Reactor performance and safety characteristics of ThN-UN fuel concepts in a PWR (original) (raw)
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Behavior of thorium plutonium fuel on light water reactors
2020
Designs using thorium-based fuel are preferred when used in compliance with sustainable energy programs, which should preserve uranium deposits and avoid the buildup of transuranic waste products. This study evaluates a method of converting uranium dioxide (UO2) to thorium-based fuel, with a focus on Th-Pu mixed oxide (ThMOX). Applications of Th-MOX for light water reactors are possible due to inherent benefits over commercial fuels in terms of neutronic properties. The fuel proposed, (Th-Pu)O2, can be helpful because it would consume a significant fraction of existing plutonium. Aside from the reactor core, the proposed fuel could be useful in existing technology, such as in a pressurized water reactor (PWR). However, licensing codes cannot support Th-MOX fuel without implementing adaptations capable of simulating fuel behavior using the FRAPCON code. The (Th-Pu)O2 fuel should show a plutonium content that produces the same total energy release per fuel rod when using UO2 fuel. Tho...
This work investigates the possibility of using thorium-based fuels as an alternative fuel for advanced power reactor APR-1400. MCNPX code version 2.7 with crosssection library ENDF.VII has been used to design an APR-1400 fuel assembly. This code has been used to study the neutronic performance of the proposed thoriumbased Fuel types (0.944 Th, U)O 2 , (0.955 Th, 233 U)O 2 , (0.934 Th, rgPu)O 2. The fuel burn-up parameters such as infinity multiplication factor (k inf), initial heavy metals concentrations, Minor actinides concentration and fission products concentration have been analyzed during 1500 effective full power days (FPDSs) for thoriumbased Fuel types and compared with the common fuel. The analysis of the horizontal thermal power and neutron flux distribution provides valuable insights into the behavior and performance of the suggested Fuel types in the APR-1400 assembly. The analysis of the neutronic results ensures the viability of using the proposed thorium-based fuel types as an alternative fuel to UO 2 because they achieved acceptable safety parameter values and provided a good power distribution through the fuel assembly compared to UO 2 .
Thorium Fuel Options for Sustained Transuranic Burning in Pressurized Water Reactors
As described in companion papers, Westinghouse is proposing the adoption of a thorium-based fuel cycle to burn the transuranics (TRU) contained in the current Used Nuclear Fuel (UNF) and transition towards a less radiotoxic high level waste. A combination of both light water reactors (LWR) and fast reactors (FR) is envisaged for the task, with the emphasis initially posed on their TRU burning capability and eventually to their self-sufficiency. Given the many technical challenges and development times related to the deployment of TRU burners fast reactors, an interim solution making best use of the current resources to initiate burning the legacy TRU inventory while developing and testing some technologies of later use is desirable. In this perspective, a portion of the LWR fleet can be used to start burning the legacy TRUs using Thbased fuels compatible with the current plants and operational features. This analysis focuses on a typical 4-loop PWR, with 17x17 fuel assembly design and TRUs (or Pu) admixed with Th (similar to U-MOX fuel, but with Th instead of U). Global calculations of the core were represented with unit assembly simulations using the Linear Reactivity Model (LRM). Several assembly configurations have been developed to offer two options that can be attractive during the TRU transmutation campaign: maximization of the TRU transmutation rate and capability for TRU multi-recycling, to extend the option of TRU recycling in LWR until the FR is available. Homogeneous as well as heterogeneous assembly configurations have been developed with various recycling schemes (Pu recycle, TRU recycle, TRU and in-bred U recycle etc.). Oxide as well as nitride fuels have been examined. This enabled an assessment of the potential for burning and multi-recycling TRU in a Th-based fuel PWR to compare against other more typical alternatives (U-MOX and variations thereof). Results will be shown indicating that Th-based PWR fuel is a promising option to multi-recycle and burn TRU in a thermal spectrum, while satisfying top-level operational and safety constraints.
Breeding Capability of Uranium and Thorium Fuel Cycles For Water Cooled Reactors
BREEDING CAPABILITY OF URANIUM AND THORIUM FUEL CYCLES FOR WATER COOLED REACTORS. Nuclear energy has contributed to fulfill the world energy demand especially in relation to the sustainable development of the world without any greenhouse effect to the environment for more than 50 years. The breeder reactors seem to have a similar trend with the renewable energies as a sustainable energy source. A fuel breeding is very essential for extending the sustainability of nuclear fuel resource and furthermore, it can be used to perform the sustainable development of the world. The present study intends to find the feasible region of design parameters for light or heavy water cooled reactors using thorium and uranium fuels which fulfill the required design characteristics such as breeding, negative void reactivity coefficient, comparable burn up with standard PWR, homogeneous core and large pin gap. The basic reactor design parameters of investigated systems are basically based on the water coolant reactor technology. The required enrichment, breeding capability and void coefficient are evaluated for light and heavy water coolants with U-Pu and Th-233 U fuel systems. A breeding condition is feasible for all investigated cases which are mainly require very tight lattice pitch for light water coolant cases and relatively larger lattice pitch for heavy water coolant. Regarding a negative void coefficient, only Th-233 U fuel system for both water coolants obtains a negative void coefficient in the breeding regions. The required design characteristics such as breeding, negative void reactivity coefficient, comparable burnup (PWR) and large pin gap can be achieved easier by heavy water cooled Th-233 U fuel system.
Eastern-European Journal of Enterprise Technologies
Comparison of thorium nitride (ThN) and uranium nitride (UN) fuel on small modular PWR in neutronic analysis has been carried out. PWR in module is one type of reactor that can be utilized because of its small size so that it can be placed on demand. Neutronic calculations were performed using SRAC version 2006, the data library using JENDL 4.0. The first calculation was fuel pin (PIJ) calculation with hexagonal fuel pin cell type. And the second calculation was reactor core (CITATION) calculation using homogeneous and heterogeneous core configurations. ThN and UN fuels use heterogeneous configurations with 3 fuel variations. The reactor geometry was used in two fuels are the same, with diameter and height active core was 300 cm and 100 cm. In this research, Np-237 was added as a minor actinide in the UN fuel to reduce the amount of Np-237 in the world and also reduce the k-eff value. For ThN fuel, Pa-231 also added in the fuel to reduce the k-eff value. The optimum configuration of...
Advanced Nuclear Fuels Based on Thorium Mixed Oxides
Journal of Engineering Research, 2023
of advanced fuel systems formed ThO 2 75 wt.% and UO 2 25 wt.%, which worked with 19.5% enrichment of U 235. It analyzed the physical properties of mixed fuels using the composition of mixtures, such as the lattice parameters, thermal conductivity, specific heat, mechanical strength, and fission gas release. The codes FRAPCON-4.0 and FRAPTRAN-2.0 adapted can calculate the composite fuel response compared with uranium dioxide fuel used for light water reactors. In addition, the increased diffusion coefficient produced lower fuel swelling compared with UO 2. Thorium fuels had included an extensive range of applications, such as pressure-tube heavy water reactors (HWRs), light water reactors (LWRs), and thorium molten salt reactors. Advanced reactors, such as sodiumcooled fast reactors, can support the thorium mixed oxide fuel [1]. Early the Shippingport reactor, in Pennsylvania, USA, was a light water breeding reactor that operated with thorium as fuel during 1977-1982 [2]. Thorium is at least three times more abundant than uranium [3]. The natural isotopic distribution of thorium is 100% of Th 232 and is not fissile, but it is a fertile material, like U 238. Thorium requires fissile materials, such as U 235 and Pu 239 , to begin the reaction. Today, exist a few mixed fuel cycles based on thorium use (Th 232 +Pu 239), (Th 232 +U 233), (Th 232 +U 235), and other formulations, including dopant additions [4]. On the other hand, it researches innovative fuels, such as uranium nitride (UN) and uranium carbide (UC), which have several advantages over UO 2 , such as increased burnup capabilities and higher
Analysis of SMART reactor core with uranium mononitride for prolonged fuel cycle using OpenMC
The neutronics performance and safety characteristics of Uranium mononitride (UN) fuel for System-Integrated Modular Advanced Reactor (SMART) has been investigated to discern the potential for non-proliferation, waste, and accident tolerance benefits of UN fuel. The neutronic evaluation of UN fuel for SMART reactor has been carried out under normal operation using OpenMC and compared with Uranium dioxide (UO 2) in terms of fuel cycle length, reactivity coefficients, Fuel depletion (burnup), thermal flux, and fission product activity. The power peaking factor (PPF) has been compared at the beginning of the fuel cycle (BOC), mid of the fuel cycle (MOC), and at the end of the fuel cycle (EOC). Results indicate that the UN fuel can be operated beyond the designed fuel cycle length of the SMART reactor, which induces the positive reactivity at the end of the fuel cycle of about 4625 pcm. However, the UO 2 showed negative reactivity after three years. The total fission product activity at the end of the fuel cycle (3.5 years) for UO 2 and UN has been founded 1.003 × 10 20 Bq and 1.023 × 10 20 Bq, respectively.
2010
This paper reports the continued evaluation of the attractiveness of materials mixtures containing special nuclear materials (SNM) associated with various proposed nuclear fuel cycles. Specifically, this paper examines two closed fuel cycles. The first fuel cycle examined is a thorium fuel cycle in which a pressurized heavy water reactor (PHWR) is fueled with mixtures of plutonium/thorium and {sup 233}U/thorium. The used fuel is then reprocessed using the THOREX process and the actinides are recycled. The second fuel cycle examined consists of conventional light water reactors (LWR) whose fuel is reprocessed for actinides that are then fed to and recycled until consumed in fast-spectrum reactors: fast reactors and accelerator driven systems (ADS). As reprocessing of LWR fuel has already been examined, this paper will focus on the reprocessing of the scheme's fast-spectrum reactors' fuel. This study will indicate what is required to render these materials as having low utilit...
Study of thorium-plutonium fuel for possible operating cycle extension in PWRs
2013
Computer simulations have been carried out to investigate the possibility of extending operating cycle length in the Pressurised Water Reactor Ringhals 3 by the use of thorium-plutonium oxide fuel. The calculations have been carried out using tools and methods that are normally employed for reload design and safety evaluation in Ringhals 3. The 3-batch reload scheme and the power level have been kept unchanged, and a normal uranium oxide fuel assembly designed for a 12-month operating cycle in this reactor is used as a reference. The use of plutonium as the fissile component reduces the worth of control rods and soluble boron, which makes it necessary to modify the control systems. The delayed neutron fraction is low compared with the reference, but simulations and qualitative assessments of relevant transients indicate that the reactor could still be operated safely. Differences in reactivity coefficients are mainly beneficial for the outcome of transient simulations for the thorium based fuel. A 50% extension of the current 12-month operating cycle length should be possible with thorium-plutonium mixed oxide fuel, given an upgrade of the control systems. More detailed simulations have to be carried out for some transients in order to confirm the qualitative reasoning presented.