Multifrequency Binary Sequence Testing at the Fast Flux Test Facility

The multifrequency binary sequence experimental technique for measuring closed-loop frequency response functions has been implemented at the Fast Flux Test Facility for routine surveillance activities. The frequency content of the standard rod movement sequence has been shown to be sufficient to normalize the data at moderate frequencies. This obviates the need for auxiliary calibration measurements and provides the reactivity worth of the test control rod. Analyses of a series of tests conducted in 1986 illustrate that the rod worths inferred from the tests are consistent with zero-power measurements. Also, the dependence of the prompt feedback time constant on reactor conditions was determined.