Tracer experiments in a research tunnel of a repository for low- and medium-active nuclear waste

Pekka Viitanen

Research output: Contribution to journalArticleScientificpeer-review

2 Citations (Scopus)


Radionuclide transport in groundwater has a major role in the safety assessment of radioactive waste disposal. The present tests were carried out at the research tunnel, 60 m below ground level, of the Olkiluoto repository. The work was done as a part of hydrogeological characterization of the research tunnel. The measurements were made between two 56 mm boreholes, 10 m and 7.5 m deep, separated by a distance of 6 m. The injection hole was plugged in order to maintain the pressure of the groundwater. The extraction hole was open at the atmospheric pressure. Thus, a pressure gradient was effected between the two holes. Uranine and 82Br were used as tracers.

The flow rate of the groundwater was measured by monitoring the descending tracer concentration in the injection hole. The primary means to measure the output concentration was based on the inactive tracer. Fourier analysis was used as a deconvolution technique to extract the residence time distribution between the two holes. The mean residence time was about 12 hours. Modeling efforts have shown that a matrix diffusion model describes the system satisfactorily.
Original languageEnglish
Pages (from-to)546-549
JournalNuclear Instruments and Methods in Physics Research. Section A: Accelerators, Spectrometers, Detectors and Associated Equipment
Issue number1-3
Publication statusPublished - 1994
MoE publication typeA1 Journal article-refereed


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