Type of neutron detector BF3 Type of signal cable Triaxial

Location of pulse preamplifier In amplifier cabinet at control room Location of pulse amplifier In amplifier cabinet at control room Distance between pulse amplifier and preamplifier 2 ft Distance between neutron detector and preamplifier 225 ft

Method of grounding A single-point grounding system is used System ground is made at the amplifier cabinet The signal cabling and neutron detector are insulated and floated above ground, being grounded at the amplifier cabinet The inner shield of the triaxial cable is connected to one electrode of the neutron detector The outer shield is connected to the case of the neutron detector The two shields are grounded at the amplifier cabinet The signal grounds in the preamplifier and amplifier are grounded at the amplifier cabinet The amplifier cabinet is grounded to building ground through grounding cable and buses

Operating problems and modifications During the initial installation, it was discovered that the start-up channels were subject to transient noise problems from several systems throughout the reactor plant The starting and stopping of cranes were a major source of noise The noise problems were eliminated by installing capacitor filters across motor starters, relays, and switches Some noise still remains in the system, but the level is not great enough to affect operation of the system