السبت، 30 يوليو 2011

مشاهدة فيلم صرخة نملة اون لاين dvd وبدون تحميل |على قناة عالية الجودة

مشاهدة فيلم صرخة نملة اون لاين dvd وبدون تحميل |على قناة عالية الجودة

Used MOX fuel and used RepU fuel is stored pending reprocessing and use of the plutonium in Generation IV fast reactors. These discharges have amounted to about 140 tonnes per year, but rise to 200 tonnes from 2010.  Used MOX fuel is not reprocessed at present.
EdF's recycled uranium (RepU) is converted in Comurhex plants at Pierrelatte, either to U3O8 for interim storage, or to UF6 for re-enrichment in centrifuge facilities there or at Seversk in Russia*.  About 500 tU per year of French RepU as UF6 is sent to JSC Siberian Chemical Combine at Seversk for re-enrichment.  The enriched RepU UF6 from Seversk is then turned into UO2 fuel in Areva NP's FBFC Romans plant (capacity 150 t/yr). EdF has used it in the Cruas 900 MWe power reactors since the mid 1980s. The main RepU inventory constitutes a strategic resource, and EdF intends to increase its utilization significantly.  The enrichment tails remain at Seversk, as the property of the enricher.
* RepU conversion and enrichment require dedicated facilities due to its specific isotopic composition (presence of even isotopes - notably U-232 and U-236 - the former gives rise to gamma radiation, the latter means higher enrichment is required). It is the reason why the cost of these operations may be higher than for natural uranium. However, taking into account the credit from recycled materials (natural uranium savings), commercial grade RepU fuel is competitive and its cost is more predictable than that of fresh uranium fuel, due to uncertainty about future uranium concentrate prices. 
Considering both plutonium and uranium, EdF estimates that about 20% of its electricity is produced from recycled materials.  Areva's estimate is 17%, from both MOX and RepU.
Areva has the capacity to produce and market 150 t/year of MOX fuel at its Melox plant for French and foreign customers (though it is licensed for 195 t/yr).  In Europe 35 reactors have been loaded with MOX fuel.  Contracts for MOX fuel supply were signed in 2006 with Japanese utilities.  All these fuel cycle facilities comprise a significant export industry and have been France’s major export to Japan.  At the end of 2008 Areva was reported to have about 30 t/yr in export contracts for MOX fuel, with demand very strong.  However, EdF has priority.
To the end of 2009 about 27,000 tonnes of LWR fuel from France and other countries had been reprocessed at La Hague.  In addition about 5000 tonnes of gas-cooled reactor natural uranium fuel was earlier reprocessed there and over 18,000 tonnes at the UP1 plant for such fuel at Marcoule, which closed in 1997.
At the end of 2008 Areva and EdF announced a renewed agreement to reprocess and recycle EdF's used fuel to 2040, thereby securing the future of both La Hague and Melox plants.  The agreement supports Areva's aim to have La Hague reprocessing operating at 1500 t/yr by 2015, instead of two thirds of that in 2008.  It also means that EdF increases the amount of its used fuel sent for reprocessing to 1050 t/yr from 2010, and Melox produces 120 t/yr MOX fuel for EdF then, up from 100 tonnes in 2009.  It also means that EdF will recycle used MOX fuel.
Under current legislation, EdF is required to have made provision for its decommissioning and final waste management liabilities by 2011, but under a new bill that deadline would be deferred until 2016. At the end of 2009, EdF was reported to have EUR 11.4 billion in its dedicated back-end fund, compared with an estimated liability of EUR 16.9 billion.
France's back-end strategy and industrial developments are to evolve progressively in line with future needs and technological developments. The existing plants at La Hague (commissioned around 1990) have been designed to operate for at least forty years, so with operational and technical improvements taking place on a continuous basis they are expected to be operating until around 2040. This will be when Generation IV plants (reactors and advanced treatment facilities) should come on line. In this respect, three main R&D areas for the next decade include:
  • The COEX process based on co-extraction and co-precipitation of uranium and plutonium together as well as a pure uranium stream (eliminating any separation of plutonium on its own). This is designed for Generation III recycling plants and is close to near-term industrial deployment.
  • Selective separation of long-lived radionuclides (with a focus on Am and Cm separation) from short-lived fission products based on the optimization of DIAMEX-SANEX processes for their recycling in Generation IV fast neutron reactors with uranium as blanket fuel. This option can also be implemented with a combination of COEX and DIAMEX-SANEX processes.

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