This progress report documents the progress of the ECN contribution in the High Active Waste experiment, a large-scale in situ test being performed underground at the Asse salt mine in Remlingen FRG, during the period April 1st through June 30th, 1990. In ch. 2 a general overview is given of the experiment development. Problems and solutions are discussed in ch. 3. (author). 4 refs.; 10 figs.