Evaluation of Dose Derived From HTO for Adults in the Vicinity of Qinshan Nuclear Power Base.

Tritium that is released from nuclear facilities, especially from nuclear reactor units, may be the main origination of tritium in the environment. Atmospheric tritiated water (HTO) is the main chemical form of tritium that is released from nuclear reactor units. HTO in the air, drinking water and foods should be monitored routinely to protect public from the radiological hazards of tritium. Here, concentrations of HTO in the air, drinking water and foods in the vicinity of Qinshan Nuclear Power (QNP) base were measured from 2012 to 2016. And based on the concentrations of HTO measured, annual dose equivalent and collective dose equivalent for adults were calculated to evaluate the radiological hazards derived from HTO. The annual dose equivalent for adults in Qinshan and Wuyuan communities were both far below the dose limit for public exposure, and both showed an increasing trend, indicating that great attention still should be payed to the releasing of tritium from nuclear reactor units in the QNP base.

Studies of particle size distribution of Non-Exchangeable Organically Bound Tritium activities in the soil around Qinshan Nuclear Power Plant.

The NE-OBT (Non-Exchangeable Organically Bound Tritium) in the soil plays a significant role in tritium migration and transformation. In order to further understand the NE-OBT activity in the soil, the particle size, vertical profile and spatial distribution of the NE-OBT activities in the soil were determined around the Qinshan Nuclear Power Plant (NPP) in China. The experimental results indicated that the NE-OBT preferred to concentrate in the soil particle sizes of 53-250 µm within the soil depth of 5 cm-25 cm. The NE-OBT activity showed significantly vertical variations, however, its largest activity did not appear at the surface soil (0-5 cm). Meanwhile, the NE-OBT had a significant spatial distribution, its activity decreased with the increasing distance from the NPP, especially from the HWRs. In this study, the NE-OBT activities have no significant relationship to the organic matter content in the soil. But the vertical profile distribution of the NE-OBT activity has a strong correlation with the NE-OBT/HTO ratio in the soil, which reflect the capability of living organisms converting HTO into NE-OBT. According to these analyses, we supposed that the NE-OBT in the soil may be derived from the microbial transformation of HTO.

AprilTag array-aided extrinsic calibration of camera-laser multi-sensor system.

This paper presents a new algorithm for extrinsically calibrating a multi-sensor system including multiple cameras and a 2D laser scanner. On the basis of the camera pose estimation using AprilTag, we design an AprilTag array as the calibration target and employ a nonlinear optimization to calculate the single-camera extrinsic parameters when multiple tags are in the field of view of the camera. The extrinsic parameters of camera-camera and laser-camera are then calibrated, respectively. A global optimization is finally used to refine all the extrinsic parameters by minimizing a re-projection error. This algorithm is adapted to the extrinsic calibration of multiple cameras even if there is non-overlapping field of view. For algorithm validation, we have built a micro-aerial vehicle platform with multi-sensor system to collect real data, and the experiment results confirmed that the proposed algorithm yields great performance.