Nuclear Techniques ›› 2019, Vol. 42 ›› Issue (9): 90301-090301.doi: 10.11889/j.0253-3219.2019.hjs.42.090301

• NUCLEAR CHEMISTRY, RADIOCHEMISTRY, RADIOPHARMACEUTICALS AND NUCLEAR MEDICINE • Previous Articles     Next Articles

The adsorption transfer mechanism of U and 238Pu in sandy aquifers

Chao ZHU Jun ZHANG Aiming CHEN   

  1. China Institute for Radiation Protection, Taiyuan 030006, China
  • Received:2019-05-06 Revised:2019-06-26 Online:2019-09-10 Published:2019-09-18

Abstract: Background

The migration of radionuclides carried by water flow in aquifer porous media is a complex physical and chemical process.

Purpose

This study aims to accurately and truly reflect the nuclide transportation in the groundwater by physical experiments and numerical simulation techniques.

Methods

First of all, the sand medium in arid area was taken as the research object, and a soil column device for saturated sandy soil dispersion and permeability test was developed for experimental test. Then, the U and 238Pu were arranged in the form of liquid point source in the form of liquid point source in the intake section of the soil column, respectively, and the concentration distribution of nuclides in the space of the soil column was measured after the test cycle. Finally, Hydrus-3D was used to establish a three-dimensional numerical model of nuclide migration and to fit the relevant experimental parameters.

Results

The experimental results showed that U migrated downward 24.3 cm along the water flow direction in soil column after 14 days, the distribution coefficient was 35 mL?g-1, the longitudinal dispersion was 22 cm, and the transverse dispersion was 25 cm. 238Pu migrated downward 2.1 cm along the water flow direction in soil column after 140 days, the peak concentration was 0.47 ng?cm-3, the distribution coefficient was 6 500 mL?g-1, the longitudinal dispersion was 2 cm, and the transverse dispersion was 25 cm. The different migration curves of U and 238Pu in heterogeneous test soil columns are mainly related to the adsorption and retention of sand media and solutes.

Conclusions

The proposed experimental method for nuclide migration in aquifer porous media can provide support for the study of the migration and transformation in soil media.

Key words: Radionuclide, Migration, Numerical simulation, U, 238Pu

CLC Number: 

  • X52