Proceedings of ICAPP ‘09 Tokyo, Japan, May 10-14, 2009 Paper 9521 All Heavy Metals Closed-Cycle Analysis on Water-Cooled Reactors of Uranium and Thorium Fuel Cycle Systems Sidik Permana 1,2 , Abdul Waris 2 , Naoyuki Takaki 3 , and Hiroshi Sekimoto 1 1 RESEARCH LABORATORY FOR NUCLEAR REACTORS, TOKYO INSTITUTE OF TECHNOLOGY 2-12-1-N1-17, O-okayama, Meguro-ku, Tokyo 152-8550, Japan Tel/Fax: +81-3-5734-2955, E-mail: permana.s.ab@m.titech.ac.jp (sidik), hsekimot@nr.titech.ac.jp(sekimoto) 2 DEPARTMENT OF PHYSICS, BANDUNG INSTITUTE OF TECHNOLOGY Gedung Fisika, Jl. Ganesha 10, Bandung 40132, Indonesia, Email:awaris@fi.itb.ac.id 3 DEPARTMENT OF ENERGY SCIENCE AND ENGINEERING, TOKAI UNIVERSITY 1117 Kitakaneme, Hiratsuka, Kanagawa 259-1292, Japan Abstract - Uranium and Thorium fuels as the basis fuel of nuclear energy utilization has been used for several reactor types which produce trans-uranium or trans-thorium as “by product” nuclear reaction with higher mass number and the remaining uranium and thorium fuels. The utilization of recycled spent fuel as world wide concerns are spent fuel of uranium and plutonium and in some cases using recycled minor actinide (MA). Those fuel schemes are used for improving an optimum nuclear fuel utilization as well to reduce the radioactive waste from spent fuels. A closed-cycle analysis of all heavy metals on water-cooled cases for both uranium and thorium fuel cycles has been investigated to evaluate the criticality condition, breeding performances, uranium or thorium utilization capability and void reactivity condition. Water-cooled reactor is used for the basic design study including light water and heavy water-cooled as an established technology as well as commercialized nuclear technologies. A developed coupling code of equilibrium fuel cycle burnup code and cell calculation of SRAC code are used for optimization analysis with JENDL 3.3 as nuclear data library. An equilibrium burnup calculation is adopted for estimating an equilibrium state condition of nuclide composition and cell calculation is performed for calculating microscopic neutron cross-sections and fluxes in relation to the effect of different fuel compositions, different fuel pin types and moderation ratios. The sensitivity analysis such as criticality, breeding performance, and void reactivity are strongly depends on moderation ratio and each fuel case has its trend as a function of moderation ratio. Heavy water coolant shows better breeding performance compared with light water coolant, however, it obtains less negative or more positive void reactivity. Equilibrium nuclide compositions are also evaluated to show the production of main nuclides and also to analyze the isotopic composition pattern especially thorium, uranium, plutonium and minor actinide isotopes. Main contribution for breeding and void reactivity condition as well as criticality condition comes from the contribution of fissile material such as Pu-239 and U-233; however, some intermediate nuclides are estimated to have some contribution to main fissile nuclides for obtaining higher or lower breeding capability and positive or negative void reactivity condition. I. INTRODUCTION Fuel sustainability of nuclear energy which mainly based on the breeding capability of the reactors, shows a similar trend with the renewable energies for maintaining a sustainable energy supply 1) . In addition, the utilization of uranium and thorium sources including some abundant source in sea water and also a recycled fuel option, which “re-use” spent fuel such as plutonium and minor actinides as a new fuel to be used for conventional or advance reactors, gives more “attractive” feature for future fuel sustainability of nuclear fuel utilization. To meet the global nuclear energy contribution especially for extending the sustainable of nuclear fuel, thorium fuel technology 2-6) has being developed well, not only for conventional reactor but also provided the thorium breeder reactor programs as well as Uranium fuel technology. Water cooled reactor technology including light water and heavy water reactors is an establish and current nuclear plant technology which is world wide use technology in common use through enormous operation experiences. This fact of water plant technology indicates that its technology is reliable and acceptable for both public and utilities such as transparent coolant is more convenient for maintenance especially for utility company. Closed cycle scheme was introduced for evaluating the optimum fuel utilization which can be adopted for both main reactor types, fast reactor and thermal reactor types. Due to the neutron economic requirement for closed cycle scheme, especially for incineration of higher actinide