Static measurements of various nuclear core parameters were completed for the highly enriched plate-type Al-clad core to be used for the Spert I integral core destructive test program. Self-limiting power excursion tests were performed with initial asymptotic reactor periods in the range of 934 to 4.6 msec to establish the transient response of the core and to obtain data for extrapolation to shorter-period tests in which violent destructive effects are expected. For tests with periods shorter than about 7 msec, fuel plate deformations were produced as a result of thermal stresses in the plates. Melting of fuel plates was obtained in two tests with periods of 5 and 4.6 msec. For tests with periods in the range of 9 to 4.6 msec, power burst shape changes were observed which result in an increase in the ratio of the energy release in the total burst to that at the time of the power peak, as the period is shortened. Maximum transient pressures never exceeded 10 psi for tests thus far performed. A series of self-limiting power excursion tests was initiated in Spert II to determine the effects of the initial system temperature on the kinetic response of the D/sub 2/Omoderated expanded …