCA and SBF areas, and area around B8 (see “Figure 1: The JET Site” for locations). A very high level of hydrocarbons (DRO) was also found in the CCA. Contamination levels outside the CCA, SBF and B8 areas were within acceptable levels for commercial/industrial use.

Excluding the results for the CCA, SBF and B8 areas (assumed would be remediated), the 95 percentile of all the results were below residential end–use screening criteria, except for arsenic and cadmium, however the concentrations of these two metals were not elevated by comparison to background levels beyond the site area.

Recommendations and Conclusions

The report recommends that the CCA, SBF and the contaminated near surface soils near B8 are remediated (removed) and validation surveys carried out. The report concludes that the survey identified a few minor areas of ground contamination but no significant contamination was identified.


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A10 Report 5 – Remediation survey, Contactors cabin area (2005)

Report 5 – Remediation Survey, Contractors Cabin Area (2005)

The former contractor’s cabin area is in the north east of the Culham site, about 400m distant from the proposed redevelopment area. It was identified by the earlier desk studies as a potentially contaminated area due principally to shot blasting activities using boron carbide grit, but also an area where there had been incidents of fly tipping.

The report presents the results of surface sampling of soils and chemical testing previously undertaken in the area for the ‘Preliminary Site Investigation’ (which showed significantly elevated concentrations of copper, lead and beryllium), and the results of validation sampling undertaken after 75mm of soil had been removed.


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