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Based on the design requirements of the first stage of the China Fusion Engineering Test Reactor (CFETR), the activation performance calculation and analysis of the components in the dual function lead-lithium blanket were performed using a neutron transport design and safety evaluation software system (SuperMC) with the fusion evaluation database JEFF3.2. A coupled burnup and transportation calculation method was used to calculate the radioactivity, residual decay heat, dose rate, and potential biological hazards of each component in the equatorial surface of the fusion reactor at different times after shutdown. The waste disposal problem of the tritium breeding blanket after the decommissioning of the fusion reactor was analyzed according to the relevant nuclear waste disposal standards in the safety and environment assessment of fusion power strategy. Results of the analysis show that under the condition of normal operation of 200 MW for 10 years, all components of the breeding blanket in the CFETR can satisfy simple recycling standards and meet the requirements of the first stage of CFETR radioactive waste treatment after 50 a of cooling.

BackgroundDue to the imaging mechanism of neutron radiography and the limitation of neutron source, neutron radiography images are prone to lack of contrast, and it is a common method to improve image quality by contrast enhancement algorithm.PurposeThis study aims to solve the problems related to low contrast and loss of details in neutron imaging.MethodsAn adaptive contrast enhancement (ACE) algorithm based on the particle swarm optimization (PSO) was proposed. First of all, the gain factor coefficient was treated as a particle and initializes a particle swarm. Then, the optimal gain factor coefficient with the PSO algorithm was calculated, and the contrast of the high frequency part of neutron images was improved through implementing this optimal gain factor coefficient in ACE algorithm. Finally, several neutron images were processed by this PSO algorithm and compared with the results of traditional optimization algorithm.ResultsThe new algorithm has obvious contrast enhancement effect for different neutron images, and the parameters such as entropy value, gray average gradient value and contrast value of the optimized image are improved compared with the traditional optimization algorithm.ConclusionsThis algorithm can enhance the contrast of image stably, which has practical significance for the wide application of neutron radiography.

BackgroundChina Dual Functional Lithium-Lead (DFLL) blanket is designed by the Institute of Nuclear Energy Safety Technology, Hefei Institutes of Physical Science, Chinese Academy of Sciences for fusion reactor. Since the designs of fusion reactor tritium breeding blankets are highly depended on neutronics calculation, nuclear data and simulation software used for DFLL cladding design is needed to be verified.PurposeThis study aims to evaluate the feasibility of nuclear data and code in DFLL cladding design by neutronics experiments.MethodsFirst of all, a DFLL mock-up was built and a series of neutronics experiments were performed on the D-T Fusion Neutron Generator. Then, a combination of Nb activated foil with reaction channel 93Nb(n,2n)92mNb and 238U fission chamber was chosen in this experiment for neutron yield measurement and relative neutron source intensity monitoring respectively. The Li2CO3 pellets and activation foils were used to measure the tritium production rates (TPR) and the multi-threshold reaction rates at different depths in the DFLL mock-up respectively. Finally, the measured TPR and reaction rates of the activation foils were compared with Monte Carlo simulation results coupled with JEFF3.2 nuclear data library.ResultsThe comparison results show that measurement uncertainty of neutron source intensity is within 4.2%, and the ratios of calculation results to experimental data (C/E) are 1.0~1.07 on TPRs and 0.77~1.1 on reaction rates.ConclusionsThe obtained results indicate that the tritium breeding ratio in neutronics design can be accurately evaluated.

BackgroundFast neutron detectors based on 4H-SiC semiconductor materials have incomparable advantages over traditional neutron detectors when used in strong radiation and high temperature environments, such as fusion plasma diagnosis, core power monitoring, and neutron oil/gas logging, because they have large threshold displacement energy, wide band gap, and fast saturation speed.PurposeThis study aims to explore the feasibility of fast neutron yield measurement by using 4H-SiC detector.MethodsFirst of all, the main performance of 4H-SiC fast neutron detector was tested by experiments using the high intensity deuterium-tritium fusion neutron generator (HINEG). Then, the reaction characteristic peak of 12C(n,α0)9Be in the high energy section was observed in pulse amplitude spectrum. The full width at half maxima (FWHM) and energy resolution were calculated.ResultsThe experimental results show that the neutron detection efficiency to fast neutrons (εE) is 8.89×10-6 n-1·cm-2 (±7.7%),FWHM (full width at half maxima) of the characteristic peak of 12C(n,α0)9Be is 190 keV, and the energy resolution is 2.26%.ConclusionsThis study verifies that the 4H-SiC fast neutron detector can be used for neutron yield measurement.

Pancreatic cancer is a kind of malignant tumor with high mortality rate. Early operation and late chemoradiotherapy are the treatment criteria, but the prognosis is still poor. Berberine, an alkaloid compound present in many herbal plants, is capable of inducing oxidative DNA damage and downregulating homologous recombination repair (HRR) in cancer cells. Poly (ADP ribose) polymerase-1 (PARP-1) is a sensor of DNA damage with key roles in DNA repair. In this study, we demonstrated that berberine and PARP inhibitor olaparib have a synthetic lethal effect on pancreatic cancer cells. The expression level of RAD51 were reduced by berberine. Correspondingly, PARP became hyperactivated in response to berberine treatment. When berberine is combined with olaparib, the expression of Rad51 and Parp are inhibited. The combination of berberine and olaparib synergistically inhibit cell activity and induce cell apoptosis. In addition, the synergistic effect of berberine and olaparib can be reversed by apoptosis inhibitor and necrosis inhibitor. Together, the results indicate that berberine combined with olaparib have a synthetic lethal effect on pancreatic cancer cells.

Molecular dynamics methods were utilized to investigate displacement cascades and tritium diffusion in α-MgT2. It was observed from collision cascades results that the stable number of defects weakly depended on temperature, while the peak and stable number of defects linearly increased with increasing the primary knock-on atom energy. The results of the mean square displacement study revealed that defects had a significant impact on tritium diffusion. The clustering of magnesium self-interstitial atoms and diffusing tritium atoms results in an increased diffusion barrier, whereas the formation of clusters between tritium interstitial atoms is relatively difficult and has no significant impact on the diffusion barrier. The presence of magnesium and tritium vacancies has a minimal effect on the diffusion barrier due to the large number of diffusing tritium atoms that offset the adsorption of vacancies on diffusing atoms. Both magnesium and tritium interstitial atoms increase the collision probability of diffusing atoms, leading to an increased diffusion prefactor. Magnesium vacancies cause significant lattice distortion, increasing the diffusion barrier, while the impact of tritium vacancies on the diffusion barrier is small due to their minimal lattice distortion effect. The research uncovered significant disparities in the diffusion properties of hydrogen and tritium, indicating that the results of the study of hydrogen storage could not be applied to tritium. [ABSTRACT FROM AUTHOR]

For validating the current evaluated neutron data libraries, neutron leakage spectra from lead and lead bismuth eutectic (LBE) cylinders have been measured using an intense D-T pulsed neutron source with time-of-flight (TOF) method by Institute of Nuclear Energy Safety Technology (INEST), Chinese Academy of Sciences (CAS). The measured leakage spectra have been compared with the calculated ones using Super Monte Carlo Simulation Program for Nuclear and Radiation Process (SuperMC) with the evaluated pointwise data of lead and bismuth processed from ENDF/B-VII.1, JEFF-3.1 and JENDL-4.0 libraries. This work shows that calculations of the three libraries are all generally consistent with the lead experimental result. For LBE experiment, the JEFF-3.1 and JENDL-4.0 calculations both agree well with the measurement. However, the result of ENDF/B-VII.1 fails to fit with the measured data, especially in the energy range of 5.5 and 7 MeV with difference more than 80%. Through sensitivity analysis with partial cross sections of 209Bi in ENDF/B-VII.1 and JEFF, the difference between the measurement and the ENDF/B-VII.1 calculation in LBE experiment is found due to the neutron data of 209Bi.

The proton decay of 53Com(3174.1 keV; 19/2−) was investigated via the fragmentation of a 58Ni primary beam. The proton-decay energy was determined with an improved precision to be 1558(8) keV. With this new result and the mass of 53Com, the 52Fe mass excess was derived to be −48330(8) keV, which is in good agreement with the AME12 value. A new recommended value of −48331.6(49) keV is given.