||The measurement of loss of activity of coupons as a result of corrosion can be performed in a multichannel gamma spectroscopy analyzer. The setup consists of a 50 mm size NaI(Tl) detector, preamplifier, spectroscopy amplifier, high voltage power supply , 1K multichannel analyzer, an ADC and a PC based data acquisition system. The counts for preset duration were measured before starting the corrosion test as well as intermittently during the corrosion test. The counts were converted into relative remnant activity by dividing the measured counts by the initial counts. A calibration curve generated by stacked Fe foil irradiation was used to correlate the relative remnant activity with the thickness loss.