Measurement Of Organically Bound Tritium(OBT)Content In Plant Samples In The Surrounding Environment Of Nuclear Facilities

In nuclear facilities,tritiumwas readily released asa kind of radionuclide,causing environmental pollution.In recent years,with the deepening of tritium research,organicallybound tritium(OBT)measurement and its impact on the environment has been the focus of attention of the current tritium research.The activity oforganicallybound tritium could not be directly measuredby instruments,nor was it easier to be measuredas other forms of tritium.At present,there were not monitor norms and methods of organic tritium in our China,environmental samples required for organic tritium analysis of the legal requirementsof the standard material did not exist,the international community was also a lack of uniform OBT standard and unified method,no relevant for OBT measurement Warranty documents,which have hindered the effectiveness of OBT measurement methods and data comparison between different laboratories.However,a large number of studies had shown that organic tritium in plant samples could well reflect the tritium activity level and the effect of tritium level on the surrounding environment during plant growth and the dose conversion coefficient of organic tritium after other biological consumption more than twice the amount of tritiated water,which was harmful.Therefore,the measurement of organic tritium was imperative.Based on the existing experimental equipment,this paper presented a set of organically bound tritium measurement processes in plants,which provided a reference for the measurement of organically bound tritium in the surrounding environment of the facility,the mechanism of tritium formation in plants and the transformation and migration behavior support.The process of organically bound tritium in the plant was mainly divided into two parts: the pretreatment of the sample and the measurement of the liquid scintilation measurement.For a newly collected plant samples,the organically bound tritium content could be measured by the process in about 5 days,and the detection limit was 0.76Bq/kg minimum.At the same time,the conditions for liquid scintilation measurement were optimized.In the whole process,according to the requirements of GUM,the method of uncertainty assessment of the process was written,and the uncertainty of the process was evaluated.It was found that the maximum contribution to the uncertainty in the whole link was that the liquid of the process,indicating that the future when the liquid scintilation measurement performance and its measurement conditions to further optimizing.Using this process,the samples collected from the residential area around Qinshan were measured and found that the content of organic tritium was decreased,and the content of organic tritium decreased with the distance from the nuclear facilities.Similarly,this paper explores its origins and provides data support for the future formation of organic tritium and the migration and transformation of tritium in the environment.In conclusion,the organic tritium measurement process and the uncertainty assessment method in this paper could meet the measurement of organic tritium content in bulk plant samples in the environment,which had certain practical value.