European
Nuclear Society
e-news
Issue 8 Spring 2005
http://www.euronuclear.org/e-news/e-news-8/presidents-contribution.htm
February 2005
All the citizen of Europe, with the unique exception of Austria, would at least keep the nuclear option open if they were convinced that nuclear waste can be safely managed. That was according to a EUROBAROMETER survey of November 2002, but I doubt the results would differ today in our EU25. And for the man-in-the-street, nuclear waste means High Level Wastes, or a mixture of High Level and Long Lived radioactive wastes when the two streams are actually segregated. I will refer to both under the acronym HLW.
The lack of industrial implementation of a disposal method for HLW constitutes undoubtedly nuclear industry’s Achilles heel. In the whole world, only one disposal site is in operation, the Waste Isolation Pilot Plant WIPP near Carlsbad, New Mexico, but it is devoted to alpha-contaminated wastes issued from the US Defense programs, and its military nature played a significant role in its local acceptance. We all know that the process is more painful for the Yucca Mountain civilian project. As far as nuclear power HLW are concerned, Finland is the most advanced country, having democratically decided upon a disposal method - the geologic disposal of encapsulated spent nuclear fuel assemblies, selected a site, and began work in Olkiluoto. Many others, including France, are in the throes of the decision process.
In the 60s and early 70s, HLW was not a public issue and the nuclear community was confident: disposal of spent fuel or HLW issued from its reprocessing would be by deep geological disposal after proper conditioning. It was just a matter of selecting the proper geological stratum combined with the proper packaging, and there was no urgency to it because the volumes concerned were trivial1 and, anyway, it was better to let the waste cool down for a few decades before putting it underground. A number of underground labs were implemented in Canada, Switzerland, Belgium and Sweden, to name a few.
It was rather late in the game, when exploratory drillings were actually taking place, that it appeared the issue was much more sensitive than anticipated by the scientific and technical community and that populations which were willing – with a various degree of enthusiasm - to accept the location of a nuclear power plant nearby, opposed very strongly the siting of a HLW disposal facility in their backyard. An when we thought the issues to elucidate and settle were corrosion rates, complexation with humic acids, migration factors, rock porosity and how it was affected by the heat generated by the waste packages, depth of the water table, geological modifications over hundreds of thousands of years and so on, the real issues were commercial on the one hand and ethical, almost metaphysical, on the other hand :
Will my farm products suffer on the market from having grown near a radioactive “dump”?
Will Mankind have polluted Mother Earth on the Day of Reckoning?
In France, where we almost rediscovered in the late 80s the meaning of the word jacquerie2, another issue was clearly raised:
How can you (you, scientific or industrial people) be presumptuous enough to pretend there is only one solution to the HLW problem?
The French case is interesting because, contrary to some other countries, the HLW issue erupted in a context where nuclear power as a whole was reasonably accepted by the public. By the end of the 80s, with very few exceptions like Plogoff, power plants had met good local acceptance and the same could be said for the Low Level disposal site being built in Soulaines by ANDRA, then an autonomous branch of the CEA. Furthermore, since 1990, the N4 plants have been put on line in Chooz and Civaux; so have Soulaines and the Marcoule MOX fabrication plant MELOX, without controversy, and the recent decision to build a 3rd generation EPR in Flamanville has met little public opposition. When Superphénix was terminated by the government in 1997, it was certainly not to answer any vast public outcry! But the HLW issue remains today a special case.
Following the troubles, sometimes violent, on the locations where ANDRA was drilling, Prime Minister Michel Rocard decreed a moratorium on any attempt of HLW disposal. Representative Christian Bataille was missioned to crisscross France to shed some light on the issue. The result of this mission was a Law enacted by the French Parliament on December 30th 1991. The “Bataille” law extended for 15 years the moratorium on actual disposal, 15 years to be devoted to R&D along three so-called axes:
Partitioning and Transmutation
Geologic Disposal, through studies in underground laboratories
Long term storage.
The French Parliament will revisit the issue before the end of 2006. As a matter of fact, all the R&D teams have almost completed their reports and the OPECST, the French Parliamentary Office for science and technology assessment, is holding its hearings on the results of these studies while the special blue ribbon panel CNE, appointed under the Law, is busy preparing its synthesis.
The first fact to underline is that HLW are actually managed today. They are not orphaned, nor are they disseminated in the environment. They are accounted for and gathered under surveillance in licensed interim storage facilities. Spent fuel assemblies are in storage pools at the plant sites, in dry storage, or in centralized underwater storage facilities, waiting for reprocessing. Vitrified wastes and long lived medium activity wastes are in dedicated dry storage facilities. Wherever they are, HLW occasion today no nuisance whatsoever to anybody.
Quite frankly, they may be too well managed: if they are safe in their interim storage facilities for 30 or 40 years, why not simply leave them there a few decades more? Why rush to disposal - at a significant political cost - when there is no actual urgency? Because! Because if we believe nuclear power has a future, if we believe it will be necessary to develop it further if we want to solve our energy–environment dilemma, if we want to increase our energy production while reducing our greenhouse gases emissions, then we cannot be content with interim solutions. Disposal is an ethical obligation. But which disposal?
Source : ANDRA
As the official assessments are still in preparation phase, allow me to offer you my own personal evalution, as one individual expert among many others: this is not an official statement of ENS or any other organisation I may belong to.
Based on results obtained mainly by the CEA teams with significant contributions from JRC’s Transuranians Institute, partitioning is now proven on the laboratory scale. Its extrapolation to pilot scale could be started if so decided. Of course, partitioning makes only sense if we know how to manage the diverse waste streams this opearation would generate! For example, separating americium today would be pointless since we know we won’t transmute it in LWRs.
Because of the untimely demise of Superphénix and the longer than expected revamping of Phénix, transmutation still relies mostly on the Superfact experiments carried out in Phénix in a European framework in the mid 80s. We know its works. It works better in fast neutrons reactors, but even in FBRs, transmutation ratios are never 100%. Any significant results would involve a series of recycling.
My own reservations about P&T is that it would add complexity to the spent fuel reprocessing-recycle for a quite questionable benefit in terms of human health, balancing actual additional operational doses today against hypothetical reduced public doses in the far future. I do believe, though, in long lived waste minimization, but not as a sophisticated add-on to our existing systems: rather as a part of the design specifications of generation 4 systems. The transition period between generation 3 and 4 might be a special case. Let me explain why:
The recycling in LWRs of the plutonium issued from spent MOX fuel is not very attractive, but spent MOX is a good way of storing plutonium before it is needed for future fast breeders. When time comes to extract this plutonium to constitute the FBR initial inventory, one might want to separate the minor actinides - that can be transmuted such plants, in order not to increase above the current accepted level the amount of minor actinides to be vitrified.
Long term Storage is not a matter for science or even R&D: it is a matter of engineering, it could be decided and implemented today. As a matter of fact, the Vitrified Waste storage buildings of La Hague or Rokkasho are very good examples of such facilities, as are many dry spent fuel storage facilities around the world. Can they be qualified as “very long-term”? May be not, but, at worst, three successive 60-year facilities is equivalent to a single 180-year facility… as long as you guarantee retrievability of the packages, which is the basis of “storage” versus “disposal”.
Sub-surface storage may be preferred to surface facilities in order to increase the physical protection: there again, it is purely a matter of engineering.
The only problem I find with long term storage is of ethical nature: I would find distateful to simply leave the legacy to my grandchildren, even if it is done cleanly and safely.
More and more, there is a kind of international consensus in favour of the disposal of HWL in a facility built in a stable underground geological stratum located at medium depth, around 500 meters. I will not discuss the respective merits of cristalline or sedimentary strata: I may have my preferences, but I am convinced that in every case one can find the right conditioning and packaging to fit the specific requirements of a given geologic medium, as long as this medium has proven to be reasonnably stable over geologic periods. The high integrity copper container design adopted in Sweden and Finland for disposal in granite is a good example of such a fit. This disposal should remain reversible at least for a significant period.
The rationale for going underground is to provide an additional barrier to the eventual dissemination of the radioactive species as well as to protect the facility against intrusions and other agressions, be they voluntary or involuntary. Opinion polls and studies tell us that the general public is usually wary of the underground, often associated with seisms or infernal powers… but experience tells us that – as long as you avoid risk-prone areas – geology is vastly more stable and “smooth” that the history of human societies! Disposed of at depth, in a proper conditioning and packaging, radioactive species can only manage to reach the surface through a series of very slow mechanisms (corrosion, leaching, diffusion, migration) giving radioactive decay ample time to play its cleansing role. Radioactive wastes are not biodegradable, as some antinuclear pamphlets rightfully state, but they are indeed “chronodegradable”!
In France, for instance, we have choosen to reprocess our spent fuel both to recover the recyclable materials and to condition the final HLW under a physico-chemical form especially stable and corrosion resitent. Physico-mathematical models qualified on experiments of accelerated corrosion and globaly validated on several “natural analogues” have convinced us that even immersed bare in pure water, the HLW glass blocks would lose only 0.1% of their mass in 10 000 years. Even if you neglect the packaging, the retention capability of the engineered barrier and, further on, of the geologic media will further delay the migration of the species very slowly released by the glass matrix. All international modelling round robins conclude that, when they finaly reach the biosphere, the most mobile surviving species exhibit a radio-toxicity the level of which lies orders of magnitude below those considered acceptable by the present regulations. That is to say: if we choose the geological disposal, we impose upon our inheritors, as far as we can figure, no nuisance we would not accept upon ourselves. This is for me the definition of an ethically as well as technically acceptable solution.
Saying that it appears today a good solution is not the same as pretending it is and will remain the best ever. That is why a minimal amount of reversibility is needed. But if you look carefully into it, the degree of reversibilty to insure is not something to decide today. The decision will have to be taken when it is time to close the disposal, i.e. in one century at least, assuming we – or rather our successors – decide to operate it till saturation. This decision will be taken based upon all the additional knowledge accumulated during those hundred years, not only about the site itself, its behaviour and its environment, but also about eventual alternative management processes which are not mature or even available today. And even if, when time comes, it is decided to close the site “irreversibly”, thousands of years will elapse before irreversibility actually takes place. For centuries after a “leaktight” closure, it will be possible to retrieve the packages, but only through a complex and costly mining operation.
Let me conclude on a note of optimism. In the 60s, disposal appeared to be a simple scientific issue. In the 80s, we learned painfully that it was a difficult social issue. But a lot has happened since 1990. The WIPP has been put to operation; Yucca Mountain has made progresses even though the road is still long before it is licensed. Finland has made its choices, both technical and political, and Sweden appears to be close behind. Alternatives to geologic disposal have been scrutinized and assessed anew within comprehensive and multinational R&D programs. I really believe that in a few decades, geologic disposal will be routine. And if, with time, we design a better mousetrap, a better way to dispose of HLW, we, or our successors shall gladly implement it.
Therefore, since the title of this Workshop is Fact and choices, let me summarize my choices for HLW management (and once again let me emphasize the “my”):
We can and should dispose of pat, present and committed HLW with our best available techniques (our grand children may dispose of their waste differently)
There is no technical reason to delay the decision to create a geologic disposal site for HLW. As there is no hurry to put hot glasses underground, we should begin with IL-LL-W (Intermediate level Long lived waste)
The “reversibility” issue is moot.
1Even
in France, where three quaters of the electricity is generated by nuclear plants,
conditioned HLW amount to ~100 grams per capita and per annum, while highly
toxic non-radioactive wastes total 100 kg/cap/a.
2 Peasants’ uprising, in reference
to an historical episode during the 100 year Anglo-French War (1258).
© European Nuclear Society, 2005