Vol.31,

Molten salt-cooled reactor is one of the six Gen-IV reactors with promising characteristics including safety, reliability, proliferation resistance, physical protection, economics, and sustainability. In this paper, a small innovative molten chloride-cooled fast reactor (MCCFR) with 30-year core and a target 120-MWt thermal power was presented. For its feasible study, neutronics, thermal-hydraulics, and radiation damage analysis were performed. The key design properties including kinetics parameters, reactivity swing, reactivity feedback coefficients, maximum accumulated displacement per atom (DPA) of reactor pressure vessel (RPV) and fuel cladding, and maximum coolant, cladding, and fuel temperatures were evaluated. The results showed the MCCFR could operate without refuelling for 30 years with overall negative reactivity feedback coefficients up the end of its life. During its 30-year life, the excess reactivity was well managed by constantly pulling out the control rods. The maximum accumulated DPA on RPV and fuel cladding were 8.92 dpa and 197.03 dpa, respectively, which are both below the design limits. Similarly, the maximum coolant, cladding and fuel center temperatures were all below the design limits during its entire lifetime. According to these results, the MCCFR core design with long life is feasible.

370

Silicon neutron transmutation doping remains one of the most viable nuclear applications for research reactors. Providing this kind of product involves an irradiation method capable of fulfilling the quality requirements of doping and alleviating the challenges related to the design and safety of the irradiation device. In this paper, we propose an irradiation device prototype for neutron transmutation doping of silicon ingots with diameters of 2 to 3 in based on the Es-Salam research reactor. The thermal hydraulic analysis of the proposed irradiation device was performed to determine the optimum conditions for cooling. The effect of the mechanical vibrations induced by the circulation of coolant in the device was quantified via experimental measurements under different flow rates. The results show that the maximum temperature reached by the silicon ingots is below the temperature limit, effectively validating the design of the irradiation device. Other investigations are prospected to further optimize the design and the irradiation conditions. The irradiation of silicon ingots with a large diameter will be considered.

350

Present designs for molten salt thermal reactors require complex online processing systems, which are technologically challenging, while an accelerator-driven subcritical molten salt system can operate without an online processing system, simplifying the design. Previous designs of accelerator-driven subcritical systems usually required very high power proton accelerators (> 10 MW). In this research, a proton accelerator is used to drive a thorium-based molten salt fast energy amplifier (TMSFEA) that improves the neutron efficiency of the system. The research results show that TMSFEA can achieve a long-term stable state for more than 30 years with a rated power of 300 MW and a stabilizing effective multiplication factor (k_eff) without any online processing. In this study, a physical design of an integrated molten salt energy amplifier with an initial energy gain of 117 was accomplished. According to the burn-up calculation, a molten salt energy amplifier with the rated power of 300 MW_th should be able to operate continuously for nearly 40 years using a 1 GeV proton beam below 4 mA during the life time. By the end of the life cycle, the energy gain can still reach 76, and ²³³U contributes 70.9% of the total fission rate, which indicates the efficient utilization of the thorium fuel.

351

A porous silica-polymer based adsorbent, isoBu-BTP/SiO₂-P, was prepared by a vacuum impregnation method and used for the recovery of ruthenium, rhodium, and palladium from nitric acid solution. The experimental results revealed that isoBu-BTP/SiO₂-P exhibited unique adsorption properties such as high saturation adsorption capacity (Ru: 0.35 mmol g^-1, Rh: 0.32 mmol g^-1, Pd: 1.05 mmol g^-1) and excellent selectivity over other metal ions, such as lanthanides (SF_PGM/M>40) in 1 M HNO₃ solution, The adsorption process conformed to the pseudo-second-order model and Langmuir model. From the UV, FT-IR and XPS analyses, it can be concluded that the strong affinity between functional groups (C-N=C) and metal ions, as well as NO₃^- played a role in coordination during the adsorption process. Furthermore, the desorption behavior was studied, and it was found that the adsorbed Pd, Rh, and Ru could be eluted with a 0.01 M nitric acid-0.1 M thiocarbamide solution, 5 M hydrochloric acid, and sodium hypochlorite (CP) solution, respectively. Finally, based on those findings, a simple process for the separation and recovery of Pd, Rh, and Ru from high-level liquid waste using isoBu-BTP/SiO₂-P was designed and proposed.

397

The analog frontend (AFE) coupling circuit is a crucial processing element for data acquisition systems based on analog-to-digital converters (ADCs). Currently, high-speed and high-resolution ADCs are predominantly designed with differential input stages. Conventional high-speed ADC drivers are mainly AC-coupled by employing transformers (Baluns) or fully differential amplifiers (FDAs) with blocking capacitors. However, the results of this study indicate that a certain degree of DC offset error exists and manifests itself as the baseline error in the presence of power dividers connecting several DC-coupled channels that implement high-dynamic-range (HDR) signal conditioning. The study involves a theoretical analysis and explanation of the baseline offset error. The offset error can potentially lead to unexpected out-of-range issues for sampling devices, including high-speed ADCs and switched capacitor array ASICs. High-performance FDAs are adopted, and an offset-free DC-coupled AFE circuit is proposed to address the aforementioned issue using two-stage amplification and a resistive attenuator. The proposed methodology is verified via circuit simulations and hardware design. Thus, the baseline offset problem can be accurately solved using the proposed circuit by minimizing the neglectable error. The proposed circuit facilitates improvements in the high-precision measurement of HDR signals in many nuclear physics experiments and some applications in the DC-coupling scheme with FDAs involving resistive power dividers.

331

Si-PIN photodetectors having features such as low cost, small size, low weight, low voltage, and low power consumption are widely used as radiation detectors in electronic personal dosimeters (EPDs). The technical parameters of EPDs based on the Si-PIN photodetectors include photon energy response (PER), angular response, inherent error, and dose rate linearity. Among them, PER is a key parameter for evaluation of EPD measurement accuracy. At present, owing to the limitations of volume, power consumption, and EPD cost, the PER is usually corrected by a combination of single-channel counting techniques and filtering material methods. However, the above-mentioned methods have problems such as poor PER and low measurement accuracy. To solve such problems, in this study, a 1024-channel spectrometry system using a Si-PIN photodetector was developed and full-spectrum measurement in the reference radiation fields was conducted for radiation protection. Measurement results using the few-channel spectroscopy dose method showed that the PER could be controlled within ±14% and ±2% under the conditions of two and three energy intervals, respectively, with different channel numbers. The PER measured at 0º angle of radiation incidence meets the −29% to +67% requirements of IEC 61526:2010. Meanwhile, the channel number and counts-to-dose conversion factors formed in the experiment can be integrated into an EPD.

493

Optimization algorithms are applied to resolve the second-order pileup (SOP) issue from high counting rates occurring in digital alpha spectroscopy. These are antlion optimizer-(ALO) and particle swarm optimization-(PSO) algorithms. Both optimization algorithms are coupled to one of three proposed peak finder algorithms. Three custom time-domain algorithms are proposed for retrieving SOP peaks, namely peak seek, slope tangent, and fast array algorithms. In addition, an average combinational algorithm is applied. The time occurrence of the retrieved peaks is tested for an elimination of illusive pulses. Conventional methods are inaccurate and time consuming. ALO and PSO optimizations are used for the localization of retrieved peaks. Optimum cost values that achieve the best fitness values are demonstrated. Thus, the optimum positions of the detected peak heights are achieved. Evaluation metrics of the optimized algorithms and their influences on the retrieved peaks parameters are established. Comparisons among such algorithms are investigated, and the algorithms are inspected in terms of their computational time and average error. The peak seek algorithm achieves the lowest average computational error for pulse parameters (amplitude and position). However, the fast array algorithm introduces the largest average error for pulse parameters. In addition, the peak seek algorithm coupled with an ALO or PSO algorithm is observed to realize a better performance in terms of the optimum cost and computational time. By contrast, the performance of the peak seek recovery algorithm is improved using the PSO. Furthermore, the computational time of the peak optimization using the PSO is much better than that of the ALO algorithm. As a final conclusion, the accuracy of the peaks detected by the PSO surpasses that for the peaks detected by the ALO. The implemented peak retrieval algorithms are validated through a comparison with experimental results from previous studies. The proposed algorithms achieve a notable precision for compensation of the SOP peaks within the alpha ray spectroscopy at a high counting rate.

460

The Accelerator-Driven Sub-critical System (ADS) is a strategic plan to solve the nuclear waste problem for nuclear power plants in China. High-energy particle accelerators and colliders contain long strings of superconducting devices, superconducting radio frequency (SRF) cavities, and magnets, which may require cooling by 2 K superfluid helium (Helium II). 2 K superfluid helium cryogenic system has become a research hotspot in the field of superconducting accelerators. In this study, the ADS Injector-I 2 K cryogenic system is examined in detail. The cryogenic system scheme design, key equipment, and technology design, such as the 2 K Joule–Thomson (J-T) heat exchanger and cryomodules CM1+CM2 design, are examined, in addition to the commissioning and operation of the cryogenic system. The ADS Injector-I 2 K cryogenic system is the first 100 W superfluid helium system designed and built independently in China. The ADS Proton Beam reached 10 MeV at 10 mA in July 2016 and 10 MeV at 2 mA in continuous mode in January 2017, and has been operated reliably for over 15000 h, proving that the design of ADS InjectorI 2 K cryogenic system, the key equipment, and technology research are reasonable, reliable, and meet the requirements. The research into key technologies provides valuable engineering experience that can be helpful for future projects such as CI-ADS (China Initiative Accelerator-Driven System), SHINE (Shanghai HIgh repetitioN rate XFEL and Extreme light facility), PAPS (Platform of Advanced Photon Source Technology), and CEPC (Circular Electron-Positron Collider), thereby developing national expertise in the field of superfluid helium cryogenic systems.

350

A non-invasive Ionization Profile Monitor (IPM) consisting of Micro Channel Plates, a phosphor screen and the optical-signal acquisition has been developed at the cooling storage ring of Heavy Ion Research Facility in Lanzhou (HIRFL-CSR). It makes the real-time profile measurements for the transverse beam cooling and orbit oscillation possible and efficient. This paper firstly describes all the IPM design criterions including the theoretical signal yield calculation, the space charge field and initial momentum evaluation, and the electrostatic field distortion simulation as well. In order to investigate the IPM performance, the beam profile measurements are done with different high voltage settings. Subsequently, some valuable beam experiments about the transverse electron cooling and orbit oscillation study are also presented. In the end, fast turn-by-turn profile measurements for the emittance blow-up research in a synchrotron are discussed. In cooperation with the newly deployed emittance instruments at the HIRFL-CSR injector, the IPM shows great prospects for the injection mismatch study, and potential values for the tune, dispersion and chromaticity measurements as well.

339

It is of particular interest to investigate nuclear fusion reactions generated by high-intensity lasers in plasma environments that are similar to real astrophysical conditions. We have experimentally investigated ²H(d, p)³H, one of the most crucial reactions in Big Bang nucleosynthesis models, at the Shenguang-II laser facility. In this work, we present a new calibration of CR-39 solid-state track detectors, which are widely employed as the main diagnostics in this type of fusion reaction experiment. We measure the dependence of the track diameter on the proton energy. It is found that the track diameters of protons with different energies are likely to be identical. We propose that in this case, the energy of the reaction products can be obtained by considering both the diameters and gray levels of these tracks. The present results would be very helpful for analyzing the ²H(d, p)³H reaction products recorded with the same batch of CR-39 solid-state track detectors.

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