A HOLISTIC APPROACH | COVER STORY
106 105 104 103 102 101 100 10-1 10-2 10-3 10-4
100
Dose from natural radiation in Japan: 2,100 μSv/y Dose limit for variant scenarios: 300 μSv/y
Dose limit for base scenarios: 100 μSv/y Cl-36 I-129 Se-79 Total
106 105 104 103 102 101 100 10-1 10-2 10-3 10-4
101 102 103 104 105 Time after repository closure (y) 106 107 100
Dose from natural radiation in Japan: 2,100 μSv/y Dose limit for variant scenarios: 300 μSv/y
Dose limit for base scenarios: 100 μSv/y Mo-93 Total C-14 101 102 103 104 105 Time after repository closure (y) Above, figure 1: Typical radiation doses calculated for disposal of vitrified high-level waste (left) and TRU (right) (see
www.numo.or.jp) 106 107 Se-79 I-129
Numerous studies have shown the practicality of
geological disposal for the more radiotoxic wastes in a wide range of geological settings. This approach meets ridiculously low safety targets that are orders of magnitude below natural background levels and extremely long assessment timescales stretching 100s of thousands or even millions of years, (see Figure 1). This stands in dramatic contrast to other chemotoxic wastes, which have release limits orders of magnitude above background and are assessed only for short time scales of hundreds of years or less. This approach is despite having no potential to decay away like radioactive waste – these wastes will be present for all time. Indeed, the global climate change threat can be attributed directly to a lack of appropriate waste management by the fossil fuel industry. Furthermore, waste pollution has now been identified by the UN as a global concern, at a level with climate change and loss of diversity, according to their Making Peace with Nature: A scientific blueprint to tackle the climate, biodiversity and pollution emergencies report. Thus, the good practice established for radwaste should also be seen from this perspective.
Need for a paradigm change Although this was not an issue in the early days, in recent decades there has been an assumption that countries benefiting from technology that produces nuclear waste should be responsible for its safe management. This is often presented as a moral issue – but contrasts markedly with other wastes for which export to other often less-developed countries occurs on a massive scale. It is also inconsistent with the fact that waste from uranium mining is decoupled from all other radioactive wastes in the nuclear fuel cycle – with wastes the responsibility of the ore producer rather than the eventual nuclear fuel user. In addition, it is also incompatible with the treatment of naturally occurring radioactive materials (NORM), despite the fact that some industries (especially oil and gas) produce large quantities of this, which has radiotoxicities equivalent to some of the higher-activity intermediate level waste (ILW). Many of the repository concepts developed in the more
advanced programmes are over-designed. They are often purpose-built structures for limited inventories, excavated
deep underground and characterised by very high- performance engineered barriers. Despite the small waste volumes involved, such facilities often have large footprints of several square kilometres and utilise large quantities of materials. These materials are often inherently valuable, for example copper, or are difficult to work with and need to be transported over large distances, like bentonite clay. Clearly, these concepts were developed before issues like sustainability and the carbon footprint were identified as concerns and hence perform poorly from an environmental impact perspective. In addition, repository implementers were originally charged only with disposal of radioactive waste and in some cases only particular waste classes. Hence there was no consideration of co-disposal of radwaste and other hazardous materials. Consequently, the potential for holistic waste management has been little considered to date. Repositories for higher activity wastes could readily
take much wider types of waste, with relatively minor modification. Of course, for this option to be realised, it is advantageous to consider this before repository projects are finalised, or better still initiated. As many countries that are already close to implementing repositories may also be suppliers of SMRs to other, less advanced countries, it could also be sensible if they concomitantly assumed responsibility for all resultant decommissioning and waste disposal. In the past this option has been a political hot potato, as opponents present this to the public, as a country being used as a global nuclear dustbin for purely commercial reasons. If, however, this is reformulated as a commitment to reduction of CO2
releases and linked to a
fair allocation of carbon credits, this may be much more acceptable. Here good and clear public communication will be key.
A holistic waste management approach If the major nuclear countries cannot find a political path to accepting foreign waste, another option would be for smaller countries to focus on regional, shared facilities – as have already been proposed for some smaller nuclear programmes in Europe. Not only is this a cost-effective approach, it is also very sensible from an environmental U
www.neimagazine.com | July 2022 | 23
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Dose (μSv/y)
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