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The data of neutron capture cross section are very important for the research of nuclear astrophysics, advanced nuclear energy development. Owing to the limitation of neutron source and detector, the experimental data of neutron capture cross section in an energy range of 1 eV–10 keV were almost blank in China. The first Chinese gamma-ray total absorption facility has been constructed in the key laboratory of nuclear data at China institute of atomic energy, which consists of 40 BaF2 detector units. The BaF2 crystal shell with a thickness of 15 cm and an inner radius of 10 cm covers 95.2% of the solid angle. On-line measurement method of neutron capture reaction cross section is established on the back-streaming white neutron source of China spallation neutron source by using the upgraded facility. The cross section of 197Au neutron capture reaction is measured for the first time under the experimental condition of irregular 30 mm neutron beam spot. The measured position of resonance peak is well consistent with the relevant data of ENDF evaluation database, which verifies the reliability of the measurement device and measurement technology, and thus laying the foundation for the acquisition of high precision cross section in future.

The back-streaming neutron beam line (Back-n) was built in the beginning of 2018, which is part of the China Spallation Neutron Source (CSNS). The Back-n is the first white neutron beam line in China, and its main application is for nuclear data measurement. For most of neutron-induced nuclear reaction measurements based on white neutron facilities, the beam of gamma rays accompanied with neutron beam is one of the most important experimental backgrounds. The back streaming neutron beam is transported directly from the spallation target to the experimental station without any moderator or shielding, the flux of the in-beam gamma rays in the experimental station is much larger than those of these facilities with neutron moderator and shielding. Therefore, it is necessary to consider the influence of in-beam gamma rays on the experimental results. Studies of the in-beam gamma rays are carried out at the back-n. Monte-Carlo simulation is employed to obtain the energy distribution and the time structure of the in-beam gamma rays. According to the simulation results, when the neutron flight time is longer than 1.0 μs the energy distribution of the in-beam gamma rays does not vary with flight time. Therefore, the time structure of these gamma rays can be measured without the correction of the detection efficiency. In this work, the time structure of the in-beam gamma rays in the low neutron energy region is measured by both direct and indirect methods. In the direct measurement, a 6Li loaded ZnS(Ag) scintillator is located on the neutron beam line and the time of flight method is used to determine the time structure of neutrons and gamma rays. The gamma rays are separated from neutrons with pulse-shape discrimination. The black filter method is used to verify the particle discrimination results. In the indirect measurement, the C6D6 scintillation detectors are used to measure the gamma rays scattered off a Pb sample on the way of the neutron beam. The time structure of the in-beam gamma rays is derived from that of the scattered gamma rays. The experimental results are in good agreement with the simulations with the time-of-flight between 12 μs and 2.0 ms. Besides, according to the simulation results, the intensity of the in-beam gamma rays is 1.21 × 106 s–1·cm–2 in the center of the experimental station 2 of Back-n, which is 76.5 m away from the spallation target of CSNS.

A laboratory scale dense-phase transport reactor was designed, fabricated and constructed to study the combustion of carbonaceous residues on spent oil sands produced during the fluidized bed pyrolysis of oil sa.nds. A wide particle-size distribution group B coked sand, dp = 130 μm, was used for the hydrodynamic and combustion studies. The average minimum fluidization velocity, Umf• determined during a series of fluidization and defluidization experiments, was 1. 7 emfs. The transition velocities were determined in flow regime transition studies: (a) the plug slugging transition velocity, Urns· was 22 emfs; (b) the turbulent fluidization transition velocity, Uc, was 50 emfs; and (c) the refluxing pneumatic transport transition velocity, Uk, was 75 cm/s. Particle residence time distribution experiments indicated the average particle residence time in the reactor was approximately six minutes in the turbulent fluidization regime. The effects of process variables on the combustion of the coked sand were investigated. Coked sand combustion experiments at different superficial gas velocities indicated that there was an preferred superficial gas velocity, approximately 60 cm/s, at which the highest coke conversion was achieved. The results also indicated that CO production rate increased whereas co2 production rate decreased with increasing superficial gas velocity. Coke conversion increased with increasing combustion temperature but leveled off above 946 K. The coke conversion increased with decreasing solids feeding rate at a fixed temperature. Coked sand combustion with oxygen enriched air as the fluidizing gas indicated that using oxygen enriched combustion gas increased the coke conversion. Preliminary studies were conducted to evaluate the effect of gaseous swirl flow on coked sand combustion. Coke conversion increased with swirl flow at a fixed temperature and solid feed rate relative to fully developed plug flow through the reactor. It is expected that coked sand combustion could approach completion with a combination of induced swirl flow, higher combustion temperatures and oxygen enriched fluidizing gas.