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Strategy and Planning
The most significant driver for land quality strategy at Sellafield is to understand, control and manage the legacy of contaminated land and groundwater to ensure protection of the workforce, the public and the environment. In addition the presence of contaminated land and groundwater also affects in a major way the cost and feasible options for managing and eventually remediating the site. We recognise that the views of our local stakeholders will be an important consideration in developing our forward strategies for the site and stakeholders will continue to be consulted for their views on any major developments in this area.
Over the next 40 years much of the contaminated land and groundwater will need to be managed in-situ as it will not be possible to excavate ground with buildings on top or in close proximity. Key objectives during this period will be to prevent an increase in the contaminated land severity and extent.
The Nuclear Decommissioning Authority (NDA) was created in 2004 to manage the public sector civil nuclear liabilities in the UK (NDA Website). Ownership of the Sellafield site passed from BNFL to the NDA in 2005 and the existing site management transferred to a new Site Licence Company (SLC), initially named British Nuclear Group Sellafield and since 1 April 2007 called Sellafield Ltd. Sellafield Ltd is required to produce Lifetime Plans (LTPs) with associated costs to show how it will manage the site through to the point at which the NDA has completed its mission. The current assumption is that the site would remain under Institutional Control and not be delicensed, but the possibility of alternative outcomes was recognised.
The physical condition of the site at the point when the NDA has completed its mission is termed the 'End State' and the use to which the land is put is termed the 'End Use'. The West Cumbria Site Stakeholder Group (WCSSG) is an independent body whose role is to provide public scrutiny of the nuclear industry in West Cumbria. The Group considered the future of the site, including end state options in 2007 on behalf of the NDA (West Cumbria Site Stakeholder Group Website), with the outcome that the preferred end use was continuing industrial and commercial reuse including research. This was influenced by the strong desire for continued significant employment in the local area. There was recognition from the stakeholders that part of the site may remain under long-term institutional control but also an aspiration from the NDA that as much of an “Outer Zone” as possible on the site would be delicensed. The WCSSG considered this work to be a first stage in an iterative consultation process and will be involved in any future developments relating to the site end-state.
The base case assumption for contaminated land management (subject to regulator approval/agreement and demonstration that it was the best practicable environmental option) is that Intermediate Level Waste (ILW) would be excavated and treated to reduce its volume (for example by concentration of the contaminated fraction of the soil in a “soil washing” process) prior to disposal in a national ILW repository. Material that was Low Level Waste (LLW) with activity greater than 37 Bq/g would be disposed of in a near surface disposal facility at Sellafield. Material that was Very Low Level Waste (VLLW) would be left in place unless excavation was required to gain access to LLW contaminated soil. A programme of local groundwater management would be implemented during the excavation phase to enable excavation of ground from below the current groundwater table. Key assumptions that underpinned the strategy were that:
- disposal routes would be available for all the wastes
- it would be possible to remove ILW soil from beneath residual building foundations
- it would be possible to reduce the volume of ILW by a treatment process
- stakeholders, including regulators, would allow VLLW soil to remain in-situ and naturally decay
- the site would be under indefinite institutional control and that delicensing would not be required
We are currently assuming that contaminated ground and groundwater would remain in-situ until 2050 while the Separation Area was being cleared of buildings and facilities, and that remediation would take place between 2050 and 2120. Activities associated with the base case strategy were primarily associated with the restoration phase of the Sellafield site post 2040 and did not identify the need for any interim containment or stabilisation measures to prevent the further spread of contamination prior to completion of decommissioning activities.
Since the formation of the Sellafield Contaminated Land Team, our strategy has been under constant review and the baseline approach now being envisaged is as follows:
- Site Characterisation 2008 -2009
- Assess data, model potential scenarios and carry out BPEO/BPM studies with stakeholder involvement. 2010 – 2015
- Institute a groundwater management "line" around Separation Area 2015 – 2020
- Remediate contaminated areas around site as they become available 2020 – 2040
- Remediate Separation Area in Zones between 2040 – 2070
- Consider opportunities to delicense / redevelop / landscape selected areas of the site
- Ongoing management of the residual areas, possibly involving waste disposal activities
Key elements of the strategy are to use the new characterisation data to develop risk based remedial approaches in conjunction with stakeholder and regulatory interaction and to optimise sustainability by effective sorting and segregation of contaminated soil and management of contaminated groundwater in order to maintain control and minimise waste.
The total financial provision for land remediation activities in the 2007 – 2008 LTP was £3.49 Billion. This estimate was based on the potential for £1.99 Billion waste disposal and remedial works plus £1.5 Billion unquantified treatment costs. In order to provide a more robust underpinning of liability estimates for the 2008 - 2009 LTP the strategy has taken account of the unquantified treatment costs associated with groundwater management and soil treatment by assuming a “basecase remediation scenario” which can be progressively refined and improved over time.
