[en] This paper presents a sulfur hexafluoride-based experimental study that was made under complex topographical conditions for the purpose of availability of plume trajectory and diffusion parameters. The study was completed through release of SF₆, from the top of a 100 m tower, and combined sample collection both in residential area and along curve. Sample analysis was made by gas chromatography-electron capture method, with diffusion parameter calculated with the minimum square for each experiment. (authors)

[en] The deposition and translocation of ¹³⁷Cs deposited on plants are studied using an aerosol simulation facility in CIRP in 2002 and 2003. The plant species involved are paddy, winter wheat, radish, Chinese cabbage and tomato. The plants are contaminated by aerosol deposition at different growth periods. Experimental results of interception factors (R), translocation factors (Tiv) and leaf area index(LAI) are reported and discussed. The basic data of deposition experiments including characteristics of aerosol particles, soil properties are provided. (authors)

[en] After 31 year operation of an uranium tailings impoundment, sub-clayey samples beneath its bottom were taken for determining concentration distribution of U, Th and Ra seeped from the impoundment. For fitting nuclide migration, one dimensional convection-dispersion model of nuclide migration in groundwater was applied, and parameters were measured such as particle size of tailings, leaching factor of nuclides from tailings and distribution coefficients of nuclides in sub-clay. Results indicate that fine tailings are the main portion of tailings, and possess higher specific activities and lower leaching factor than coarse tailings. The sub-clay has a strong adsorption ability to nuclides, and distribution coefficients of U, Th and Ra are 62, 1.3 x 10³ and 9.8 x 10² mL/g, respectively. The natural and man-made sub-clay layers beneath the impoundment can reduce effectively nuclides seepage and migration. (authors)

[en] The theoretical calculations of the influence caused by the pipe in measurement installation on moisture response are carried out by means of two-group theoretical model. The comparisons between Fe and Cu pipes whose thickness is different for the influence on thermal neutron flux and on moisture response are made. The derivation of a part of theoretical formulas is given

[en] After 31 years operation of an uranium tailings impoundment, sub-clay samples beneath its bottom were taken for determining concentration distribution of U, Th and ²²⁶Ra migration from the impoundment. For study of nuclide migration, parameters were measured such as particle size of tailings, nuclide specific activities and leaching factors of tailings, and distribution coefficients of nuclides in sub-clay. One dimensional convection-dispersion model of nuclide migration was applied for fitting nuclide distribution in sub-clay. The result indicates that the sludge is the main component of tailings, and possess higher specific activities and lower leaching factor than coarse tailings. Sub-clay has a strong adsorption ability to nuclides, and the natural and man-made sub-clay layers beneath the impoundment bottom can effectively reduce nuclides seepage and vertical migration distance. Distribution coefficients of U, Th and ²²⁶Ra are 62, 1.3 x 10³ and 9.8 x 10² mL/g, respectively. The vertical migration distances at which the concentrations of nuclides reduce to background level are 1.2 m for U and 0.2 m for Th and ²²⁶Ra. (authors)

[en] A dynamic food-chain model and program, DYFOM-95, for predicting the radiological consequences of nuclear accident has been developed, which is not only suitable to the West food-chain but also to Chinese food chain. The following processes, caused by accident release which will make an impact on radionuclide concentration in the edible parts of vegetable are considered: dry and wet deposition interception and initial retention, translocation, percolation, root uptake and tillage. Activity intake rate of animals, effects of processing and activity intake of human through ingestion pathway are also considered in calculations. The effects of leaf area index LAI of vegetable are considered in dry deposition model. A method for calculating the contribution of rain with different period and different intensity to total wet deposition is established. The program contains 1 main code and 5 sub-codes to calculate dry and wet deposition on surface of vegetable and soil, translocation of nuclides in vegetable, nuclide concentration in the edible parts of vegetable and in animal products and activity intake of human and so on. (24 refs., 9 figs., 11 tabs.)

No abstract available

[en] The environmental background radiation level investigation surrounding Tianwan Nuclear Power Plant was conducted for 2 years by China Institute for Radiation Protection. The investigation results are all collected in this paper and discussions are made on some results, such as ⁹⁰Sr and ³H contents in water bodies, ¹³⁷Cs and ⁷Be contents in plant, ¹³⁷Cs and ⁴⁰K contents in animal and animal products, ¹³⁷Cs contents in soil, plant and animal, as well as considerations in choosing indicating organism, etc. Main conclusions are presented as well. (author)

[en] This paper summaries the implementation quality assurance programme for environmental background radiation investigation around Tianwan NPP. It includs organization and personnel, document control, traceability of data and instrument calibration, and quality control during the investigation process, quality record, self-check and verification. Finally, it gives the basic evaluation and existing problems. This paper stresses that a quality control is to prevent unqualification rather than prove the correctness in the process. (authors)