Remix & Return is a concept for solving the vexing problem of the disposal of radioactive waste. It refers to remixing waste with uranium mine and mill tailings, then returning the mixture to the mines from which it came. The average original level of radioactivity of the uranium ore before it was extracted is first estimated, and this becomes the upper, “natural” limit of the tailings and waste that may be reinserted into a given mine.
Remix & Return possesses the fundamental, psychologically satisfying virtue of restoring radioactive materials to their natural place in the environment. Aside from the possibility of minor leakage owing to their different compaction and composition than those of the original ore, the returned materials would not pose any new risk, unlike with other disposal options (of course, uranium ore in its natural setting also leaks radon gas and other radioactive substances). While shifting from the open pit and strip mining common in the past to underground mining would entail considerable expense, this practice would extract far less dirt and rock (perhaps only 1/8 to 1/10 as much as with strip mining), which would protect the surface environment and reduce the cost and pollution associated with larger amounts of mine tailings. It may also be possible to construct modular mini-mills at some mine entrances, thereby increasing security, eliminating transportation costs, concentrating tailings, and simplifying Remix & Return.
Excavation of a mine would double as preparation of a disposal site, so there would be no expense for constructing new sites, including the considerable financial and non-monetary costs of debating where to locate waste disposal sites or whether simply to dump low-level waste in ordinary toxic waste sites. This “natural” approach to nuclear waste disposal would simultaneously remove from the surface the non-radiation problems caused by the toxic metals in such waste, arguably a greater risk to plants, animals, and humans than low-level radioactivity.
In addition, Remix & Return can lead to an end of irresponsible, uncontrolled dumping of low-level radwaste into the oceans.
Many closed uranium mines in the United States, the CIS countries, and elsewhere can be employed for Remix & Return. When no empty uranium mine would be located nearby, Remix & Return might be adjusted to permit insertion into other appropriate mines, e.g., vanadium and cobalt mines, in order to minimize transportation. The concept would be to create the equivalent of an average uranium ore body. Leakage from such a refilled mine would need to be set at a minimal level, perhaps by lining the inner surface of the mine.
Already some uranium mining operations reinsert mining tailings into the mines. Thus far, efforts by mining companies to return the entire amount of mine tailings to mines have been frustrated by their low density compared to that of the original ore. But channeling a portion of the funding for building geological disposal sites into solving this problem and the related problem of possible incremental leakage from low-density remixed waste could lead to better methods of compaction. Existing compaction technologies could be used to fashion baseball-sized spheres of the diluted, low-level waste at twice the density of the original ore, then these spheres could be rolled down a chute into the mine. This could solve the space problem and also minimize the possibility of leaching from the dense waste spheres.
The effectiveness of Remix & Return could be enhanced if special provisions were made for ore deposits in which the concentration of uranium would exceed that in the average mine. For instance, the new Cigar Lake mine in Canada contains ore with up to 19 percent uranium. Such concentrated deposits can be viewed as precious assets of a disposal program in that they would permit a much higher level of radioactivity in the nuclear waste mixture returned to the mine, on the principle that this would simply be replacing the original natural radioactivity.
Remix & Return may be undertaken by a single country or by several in collaboration even prior to the negotiation and ratification of an international agreement, or in spite of a failure to achieve broad international consensus.
Dealing with Objections
The objections that almost all countries have to accepting nuclear waste from abroad would presumably be somewhat fewer in the case that the accepting country had been the original source of the fuel. For existing waste, a special payment to the accepting country would prove necessary; but the possibility of providing work for miners to return the mixed, diluted waste to the mines would help to overcome objections. Once the Remix & Return system would become the standard procedure, this could all be arranged in advance.
To the objection that the inclusion of high-level waste would surely raise the level of radioactivity beyond that of the original mine, one can point out that only a detailed, quantified study can determine this; and that the diversion of nuclear material into weapons reduces the amount of radioactivity to be returned.
The worldwide shift to In Situ Leaching (ISL) (injecting acid or alkaline liquid to release uranium from its location underground and then suck it up to the surface) tends to undercut the rationale for Remix & Return. This can, however, be remedied in part by reopening hundreds of old underground uranium mines for disposal of nuclear waste. Then it would be necessary to work with and compensate mining companies for digging new underground mines instead of resorting to the less expensive ISL method. While ISL is touted as being more environmentally benign than underground mines, in fact an underground mine that became a Remix & Return disposal site would be far better for the environment than an ISL process that can contaminate groundwater and leaves the exceedingly difficult problem of disposal of nuclear waste unsolved.
In effect, Remix & Return would require uranium mining companies to become radwaste disposal companies as well, and so it would be necessary to compensate them appropriately for their efforts. Or the mining companies could sell their valuable empty mines to disposal companies.
Remix & Return would put an end to the dangers associated with high-level waste by putting an end to high-level waste itself. In this mode, Remix & Return accomplishes the same feat as firing the high-level waste on a rocket into the Sun or burying it in a subduction fault that carries it down into the Earth’s mantle: it permanently puts an end to high-level waste as a problem. Upon full dilution of the high-level waste into the giant heaps of tailings, it would cease to be of danger as a serious terrorist threat.
By reconstructing an analogue of the original ore body, Remix & Return places the resulting low-level waste back into its fitting natural setting. In contrast to the situation at all geological disposal sites, the inevitable seepage of radioactivity from the former mine would be at or below the natural level.
Thus Remix & Return may actually be capable of safely disposing of 100 percent of (fully diluted) high-level waste as well as low-level waste, for a complete solution of the enormous and seemingly intractable problem of safe disposal of nuclear waste. So carefully calculating the various quantities and radioactivity levels preexisting, extracted, mixed, and returned should become a high priority. Even if the initial level of radioactive emissions from spent fuel fresh from a reactor would exceed the limit allowable for safe dilution via Remix & Return, 10-20 years of cooling in a storage pool at the reactor site could bring it down to the right level.
Remix & Return would simply extend existing reinsertion practices to include, to the extent possible, all high-level and low-level radwaste–spent fuel, mining and mill tailings, liquid and solid nuclear waste from refining and power generation, and other radwaste such as medical cesium. This would best be accomplished by an international agreement that would make Remix & Return the only legal solution worldwide for radwaste. Every school child would learn that radwaste is programmed, before it is generated, to be remixed and returned to specified mines–ideally, those from which it originated.
See also: Sea-Based Nuclear Waste Solutions and Intriguing Anomalies: An Introduction to Scientific Detective Work
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Kenneth J. Dillon is an historian who writes on science, medicine, and history. See the biosketch at About Us.