Recycling Spent Nuclear Fuel Option for Nuclear Sustainability and more proliferation resistance In FBR

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1 Recycling Spent Nuclear Fuel Option for Nuclear Sustainability and more proliferation resistance In FBR SIDIK PERMANA a, DWI IRWANTO a, MITSUTOSHI SUZUKI b, MASAKI SAITO c, ZAKI SUUD a a Nuclear Physics and Bio Physics Research Group, Bandung Institute of Technology, Gedung Fisika, Jl. Ganesha 10, Bandung 40132, INDONESIA psidik@fi.itb.ac.id b Department of Science and Technology for Nuclear Material Management (STNM), Japan Atomic Energy Agency (JAEA), 2-4 Shirane, Shirakata, Tokai Mura, Naka-gun, Ibaraki JAPAN, c Research Laboratory for Nuclear Reactors, Tokyo Institute of Technology O-Okayama, Meguro-ku, Tokyo JAPAN Abstract: - Spent nuclear fuels (SNF) from the reactors have some advantages to be used and recycled in term of reducing environmental impact from spent nuclear fuel as a waste, increasing sustainability of nuclear fuel as well as the concern of nuclear non-proliferation of nuclear fuel material. Recycling program of transuranic (TRU) is adopted and shows some advantages to be loaded into fast reactor has been investigated in this present study focus on sustainability nuclear fuel and nuclear non-proliferation aspect in fast breeder reactor (FBR). Actinide composition and isotopic plutonium aspect is based on a fast breeder reactor (FBR) type which is loaded by some different fuel composition in the core regions of FBR. The inventory mass ratio of higher burnup gives less inventory ratio for both plutonium and transuranium inventory ratios. In case of shorter cooling time process, transuranium inventory attains better inventory ratio than plutonium and for longer cooling time process, plutonium obtains better than transuranium. Transuranium fuel loading in UTRU fuel type gives significant contribution to increases more inventory ratio of plutonium in comparing with its plutonium production of MOX fuel type. In the same time, transuranium inventory ratio is also significantly reduced for transutanium fuel loading in the FBR core. In short, transuranium fuel loading can be estimated to produce more plutonium inventory and to reduce the composition of tranuranium or MA compostion in the core region. More compositions of even mass of plutonium isotopes are obtained for transuranium fuel loading such as Pu-238 and Pu-240. The increasing composition of even mas is considered to improve proliferation resistance level of FBR core in term of material barrier of plutonium isotopes. More MA fuel loading in transuranium fuel as well as longer reactor operation time will produce more even mass plutonium which affect to the increase of plutonium proliferation resistance level. Key-Words: spent nuclear fuel, recycling program, light water, FBR, inventory ratio, transuranium, plutonium, proliferation resistance 1 Introduction Recycling program of spent nuclear fuels (SNF) from the reactors have some advantages to be used and recycled in term of reducing environmental impact from spent nuclear fuel as a waste, increasing sustainability of nuclear fuel as well as the concern of nuclear non-proliferation of nuclear fuel material. Recycling program of SNF of light water reactors (LWR) is required because of its potential to reload some SFN as fresh fuel for instance recycling uranium and plutonium, instead of once through fuel option. Recycling SNF option such as recyling SFN uranium and plutonium as a MOX fuel type, has been developed as a commercialized program and in addition, recycling option of minor actinide (MA) is also considered to ISBN:

2 be used in water cooled reactors and in other reactor types. This recycling MA option will have some benefit not only to reduce its actinides accumulation but also soem consideration to increase nuclear nonproliferation level suach as plutonium proliferation resistance issue by adopting some recycling MA. A typical spent fuel composition of LWR based on discharged fuel burnup of 33 GWd/t and cooling 3 years is shown in Figures 1. It shows some main actinides of spent nuclear fuels as well as fission product (FP). Uranium, plutonium and minor actinide (MA) are hevay nuclides which can be used as new fresh fuel after reproccesed and recycling process and fission product (FP) is light nuclide as material product from fission reaction in the reactors. Plutonium and some minor actinides (MA) are classified as transuranium (TRU) material which has higher mass number than uranium and those are produced from nuclear reaction in nuclear facilities such as in nuclear reactors. Recycling program of SNF LWR including partial and full closed cycle options can be applied for thermal neutron reactor type and fast reactor type as well as some other innovative reactors. In case of fast reactor technology, it shows some advantages in term of high fuel breeding capability and high level of reducing spent fuels by burning process in the same time. Loading some recycling MA also can be considered to increase more proliferation resistance of nuclear material because of higher level of material barrier[1-4]. Recycling program of transuranic (TRU) is adopted and shows some advantages to be loaded into fast reactor has been investigated in this present study focus on sustainability nuclear fuel and nuclear nonproliferation aspect in fast breeder reactor (FBR). Some investigations have been conducted to use transuranium material in nuclear reactor facilities for some purposes such as to extend the nuclear reactor operation time as a long life reactor program [5, 6], to evaluate high burning MA capability [7], to investigate some transmutation TRU capability [8] and to evaluate a recycling program for MA loading option in LWR type [9]. 2 Problem Formulation A potential program for recycling option of transuranium from spent nuclear fuel (SNF) will be presented and discussed in this present paper based on two main considerations such as nuclear fuel sustainability and nuclear non-proliferation aspect. Fuel sustainability of nuclear material will be evaluated based on inventory ratio of some actinides and nuclear non-proliferation aspect is also evaluated based on production of plutonium and its compositions. A fast breeder reactor (FBR) type is adopted in this analysis for different loading materials in the core regions of FBR as well as reactor operation analysis. Different loading materials which are used in the FBR core, are produced from spent nuclear fuel (SFN) of light water reactor (LWR). In this section, spent fuel analysis, Actinide composition and plutonium composition in core region FBR, effect of burnup and cooling SNF LWR to inventory ratio of FBR, and Transuranium Loading Effect to Inventory Ratio of FBR. 2.1 Spent Fuel Analysis Composition Figure 1 Spent Nuclear Fuel Element Composition of LWR Analysis of spent nuclear fuel based on LWR type was conducted by adopting ORIGEN computer code [10] based on fuel behavior and fuel compositions for different burnup and decay fuel time. Some typical fuel burnups and initial enrichment of uranium as fresh fuel of PWR is used as standard case of spent fuel composition. Initial fuel loading as fresh fuel from the beginning of operation up to spent fuel at end operation as well as cooling process after discharged fuel from the reactors are adopted. The evaluation of burnup effect and cooling effect to the behavior of spent nuclear fuel is based on some parameters for fuel burnup level of 33 GWd/t, up to 60 GWd/t as well as parameter for decay time process from 1 year cooling up to 30 years cooling time. Actinide compositions are sensitive to burnup level and decay time in particular for some plutonium isotopes and minor actinides [11]. These composition of spent nuclear ISBN:

3 fuel of LWR will be used as a loading fuel of fresh fuel in reactor core of FBR tyepe. Some typical composition from different burnup and cooling time of LWR will be loaded into the FBR core. Those different loaded fuel in FBR will be analyzed its effect to FBR behavior of reactor criticality, inventory and actinide composition of spent nuclear fuel of FBR after reactor operation from the beginning of operation. 2.2 Actinide and Plutonium Composition in Core Region FBR From fresh nuclear fuel which is loaded into the reactor, will produce some actinides as well as fission products during reactor operation. Nuclear reaction chain and transmutation process of actinide in the reactor is the basis to produce some composition of nuclear fuel from the beginning of reactor operation up to the end of operation. Actinide production in the core is based on the compostion of uranium fuel, neptunium, plutonium, americium dan curium. Uranium and plutonium are produced as main actinide and neptunium, americium and curium are classified as minor actinide because of small composition in comparing with main actinide. Recycling and reprocessing program of spent nuclear fuel have some potentials of proliferation which can be used for contructing non-peaceful uses or destructive devices. An approach to reduce some potential of nuclear material utilization for nuclear proliferation issue should be pursued such as to increase the level of proliferation resistance. This increasing level in based on a composition of material barrier aspect in intrinsic feature of proliferations as well as extrinsic aspect of proliferations. This material barrier is based on some of the importance feature of high intensity level of decay heat (DH) and level of spontaneous fission neutron (SFN). In case of plutonium, high level of material barrier is shown by increasing of even mass number composition of plutonium isotopes. One of the potential transmutation option is by adopting doping or loading minor actinide (MA) in the reactors to produce more protected plutonium proliferation by high composition of even mass of plutonium from converted MA [1-4]. Therefore, plutonium compsotion of spent nuclear fuel of FBR core will be analyzed to evaluate its effect to nuclear nonproliferation resistance of intrinsic factor especially from the compostion of even mass of plutonium which shows its significant level to increase material barrier of isotopic plutonium [1-4]. 2.3 Reactor Core of FBR Design Fast breeder reactor or FBR system was adopted for this evaluation because fo the potential benefit for future commercial nuclear energy. The benefit of FBR utilizations are for extending nuclear fuel utilization which is connected to fuel sustainability of fuel breeding capability as well as self fuel inventory production. FBR design can be used to burn some spent nuclear fuel such as minor actinide. This burning process is used to produce some additional energy from spent nuclear fuel and to reduce environmental impact from spent fuel because of less volume production. FBR design as a typical reactor type of fast reactor is use a coreblanket fuel arrangement. This arrangement is designed for some core regions for maintaining criticality of reactor operation and some blanket regions which is used for fuel breeding regions[12]. An integrated code system was used for evaluating reactor core behavior for whole FBR core configuration and for nuclide data library, it was used JFS-3-J-3.2R which is based on the JENDL 3.2 [13-16]. 2.4 Inventory ratio of FBR Composition of actinide or heavy metal (HM) of the FBR system was evaluated for several fuels loading composition as initial fresh fuel which is based on some compsoition of spent nuclear fuel of LWR types. These actinide composition of FBR comes from fuel composition production during reactor operation from the beginning of cycle or operation up to the equilibrium compsotion of FBR. Inventory ratio of actinide is used based on the mass inventory of actinide at equilibrium discharged fuel and initial fuel supply. It is also adopted to analyze the fuel mass balance of FBR supply and discharged. Actinide or HM production is compared with the initial supply fuel actinide to estimate the sustainability aspect of nuclear fuel production than comsumption. Composition of actinide is also evaluated to show its fuel inventory is over production or smaller production than supply fuel which is required for reactor operation. Inventory ratio higher than unity can be classified than fuel breeding process is attained and if it less than unity can be estimated only fuel conversion process was occurred. In this evaluation, inventory rasio will be focused on inventory ratio of plutonium composition and transuranium composition. Plutonium inventory is evaluated to estimate the breeding gain from plutonium production than consumption. Transuranium inventory ratio is ISBN:

4 evaluated to analyze production rate of actinide with excluding uranium. This production rate of transuranium also can be used to estimate the minor actinide production. 3 Problem Solution Some obtained results from recycling option of transuranium from spent nuclear fuel (SNF) will be shown in this section and continued by discussing. The main idea of this analyses are sustainability aspect of actinide inventory and nuclear nonproliferation aspect based on isotopic plutonium composition. These actinide composition and isotopic plutonium aspect is based on a fast breeder reactor (FBR) type which is loaded by some different fuel composition in the core regions of FBR. Effect of burnup and cooling SNF LWR as loaded fuel material of MOX fuel in the core region of FBR to the mass inventory ratio of whole FBR will be analyzed. In addition, transuranium fuel loading in the core region to the inventory of actinide will also been evaluated based on the transuranium fuel type and it is compared with MOX fuel type. Obtained results of plutonium isotopic composition will be shown and discussed to estimate the plutonium proliferation level. All those actinide compsotion and plutonium isotopic compositions are based on the equilibrium compsotion of discharged fuel and initial fuel supply as a fresh fuel. 3.1 Effect of Burnup and Cooling SNF LWR to Inventory ratio FBR Attaining fuel breeding in this paper will be based on the inventory ratio of mass production in comparing with supply fresh fuel. Different fuel loadings based on MOX fuel type are shown in Figs 2 and 3. Different fuel loadings in this case are coming from the different spent nuclear fuels of LWR which is basically produced by the different composition from the effect of burnup and cooling time process in the LWR type. These different fuel compositios are loaded in the core regions of FBR which will affects to the fuel compositions of FBR type. The figures show inventory mass ratio of FBR type from plutonium inventory and transuranium inventory ratios. The different fuel loading caused by different burnup of LWR type is shown in fig. 2 that shows higher burnup gives less inventory ratio for both plutonium and transuranium inventory ratios. Plutonium inventory ration obtains slightly higher ratio than transuranium which shows better plutonium production ratio of plutonium than transuranium. Transuranium composition is based on composition of plutonium plus minor actinide (MA) and less transuranium ratio than plutonium is estimated from the decreasing production of MA which causes in total transuranium inventory becomes less. Figure 3 shows the effect of different cooling time process in LWR as loading material to the inventory ratios based on MOX fule type of FBR. Its shows longer cooling time process obtains higher inventory ratio than shorter cooling time especially for plutonium inventory. In case of shorter cooling time process, transuranium inventory attains better inventory ratio than plutonium and for longer cooling time process, plutonium obtains better than transuranium. Inventory Ratio of MOX fuel Type in Core Regions Figure 2 Inventory ratio of Plutonium and Transuranium based on MOX Fuel type in core region for different Burnup of SFN LWR as supplied fuels Inventory Ratio of MOX fuel Type in Core Regions Figure 3 Inventory ratio of Plutonium and Transuranium based on MOX Fuel type in core region FBR for different Cooling time of SFN LWR as supplied fuels ISBN:

5 3.2 Transuranium Loading Effect to Inventory Ratio of FBR The effect of transuranium fuel loading based on TRU fuel type in the core region of FBR is obatined and will be compared with MOX fuel type to estimate the effect of more actinide compositions are loaded in the FBR core especially from the additional composition of MA loading. The effect of transuranium fuel loadings to the actinide inventory ratios are shown in Fig 4. Figure shows transuranium fuel loading in UTRU fuel type gives significant contribution to increases more inventory ratio of plutonium in comparing with its plutonium production of MOX fuel type. In the same time, transuranium inventory ratio is also significantly reduced for transutanium fuel loading in the FBR core. Inventory Ratio of MOX fuel and TRU fuel Types in Core Regions Figure 4 Inventory ratio of Plutonium and Transuranium based on MOX and TRU Fuel types in core region FBR of SFN LWR as supplied fuels This condition is occuring because of the transuranium fuel loading gives additional MA composition to the composition of plutonium in TRU fuel type which gives some additional significant plutonium production from converted MA. Some additional converted MA into plutonium for instance more even mass plutonium are produced from conversion process of MA. This conversion process is effective to give some breeding gain of plutonium at the end of operation and in the same time, some MA becomes less which affect to the decreasing of transuranium inventory ratio at the end of cycle. This transuranium fuel loading is good candidate to produce mre plutonium inventory and to reduce the composition of tranuranium or MA compostion in the core region. However, in case of mass balance for MA production is not so good condition especially for future MA mass balance. 3.3 Isotopic Composition of Plutonium Plutonium production at the equilibrium fuel condition and its plutonium compsotion are evaluated for different fuel type of MOX and TRU fuel types. Plutonium compsotion analysis is based on the isotopc plutonium compsotion from plutonium vector composition of each plutonium isotopes. The vector of plutonium isotope can be used also for plutonium quality which shows the composition of fissile material of Pu-239 and Pu- 241 in comparing with even mass plutonium. In addition, this analysis of vector composition of plutonium will be used for evaluating of proliferation resistance level of plutonium which is based on isotopes composition of even mass plutonium. This even mass plutonium composition has already used as parameter control for some some categorizations of plutonium for plutonium proliferation resistance purpose for several plutonium grades or categorizations [17-20]. As mentioned before, those categorization of even mass plutonium based is considered because of the isotopic plutonium has specific parameters for material barriers of plutonium especially for even mass plutonium such as effect of decay heat (DH) activity and spontaneous fission neutron (SFN). High intensity of DH and SFN from even mass plutonium are adopted to estimate the level of material barrier to increase the level of technical difficulties to construct a nuclear explosive device and more difficult to control pre-initiation of high explosive especially from the contribution of Pu-238 and Pu-240 [18-20]. Obtained results of isotopic plutonium compositions for different fuel loading are shown in Figs. 5 and 6 which show some composition of plutonium based on Pu-238 up to Pu-242. The figure show each plutonium isotops has their own compsotion trend for different fuel loading of MOX and TRU fuel types. Pu-238 for MOX fuel loding is decreasing for longer reactor operation which show composition of Pu-238 at the end of cycle (EOC) is less than beginning of cycle (BOC). In case of TRU fuel loading, Pu-238 composition obtains more significant increase for longer operation (EOC) than BOC. Pu-239 and Pu-242 are decreasing as well as Pu-240 is increasing for longer operation time of both loading fuel types. In case of Pu-241, its composition is increasing for MOX fuel and it is ISBN:

6 decreasing for TRU fuel loading for longer operation time. Even mass plutonium compsotion of Pu-238 is shown higher for TRU fuel type than MOX fuel becuase of the contribution of converted MA in TRU fuel during reactor operation whichproduced more Pu-238 from some converted MA. Pu-240 is also attaining higher for longer operation for both fuel types, because of the production of Pu-240 is more effective for longer operation and in the same time some contributions from converted Pu-239 into Pu-240 from capturing neutron are also effective. Increasing Pu-240 will be started from the decresing composition of Pu-239 for longer operation because of conversion prosess into Pu-240 and main contribituion is comeing from the fission process of Pu-239 as fissile material for maintaining reactor operation. Figure 5 Plutonium Composition [% wt] based on MOX Fuel type in core region FBR of SFN LWR as supplied fuels Figure 6 Plutonium Composition [% wt] based on TRU Fuel type in core region FBR of SFN LWR as supplied fuels Higher compositions of even mass of plutonium isotopes are obtained at equilibrium condition for transuranium fuel loading such as Pu-238 and Pu The increasing composition of even mas is considered to improve proliferation resistance level of FBR core in term of material barrier of plutonium isotopes. Therefore, more MA loading in transuranium fuel as well as longer reactor operation time will produce more even mass plutonium which affect to the increase of plutonium proliferation resistance level. FBR system in core region can be more proliferation resistance by adopting more MA loading in the core. 4 Conclusion The main idea of this analyses are focused on sustainability aspect of actinide inventory and nuclear non-proliferation aspect based on isotopic plutonium composition. These actinide composition and isotopic plutonium aspect is based on a fast breeder reactor (FBR) type which is loaded by some different fuel composition in the core regions of FBR. Plutonium inventory ration obtains slightly higher ratio than transuranium which shows better plutonium production ratio of plutonium than transuranium. Transuranium composition is less than plutonium which is estimated from the decreasing production of MA which causes in total transuranium inventory becomes less. The inventory mass ratio of higher burnup gives less inventory ratio for both plutonium and transuranium inventory ratios. Its shows longer cooling time process obtains higher inventory ratio than shorter cooling time especially for plutonium inventory. In case of shorter cooling time process, transuranium inventory attains better inventory ratio than plutonium and for longer cooling time process, plutonium obtains better than transuranium. Transuranium fuel loading in UTRU fuel type gives significant contribution to increases more inventory ratio of plutonium in comparing with its plutonium production of MOX fuel type. In the same time, transuranium inventory ratio is also significantly reduced for transutanium fuel loading in the FBR core. This condition is occuring because of the transuranium fuel loading gives additional MA composition to the composition of plutonium in TRU fuel type which gives some additional significant plutonium production from converted MA. This transuranium fuel loading is good candidate to produce mre plutonium inventory and to reduce the composition of tranuranium or MA compostion in the core region. Higher compositions of even mass of plutonium isotopes are obtained at equilibrium condition for transuranium fuel loading such as Pu- 238 and Pu-240. The increasing composition of even mas is considered to improve proliferation resistance level of FBR core in term of material barrier of ISBN:

7 plutonium isotopes. Therefore, more MA loading in transuranium fuel as well as longer reactor operation time will produce more even mass plutonium which affect to the increase of plutonium proliferation resistance level. Acknowledgements We would like to acknowledge and extend our gratitude to research innovation program of Institut Teknologi Bandung and the research program of ministry of research, technology and higher education for the research grant. References: [1] M. Saito, Multi-Component Self-Consistent Nuclear Energy System for Sustainable Growth, Prog. in Nucl. Energy, 40[3-4], 365 (2002). [2] Y. MEILIZA, M. SAITO and H. SAGARA., Protected Plutonium Breeding by Transmutation of Minor Actinides in Fast Breeder Reactor, J. Nucl. Sci. Technol., Vol. 45[3], 230 (2008). [3] S. Permana, M. Suzuki, M. Saito, Effect of TRU Fuel Loading on Core Performance and Plutonium Production of FBR, Nucl. Eng. Des, 241, (2011). [4] S. Permana, M. Suzuki, M. Saito, Basic Analysis on Isotopic Barrier of Material Attractiveness Based on Plutonium Composition of FBR, J. Nucl. Sci. Technol., 48[5], (2011). [5] S. Permana., Z. Suud, Core Performance and Plutonium Production of Small Long Life Fast Reactor using Doping Actinides, Proc. of ICAPP, May 10-14, 2009, Tokyo-Japan. [6] S. Permana., Z. Suud, and M. Suzuki, 2009, Trans-uranium doping utilization for increasing protected plutonium proliferation of small long life reactor, Proc. of Global, September 6-11, 2009, Paris, France,. [7] H. Choi and T. J. Downar, A Liquid-Metal Reactor for Burning Minor Actinides of Spent Light Water Reactor Fuel I: Neutronics Design Study, Nucl. Eng. Des., 133, 1 22 (1999). [8] Edward A. Hoffman and Weston M. Stacey, Comparative Fuel Cycle Analysis of Critical and Subcritical Fast Reactor Transmutation Systems, Nucl. Technol., 144, 83 (2003). [9] T. A. Taiwo, et al., Assessment of a Heterogeneous PWR Assembly for Plutonium and Minor Actinide Recycle, Nucl. Technol., 155, 34 (2006). [10] S. B. Ludwig and A. G. Croff., ORIGEN 2.2 Isotope Generation and Depletion Code Matrix Exponential Method, Oak Ridge National Laboratory (2002). [11] S. Permana, M. Suzuki, M. Saito, Proliferation Resistance Analysis of Plutonium from LWR during multi-recycling with MA in FBR, Proc. of ICAPP, May 16-19, 2011, Chiba-Japan. [12] S. Ohki, et al., Design Study of Minor Actinide Bearing Oxide Fuel Core for Homogeneous TRU Recycling Fast Reactor System, The 10th OECD/NEA P&T Meeting, October 6-10, 2008, Mito, Japan. [13] M. Nakagawa, K. Tsuchihashi, SLAROM: A Code for Cell Homogenizations Calculation of Fast Reactor, JAERI 1294, Japan Atomic Energy Research Institute (1984). [14] T. B. Fowler, D. R. Vondy, G. W. Cunningham, Nuclear Reactor Core Analysis Code: CITATION, Oak Ridge National Laboratory report, ORNL-TM-2496, Rev2, USA (1971) [15] G. Chiba et al., The Revision of Nuclear Constant Set for Fast Reactor JFS-3-J3.2, J. At. Energy Soc. Jpn., 14, 335 (2002). [16] T. Nakagawa et al., Japanese Evaluated Nuclear Data Library Version 3 Revision-2: JENDL-3.22, J. Nucl. Sci. Technol., 32, 1259 (1995). [17] International Atomic Energy Agency, Information Circular, INFCIRC/153, (1972). [18] B. Pellaud, Proliferation aspects of plutonium recycling, J. Nucl. Mater. Managements, XXXI, No. 1 (2002). [19] G. Kessler, Plutonium denaturing by Pu- 238, The First Int. Sci. Technol. Forum on Protected Plutonium Utilization for Peace and Sustainable Prosperity, March 1 3, 2004, Tokyo, Japan. [20] G. Kessler, Plutonium denaturing by Pu- 238, Nucl. Eng. Des., 155, (2007). ISBN: