"began operational" is correct and usable in written English.
You can use it to indicate that something has started to be used for its intended purpose. For example: "The factory began operational in the summer of 2020."
In the early stages after the Three Gorges Dam (TGD) began operational ten years ago, the suspended sediment content (SSC) and fluxes in the middle and lower reaches of the river decreased noticeably.
Tunny began operational use in June 1941, and by July 1942 Bletchley Park was in a position to read the messages regularly thanks, in particular, to a series of breakthroughs by British mathematician William Tutte.
* The F/A-18 Super Hornet, a larger version with 25% more wingspan, began operational flights last year and saw its first combat action in November, when it struck Iraqi targets in the "no-fly" zone.
Department officials say they hope by 2016 to begin operational testing, which involves a limited deployment at several facilities in the Pacific Northwest.
Nasa hopes a second company can also soon begin operational cargo deliveries to the station.
Nasa has a second company it hopes also can soon begin operational cargo deliveries to the station.
On 31 March 1945 Galland flew 12 operational jets to Munich to begin operations.
(2) For a new facility or supplier that begins operation on or after January 1 , 2010and becomes subject to the rule in the year that it becomes operational, report emissions beginning with the first operating month and ending on December 31 of that year.
By the time the fourth submarine, HMS Vengeance, began its operational life in November 1999, it had been gone for the best part of a decade.
Intelligence officials say Abdelaziz began providing operational and financial support to two terrorist cells in northern Morocco that plotted attacks in Morocco and France.
