[en] This preliminary report covers the results of the test program of safety/relief valve (SRV) discharge load phenomena and the effects upon the Mark I primary containment torus structure of the Monticello Nuclear Power Plant. The objectives of the test were to provide a data base for verifying/improving analytical models and to measure the structural response of the torus to SRV discharges. Objectives, instrumentation, and test plan are described. Results of continuing data evaluation will be included in the final report scheduled for publication later in 1977