The Frequently asked questions:
- You scare us with the Greenhouse Effect, but if the next glacial age is close at hand, we shall be all too happy for a little more heat!
Mankind has enjoyed our current interglacial period for the last 10 000 years or so, which happens to be the total duration of the previous interglacial era. As a matter of fact, Arrhenius, who discovered the greenhouse effect of carbon dioxide in 1896, shared you views.
- We are burning oil and coal so fast that very soon there will be no CO2 left to send in the atmosphere. So, why worry?
There is too much oil and far too much coal to burn before CO2 emissions start to dwindle. If we wait for this « spontaneous » decrease, we shall not prevent a climate catastrophe.
- In 1973, we were told that there was only thirty years of oil left. Now, 35 years later, they scare us by pretending there is only forty years left! They should go back to elementary school!
In both cases, the "x" years apply only to proven reserves and not to ultimate resources. The proven reserves of 1973 have long been burnt but, through exploration efforts and progress in production techniques, part of the ultimate resources has been turned into proven reserves... Unfortunately, total resources have not increased.
The real issue is not oil depletion, but the much closer day when oil production is no longer able to follow the growth of demand. Come this day, we shall deeply regret good old year 2008, when oil price was only a mere $ 100 per barrel.
- Natural gas is claimed to be a clean energy source. True or false?
Both! Natural gas is made of almost pure methane: when burning, it does not cause acid rains nor does it emit aerosols containing volatile organic compounds or heavy metals. In terms of “conventional” pollution, natural gas is therefore much cleaner than oil and coal.
As far as greenhouse gases emissions are concerned, burning gas emits only half as much as burning coal, but still a lot. Furthermore, methane is a greenhouse gas 25 times as potent as CO2: beware of leaking gas-pipes!
- Nuclear power may emit very little amount of Greenhouse gases, but it produces dangerous radioactive waste: where is the benefit?
The risks caused by greenhouse gases and radioactive waste differ by orders of magnitude.
Billions of tons of CO2 are released every year in the atmosphere, and we know that if we go on like this, we shall trigger a climate catastrophe of planetary scale.
- If radioactive waste packages are not so hazardous, why don’t you keep them stored in buildings? Why do you want to hide them underground where they shall be forgotten some day?
We plan to dispose of long-lived radioactive waste in deep geological storage in order to add another barrier between the radiations it emits and us. But also in order to protect the waste against any human intrusion, whether voluntary or not: located 500 meters under the ground surface, they will be safe. History has proven to be much more troublesome than Geology…
- Among my relatives and friends, I notice more and more cases of thyroid cancer over the years. My GP says it’s because of the radioactive fallouts from Chernobyl. What do you say?
As a matter of fact, all the developed countries have been experiencing an increase in the number of diagnosed and treated thyroid cancers. But the specialists, both oncologists and endocrinologists, see no relationship whatsoever with the Chernobyl accident, for the following reasons:
It should also be mentioned that the death rate from thyroid cancer in women has decreased during the same period. It is likely that most of the explanation comes from a more systematic preventive screening, using inproved methods (scintigraphy, echography) which detect cancers which would not have been detected previously. This may not be the full explanation.
- It appears that breeder reactors are going to play a big part in the future "Generation IV". If so, why did the French stop their Superphénix breeder?
Rating 1200 MWe, operated by NERSA (51% EDF and 49% other European utilities) from 1985 to 1997, Superphénix remains the most powerful breeder ever.
The French Green Party demanded the immediate and definitive shutdown of Superphénix as a sine qua non condition for them to join with the Socialist Party and the Communist Party to form the "majorité plurielle" which ruled France from 1997 to 2002. When appointed, Prime Minister Lionel Jospin fulfilled his promise and passed a decree to shut the plant down, while Environment Minister Dominique Voynet made sure that the dismantling would become irreversible before the end of her mandate.
A breeder uses roughly 80 times less uranium to produce the same amount of electricity as a “conventional” nuclear reactor. This frees nuclear power for many centuries from any concern about uranium resources: that is why, in a context of nuclear “renaissance”, there is a renewed interest in breeders.
- The lower the grade of the uranium ore, the larger the amount of energy needed to extract it. Don’t you forget this amount of energy into account when establishing the energy balance of a nuclear kWh?
In a typical mining operation (say 2 to 4 kgU per ton of ore; an open pit operation with a rather high total of 20 tons of rocks to move per ton of ore), the direct consumption of energy expressed in equivalent of electrical MWh/tU is at around 50 MWh split into 30 for mining (mainly as fuel for trucks and showels) and 20 for milling (mainly as electricity for crushing and grinding).
This does not include the "energy content" of consumables (explosives, reagents), likely to add a maximum of about 10% to the total.
Considering the use of the uranium in a modern Light Water Reactor such as an EPR, these 50 to 55 MWH are representing about one thousandth of the electricity produced at this reactor per ton of U (expressed as natural uranium fuel content).
- When addressing the resources issue, you mention lithium and not deuterium as a raw material for fusion. Why?
The “ingredients” of fusion are deuterium and tritium. There is so much deuterium in ordinary water that resource is not an issue. But tritium has a short half-life (12 years), and must be produced by neutron capture from enriched lithium – and lithium is far less abundant than deuterium.
- "What should one think of this map of nuclear waste disposal published by ANDRA ?
First, it would be possible to send them to the Sun, but the reliability of the rockets is not high enough: the risk of dispersion due to an explosion of the launcher is much higher than the risk of seeping back to the surface from a deep underground repository ! Frankly speaking, the centre of the Earth is quite beyond reach, but there were studies to bury the waste packages in some “subduction zone” where the mantle plunges, slowly but certainly, because of the continental drift. One cannot control this phenomenon, which is not reversible, and there is a possibility that, once within the magma, the waste could reappear during a volcanic eruption... In short, these remain paper studies.
It was also considered to bury the waste below the ocean floor (sub-seabed disposal), in the benthic plains far from any rift, but the oceans are taboo.
That’s why, today, we are convinced that the best way to isolate the long lived waste from the biosphere is to dispose of the packages in a deep (circa 500 m) geological stratum which has remained stable for millions of years, which is the case as far as the zones marked on the ANDRA map are concerned: clay and marl are very stable sedimentary strata, with enough plasticity to heal any fault of ancient seismic origin. In these media, there is little water and this "geological" water migrates very slowly. It is of importance, because water corrosion is the only mechanism which could – very slowly - extract radioactive species from the massive glass blocks of which they are components. And after, this water must seep its way up to the surface… without loosing the radioactive species along the way (and clay is a very efficient "getter" for most such species). Meanwhile, of course, radioactivity keeps decaying.