The state Board of Examiners for Nursing on Wednesday placed the registered nursing programs at three colleges on conditional status for one year because too many students have failed the R.N. licensing exam. The programs – at Central Connecticut State University in New Britain and Gateway Community College in New Haven and the University of St. Joseph’s accelerated program in West Hartford – are expected to present correction plans to the board in June. To avoid conditional status, the programs must have a passing rate of at least 80 percent among students taking the licensing exam for the first time after graduation. Central’s most recent passing rate was 74 percent while Gateway and St.