A reactor system for the epoxidation of ethylene, which reactor system comprises an elongated tube having an internal tube diameter of more than 40 mm, wherein contained is a catalyst bed of catalyst particles comprising silver and a promoter component deposited on a carrier, which promoter component comprises an element selected from rhenium, tungsten, molybdenum and chromium; a process for the epoxidation of ethylene comprising reacting ethylene with oxygen in the presence of the catalyst bed contained in the reactor system; and a method of preparing ethylene glycol, an ethylene glycol ether or an ethanol amine comprising obtaining ethylene oxide by the process for the epoxidation of ethylene, and converting the ethylene oxide into ethylene glycol, the ethylene glycol ether, or the ethanol amine. Preferably, the internal tube diameter is at least 45 mm.