Alpha Reactors are highly valuable items worth 3500 N-Meseta each and are randomly generated across the Aelio region daily. They are meant to be sold. In PSO2, they work just like Meseta Crystals. Mag's Sonar set to Valuable Items can detect them. Sell them directly from your Inventory or Item Shop. Nearly 50k worth of reactors are generated daily so pick them up and sell them for easy money.