Land Quality Management Preferred Option March 2011
The LQM strategy relates to the management of any contaminated ground or groundwater for which NDA or our Site Licence Companies are deemed responsible under relevant statutory provisions until the declared Site End State is reached and NDA’s mission is complete. The strategy considers management of radioactive and non-radioactive contamination once it is in the ground or groundwater until the material is determined and managed as waste (discussed in Integrated Waste Management strategies). The first principle of LQM is to prevent contamination of ground and groundwater in the first place. However, the actual activities required to prevent contamination of ground or groundwater, e.g. prevent leaks from facilities and manage gaseous or liquid discharges, are more appropriately covered in the strategy for Asset Management and for Low Level Waste (Liquid and Gaseous Discharges strand) respectively.
Within these boundaries, the LQM strategy needs to consider how land quality will be managed to protect people and the environment as well as the rate at which the Site End State will be achieved.
Interfaces
The LQM strategy interfaces with a number of other Topic Strategies in addition to the majority of the enabling strategies. The most notable interfaces are:
- Site End State Strategy is relevant because the nature and extent of contaminated ground and groundwater will influence the selection of a practical and achievable Site End State. Conversely, the Site End State describes the ultimate restoration objective for LQM.
- Decommissioning Strategy is relevant because consistency between the topics in the Site Restoration theme is key, for example, the relative timing of decommissioning activities will impact on requirements for control, monitoring and remediation of land contamination, and may risk (re)contaminating land.
- Integrated Waste Management topics are relevant because a robust understanding of the volume of ground and groundwater likely to be excavated and managed as waste will inform the development of national solutions and the infrastructure required for waste management in the UK. Conversely, the waste hierarchy has a direct influence on land quality management and plans
- for managing land quality are influenced by the availability of waste routes.
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Credible Options
- Having identified an area of concern, there is a wide range of techniques available for the control or remediation of contaminated ground. Some techniques can be applied to land directly (in-situ) where others are applied once the material has been excavated (ex-situ). Rather than describing options for each and every available technique, the options have been grouped at a high level:
1. In-situ management to achieve remediation objective without intervention, e.g. Monitored Natural Attenuation
2. In-situ management to achieve remediation objective with intervention, e.g. via enhanced control or attenuation
3. Ex-situ remediation to allow excavated material to be reused / recycled
4. Ex-situ disposal
There are also options for the rate at which remediation objectives are achieved:
1. Continuous land quality management to achieve the Site End State as quickly as possible
2. Deferred land quality management to achieve the Site End State only as quickly as is necessary to remain safe and protect the environment
In all cases, the rate will need to be safe for people and the environment and accommodate the overall decommissioning programme.
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Current Position
- The 2006 NDA Strategy guides Site Licence Companies to:
- accelerate characterisation of land;
- develop fully costed and robust long-term management plans;
- create and maintain appropriate records; and,
- monitor contamination whilst plans are being developed.
The 2006 Strategy also references the role of the Regulators who will subject plans to independent scrutiny and exercise powers as necessary to protect people and the environment.
The 2006 NDA Strategy is being implemented; all SLCs have an improved conceptual model of land quality and have developed or are developing land quality management plans. The plans do however typically rely on excavation and disposal of contaminated ground (soil and rubble).
It is evident that the volume of land estimated to be or have potential to be radioactively contaminated exceeds the LLW disposal capacity currently planned for the UK. There is potential that much of the excavated material could be sentenced as LLW and therefore the current situation does present a risk, to both this strategy and the delivery of LLW strategy.
Risk to people and the environment is our primary and enduring consideration in deciding how to manage land contamination. How we manage this risk depends on the nature, extent and likely behaviour of any contamination and therefore requires a case-specific assessment. Our strategy is to employ early risk-based decision-making.
At higher levels of risk there is less flexibility in the way we manage land quality; the decision is driven by the need to reduce risk. Action will be taken as soon as reasonably practicable to minimise the time at risk.
It is essential to predict if and how risk will change with time. At lower levels of risk, it may be better to intervene promptly to prevent the problem worsening and becoming more difficult and costly to resolve. For some areas of contamination the risk will decrease with time as a consequence of naturally occurring physical, chemical and biological processes. In these cases, it might be appropriate to leave the contamination where it is and make use of a process called Monitored Natural Attenuation rather than intervene.
As levels of risk decrease, the Waste Hierarchy has greater influence on decisions about how best to manage land quality. In this context, our strategy is to maximise re-use of material and minimise the volume being excavated and disposed of as waste. Furthermore, the Strategic Environmental Assessment of options identified that detrimental effects of land quality management are mainly associated with ex-situ solutions where the first step is to extract the contaminated material from the ground prior to treatment for re-use or disposal. Therefore, because intervention may do more harm than good, there may be situations where it is preferable to manage contamination in-situ. This could involve controlling contamination or using in-situ remediation techniques including Monitored Natural Attenuation to restore the land. We will explore opportunities for managing contamination in-situ while still achieving the level of restoration required for the Site End State and to release land for other uses.