A second series of nine full scale containment response tests to blowdown was carried out at Marviken, Sweden, in 1976. These new experiments were supplementary to the first series of sixteen tests and were mainly oriented towards studies of oscillatory phenomena inside the containment. Specifically, the objective was to provide information on pressure oscillations in the vent system and in the wetwell water pool under different conditions.
The measurement system had been significantly augmented as compared with that of the previous test series and allowed the oscillations to be studied for frequencies' up to 100 Hz.
These experiments were carried out as a multi-national project, as in the first series of tests.
The agreement set up between the parties reflected a special interest in the investigation of the influence of the following factors on the oscillations, mainly those of the pressure, in the containment.
- Total vent pipe area.
- Submergence depth (varying pool level).
- Pool surface area (reduced by a partition wall).
- Pool mass (varying pool level and pool surface area).
- Vent flow path geometry.
- Pool temperature (due to heating during blowdown).
- Vent mass flow rate.
Mixture composition in vents (fraction of air).
In the current reviewing and modification of the test conditions leading to the test matrix the interest became focused on variations of the vent mass flow rate, the concentration of air in the vent flow, the pool mass and indirectly the pool temperature. Although the objective was to get a basis for an increased understanding of the mechanisms behind the oscillations in the containment and particularly in the wetwell pool it was not part of the project's program to develop models for predicting amplitudes and frequencies of such oscillations. A separate study performed in conjunction with the blowdown tests was designed to measure impact loads caused by the rising wetwell pool. The objective was to determine the order of magnitude of these loads so that theoretical models could be verified.
The reports present the second series of Marviken containment experiments. They contain descriptions of the test facility, the instrumentation and data acquisition systems and describes the test program and the data processing. A summary report serves as an introduction to the mass of test data produced in the nine blowdown tests and contains diagrams of the fundamental variables which have been selected for illustration. Finally a short review is given of the accuracy of these variables.
It should be noted that the direct application of the data to develop theoretical models for e.g. predicting amplitudes and dominant frequencies was not within the scope of the project but was left to the participating organizations.
The organizations represented were from Denmark, Germany, Finland, France, Japan, the Netherlands, Norway, Sweden and the United States.
The official documentation of the project is given in the reports and appendices, the titles of which are listed on the back cover.