Occurrence of HTO and NE-OBT in soil in the vicinity of the Qinshan Nuclear Power Plant

In this study, concentrations of tritiated water(HTO) and non-exchangeable organically bound tritium(NE-OBT) and the NE-OBT/HTO ratios were determined in soil around Qinshan Nuclear Power Plant(NPP), Zhejiang, China, and their vertical profile and spatial distribution were investigated. Results showed variations in both the HTO and NE-OBT concentrations in the vertical profile. The HTO concentrations generally decreased firstly and then increased with the increasing depths, but the trend was not significant. The NE-OBT concentrations in the surface soils(0–5 cm) were considerably lower than those in the deep soils(5–25 cm) at all the sites. The NE-OBT/HTO ratios also show a variable vertical profile, initially increasing and then decreasing with increasing soil depth.Both the HTO and NE-OBT concentrations decreased with the increasing distance to the HWRs in deep soil layers(5–25 cm), revealing that the released tritium from the NPP affected the spatial distribution.

Collimated LaBr_3 detector response function in radioactivity analysis of nuclear waste drums

The properties of a Lanthanum bromide(LaBr3)detector and its response functions were investigated via experiments and simulations in this paper.The LaBr3detector had good relative energy resolution and higher efficiency than a high-purity germanium detector.Monte Carlo and other numerical methods were used to calculate the efficiencies of a LaBr3detector with a square collimation window.A model of the numerical method was established based on a pure geometric model that was consistent with the experimental situation.The results showed that the detector response functions calculated by these methods were in great agreement with experimental results.

System Monitoring Program Development Process in the Nuclear Power Plant

Performance monitoring is the important part of the equipment reliability process description( AP913),and the system performance is the main content of monitoring. The purpose of system performance monitoring is to identify early performance degradation of system and equipment in time,evaluate the overall health of system, and carry out corrective actions in a timely manner. Performance monitoring also has the corresponding experience feedback. The paper introduces the process of system monitoring program development. In the end,the paper takes an example of the turbine control fluid system( GFR) in a domestic nuclear power plant. The example shows the process is good for the analysis.

Effect of Mn content on microstructure and properties of AlCrCuFeMnx high-entropy alloy

AlCrCuFeMnx(x=0,0.5,1,1.5,and 2)high-entropy alloys were prepared using the vacuum arc melting technology.The microstructure and mechanical properties of AlCrCuFeMnxwere analyzed and tested by XRD,SEM,TEM,nanoindentation,and electronic universal testing.The results indicate that the AlCrCuFeMnxhigh-entropy alloy exhibits a dendritic structure,consisting of dendrites with a BCC structure,interdendrite regions with an FCC structure,and precipitates with an ordered BCC structure that form within the dendrite.Manganese(Mn)has a strong affinity for dendritic,interdendritic,and precipitate structures,allowing it to easily enter these areas.With an increase in Mn content,the size of the precipitated nanoparticles in the dendritic region initially increases and then decreases.Similarly,the area fraction initially decreases and then increases.Additionally,the alloy’s strength and wear resistance decrease,while its plasticity increases.The Al Cr Cu Fe Mn1.5alloy boasts excellent mechanical properties,including a hardness of 360 HV and a wear rate of 2.4×10^(-5)mm^(3)·N^(-1)·mm^(-1).It also exhibits impressive yield strength,compressive strength,and deformation rates of 960 MPa,1,700 MPa,and 27.5%,respectively.

Tritium concentrations in precipitation in Shanghai

Tritium concentrations in precipitation can be used as a criterion to evaluate the tritium baseline of the environment. The tritium concentration in precipitation in Shanghai during 2014-2015 was determined. Values ranged from 0.68 ± 0.04 to 4.11 ± 0.39 Bq/L, and it showed a decreasing trend compared with historical data; however,the values were slightly higher than the natural background tritium level. Additionally, the tritium concentration shows a seasonal variation: It was higher in autumn and winter and lower in summer and spring. A comparison of concentrations in precipitation in Shanghai and around the Qinshan Nuclear Power Plant reveals no correlation,implying that the nuclear power plant operations may not affect the environment of Shanghai. Thus, the raised tritium concentrations in Shanghai might be due to the effects of monsoons, spring leak, raindrop, or other activities that generate tritium there. Those activities may include chemistry research that uses tritium as a tracer.

Apparatus for determining permeability of hydrogen isotopes in molten-salt

In order to provide data on diffusion coefficients and solubility constants of tritium in molten salts for the critical issue of tritium control in the Thorium Molten Salt Reactor(TMSR)program,a two-chamber permeability apparatus separated by a nickel plate had been developed for determining the permeability of hydrogen isotope in molten salts.Descriptions on the permeability apparatus,experimental procedure and the analytical method for determining the diffusivity and solubility of hydrogen isotope in molten salts were presented in this paper.To assess the performance of the apparatus,the blank tests without molten salt were conducted at300-700℃.The results showed that the nickel plate acting as the window for hydrogen isotope permeation in the apparatus seemed to have less effect on experiments of determining the permeability of hydrogen isotope in molten slat at 500-700℃.Furthermore,the applicability of the apparatus with molten salt was also evaluated experimentally,with test experiments of molten Flinak(LiF-NaF-KF)at 500℃,600℃and 700℃.Diffusion coefficients and solubility constants of hydrogen in molten Flinak can be derived from those test experiments,which were correlated to D_(Flinak-H)=7.06×10^(-5)e^(-54.9/(R_gT))m^2/s and s_(Flinak-H)=1.67×10^(-7)e^(27.0/(r_gt))mol-H_2/(m^3 Pa).

The Result Integration Algorithm Based on Matching Strategy

The following paper provides a new algorithm： a result integration algorithm based on matching strategy. The algorithm extracts the title and the abstract of Web pages, calculates the relevance between the query string and the Web pages, decides the Web pages accepted, rejected and sorts them out in user interfaces. The experiment results in dieate obviously that the new algorithms improve the precision of meta-search engine. This technique is very useful to metasearch engine.

A mesoscale model based on Monte-Carlo method for concrete fracture behavior study

An aggregate generation and packing algorithm based on Monte-Carlo method is developed to express the aggregate random distribution in cement concrete. A mesoscale model is proposed on the basis of the algorithm. In this model, the concrete con- sists of three parts, namely coarse aggregate, cement matrix and the interracial transition zone （ITZ） between them. To verify the proposed model, a three-point bending beam test was performed and a series of two-dimensional mesoscale concrete mod- els were generated for crack behavior investigation. The results indicate that the numerical model proposed in this study is helpful in modeling crack behavior of concrete, and that treating concrete as heterogeneous material is very important in frac- ture modeling.