Automatic device for in-core creep testing of materials at a permanent deformation rate

Described is a device including a loading mechanism with an electromechanical drive located in a nuclear reactor channel, as well as the control and protection blocks ensuring creep testing of materials at a permanent deformation rate. The operating regime of the drive motor is given by the logical scheme and it is supported by the automatic control and stabilization scheme. In the motor switching-on and reversing circuits there are no contact switches, which functions are performed by a controllable thyristor bridge circuit ensuring increased reliability of device long-term operation. The device for interactor testing has been operated for a year. The loading mechanism is located in a central loop channel of the BR-10 reactor with neutron flux intensity of about 1x1015 netr/cm2. Presented are the device performance: 1) the maximum instability of the rotation velocity of the driver electric motor for the whole period of operation does not exceed 0.7-1.0%; 2) the protection device ensures reliable operation of the discharging system with the increase of the fixed level of the twisting moment by 1.0-1.5%; 3) the accuracy of determination of the angle of rotation of the force shaft is about +-20'; 4) the minimum deformation rate of the sample practically realized by means of the given device during reactor operation at stationary power levels, is (1-2)x10-7 hr-1