Preparation of Reference Materials on Radiochemical Analysis for Low-Level Radioactive Waste Generated From Japan Atomic Energy Agency

In order to prepare simulated reference materials of solidified products using a laboratory-scale electric furnace instead of a plasma heating device, melting tests of miscellaneous simulated solid wastes were conducted. Over 90% of Cs was remained in the solidified product by keeping the basicity (CaO wt%/SiO₂ wt%) to be 0.05. Under the optimum melting conditions, reference materials containing α-ray emitting nuclides (²³⁷Np, ²⁴¹Am and ²⁴⁴Cm) or γ-ray emitting nuclides (⁶⁰Co, ¹³⁷Cs and ¹⁵²Eu) were prepared. For reference materials containing β-ray emitting nuclides such as ¹⁴C and ³⁶Cl, a preparation method with nuclear reaction ¹⁴N(n, p)¹⁴C or ³⁵Cl(n, γ)³⁶Cl by thermal neutron irradiation was attempted. The radioactivity concentrations of the reference materials were evaluated from radiochemical analysis. It was confirmed that the reference materials could be successfully prepared on the present preparation methods.