【作者】 花威；

【导师】 文万信；

【作者基本信息】 苏州大学 ， 生物医学工程， 2008， 硕士

【摘要】 氚(3H)是一种广泛存在于自然界的宇生放射性核素,也是核工业生产过程产生的人工核素,会产生公众照射剂量和职业照射剂量。反应堆运行过程中,氚化水(HTO)是主要的放射性液态和气态流出物,氚也是辐射工作人员的放射性内污染的主要核素之一。人体体内氚浓度的测量以及氚致辐射剂量的研究是氚公众照射和职业照射危害评估及其防护的主要参考依据。本论文从三方面对体内氚的测量和氚代谢动力学做了较系统的研究。我们与一轻水压水堆核电厂合作,现场采集部分摄氚工作人员的尿样,实验研究了影响体内氚浓度测量准确性的因素,系统比较了尿样不处理、加高锰酸钾蒸馏去色和直接蒸馏去色三种样品预处理方法以及内标准法和外标准法两种计数效率刻度方法的准确性和适用性。通过系统实验研究,认为使用低本底液闪仪采用原始尿样结合外标准法刻度效率方法比较适合大批量摄氚人群的体内氚浓度的快速准确测量。通过现场实验研究了氚的生物半排期和体内有机氚的比例。实验结果表明,体内氚半排期平均为10.6天,并且与工作人员的生理状况和生活习惯等因素有关。正常情况下体内有机氚约相当于氚化水的8.3%～14.1%,在体肤意外接触氚的情况下,体内有机氚的含量会骤增,最大达到氚化水的32倍,有机氚对氚致内照射剂量的贡献不应忽略。根据实验测得的体内氚浓度数据,计算了氚致待积剂量。在实际工作中,某些摄氚辐射工作人员往往在一段时间内持续摄氚,我们应用核素代谢动力学模型研究了持续摄氚条件下体内氚的累积、代谢和待积有效剂量。理论计算和分析表明,一次性体内氚浓度测量将低估持续摄氚所致的实际剂量,在持续摄氚情况下,应计算持续摄氚量所致的待积有效剂量。更多还原

【Abstract】 Tritium, a very common cosmogenic radionuclide in nature and an artificial nuclide which can be produced in nuclear industry, will result in the public exposure dose and professional exposure dose. During nuclear power plants are running correctly, HTO, whether in liquid or gaseous state, is a very important radioactive effluence and the effluence of tritium is one of the nuclides which result in internal irradiation in radiation worker. Measurement of density of internal tritium and the research of tritium lead to dose is the main reference of the public exposure and the hazardous evaluation and protect of professional exposure of tritium. This experiment research the measurement of internal tritium and metabolic dynamics from three aspects.Cooperate with a light water reactor nuclear power plant , we collect some urine samples of workers who intake tritium, research the factors which influence the exacts of measurement of urine tritium, and compare three sample pretreatment methods,urine without deal, adding KMnO4 to distill stripping and directly distill stripping, and compare the exact and applicability of the counting efficiency of internal standard method and external standard method. Through systematic empirical study, we think that using low background Multi-purpose Scintillation Counter and adopting primitive urine sample with external standard scale efficiency method is more suitable for the quickly exact measurement of internal tritium density of a large number people taking tritium.Through the field experimentation, we research the biology elimination half-time of tritium and the ratio of the internal organism tritium. The experiment gets the half life of tritium in the human body is on an average of 10.6 days. Related With the staff’s physical conditions and living habits. The concentration ratio of organically bond tritium to free tritium water is from 8.3% to 14.1% in the normal work condition, and when the workers intake tritium unexpectedly, the concentration of organically bond tritium will increase sharply, the biggest times is 32 as more as free tritium water, so the proportion of organically bond tritium can not be neglected.We calculate the cumulative accumulated-effective dose of tritium based on the data of internal tritium density.In practical work, some radiation worker continued to taking tritium for a period of time, so we use nuclide metabolic dynamics model to research the accumulation of internal tritium, metabolism and the accumulated-effective doses under a sustained intake of tritium conditions. Theoretical calculations and analysis show that one time measuring the concentration of tritium will underestimate the actual dose of intake tritium. So, under a sustained intake of tritium condition, we should calculate the cumulative accumulated-effective dose.更多还原