HFIR instrumentation error analysis

The accuracies of the measurements of operating conditions made by the electronic safety system at the High Flux Isotope Reactor were calculated theoretically. The technique was small-signal sensitivity analysis of the errors as they accumulated through cascaded instruments in various systems. The error bounds (for 99.7 percent probability) at typical operation of 100 MW thermal power (mode 1) were approximately 4.05 MW in heat power, 1.820F in inlet temperature, and 5.95 MW in perceived heat power on flux-to-flow ratio. The error bound in flow at the nominal flow trip point of 1500 gpm was approximately 86 gpm. The maximum unfavorable error in perceived heat power in flux-to-flow measurement was +420 kW for operation in research mode 2 (lower coolant flow and, hence, lower power; and approximately the same temperature difference as in mode 1), and +17.1 kW for mode 3 (no coolant flow, static operation, and, hence, low power)