论文部分内容阅读
The impregnation behavior of molten 2LiF-BeF2 (FLiBe) salt into a graphite matrix of fuel elements for a solid fuel thorium molten salt reactor (TMSR-SF) at pressures varying from 0.4 to 1.0 MPa was studied by mercury intrusion, molten salt impregnation, X-ray diffraction, and scanning electron microscopy techniques. It was found that the entrance pore diameter of the graphite matrix is less than 1.0 μm and the contact angle is about 135°. The threshold impregnation pressure was found to be around 0.6 MPa experimentally, consistent with the pre-dicted value of 0.57 MPa by the Washbu equation. With the increase of pressure from 0.6 to 1.0 MPa, the average weight gain of the matrix increased from 3.05 to 10.48％, corresponding to an impregnation volume increase from 2.74 to 9.40％. The diffraction pattes of FLiBe are found in matrices with high impregnation pressures (0.8 MPa and 1.0 MPa). The FLiBe with sizes varying from tens of nanometers to a micrometer mainly occupies the open pores in the graphite matrix. The graphite matrix couldinhibit the impregnation of the molten salt in the TMSR-SF with a maximum operation pressure of less than 0.5 MPa.