The possibility for spark-initiated explosions in deuterium containing 0.5 to 70 mol% uranium hexafluoride at pressures up to 2.8 MPa has been investigated. No explosions were observed under these conditions, although spark-initiated formation of the reaction product beta-uranium pentafluoride occurred. The spark potential for deuterium containing 0 to 25 mol% uranium hexafluoride at pressures up to 2.8 MPa is also reported. For pure deuterium, the voltage to produce a 1-mm-long spark ranged from 10 kV at 250 kPa to 24 kV at 2.7 MPa. The addition of uranium hexafluoride increased the spark voltage sharply; at 2.3 MPa the addition of 7 mol% UF6 raised the spark voltage from 24 to 73 kV.