From the press release
https://www.businesswire.com/news/home/20200828005299/en/
"NuScale spent over $500 million, with the backing of Fluor, and over 2 million labor hours to develop the information needed to prepare its DCA application"
Not cheap :)
On scaling down reactors to micro size (nuscale is kind of larger) and costs:
https://www.youtube.com/watch?v=7gtog_gOaGQ
$0.25/kWh until large series (17mn30s).