Description of the Performance Demonstration Initiative (PDI) Program
The Nuclear Regulatory Commission (NRC) establishes rules and regulations for the operation of domestic nuclear facilities, which are published in the United States Federal Register under 10CFR50. The NRC has established the ASME Boiler and Pressure Vessel Code as the engineering authority for the design, construction, and operation of nuclear reactors. Section XI of the ASME Code contains the rules for in-service inspection of nuclear plant components. Appendix VIII describes the additional requirements for performance demonstration of UT examinations systems that integrate personnel, equipment, and procedures into a single entity. That entity is the PDI program owned by the utilities. EPRI is the operator of the PDI program.
In order to be used by a vendor during an examination, ultrasonic equipment and probes must successfully meet the requirements of the general procedure through performance demonstration on controlled samples as administrated at the EPRI PDI laboratory.
PDI Procedures for Studs and Bolts Ultrasonic Examination
PDI-UT-5 is a generic PDI procedure providing an examination method to detect, locate and evaluate circumferentially oriented notches or flaws that are primarily perpendicular to the stud or bolt axis. It can be performed on studs or bolts with or without a center bore hole. The examination is realized from one or both ends using a zero-degree longitudinal wave search unit.
Qualified Equipment
Inspectors may utilize any combination of a qualified instrument and probe.
The EPOCH™ 650 flaw detector is qualified for use with all qualified probes.
Qualified Evident probes are outlined in the following table:
| Model | Element Size (in.) | Frequency (MHz) | Wedges or Angles |
| V111 | 0.500 | 10 | 0° |
| A111S | 0.500 | 10 | 0° |
| A10L | 0.500 | 10 | 0° |
Qualified Legacy Equipment
Note that the following models were also qualified during their lifetimes for UT-5:
- EPOCH 600 flaw detector
- EPOCH 1000 flaw detector
- EPOCH II, III, 4, and XT flaw detectors
- SONIC 1200S, 136, and 137 flaw detectors
Customers should refer to PDI tables for specific qualification matrices.
Updates will be provided on a regular basis as we are actively pursuing these areas.
