Abstract: An EMAT device for non-destructive inspection of the surface of a tube for cracks using acoustic surface waves includes a pulsed magnet having an active surface for facing the surface of a tube to be inspected. A receive emat coil is on the active surface and a transmit emat coil is on the opposite surface of the receive coil. The transmit emat coil has a scan surface for scanning over the tube surface. A transmitter for generating and transmitting an RF signal to the transmit emat coil is provided for generating a transmitted acoustic wave signal along the tube, the transmitted wave creating a reflected acoustic wave if a crack in the tube is encountered, the reflected wave generating a reflection signal in the receive emat coil. A receiver is connected to the receive emat coil for receiving the reflection signal.

Abstract: An EMAT arrangement utilizes separate transmitter and receiver EMATs which may each be connected to a tuning capacitor by a stripline cable. An electrostatic shield may also be provided between the coils and the coils can be offset from each other by ½ the pitch distance of sections in the coil. This reduces the duration of main bang, thus making it possible for the EMAT arrangement to detect structures which are very close to the coils.

Abstract: An EMAT testing device for nondestructively testing tubes for surface defects and displaying the results has a EMAT transmitter arranged collinear with a pair of EMAT receivers. The EMAT receivers each receive a pair of oppositely propagating circumferential acoustic surface waves from the transmitter at different times and the relative amplitudes of the received waves are compared to located defects adjacent the receivers in the tube.

Abstract: An EMAT arrangement utilizes separate transmitter and receiver EMATs which may each be connected to a tuning capacitor by a stripline cable. An electrostatic shield may also be provided between the coils and the coils can be offset from each other by 1/2 the pitch distance of sections in the coil. This reduces the duration of main bang, thus making it possible for the EMAT arrangement to detect structures which are very close to the coils.

Abstract: A variable power source is provided having multiple power modules each of which can produce a portion of the total range of voltage required for pulsed operation of an electromagnetic acoustic transducer electromagnet. The power modules are connected in series, and controlled by individual potentiometers which are simultaneously adjusted. Selector switches are provided for enabling or disabling each module. The output of the power modules is connected to a pulser/controller for wave forming prior to sending the output signal to the electromagnet. A noise filter can be placed between the power modules and the pulser. LED-type indicators on the selector switches may be used to indicate the operational status of the modules.

Abstract: An apparatus and method for scanning the outer profile of control rods in a control rod assembly includes a plurality of rotatably mounted ultrasonic transducers which are mounted for rotation about the axis of at least some of the control rods in the assembly. The assembly is moved in a linear path parallel to the axis of the control rods, past the rotating transducers for scanning the surfaces of the control rods in helical paths. By distributing the transducers in a selected configuration, all control rods in the assembly can eventually be scanned.