Framing the management challenges within

Stewardship for radiological liabilities must be framed for very long time horizons. Given the long half-lives of many relevant radionuclides, and compared with the average human life, ‘long term’ in essence means eternity.

However, it is also clear that, during the life cycle of site management, the stewardship will encompass an extremely broad range of issues and activities.

Some of these may be relatively transient in character (e.g. a time frame of a few years), others will specifically envisage engagements for several decades (e.g. leasehold agreements for land uses and liability for defects in engineered system components) and others again will envisage timescales of centuries or even millennia (e.g. performance hopes for containment under the prevailing environmental conditions).

Some studies propose separating ‘nearer term’ and ‘longer term’

challenges as a pragmatic way of developing a comprehensible and affordable long term stewardship programme [15]. However, expressions such as nearer term (or short term) and longer term (or long term, etc.) can be and are given a wide spectrum of usages. It may be helpful to distinguish between different strategic planning horizons on the basis of the actors involved (viz. present versus future generations) and on the basis of hypotheses about system stability and change.

Regarding the actors involved, it is useful to follow the sustainability literature, where it is now commonplace to distinguish between present and future generations. This distinction is not associated with a specific period (is a generation 15, 25 or 35 years?), rather it is based on a question of agency:

of actions by some people, on behalf of or for others. In reality, it is the respon-sibility of the present generation of policy makers and stakeholders to determine the ways in which the interests of future generations (and, by extension, of other species and ecosystems) are to be provided for. Provision for the needs of future generations can be assured only through principled choices of resource use (investment and protection decisions) whose stewardship intent is to maintain and enhance the opportunities and security of future generations. Stewardship actions must be viable and acceptable to the present day stakeholders, at the same time as being motivated with respect to future generations.

Regarding system durability, there are important time horizons related to the stability and finiteness of stewardship strategies. This applies to institu-tional matters and also to engineering solutions.

Institutional arrangements, including financial conditions, workforce and legal frameworks, can change quite quickly (on a scale of a few years) even when clear and ‘binding’ agreements have been made. The prevailing frameworks of government and of governance can also change rapidly (the rise and fall of political regimes) but in a deeper sense change more slowly (the rise and fall of civilizations). Therefore, the durability of stewardship for the longer term will depend on rooting the stewardship function in cultural values, purposes and understanding. This may be referred to as the archeological time frame.

Technological solutions (such as near surface containment), when put in place with attention to environmental and geological conditions and with a view to durability, can be proposed reliably for time horizons ranging from decades to hundreds of years. The longer the time horizon, the greater the extent to which performance is associated with the properties of natural systems and is, therefore, dependent on these. Therefore, in the longer term, a scientific characterization of natural processes is the determinant, and there is inevitably an element of indeterminacy associated with the long term evolution of natural processes. This may be referred to as the geological time frame.

These various considerations lead to the recognition of three time frames as being complementary for stewardship functions:

— One generation (approximately 30 years);

— Archaeological spans (of the order of 100–1000+ years);

— Geological spans (e.g. 1000–10 000+ years).

The main challenges for stewardship relate to the transitions in the planning horizon between one generation (the present period of activity) and the archaeological and geological horizons.

The ‘nearer term’ stewardship challenges are more likely to gain support from stakeholders, because they will probably be based upon existing and proven methodologies. These challenges may be economic (discussed further in Section 7), technical or institutional ones, or may involve ownership or measur-ability of success. While there is always the likelihood that technology will advance over time, there will be less confidence in institutional or financial stability, as the recent past shows only too well.

Convincing stakeholders to accept a stewardship programme when the longer term issues are less developed will be a challenge in itself. The way in which the longer term challenges (responsibilities and obligations, etc.) are framed may have a substantial bearing on the acceptance, or non-acceptance, of the immediate ‘steps’ (or nearer term solutions). The mechanisms of involving stakeholders are very country and culture specific (e.g. see Ref. [23]

and references therein).

It will, therefore, be important to incorporate within the longer term process a mechanism that will allow a reappraisal of the control measures and financial provision on a regular basis (this may be a 25 or 50 year period, for example).

For the longer term issues, although very real and significant, satisfactory answers may not be attainable. The pursuit of those answers will probably be very expensive, and demonstrating progress on an annual basis might be difficult. A lack of demonstrable progress for the resources expended can undermine a programme’s credibility in general. Therefore, it was suggested [15] to pursue the longer term issues by a different means. The very act of continuing nearer term activities is likely to clarify actual longer term needs. It must be noted, however, that with this approach, while circumventing the possible paralysing effect of having to design for millennia, there may be no guarantee that the nearer term activities are continued for any length of time beyond, say, one generation.

Such a separation allows, at least, a definition of stewardship to be made from the bottom or from an implementation viewpoint. The danger in defining stewardship from the top down and building a stewardship programme in this way is that the definition and resultant programme to fulfil the responsibilities of a top-down definition must be excessively broad and all-encompassing to be capable of handling every conceivable eventuality.

While there may be no direct solutions to maintaining the ability to manage long term stewardship for thousands of years, focusing on shorter term (100 years or so) solutions will keep people involved at the site, which will allow for evaluation of the changes required over time. If too much energy is spent on trying to solve the problems of 2214 with today’s knowledge, opportunities may

be lost to take the best decisions for the short term and unreasonable or unrealistic solutions may be recommended for the long term.

5.2. DECISION MAKING IN THE PRESENCE OF LARGE