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4.7.1 Post-remediation activities

Contents
4.7.1.1 Release of areas
4.7.1.2 Unrestricted use
4.7.1.3 Restricted use
4.7.1.4 Restricted access
4.7.1.5 Removal of restrictions
4.7.1.6 Monitoring and surveillance plan
4.7.1.7 Record keeping

After the remediation has been completed, the degree, the extent and the duration of control, if any, ranging from monitoring and surveillance to restriction of access, should be reviewed and formalized with due consideration of the residual risk. The organization responsible for the surveillance and verification of activities should be clearly identified.
If necessary, specific restrictions should be established for the following purposes [IAEA-2003]:

  • To control the removal of radioactive material from contaminated areas or the use of such material, including its use in commodities;
  • To control access to contaminated areas;
  • To control the future uses of contaminated areas, including use for the production of foodstuffs and water use, and to control the consumption of foodstuffs from contaminated areas.

4.7.1.1 Release of areas

There are several possible end points for the remediation process [IAEA-2007a]:

  • Use of the area may be unrestricted;
  • Use of the area may need to be restricted in some or all parts and control may need to be exercised, for example, through a system of planning consents;
  • Access to the area may need to be restricted and measures may need to be put into place to enforce this.

In each case, further surveillance and monitoring may be required to confirm the long term effectiveness of the programme of remediation, and additional controls may need to be imposed on the basis of the monitoring results.

The degree, the extent and the duration of control, if any, ranging from monitoring and surveillance to restriction of access, should be reviewed and formalized with due consideration of the residual risk.

4.7.1.2 Unrestricted use

If the chosen remediation process involved the removal of contamination itself, and if the area meets the required remediation end criteria, the area may be released without restrictions. In this situation, the prevailing conditions are considered to be the residual background conditions for a new practice or for use of the land for habitation [IAEA-2007a].
The remediation of the site for any new practice should be conducted on the basis of the guidance presented in [IAEA-2006a].

4.7.1.3 Restricted use

The term ‘restricted use’ means that some types of use are allowed while others are not; for example, in certain cases the use of an area for forestry may be possible but its use for agriculture may be prohibited. Where a significant part of the exposure due to residual contamination arises from the food chain, the use of agricultural countermeasures should be considered. Similarly, the use of an area for recreational, industrial or certain agricultural purposes may be appropriate, but its residential use may not be. Impacts of the residual contamination on aquifers should also be considered in this evaluation.

In cases where all reasonable remediation options are insufficiently protective or in cases where the optimized remediation options do not include removal of the contamination itself, specific restrictions on the future uses of the contaminated areas may be required to be imposed. Specific restrictions may also be required to be established for controlling the removal of material from such areas or the use of such material [IAEA-2007a].

4.7.1.4 Restricted access

Restriction of access to contaminated areas will be required to be maintained in cases of serious residual contamination. The degree of any such restrictions should be determined by the regulatory body. Depending on the type and levels of residual contamination, access control measures may vary from the placing of warning signs to fencing of various types and guarded control stations. Area control personnel should have the legal authority to deny access to the area, if required [IAEA-2007a].

4.7.1.5 Removal of restrictions

If the monitoring and surveillance programme has verified the long term effectiveness of the remedial measures in eliminating unacceptable risks to human health and the environment, consideration should be given to removing any restrictions applied to the area and ending or reducing the extent of the monitoring and surveillance. If the option of ending or reducing these services is considered, the value of the monitoring and surveillance in promoting and maintaining public confidence should be taken into account. In considering the long term effectiveness of remedial measures, the environmental influence of physical, chemical, geological and other factors should be evaluated. In particular, contamination of groundwater may not become apparent for some time and may do so at some distance from the source of the contamination. Such considerations should be documented in the remediation plan [IAEA-2007a].

4.7.1.6 Monitoring and surveillance plan

A monitoring and surveillance plan should be required to be prepared for any remediated areas where restrictions are maintained after remediation has been completed. The plan should be subject to periodical review and to approval by the regulatory body.

The extent of such monitoring and surveillance plans should be based on the residual risks and their degrees of uncertainty and on the need to verify the long term stability of the radiological conditions. Monitoring and surveillance programmes should include, as necessary, environmental monitoring (of dose rates, activity concentrations in soil, water and air, biological indicator species and foodstuffs), whole body monitoring (if applicable) and dose assessment.

Decisions regarding the routine maintenance of such monitoring and surveillance programmes should be documented in the remediation plan. The results of the monitoring and surveillance programmes should be required to be documented and made readily available to interested parties to assist in maintaining public confidence. An invitation to interested parties to participate in the decision making should be required also in the post-remediation phase [IAEA-2007a].

4.7.1.7 Record keeping

Records are required to be kept to document the remediation programme and any lessons learned and changes made during its implementation. Such records should include: descriptions of activities performed; data from the monitoring and surveillance programmes; occupational health and safety records for the remediation workers; records of the types and quantities of waste produced and of their management and disposition; data from environmental monitoring; records of financial expenditures; records of the involvement of interested parties; records of any continuing responsibilities for the site; identification of locations that were remediated and those with residual levels of contamination remaining; specifications of any areas that remain restricted and the restrictions that apply; statements of any zoning and covenant restrictions or conditions; and statements of lessons learned.

Failures in the implementation of remedial measures may arise from a lack of consensus among interested parties, often in the negotiations during the decision making process regarding the implementation of the remediation plan. While some conflicts between interested parties are apparent at the outset of the decision making process, others may arise much later, for example during discussions in which the actual implications of alternative decisions are made explicit. All conflicts and their resolution in the decision making process should be documented [IAEA-2007a].