[en] ASEA-ATOM carried out an experiment in Forsmark 1 in 1978, in conjunction with discharge test, by means of the safety/relief valves. The tests have been carried out for the case of single valve actuation (SVA), multiple valve actuations (MVA) and consecutive valve actuations (CVA). During MVA tests, up to 12 valves have been used. One of the aims of the experiment was to confirm the operation of the new design of mitigator of the discharge pipes and another was to survey the pressure oscillations in the pool and the vibratory behaviour of the structures and components. The results of these measurements are presented in a number of reports. This report contains an abstract of the results of the measurements presented in these reports. This report also describes the theoretical background and comparisons between test and theoretical results. It is clear that very good agreement has been established between earlier steam discharge experiments, using a mitigator of the type fitted in Forsmark 1, and this experiment. This is based on the fact the amplitude, frequency and distribution of the pressure oscillations in the condensation pool are basically equal to the values predicted by calculations based on the earlier experiments. The low maximum acceleration amplitudes predicted by the beam type structural model have been confirmed, but the frequency content of the response is not very well represented by this type of model. The shell-beam finite element model of the structure gives better agreement with the measured frequency. (author)