Waste Transmutation Blanket Research Articles

Preliminary analysis of liquid LiPb MHD flow and pressure drop in DWT blanket of FDS-I

The dual-cooled waste transmutation (DWT) blanket of FDS-I (fusion-driven subcritical system) has been proposed to transmute long-lived nuclear waste, to breed nuclear fuels such as tritium and plutonium and to generate energy. The special magnetohydrodynamics (MHD) problems of liquid metal LiPb coolant in the DWT blanket are caused by the “banana shape” blanket module. The MHD effects of liquid metal LiPb fluid have been analysed and simulated by using computation fluid dynamics (CFD) software FLUENT added MHD user subroutine. The velocity profile and pressure distribution of LiPb flow in bend channels have been presented. The effect of wall conductance ratio of wall, including electrically insulting coating, electrically insulated flow channel insert (FCI) and electrically conducting wall, on flow velocity is analyzed.

Design status and development strategy of China liquid lithium–lead blankets and related material technology

A series of fusion reactors (named FDS series) have been designed and assessed in China, with four types of liquid lithium lead blankets including the RAFM steel-structured He-cooled quasi-static LiPb tritium breeder (SLL) blanket, the RAFM steel-structured He–LiPb dual-cooled (DLL) blanket, the RAFM steel-structured refractory material thermally-insulated high temperature LiPb (HTL) hydrogen production blanket and the RAFM steel or optionally the austenitic stainless steel-structured He–LiPb dual-cooled high level waste transmutation (DWT) blanket. To demonstrate and validate the feasibility of the candidate blankets for fusion energy application, the three-phases-strategy of TBM (test blanket module) development, i.e. material R&D and out-of-pile experimental mockup, EAST-TBM and ITER-TBM have been proposed. A brief overview of the four types of LiPb blanket designs and their goals are given. Material technology requirement and development strategy are also presented in this paper.

Conceptual design activities of FDS series fusion power plants in China

A series of fusion power plants (named FDS series) have been designed and assessed for the examination of the feasibility and the safety, environmental and economical potential of fusion with emphasizing the blanket design optimization on neutronics, thermal-hydraulics, electro-magnetics, material, structural performance analyses in China. Four concepts have been developing, which are the fusion-driven subcritical system (FDS-I) with the goal of transmutation of the long-lived nuclear wastes and breeding of fissile nuclear fuels, the fusion power reactor (FDS-II) with the goal of electricity generation, the fusion-based hydrogen production reactor (FDS-III) and the spherical tokamak-based compact reactor (FDS-ST). Four types of blankets, including the He/LiPb dual-cooled high level waste transmutation (DWT) blanket, the He single-cooled LiPb tritium breeder (SLL) blanket and the He/LiPb dual-cooled (DLL) blanket, the high temperature liquid LiPb (HTL) blanket, and Test Blanket Modules (TBMs) and the testing strategy have been studied. R&D status on materials, design and analysis tools are also presented.

Conceptual design of the fusion-driven subcritical system FDS-I

The fusion-driven subcritical system (named FDS-I) was previously proposed as an intermediate step toward the final application of fusion energy. A conceptual design of the FDS-I is presented, which consists of the fusion neutron driver with relatively easy-achieved plasma parameters, and the He-gas/liquid lithium–lead Dual-cooled subcritical Waste Transmutation (DWT) blanket used to transmute long-lived radioactive wastes and to generate energy on the basis of self-sustainable fission and fusion fuel cycle. An overview of the FDS-I is given and the specifications of the design analysis are summarized.

Neutronics safety analysis in severe transients of the dual-cooled waste transmutation blanket for the FDS-I

The conceptual design of the fusion-driven subcritical system FDS-I with the multifunctional subcritical dual-cooled waste transmutation (DWT) blanket proposed as a middle step toward the final application of fusion energy was presented previously. Safety is a key concern for the innovative conceptual system. The potential safety characteristic is expected as one of the advantages of FDS-I for the transmutation and incineration of nuclear waste compared with the critical reactor. With the intent of evaluating the inherent and passive safety features of FDS-I, the reactivity coefficients (e.g. the coolant density/void effect and the Doppler feedback), which are similar to those in critical reactors, and the kinetics quantities (e.g. neutron generation time and β eff), which are influenced by the external neutron source of the source-driven system, are calculated and analyzed. In addition, the specific transient scenarios for FDS-I, which show the effects of the source power perturbation on the safety parameters, is presented.

Preliminary transient thermal analysis for safety of the dual-cooled waste transmutation blanket for the FDS-I

The dual-cooled waste transmutation (DWT) blanket is one of the key components of the fusion-driven subcritical system (FDS-I). Because of the large energy gain, the heat removal in accidents remains a major safety concern. In this contribution, several representative transients such as unprotected loss of flow accident in helium gas and LiPb (ULOFA), protected loss of flow accident in helium gas and LiPb (LOFA) and loss of power accident (LOPA) are calculated and analyzed. The blanket will not melt until several hours if the plasma core is shut down in time when the accidents occur. It has enough time to start additional action to keep the system safety. The results show that passive solution to shut down the plasma shall be given due to the little scale of responding time. Also, the results show an effective active heat removal solution such as liquid metal (LM) drain system and emergency blanket cooling system is needed.

Analysis on fuel cycle schemes in the dual-cooled waste transmutation blanket for the FDS-I

The fusion-driven subcritical system (FDS-I) which consists of the fusion neutron driver with feasible and easy-achieved plasma parameters and the multifunctional subcritical blanket (DWT) was proposed as an intermediate step toward the final application of fusion energy. In this contribution, fuel configuration and chemical form to be adopted in the FDS-I and possible fuel cycle schemes are clarified and analyzed based on the general survey. The influences of initial fuel loadings on the fuel cycle parameters are presented. Optimal analysis on the in-pile operation length is discussed and some recommendations are given to guide the design of optimized fuel cycle scheme on the basis of comprehensively considering the balance of the spent fuel loadings and the transmutation capacity.

Probabilistic safety assessment of the dual-cooled waste transmutation blanket for the FDS-I

The subcritical dual-cooled waste transmutation (DWT) blanket is one of the key components of fusion-driven subcritical system (FDS-I). The probabilistic safety assessment (PSA) can provide valuable information on safety characteristics of FDS-I to give recommendations for the optimization of the blanket concepts and the improvement of the design. Event tree method has been adopted to probabilistically analyze the safety of the DWT blanket for FDS-I using the home-developed PSA code RiskA. The blanket melting frequency has been calculated and compared with the core melting frequencies of PWRs and a fast reactor. Sensitivity analysis of the safety systems has been performed. The results show that the current preliminary design of the FDS-I is very attractive in safety.

Activation Characteristics of Fuel Breeding BlanketModule in Fusion Driven Subcritical System

Shortage of energy resources and production of long-livedradioactivity wastes from fission reactors are among the main problemswhich will be faced in the world in the near future. The conceptualdesign of a fusion driven subcritical system (FDS) is underway inInstitute of Plasma Physics, Chinese Academy of Sciences. There arealternative designs for multi-functional blanket modules of the FDS,such as fuel breeding blanket module (FBB) to produce fuels for fissionreactors, tritium breeding blanket module to produce the fuel, i.e.tritium, for fusion reactor and waste transmutation blanket module to try topermanently dispose of long-lived radioactivity wastes from fissionreactors, etc. Activation of the fuel breeding blanket of the fusiondriven subcritical system (FDS-FBB) by D-T fusion neutrons from the plasma and fissionneutrons from the hybrid blanket are calculated and analysed under theneutron wall loading 0.5 MW/m2 and neutron fluence15 MW.yr/m2. The neutron spectrum is calculated with theworldwide-used transport code MCNP/4C and activation calculations arecarried out with the well known European inventory code FISPACT/99 with thelatest released IAEA Fusion Evaluated Nuclear Data Library FENDL-2.0and the ENDF/B-V uranium evaluated data. Induced radioactivities, doserates and afterheats, etc, for different components of the FDS-FBB arecompared and analysed.

Influence of blanket structural materials on liquid metal Pb–17Li flow in the FDS

The Dual-cooled Waste Transmutation Blanket design of the Fusion-Driven Sub-critical System is a dual-cooled liquid metal Pb–17Li and He system with Chinese Low Activation Martensitic steel structure. The effects of the structural material on liquid metal MHD flow, including pressure drop and heat transfer, are presented. The influences of the wall conductance of the duct wall on the MHD pressure drop have been analysed and estimated. The pressure drop is too large to be accepted when Pb–17Li coolant flows in these ducts without insulating coating. This can be improved by using Al 2O 3 electrically insulating coating, while heat transfer must also be cautiously considered.

Fusion-Driven Sub-Critical Dual-Cooled Waste Transmutation Blanket: Design and Analysis

The Fusion-Driven Sub-critical System (FDS) is one of the Chinese programs to be further developed for fusion application. Its Dual-cooled Waste Transmutation Blanket (DWTB), as one the most important part of the FDS is cooled by helium and liquid metal, and have the features of safety, tritium self-sustaining, high efficiency and feasibility. Its conceptual design has been finished. This paper is mainly involved with the basic structure design and thermal-hydraulics analysis of DWTB. On the basis of a three-dimensional (3-D) model of radial-toroidal sections of the segment box, thermal temperature gradients and structure analysis made with a comprehensive finite element method (FEM) have been performed with the computer code ANSYS5.7 and computational fluid dynamic finite element codes. The analysis refers to the steady-state operating condition of an outboard blanket segment. Furthermore, the mechanical loads due to coolant pressure in normal operating conditions have been also taken into account. All the above loads have been combined as an input for a FEM stress analysis and the resulting stress distribution has been evaluated. Finally, the structure design and Pb-17Li flow velocity has been optimized according to the calculations and analysis.

Analysis on stress field of the dual-cooled waste transmutation blanket for the FDS

This paper mainly deals with stress field numerical calculations and analysis of the Dual-cooled waste transmutation blanket (DWTB). A comprehensive finite element method (FEM) structure analysis has been performed with the computer code ANSYS5.7. The analysis refers to the steady-state operating condition of an outboard blanket segment. Thermal stresses caused by the temperature gradients in the blanket structure have been calculated. Furthermore, the mechanical loads due to coolant pressure in normal operating conditions have been also taken into account. All the above loads have been combined as input for a FEM stress analysis and the resulting stress distribution has been evaluated.

MHD simulation of the liquid metal/helium gas dual-cooled waste transmutation blanket for FDS

Numerical simulation of magnetohydrodynamic (MHD) flow is implemented by using the commercial code package PHOENICS, in which the momentum source term of Lorentz force is added by applying FORTAN subroutine. Assuming simplified condition of a square duct, the numerical approach is applied to simulate the velocity profile in MA-zone in the design of dual-cooled waste transmutation blanket (DWTB) for a fusion-driven sub-critical system (FDS). The high velocity of closing FW side will improve the heat transfer between liquid metal and the walls of duct, due to high Hartmann number, but the MHD pressure drop will be increased. The compromise between the heat transfer and MHD pressure drop can be taken as reference for the design of the transmutation blanket.

Thermal-hydraulic analysis of the dual-cooled waste transmutation blanket for the FDS

A conceptual structure design and the thermal-hydraulic analysis of the pressurized helium gas and LiPb eutectic dual-cooled waste transmutation blanket for the Fusion-Driven Sub-critical System (FDS), which is being designed for multi-purposes (transmuting nuclear wastes from fission power plants, breeding fissionable nuclear fuel for fission power plants and breeding tritium for sustainable operation) based on the Tokamak fusion core with the minor radius of 1 m, the major radius of 4 m, the elongation of 1.7 and the responding neutron wall loading of 0.5 MW/m 2, have been presented.

Neutronics analysis of the dual-cooled waste transmutation blanket for the FDS

A preliminary conceptual design of dual-cooled long-lived radioactive waste transmutation blanket for the Fusion-Driven sub-critical hybrid System (FDS) is presented on the basis of feasible plasma physics and technology level i.e. the neutron wall loading is assumed to 0.5 MW/m 2 with availability of 50%. The concept has the attractive advantages e.g. tritium is self-sustainable, plutonium for the purpose of neutron multiplication is self-sustainable and the thermal power output is stable. The one-dimensional neutronic transport calculation using the discrete ordinate method and burnup calculation using the direct numerical method are carried out to assess the performance of the blanket.

Overview of Fusion-Fission Hybrid Reactor Design Study in China

The motivation for developing fusion-fission hybrid reactors is discussed in the context of electricity power requirements by 2050 in China. A detailed conceptual design of the Fusion Experimental Breeder (FEB) was developed from 1986-1995. The FEB has a subignited tokamak fusion core with a major radius of 4.0 m, a fusion power of 145 MW, and a fusion energy gain Q of 3. Based on this, an engineering outline design study of the FEB, FEB-E, has been performed. This design study is a transition from conceptual to engineering design in this research. The main results beyond that given in the detailed conceptual design are included in this paper, namely, the design studies of the blanket, divertor, test blanket, and tritium and environment issues. In-depth analyses have been performed to support the design. Studies of related advanced concepts such as the waste transmutation blanket concept and the spherical tokamak core concept are also presented.