थोरियम ईंधन चक्र

थोरियम ईंधन चक्र ( thorium fuel cycle) एक नाभिकीय ईंधन चक्र है जो थोरियम के समस्थानिक Th-232 का उपयोग उर्वर पदार्थ (फर्टाइल मैटेरियल) के रूप में करता है। रिएक्टर में Th-232 बदलकर यूरेनियम-२३३ बन जाता है जो नाभिकीय ईंधन है। थोरियम के साथ नाभिकीय अभिक्रियाएँ थोरियम भीगी हुई लकड़ी के समान है। जिस प्रकार भीगी लकड़ी को जलाने के लिए पहले भट्टी में सुखाना पड़ता है उसी तरह थोरियम को विखण्डनीय युरेनियम में बदलना पड़ता है ।" — रतन कुमार सिन्हा, भारत के परमाणु ऊर्जा आयोग के भूतपूर्व अध्यक्षDate set for fuel reactor http://www.telegraphindia.com/1130903/jsp/nation/story_17305278.jsp द टेलीग्राफ 2 September 2013 4 September 2013 https://web.archive.org/web/20130908005511/http://www.telegraphindia.com/1130903/jsp/nation/story_17305278.jsp 8 सितंबर 2013 live 220px In the thorium cycle, fuel is formed when Thorium 232 captures a neutron (whether in a fast reactor or thermal reactor) to become Thorium 233 yes. This normally emits an electron and an anti-neutrino (Antineutrino) by beta- decay to become Protactinium 233 yes. This then emits another electron and anti-neutrino by a second beta- decay to become Uranium 233, the fuel: कचरा विखण्डन उत्पाद Nuclear fission produces radioactive fission products which can have half-lives from days to greater than 200,000 years. According to some toxicity studies, http://hal.archives-ouvertes.fr/docs/00/04/14/97/PDF/document_IAEA.pdf PDF Le Brun C. L. Mathieu, D. Heuer and A. Nuttin Impact of the MSBR concept technology on long-lived radio-toxicity and proliferation resistance Technical Meeting on Fissile Material Management Strategies for Sustainable Nuclear Energy, Vienna 2005 2010-06-20 https://web.archive.org/web/20120522034033/http://hal.archives-ouvertes.fr/docs/00/04/14/97/PDF/document_IAEA.pdf 22 मई 2012 live the thorium cycle can fully recycle actinide wastes and only emit fission product wastes, and after a few hundred years, the waste from a thorium reactor can be less toxic than the uranium ore that would have been used to produce low enriched uranium fuel for a light water reactor of the same power. Other studies assume some actinide losses and find that actinide wastes dominate thorium cycle waste radioactivity at some future periods. http://lpsc.in2p3.fr/gpr/english/NEWNRW/NEWNRW.html#foot284 Nuclear Energy With (Almost) No Radioactive Waste? according to computer simulations done at ISN, this Protactinium dominates the residual toxicity of losses at 10000 years July 2001 Brissot R.; Heuer D.; Huffer E.; Le Brun, C.; Loiseaux, J-M; Nifenecker H.; Nuttin A. Laboratoire de Physique Subatomique et de Cosmologie (LPSC) 19 जून 2015 https://web.archive.org/web/20110525091426/http://lpsc.in2p3.fr/gpr/english/NEWNRW/NEWNRW.html#foot284 25 मई 2011 dead ऐक्टिनाइड कचरा In a reactor, when a neutron hits a fissile atom (such as certain isotopes of uranium), it either splits the nucleus or is captured and transmutes the atom. In the case of Uranium 233, the transmutations tend to produce useful nuclear fuels rather than transuranic wastes. When Uranium 233 absorbs a neutron, it either fissions or becomes Uranium 234 yes. The chance of fissioning on absorption of a thermal neutron is about 92%; the capture-to-fission ratio of Uranium 233, therefore, is about 1:12 — which is better than the corresponding capture vs. fission ratios of Uranium 235 yes (about 1:6), or Plutonium 239 or Plutonium 241 yes (both about 1:3).http://www-pub.iaea.org/MTCD/publications/PDF/TE_1450_web.pdf PDF International Atomic Energy Agency IAEA-TECDOC-1450 Thorium Fuel Cycle-Potential Benefits and Challenges May 2005 2009-03-23 https://web.archive.org/web/20160804054758/http://www-pub.iaea.org/MTCD/publications/PDF/TE_1450_web.pdf 4 अगस्त 2016 live http://www.nndc.bnl.gov/chart/ Interactive Chart of Nuclides Brookhaven National Laboratory 2 March 2015 https://www.webcitation.org/6HZybjtOa?url=http://www.nndc.bnl.gov/chart/ 23 जून 2013 live Thermal neutron cross sections in barns (isotope, capture:fission, f/f+c, f/c) 233U 45.26:531.3 92.15% 11.74; 235U 98.69:585.0 85.57% 5.928; 239Pu 270.7:747.9 73.42% 2.763; 241Pu 363.0:1012 73.60% 2.788. The result is less transuranic waste than in a reactor using the uranium-plutonium fuel cycle. Uranium 234, like most actinides with an even number of neutrons, is not fissile, but neutron capture produces fissile Uranium 235. If the fissile isotope fails to fission on neutron capture, it produces Uranium 236 yes, Neptunium 237 yes, Plutonium 238 yes, and eventually fissile Plutonium 239 and heavier isotopes of plutonium. The Neptunium 237 can be removed and stored as waste or retained and transmuted to plutonium, where more of it fissions, while the remainder becomes Plutonium 242 yes, then americium and curium, which in turn can be removed as waste or returned to reactors for further transmutation and fission. However, the Protactinium 231 yes (with a half-life of 3.27 4 years) formed via (n,2n) reactions with Thorium 232 (yielding Thorium 231 that decays to Protactinium 231 yes), while not a transuranic waste, is a major contributor to the long-term radiotoxicity of spent nuclear fuel. यूरेनियम-232 प्रदूषण Uranium-232 is also formed in this process, via (n,2n) reactions between fast neutrons and Uranium 233, Protactinium 233 yes, and Thorium 232: Uranium-232 has a relatively short half-life (68.9 years), and some decay products emit high energy gamma radiation, such as Radon 224 yes, Bismuth 212 yes and particularly Thallium 208 yes. The full decay chain, along with half-lives and relevant gamma energies, is: thumb|right|300pxUranium 232 yes decays to Thorium 228 yes where it joins the decay chain of Thorium 232 Thorium-cycle fuels produce hard gamma emissions, which damage electronics, limiting their use in military bomb triggers. Uranium 232 cannot be chemically separated from Uranium 233 from used nuclear fuel; however, chemical separation of thorium from uranium removes the decay product Thorium 228 and the radiation from the rest of the decay chain, which gradually build up as Thorium 228 reaccumulates. The hard gamma emissions also create a radiological hazard which requires remote handling during reprocessing. सन्दर्भ इन्हें भी देखें तीन चरणों वाला भारत का परमाणु ऊर्जा कार्यक्रम श्रेणी:नाभिकीय ऊर्जा