WASHINGTON — The House Oversight Committee launched a probe Monday into reports of the mysterious disappearances or deaths of at least 10 scientists and researchers working in US nuclear or rocket technology, according to letters obtained by The Post. “If the reports are accurate, these deaths and disappearances may represent a grave threat to U.S. national security and to U.S. personnel with access to scientific secrets,” wrote Oversight Chairman James Comer (R-Ky.) and Rep. Eric Burlison (R-