Normally Steam drum RT is a 100% welds with joint efficency 1.00. Yes you can substitute by a proper UT with recording facility with proper calibration and demonstration proficiency by qualified ASNt NDT Level II skilled operator having good mentality for defect exploration.
regards
Debasis Mitra
Sr. Engineer (Inspection Services)
ASNT NDT Level III (RT,UT,MT)
Haldia Petrochemicals Limited ; Plant ; West Bengal ; India