Study on core radius minimization for long life Pb-Bi cooled CANDLE burnup scheme based fast reactor (original) (raw)
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Optimization of Small Pb-Bi Cooled Modified CANDLE Burnup based Long Life Fast Reactors
Indonesian Journal of Physics, 2012
In this study optimization of modified CANDLE burnup scheme based long life Pb-Bi Cooled Fast Reactors with natural Uranium as Fuel Cycle Input for small long life reactors has been performed. In this design the reactor cores are subdivided into several parts with the same volume in the axial directions. The natural uranium is initially put in region 1, after one cycle of 10 years of burn-up it is shifted to region 2 and the region 1 is filled by fresh natural uranium fuel. This concept is basically applied to all regions, i.e. shifted the core of I’th region into I+1 region after the end of 10 years burn-up cycle. In this paper we discuss the characteristics of several designs of small long life Pb-Bi cooled fast reactors with modified CANDLE burn-up scheme. Four power levels of 250MWt, 400MWt, 600MWt, and 800MWt were investigated. For 250MWt and 400MWt cores we employed 67.5% high fuel volume fraction nitride fuels with large pin diameter of 1.35 cm while for 600and 800MWt cores w...
Application of Modified CANDLE Burnup to Very Small Long Life Gas-Cooled Fast Reactor
Advanced Materials Research, 2013
ABSTRACT Gas-cooled Fast Reactor is a good candidate for fourth generation nuclear power plant that projected to be used started in 2030. In this study, modified CANDLE burn-up strategy is adopted to create 300 MWt long life Gas-cooled Fast Reactor with metallic fuel U-10wt%Zr without enrichment. This design demonstrated excellent performance with the average discharge burn-up is about 25.9% HM.
Design research of small long life CANDLE fast reactor
Annals of Nuclear Energy, 2008
The feasibility of a small long life fast reactor with CANDLE burn-up concept was investigated. It was found that a core with 1.0 m radius and 2.0 m length can bring about CANDLE burn-up with nitride (enriched N-15) natural uranium as fresh fuel. Lead-Bismuth is used as coolant. From equilibrium analysis, we obtained the burn-up velocity, output power distribution, core temperature distribution, etc. The burn-up velocity is less than 1.0 cm/year, which easily permits a long core life design. The averaged core discharged fuel burn-up is about 40%. For better understanding of the effect of the coolant to fuel volume ratio, comparison was made among five cases. In these cases the coolant channel radii were different from one case to another, while fuel pin pitch was fixed. Comparisons were also made with a fixed coolant channel radius and different fuel pin pitches. A simulation of core operation is implemented and the results show that the present design can establish the long time steady CANDLE burn-up successfully without a burn-up control mechanism.
Journal of Physics: Conference Series, 2020
Comparative study of the conceptual design of Gas-cooled Fast Reactor (GFR) core type tall versus pancake based on modified CANDLE-B (MCANDLE-B) burnup strategy has been done. MCANDLE-B is a burnup strategy that utilizes natural uranium or depleted fuel as its input cycle. The conceptual design of a reactor core that compared is the tall cylinder and the pancake cylinder. In this case, the fuel used is U-10%Zr, SS-316 as a cladding material and helium as a coolant. The total volume of the two reactor cores is the same, namely 15.4 m3. SRAC 2K6 software with PIJ and CITATION modules is used to carry out simulations. The PIJ module is used for fuel cell calculations and the CITATION module is used for reactor core calculations. The results of the comparison show that the pancake core allows the reactor core to use fuel with a volume fraction of 50%: 10%: 40%, for fuel, cladding and coolant respectively. The design obtained can be operated for 10 years without refueling.
Study on small long-life LBE cooled fast reactor with CANDLE burn-up – Part I: Steady state research
Progress in Nuclear Energy, 2008
Small long-life reactor is required for some local areas. CANDLE small long-life fast reactor which does not require control rods, mining, enrichment and reprocessing plants can satisfy this demand. In a CANDLE reactor, the shapes of neutron flux, nuclide number densities and power density distributions remain constant and only shift in axial direction. The core with 1.0 m radius, 2.0 m length can realize CANDLE burn-up with nitride (enriched N-15) natural uranium as fresh fuel. Leade Bismuth is used as coolant. From steady state analysis, we obtained the burn-up velocity, output power distribution, core temperature distribution, etc. The burn-up velocity is less than 1.0 cm/year that enables a long-life design easily. The core averaged discharged fuel burn-up is about 40%.
A conceptual design study of very small 350 MWth Gas-cooled Fast Reactors with Helium coolant has been performed. In this study Modified CANDLE burn-up scheme was implemented to create small and long life fast reactors with natural Uranium as fuel cycle input. Such system can utilize natural Uranium resources efficiently without the necessity of enrichment plant or reprocessing plant. The core with metallic fuel based was subdivided into 10 regions with the same volume. The fresh Natural Uranium is initially put in region-1, after one cycle of 10 years of burn-up it is shifted to region-2 and the each region-1 is filled by fresh Natural Uranium fuel. This concept is basically applied to all axial regions. The reactor discharge burn-up is 31.8% HM. From the neutronic point of view, this design is in compliance with good performance.
AIP Conference Proceedings, 2012
A conceptual design study of Gas Cooled Fast Reactors with Modified CANDLE burn-up scheme has been performed. In this study, design GCFR with Helium coolant which can be continuously operated by supplying mixed Natural Uranium/Thorium without fuel enrichment plant or fuel reprocessing plant. The active reactor cores are divided into two region, Thorium fuel region and Uranium fuel region. Each fuel core regions are subdivided into ten parts (region-1 until region-10) with the same volume in the axial direction. The fresh Natural Uranium and Thorium is initially put in region-1, after one cycle of 10 years of burn-up it is shifted to region-2 and the each region-1 is filled by fresh natural Uranium/Thorium fuel. This concept is basically applied to all regions in both cores area, i.e. shifted the core of i th region into i+1 region after the end of 10 years burn-up cycle. For the next cycles, we will add only Natural Uranium and Thorium on each region-1. The calculation results show the reactivity reached by mixed Natural Uranium/Thorium with volume ratio is 4.7:1. This reactor can results power thermal 550 MWth. After reactor start-up the operation, furthermore reactor only needs Natural Uranium/Thorium supply for continue operation along 100 years.
Progress in Nuclear Energy
The current paper proposed a Pb-208 cooled CANDLE fast reactor in a power range from small to medium one. Since Pb-208 capture and inelastic-scattering cross sections are significantly smaller in a wide energy range and are increasing more rapidly in the high energy range than other Pb isotopes of natural lead, the proposed CANDLE will have a better neutron utilization and a better coolant reactivity feedback. As consequence the core dimensions (both height and radius) and the associated pressure drop can be reduced, which leads to an additional advantage for reactor construction, operation and transportation. Moreover, it was investigated as well that the power shape can be flattened by loading the thorium fuel in the inner core zone, which leads to a reduced radial peaking factor and a higher burn-up.
18th International Conference on Nuclear Engineering: Volume 2, 2010
The CANDLE (Constant Axial shape of Neutron flux, nuclide densities and power shape During Life of Energy production) burnup strategy is a new burnup concept. The CANDLE reactors generate energy by using only natural or depleted uranium as make up fuel and achieve about 40% burnup without fuel recycling of the conventional nuclear energy concept. So far the CANDLE cores feature a relatively large peak-to-average power density and discharge burnup distribution. Peaked power and burnup distribution are undesirable as they deteriorate economical performance. The objective of this paper is to study the feasibility of power flattening of sodium cooled large scale CANDLE reactor toward commercial use by using thorium fuel loading into the inner core zone. When power density profile becomes flat, it is expected that the axial position of burning region is aligned at the same height for each radial position. It makes core height shorter and raises the average power density farther. The shorter core has usually more merits such as smaller loss of coolant pressure obtained during passing fuel channel and more negative coolant void coefficient. For this purpose, thorium is added uniformly to the uranium fuel in the inner core. If we choose the amount of thorium proper, net radial current of neutrons in the inner core becomes zero in the inner core, and at the boundary between inner and outer core enough neutrons leak from the uranium region and the net radial current is still zero at this point. In the outer region the neutrons leak outward. By this way, we can make the power density distribution flat in the inner core. In the present work, the power density profile is intended flatten for the metallic fuel CANDLE reactors by adding thorium uniformly in the inner core region. The maximum axially integrated power density (radial peaking factor) decreases from 1.87 with only uranium fuel to 1.44 with uranium and thorium fuels. We can expect increasing average discharge burnup and decreasing fuel inventory and pressure drop.
Design study on small CANDLE reactor
Energy Conversion and Management, 2008
A new reactor burn-up strategy CANDLE was proposed, where shapes of neutron flux, nuclide densities and power density distributions remain constant but move to an axial direction. Here important points are that the solid fuel is fixed at each position and that any movable burn-up reactivity control mechanisms such as control rods are not required. This burn-up strategy can derive many merits. The change of excess reactivity along burn-up is theoretically zero, and shim rods will not be required for this reactor. The reactor becomes free from accidents induced by unexpected control rods withdrawal during power operation. The core characteristics, such as power feedback coefficients and power peaking factor, are not changed along burn-up. Therefore, the operation of the reactor becomes much easier than the conventional reactors especially high burn-up reactors. The transportation and storage of replacing fuels become easy and safe, since they are free from criticality accidents. In our previous works it appeared that application of this burn-up strategy to neutron rich fast reactors makes excellent performances. Only natural or depleted uranium is required for the replacing fuels. The average burn-up of the spent fuel is about 40% of total charged fuel. It is equivalent to 40% utilization of the natural uranium without the reprocessing and enrichment. This reactor can be realized for large reactor, since the neutron leakage becomes small and its neutron economy becomes improved. In the present paper we try to design small CANDLE reactor, whose performance is similar to the large reactor, by increasing its fuel volume ratio of the core, since its performance is strongly required for local area usage. Small long-life reactor is required for some local areas. Such a characteristic that only natural uranium is required after second core is also strong merit for this case. The core with 1.0 m radius, 2.0 m height can realize CANDLE burn-up with nitride (enriched N-15) natural uranium as fresh fuel. Lead-Bismuth is used as a coolant. From equilibrium analysis, we obtained the burning region velocity, power density distribution, core temperature distribution, etc. The burning region velocity is less than 1.0 cm/year that enables a long-life design easily. The core averaged discharged fuel burn-up is about 40%.