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2.10.3 Transition to the stewardship phase

Contents
2.10.3.1 Consideration of non-radiological hazards

When an extended period of institutional control is the selected management option for the site, the active remediation period will be followed by a period where control might be transferred to the steward, who might be another party. This would require appropriate planning and regulatory control [BANAEE]. The major milestone in this process is the decision that clean-up has been achieved.

Transition criteria

Description
Regulatory based transition criteria Results of the periodic review indicate that the results of the remediation actions meet the plans.
For sites where residues remain a post-closure plan has been approved, a survey plan recorded and the ompetent authorities notified of the volumes and types of residues present.
Performance assessment has been made and analysis requirements have been met.
Title, deeds, property transfer documentation and any deed restrictions or covenants have been put into place prior to the transition.
The long term stewardship plan has been approved by the competent authorities.

Infrastructure transition needs All required physical and administrative institutional controls are in good condition.
All accesses and utilities required for the site have been maintained.
Monitoring wells, monitoring equipment and ancillary equipment are in good condition.
Monitoring data and maintenance records have been reviewed to determine the condition of the wells, and procedures are in place for maintaining and monitoring the performance of the equipment.
Any leachate collection system, related monitoring equipment and ancillary equipment are in good condition.
Groundwater remediation equipment is operational, maintained and monitored.
Engineered caps or covers are in good condition. Monitoring data or the results of periodic reviews indicate that the cap is performing in accordance with closure requirements.
Physical site boundaries have been located and are consistent with the legal description recorded with the appropriate authorities and any deed restrictions.

Record keeping The project file contains management plans, i.e. sampling, quality assurance and quality control (QA/QC) and monitoring plans, and final decontamination and decommissioning reports.
Monitoring data and maintenance records have been reviewed to determine the condition of the wells, and procedures are in place for conducting maintenance and monitoring performance of the equipment.
Data necessary for long term stewardship have been identified and documented, and the data types have been defined.
Institutional control requirements have, if required, been incorporated into the land use plan.
Site documentation and project files contain the residual contaminant source term, contaminant concentration and location, and potential risks to human health and the environment.
Site documentation and project files contain current as-built drawings of surface and subsurface site features, residue locations, engineered features, monitoring wells, access and physical institutional controls.
Required land use restrictions have been properly recorded with the competent authorities.
Historical and archaeological resources at or near the site have been located and documented.
Ecological concerns that may require modification of long term stewardship activities have been documented.
Safety analysis reports, emergency preparedness documents and management plans are all in existence.

Scope, schedule and budget There is a transition schedule that includes adequate review periods for documentation, site inspections and development of additional documentation.
The basis for the transition is included in the description of the proposed site.
The resources and personnel that are critical to accomplishing the tasks that are required in the transition phase have been identified.
There is a listing of baseline changes that have been approved or of any new contracts or modifications necessary before the transition can take place.
The expectation that the site will continue to perform as designed over the design life period is inherent in the long term stewardship process.
The proposed site scope has to be consistent with regulatory requirements.

Special conditions Any special historical or cultural/archaeological resources are identified and documented as well as reviews required of the condition of historical or cultural resources under stewardship.
Any special ecological concerns such as the management of threatened or endangered species are included in the scope and cost estimates.
Special management conditions for sites exposed to natural hazards, such as flooding or earthquakes, are documented and incorporated into the management plans. Storm water requirements are incorporated into the long term stewardship plans.

Table 2.11 Criteria for the transition from closure to longterm stewardship [KRISTOFFERSON]

Provisions need to be made for a scheduled and smooth transition period in order to ensure (also see Table 2.11) that:

  • All the necessary responsibilities have been transferred and there are no uncertainties over which responsibilities belong to which party.
  • All necessary records have been preserved.
  • There is continuity of the post-remediation and compliance monitoring activities as well as maintenance of the necessary infrastructure.
  • The engineered containments for the residual contamination continue to be maintained.
  • There is uninterrupted compliance with site use restrictions and other controls to ensure the integrity of any engineered containments.

In reality, it may be a question of definition when the active remediation period ends and when a site is actually transferred into the long term stewardship phase. This may also occur at different times for different environmental compartments. For instance, at a given site a groundwater treatment scheme may continue long after the surface soil remediation has been completed. Thus, while the site use may be controlled under a stewardship programme, the underlying aquifers may still be actively remediated. If the groundwater remediation is carried out by the steward, it could be claimed, however, that this is part of the stewardship programme.

Several stewards may be involved for a given period of time with the same site: one could be a user of the surface area, while another organization is responsible for the monitoring of the groundwater and possibly its remediation.

The range of activities, decisions and related records for the transition of a USDOE site from closure to long term stewardship is discussed, for example, in [CLAYTON]. The slow progress of remediation and towards stewardship has been a major concern at many sites, and strategies have been developed to accelerate this transition.

2.10.3.1 Consideration of non-radiological hazards

While this document is concerned with residual contamination from activities involving radioactivity, most, if not all, radiologically contaminated sites will also exhibit some level of non-radiological contamination. This comes primarily from the fact that many sites will have had a number of different processes occurring on them historically. Practices that would not be acceptable today may have led to chemicals and hazardous materials entering the soil, surface water and groundwater, for example due to inadequate containment, poor disposal practices or accidents. In the case of mining, for instance, operators may have not been aware of the hazard posed by certain constituents in the geological material they have been using.

There are a number of potential problems with sites exhibiting cocontamination [IAEA-2006b]. For example, in many countries the legislation dealing with radiological and non-radiological contaminants may differ considerably, both in terms of environmental risk assessment and in authorization for disposal.

The environmental risk from non-radiological contaminants may in some cases be greater than that from the radiological species present, but this is often ignored due to the general perception of increased risk from radioactivity.

The presence of other contaminants alongside radionuclides may result in the latter’s mobilization or attenuation through changes in chemistry [IAEA-2006d] It is only through a comprehensive knowledge of all contaminant species present that predictions of remediation success and engineering integrity can be made.