核电站工作场所中子能谱和周围剂量当量率测量

摘要

Neutron ambient dose equivalent is one of the main objects for radiation protection survey in nuclear power plant. Estimation of neutron ambient dose equivalent strongly depends on the knowledge of the neutron distribution along with their energies. The neutron spectra and ambient dose equivalent rates, at five sites inside the containment of heavy water reactor at TQNPC, had been measured using a self-made multisphere spectrometer. The multisphere spectrometer consists of a 3 He proportional counter and nine polythene spheres with different diameters from 2. 5 inch to 12 inch. Response functions of the spectrometer were calculated with the MCNP code, and were calibrated and verified by a standard 252 Cf neutron source. The neutron ambient dose equivalent rates and their energy distributions at the sites were also derived from the measured neutron spectra, and the results were compared with that measured by neutron ambient dose equivalent rate meter and CR-39 trace etching detectors. The measured results can provide the relevant reference data for neutron dose survey in nuclear power plant.%中子周围剂量当量是核电站辐射防护监测的主要对象之一，而中子周围剂量当量的评估强烈依赖中子的能量分布。利用自制的多球谱仪对秦山第三核电有限公司( TQNPC)重水反应堆安全壳内5个位置的中子能谱和周围剂量当量率进行了测量。该谱仪由1个3 He正比计数器以及9个2.5~12英寸不同直径的聚乙烯球组成，响应函数通过MCNP程序计算，并利用标准252 Cf中子源进行了校准和验证。通过测量的中子能谱，获得了不同工作区域的中子周围剂量当量率及其能量分布，并与中子周围剂量当量率仪和CR-39径迹蚀刻探测器的测量结果进行了比较，为核电站中子剂量的监测提供了相关参考数据。