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The amount of boron carbide (B 4 C) installed in shim rod assembly bundle which covers the shutdown margin (SDM) demands has been preliminary analyzed by Super Monte Carlo Calculation Program for Nuclear and Radiation Process (SuperMC), which was developed by FDS Team. Based on absorbent material amount and shim rod assembly dimension limits, the optimal number and arrangement of absorbent rods have been determined. Calculation on the nuclear reaction gas production and the 10 B burn-up has been performed. Following the first step, the burn-up dependence diametral swelling of boron carbide pellets and the release of gaseous product within absorbent rods have been analyzed. The air gap and the gas plenum were designed to avoid the absorber-cladding mechanical interaction (ACMI) and hold the released gaseous reaction gases simultaneously. It is calculated that the optimized design of the bundles is set as follows: the absorbent rods number is 19, the cladding thickness is 0.6 mm, the boron carbide pellets radius is 11.84 mm, the air gap thickness is 0.4 mm and the gas plenum length is 1010 mm. [ABSTRACT FROM AUTHOR]

• The coupling code executes through the GUI supported by SALOME. • TRACE and SCF have explicit meshes. • Data mapping within the coupling code is automatic and accurate. • Visual post-processing is available. • The coupling code has good universality and scalability. The system thermal–hydraulic code TRAC/RELAP Advanced Computational Engine (TRACE) and the sub-channel code SubChanFlow (SCF) have been coupled together based on the Interface for Code Coupling (ICoCo) and the SALOME platform. It is a server-client system where TRACE and SCF are computational engines, ICoCo transfers the coupling data, and SALOME supervises the two clients' synchronization. TRACE and SCF run serially. The coupled code adopts the domain-overlapping (assisted by a Dynamic Implicit Additional Source (DIAS) method) and the Operator Split (OS) explicit coupling approaches. The MEDCoupling library manages the field mapping between different meshes of TRACE and SCF. The YACS module in SALOME provides developers with useful tools that can implement numerical codes in SALOME. It provides users with Graphic User Interfaces (GUI) that can construct and execute the coupling simulations as well. Users can conveniently build/optimize/execute the coupling schemes in SALOME. The coupled code has been verified with an AP1000 feedwater-temperature-drop transient. [ABSTRACT FROM AUTHOR]

• A CFD code and a Sub-channel code were coupled based on a generic architecture. • The generic coupling architecture adopted was presented. • The data transfer method and the transient calculation stability were checked. This paper describes a multi-scale thermal–hydraulic coupling system, which combines the capabilities of the open-source TrioCFD code and of the sub-channel code SubChanFlow (SCF) aiming to improve the description and prediction of the multi-scale thermal–hydraulic physical phenomenon inside the reactor vessel. This is a parallel coupling system based on the ICoCo (Interface for Code Coupling) concept, where each code is first wrapped by the ICoCo interface and then it is compiled to a shared library. A parallel C++ script was developed as the supervisor, which utilizes the two shared libraries and supervises the calculation of the coupled system. The MEDCoupling libraries developed by CEA provide a generic way to handle the mesh interpolation and field mapping between different domains of TrioCFD and SCF. Moreover, the explicit temporal coupling method and the domain-decomposition approach are adopted and presented in this paper. An academic problem is developed to test the multi-scale coupling code. The results indicate that the inter-code data exchange works well and that the coupled code TrioCFD/SCF can deal with various time-dependent boundary conditions. [ABSTRACT FROM AUTHOR]

• The DIAS method correlates the system codes simulation with high-resolution data. • The system codes predict heat and mass transfer more accurately with DIAS method. • DIAS correlates coolant temperature and velocity, pressure, and boron concentration. • High-resolution simulation can be improved by DIAS method. The paper describes a Dynamic-Implicit-Additional-Source (DIAS) method for a domain-overlapped multi-scale coupling of a system-code, sub-channel code, and CFD code aiming to improve the simulation of the thermal-hydraulics phenomena e.g. the heat, mass, solute transfer in the Nuclear Reactor Pressure Vessel (RPV). This method is developed to correlate the essential physical parameters predicted by the nuclear system thermal-hydraulic code with more precise data derived from sub-channel or Computational Fluid Dynamic (CFD) solutions, enabling the system-code to produce more realistic mass and heat transfer within the RPV. The DIAS-method is used in combination with the domain-overlapping coupling approach and it currently correlates four system-codes parameters: the coolant velocity, the pressure drop, the coolant temperature, and the boron concentration. The three-dimensional velocity and pressure fields predicted by a sub-channel or CFD codes are used to calculate the new friction and form loss coefficients on the fly (in the momentum equation) at all the overlapped edges in the system-code with increased accuracy. Additionally, the coolant temperature distribution predicted by the system-code is correlated based on the three-dimensional temperature field gained from the sub-channel or CFD codes by adding a dynamic-implicit heat source or sink to the energy equation. Such kind of source/sink was also added to the solubility equation of the system-code to predict the boron concentration based on the corresponding high-resolution fields provided by the high-resolution thermal-hydraulic solvers. All of the three newly added items are named as the Dynamic-Implicit-Additional-Source (DIAS) since they are not the traditional fixed-explicit appendixes to the original system of governing equation set but they are dynamically tuned and implicitly calculated along with the solution process. The complete DIAS-method was verified with an academic 3D coolant-mixing problem in a Reactor Pressure Vessel (RPV). Results obtained from the test cases indicate that the mass, heat and solute transfer in the RPV could be better predicted by the coupled codes with the DIAS method. Finally, the DIAS method is proved an efficient and powerful approach for multi-scale thermal-hydraulic coupling based on the domain-overlapping approach. [ABSTRACT FROM AUTHOR]

A novel on-chip bandpass filter (BPF) design with controllable transmission zeros (TZs) for high out-of-band rejection is proposed using the hybrid coupling technique. The proposed hybrid coupling filter consists of two symmetrical hybrid coupling spiral structures where the mutual electric and magnetic couplings are introduced to generate two TZs in the high frequency band. The center frequency, bandwidth, and transmission zero position of the proposed filter can be well controlled. To illustrate the principle of this configuration, an equivalent circuit with odd- and even-mode analysis is discussed. Moreover, another transmission zero in the low frequency band can be further generated by loading a quasi-distribution structure. The proposed hybrid coupling filter is fabricated using commercial high resistance silicon technology. The measured results show that the proposed filter can achieve a 3 dB bandwidth from 1.85 to 2.33 GHz, which indicates a fractional bandwidth of about 26 %. In addition, more than 40 dB of suppression is achieved from 3.15 to 5.55 GHz. A return loss of 29 dB and a minimum insertion loss of 2.5 dB are achieved at the center frequency with a minimized size 1.6 mm × 0.8 mm. The simulated and measured results are in good agreement. [ABSTRACT FROM AUTHOR]