Automatic-Ranging Picoammeter for Reactor Control and Protection

An automatic-ranging picoammeter covering full-scale ranges from 3 X 10-11 to 1 X 10-3amperes with a 50% over-range capability has been designed, built, tested, and installed for use with Babcock & Wilcox´s Lynchburg Pool Reactor. The unit incorporates three major improvements over previous instrumentation and commercially available equipment: (1) elimination of manual range changing, (2) provision for adjustable power level trips throughout the operating range of the reactor, and (3) provision for a trip function upon detection of a period shorter than that preset into the instrument.