Document: NUREG-0800
Document ID: 60504484-b86d-4048-bba0-59d150675db4
Document Type: srp
Title: TURBINE DISKROTOR  INTEGRITY
Source: NUREG-0800
Source URL: https://www.nrc.gov/docs/ML0520/ML052070578.pdf
Revision Date: 2023-06
Chapter: 10
Section ID: 10.2.3
CFR Part: 
CFR Title: 

Content:
important that low-pressure diskrotors be made of a tough material. The use of suitable design, materials, fabrication techniques, coating processes, nondestructive examinations during the fabrication process, and inservice inspection can greatly reduce the probability of a 9 turbine diskrotor failure. The materials properties, including descriptions of the procedures to minimize flaws and improve fracture toughness, are reviewed to establish that sufficient information is provided to permit an evaluation of the adequacy of the low-pressure diskrotor materials. Included in this information are: a. A discussion of the ductile-brittle transition temperatures (FATT or NDT) of the materials and the tests and standards used to determine them. b. The Charpy V-notch test program used to establish minimum upper-shelf energies of the diskrotor materials. c. The fracture toughness test program used to establish minimum upper-shelf toughness of the diskrotor materials. 2. Fracture Toughness The fracture toughness of the materials and the materials tests or correlations of Charpy and tensile data to toughness properties are reviewed to establish that the turbine diskrotor materials exhibit adequate fracture toughness at normal operating temperature and during startup. 3. Preservice Inspection The preservice inspection program information is reviewed to verify that the diskrotor forgings are first machined with minimum excess stock prior to heat treatment; that visual and surface inspections are performed on all finished machined surfaces; and that a 100% volumetric (ultrasonic) examination is performed; that before welding and/or brazing, all surfaces prepared for welding will be surface examined; that after welding and/or brazing, all surfaces exposed to steam will be surface examined, giving particular attention to stress risers and welds; and that welds will be ultrasonically examined in the radial and radial-tangential sound beam directions.10 4. Turbine DiskRotor Design