Document: NUREG-0800
Document ID: 9756acc3-3645-4542-87b2-dba98ae1d5d5
Document Type: srp
Title: TURBINE ROTOR INTEGRITY
Source: NUREG-0800
Source URL: https://www.nrc.gov/docs/ML0631/ML063190015.pdf
Revision Date: 2023-06
Chapter: 10
Section ID: 10.2.3
CFR Part: 
CFR Title: 

Content:
e acceptable if the following criteria are met. The ratio of the fracture toughness (KIc ) of the rotor material to the maximum tangential stress at speeds from normal to design overspeed should be at least 10 /mm (2 /in), at minimum operating temperature. Bore stress calculations should include components due to centrifugal loads, interference fit, and thermal gradients. Sufficient warmup time should be specified in the turbine operating instructions to ensure that toughness will be adequate to prevent brittle fracture during startup. Fracture toughness properties can be obtained by any of the following methods: A. Testing of the actual material of the turbine rotor to establish the KIc value at normal operating temperature. B. Testing of the actual material of the turbine rotor with an instrumented Charpy machine and a fatigue precracked specimen to establish the KIc (dynamic) value at normal operating temperature. If this method is used, KIc (dynamic) shall be used in lieu of KIc (static) in meeting the toughness criteria above. 10.2.3-5 Revision 2 - March 2007 C. Estimating of KIc values at various temperatures from conventional Charpy and tensile data on the rotor material using methods are presented in J. A. Begley and W. A. Logsdon, Scientific Paper 71-1E7-AMSLRF-P1. This method of obtaining KIc should be used only on materials which exhibit a well-defined Charpy energy and fracture appearance transition curve and are strain-rate insensitive. The staff should review the test data and the calculated toughness curve submitted by the applicant. D. Estimating "lower bound" values of KIc at various temperatures using the equivalent energy concept developed by F. J. Witt and T. R. Mager, ORNL-TM- 3894. The staff should review the load-displacement data from the compact tension specimens and the calculated toughness data submitted by the applicant. 3. Pre-service Inspection. The applicant's pre-service inspection program is acceptable if it meets the following