What year is it?
I doubt it's anything abnormal.
All electric pumps are quite noisy, and on most cars they are actualy in the fuel tank, which dampens the noise.
However some cars, especialy older injected ones will have the pump in the boot, under the car, or in the engine bay.
In these cars it's quite common to be able to hear it.
The other option is its some like and engine fan running constantly, or interferance from the ignition system effecting the radio.
But thier both easy to spot, if you open the bonnet you'll soon know if the fan is running. And you will be able to hear any interferance coming from the speakers.