Preparation of radiochemically pure 79Se and highly precise determination of its half-life

The work presented in this article concerns the development of a method for the determination of selenium-79 in fission product (FP) solutions resulting from nuclear fuel reprocessing. 79Se (T1/2
= 106 y) was measured using electrothermal vaporisation coupled with inductively coupled plasma mass spectrometry (ETV-ICP/MS) after a single chemical separation step to extract Se from the high activity solution (1010 Bq l−1). The results showed that the ion exchange method produced a solution sufficiently decontaminated with respect to major β/γ emitters and had a significant selenium recovery yield (85%). ETV parameters, for example furnace program, quantity of palladium nitrate used as chemical modifier, and gas flow rates, were optimised. The association of ETV and chemical separation eliminated all the interferences normally associated with the determination of 79Se. The concentration of 79Se measured in the fission products solution was 0.43 mg l−1.

Determination of selenium-79 in solutions of fission products after pre-treatment by ion exchange chromatography and ETV-ICP-MS

Decay data: review of measurements, evaluations and compilations.

Development of a radiochemical separation for selenium with the aim of measuring its isotope 79 in low and intermediate nuclear wastes by ICP-MS.

The half-life of126Sn has never been measured accurately. The value quoted in the literature is approximately ∼105y, which was measured in 1958. In the present work we measured accruately the half life of126Sn to be (2.5±0.2)×105y using a radiochemical method.

Measurement of the half life of126Sn using a radiochemical method

This paper presents a radiochemical separation procedure of79Se from high level liquid radioactive waste, with nitrobenzene extraction and with sulfur dioxide precipitation. The procedure gives a chemical yield of selenium greater than 60%, and satisfactory decontamination is observed for all the relevant radioactive nuclides. Liquid scintillation counting were used for the measurement of79Se radioactivity. The79Se samples obtained from the procedure were used successfully in79Se half-life detemination.

A procedure for the separation of79Se from fission products and application to the determination of the79Se half-life

The half-life of79Se, a long-lived fission product nuclide, has never been measured accurately. The value quoted in the literature is an upper limit, ≤6.5·104 y, measured in 1949. In the present work we measured accurately the half-life of79Se to be (4.8±0.4)·105 y using a radiochemical method.

Li Daming

Papers

A procedure for the separation of79Se from fission products and application to the determination of the79Se half-life

Measurement of the half-life of79Se using a radiochemical method