Axial void fraction distribution measurement method and neutron multiplication factor evaluating method

摘要

A first intensity A_z expressed as A_z=a_zxE^alpha, a first reference intensity A_o expressed as A_o=a_oxE^alpha, a second intensity B_z expressed as B_z=b_zxE, and a second reference intensity B_o=b_oxE, are evaluated. The first intensity and the first reference intensity are of radioactive nuclides generated by a neutron capture reaction of a heavy nuclide or a fission product nuclide. The second intensity and the second reference intensity are of radioactive fission product nuclides except nuclides generated by a neutron capture reaction. The reference intensities are measured where the void fraction is known. Also a correlation curve of (a_z/a_o) and a void fraction is evaluated. Finally an axial void fraction distribution is evaluated based on the value of (a_z/a_o) and the correlation curve.