oleocene.org

Environnement2100 a écrit : l'exploitation d'une mine d'uranium est une chose fort déplaisante sur le plan environnemental. Entre autres :
- beaucoup de minerais sont à faible teneur ; on éventre donc des montagnes pour récupérer de petites quantités, et les déchets sont au minimum toxiques, parfois radio-actifs ; donc tous les pays "modernes" font tout ce qu'ils peuvent pour éviter d'en chercher chez eux

energybulletin a écrit : Coal Combustion: Nuclear Resource or Danger
Alex Gabbard, Oak Ridge National Laboratory

Over the past few decades, the American public has become increasingly wary of nuclear power because of concern about radiation releases from normal plant operations, plant accidents, and nuclear waste. Except for Chernobyl and other nuclear accidents, releases have been found to be almost undetectable in comparison with natural background radiation. Another concern has been the cost of producing electricity at nuclear plants. It has increased largely for two reasons: compliance with stringent government regulations that restrict releases of radioactive substances from nuclear facilities into the environment and construction delays as a result of public opposition.

Partly because of these concerns about radioactivity and the cost of containing it, the American public and electric utilities have preferred coal combustion as a power source. Today 52% of the capacity for generating electricity in the United States is fueled by coal, compared with 14.8% for nuclear energy. Although there are economic justifications for this preference, it is surprising for two reasons. First, coal combustion produces carbon dioxide and other greenhouse gases that are suspected to cause climatic warming, and it is a source of sulfur oxides and nitrogen oxides, which are harmful to human health and may be largely responsible for acid rain. Second, although not as well known, releases from coal combustion contain naturally occurring radioactive materials--mainly, uranium and thorium.

Former ORNL researchers J. P. McBride, R. E. Moore, J. P. Witherspoon, and R. E. Blanco made this point in their article "Radiological Impact of Airborne Effluents of Coal and Nuclear Plants" in the December 8, 1978, issue of Science magazine. They concluded that Americans living near coal-fired power plants are exposed to higher radiation doses than those living near nuclear power plants that meet government regulations. This ironic situation remains true today and is addressed in this article.

The fact that coal-fired power plants throughout the world are the major sources of radioactive materials released to the environment has several implications. It suggests that coal combustion is more hazardous to health than nuclear power and that it adds to the background radiation burden even more than does nuclear power. It also suggests that if radiation emissions from coal plants were regulated, their capital and operating costs would increase, making coal-fired power less economically competitive.


...Both the benefits and hazards of coal combustion are more far-reaching than are generally recognized. Technologies exist to remove, store, and generate energy from the radioactive isotopes released to the environment by coal combustion. When considering the nuclear consequences of coal combustion, policymakers should look at the data and recognize that the amount of uranium-235 alone dispersed by coal combustion is the equivalent of dozens of nuclear reactor fuel loadings. They should also recognize that the nuclear fuel potential of the fertile isotopes of thorium-232 and uranium-238, which can be converted in reactors to fissionable elements by breeding, yields a virtually unlimited source of nuclear energy that is frequently overlooked as a natural resource.

In short, naturally occurring radioactive species released by coal combustion are accumulating in the environment along with minerals such as mercury, arsenic, silicon, calcium, chlorine, and lead, sodium, as well as metals such as aluminum, iron, lead, magnesium, titanium, boron, chromium, and others that are continually dispersed in millions of tons of coal combustion by-products. The potential benefits and threats of these released materials will someday be of such significance that they should not now be ignored.
(X Jan 2007)
Contributer EG writes: "More energy goes up the smokestacks of coal fired power plants in the form of uranium and thorium than the coal produces."

It's likely that Oak Ridge National Laboratory has a vested interest in pointing out problems with coal. Nonetheless, their studies may be relevant. -BA

UPDATE from MP: "The information about radioactive emissions from coal plants being more than from nuclear ones has been known for years, was in the press in the 70's or 80's, as I remember. Not new with the ORNL study "

transhuman a écrit : A peine deux jours ont passés depuis la révélation ecolo de georges qu'une étude sort nous révélant que la combustion dégage elle aussi des matières radio actives

gte79 a écrit :J'ai bossé dans l'extraction d'uranium au Canada, pays "moderne" s'il en est, et je peux t'affirmer qu'on est loin d'y faire n'importe quoi, toutes les activités sont suivies par des organismes de contrôle extrêmement stricts (qui ont le pouvoir de faire arrêter les opérations), et ce depuis l'étude de faisabilité jusqu'au réaménagement de la mine...

Je te le répète, et je pense être mieux placé que toi pour en parler, pour avoir bossé sur un site minier d'uranium dans l'ouest canadien, toutes les activités sont extrêmement encadrées.

gte79 a écrit :Je sais que l'exploitation pétrolière en Athbasca est très couteuse en énergie et polluante. Par contre, "éco-terroriste", le Canada ? Faudrait pas exagérer non plus !

Environnement2100 a écrit : on a même un excellent film sur le sujet ici même .

Environnement2100 a écrit :Au lieu de prendre les choses avec hauteur, prends ta calculette, et un peu d'altitude

Environnement2100 a écrit :Sais-tu à quel point ?
L'Athabasca sort environ 2Mbbl/d de "brut", soit 300 000 t/j, ce qui conduit à 1.1Mt CO2 par *jour* soit 400 Mt/an, soit quasiment l'équivalent de la totalité de la production française. Et tout ça pour quoi à ton avis ?

gte79 a écrit :

Environnement2100 a écrit :Sais-tu à quel point ?
L'Athabasca sort environ 2Mbbl/d de "brut", soit 300 000 t/j, ce qui conduit à 1.1Mt CO2 par *jour* soit 400 Mt/an, soit quasiment l'équivalent de la totalité de la production française. Et tout ça pour quoi à ton avis ?

OK OK... la conso mondiale actuelle est de 80 Mbbl/jour. Méchants saoudiens, méchants russes, méchants vénézueliens, vous pourrissez notre planète... Oups, j'oubliais, c'est nous qui consommons ce pétrole