Some radioactive elements like tritium and krypton-85 are very difficult and very expensive to trap. But the La Hague plant is permitted to discharge most if not all into the environment. Permission was granted by the Nuclear Safety Authority which oversees all installations. Its CEO is Andre-Claude Lacoste.
Q: How are the discharges from La Hague site determined?
A: It is a process in which the operator, in this case Areva, now writes us to explain what waste they would like to do. First we do a technical study using our technical back-up, the Nuclear Security Protection Institute (IRSN), to verify if the request is technically reasonable or if the request corresponds to reasonable norms. A second study determines if the waste such as requested will have an impact on the populations of the area. We then try to set a waste authorisation level as low as possible , taking the 2 element into account.
Q: When processing spent fuel, rare gases are released, they include krypton-85. This gas can't be trapped so the norm will be proportional to the site's activity. Is that correct?
A: In such a case, we tell Cogema to reexamine they way they can modify their processes and the way they can trap waste. We then set a deadline for them to show us their research results.
Q: Can we trap krypton-85?
A: Not yet. But we asked Cogema to reduce this type of waste. It isn't easy.
A team from the plant takes samples and monitors its radioactive fallout. We met its leader accompanied by the site's PR director.
Q: Is the site's waste contaminating the environment?
A: I wouldn't say "contamination" Based on our measures, we detect natural radiation. We are so to speak, in the background of natural radioactivity.
Q: If it isn't contamination, what is it?
A: I would say absense of impact. There are...Let's start over again! (The head of the site's PR intervenes.)
Q: The question is: Is the environment contaminated? It isn't contaminated?
A: No, it isn't.
Q: You find traces in the environment but it's not contaminated?
We understand the awkwardness of these Areva employees. Since the plant opened, their PR task is impossible. They must recognise the plant discharges radioactive waste, but without using the word "contamination" There are just "trace". There is radioactive waste in the environment but the nuclear industry says: This waste isn't dangerous since it's below health norms. There is a problem when Areva says they are below the norms. The question should be: "Which norms apply?" These norms are based on the Hiroshima and Nagasaki model with populations exposed to intense yet very short external radiation. La Hague is different. People living nearby permanently breathe and eat weakly contaminated elements in the air or food chain. They absorb very low levels but continuous doses of radiation inside the body: "internal contamination" which is chronic and at low levels. It isn't the same system or same model. Take Chernobyl, for example. By using the Hiroshima/Nagasaki model, scientists said: "Near Chernobyl, we'll never see an increase in cancer." 5 year later, they realised there was an epidemic of thyroid cancer among the young. They then had to admit that the model was wrong.
This issue is same around nuclear sites. A risk model is applied yet it isn't representative. Around La Hague there is the impact of environmental contamination. And it will certainly lead to a health impact. Using this model to perdict the number of cancers near La Hague is scientific absurdity. Exposure to low doses of radiation increase the risk of cancer. This has been confirmed by the International Commission on Radiological Protection. The commission considers that, using all existing studies on man and animals, the no-threshold risk model is the most realistic one. A model considering that any dose, even low, increases the risk of cancer, is the model that best reflects a reality.
Reprocessing plants discharge 80% of Europe's radioactivity. Environmentalists and some policians are questioning their necessity. Why reprocess waste? We begin compiling a detailed report on a technology presented as "recycling". Areva show the nuclear fuel cycle as a closed circle. There's no mention of waste. When bottle is recycled 100% of the matter is used.What about nuclear waste? Avera plays at transparency and lets us visit the La Hague site with its directior Eric Blanc. We put on nuclear workers' gear: Areva boiler suit, Cogema socks and a safety kit. Spent fuels from 58 plants in France and certain foreign countries reach La Hague by road and train. These are unloaded in totally sealed bays by robots. Any contact with the fuel would be fatal.
We are near the unloading cell itself. It's the cell we see through the security porthole. We see the unloading dock. The pincers are descending to the spent fuel element. We'll see the spent fuel element being lifted. After unloading, the fuels are placed in a pool to await reprocessing. They must cool down more and become inactive. This is one of 4 intermediatly storage pools of spent fuel elements. In this pool, the water is 9 meters deep, 4 meters of which are above the baskets and fully protect us from the radiation. The water itself is contaminated by the particles from the reactors. The water is permanently filtered by the pumps along the pool. How long are the spent fuel elements stored here? On an average, they stay here for 5 years. France has treated waste from Europe and Japan. Today, it mainly reprocesses the 1400 tons of French fuel that arrive here each year. The cells leave the pool, are cut and placed in a nitric acid bath. This process seperates the different elements present. In the end, there is left: 95% uranium, 1% plunium, and 4% stabilised waste. Our visit illustrates that reprocessing does not neutralise radioactivity as many think, but concentrates it in stabilished waste. Which is extremely dangerous as it contains 99% of the radioactivity. It's poured into molten glass containers, then stored in ventilated pits. We are allowed to visit them. Foe example, if we use a 1000-megawatt reactor, it will annually produce 20 tons of spent fuels. usind these 20 tons, we will produce 15 to 20 glass containers. In other words a reactor will produce high-activity waste amounting to this surface on the ground. If we were to convert this into total French production, all that France consumes in nuclear electricity, which is 80%, will annually generate only this surface in terms of high-activity waste. The surface of the vitrified containers is weak. But some of this high-activity waste will be dangerous for several hundred thousand years!
Nuclear waste history(1)
Nuclear waste history(2)
Nuclear waste history(3)
Nuclear waste history(4)
Nuclear waste history(6)
Nuclear waste history(7)
No comments:
Post a Comment