Abstract: A nuclear power plant includes a containment, a region exposed to radiation in the containment and a signal transmission system. A modulator disposed inside the region exposed to radiation converts an analog measured value provided by an associated sensor into a PWM signal. A demodulator disposed outside the region exposed to radiation reconstructs the measured value from the PWM signal. The modulator is implemented by using radiation-hardened, preferably analog, circuit technology and includes adaptable measured value normalization, a sawtooth generator and a comparator. A signal transmission line being DC-isolated from an output of the comparator connects the demodulator to the modulator. A method for transmitting a measured value from a region exposed to radiation in a containment of a nuclear power plant to an external evaluation system is also provided.