Preparation of Zr isotope standard solution for isotope dilution mass spectrometry

Konda, Miki; Asai, Shiho; Hanzawa, Yukiko  ; Magara, Masaaki  

It is important to measure the inventory of radionuclides in high-level radioactive waste for safe and reasonable geological disposal of the waste. For verification of the reliability of the inventory assessment by measured value, we planned to quantify the long-lived nuclides Zr, that is important for safety evaluation of radioactive waste disposal, using isotope dilution inductively coupled plasma mass spectrometry (ID-ICP-MS) we developed. Spike (isotope standard solution) is required to apply the IDMS. We prepare Zr isotope standard solution by dissolving the metallic Zr isotope standard. The metallic Zr dissolves in HF, but HF dissolve glass and has high toxicity. Therefore it is necessary to reduce an amount of HF and to simplify a dissolution method. At first, we examined the dissolution method of the metallic Zr. The isotope standard of Zr was dissolved under optimum condition that obtained by the previous examination. The prepared Zr isotope standard solution was measured using the IDMS to determine concentration, which gave us a high-accuracy value.