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:
ained from Charpy tests performed in accordance with specification ASTM A-370 should 14 be no higher than -18 C (O F) for low-pressure turbine diskrotors. 15 Nil-ductility transition (NDT) temperature obtained in accordance with specification ASTM E-208 may be used in lieu of FATT. NDT temperatures 16 should be no higher than -35 C (-30 F).17 c. The Charpy V-notch (C ) energy at the minimum operating temperature of each v low-pressure diskrotor in the tangential direction should be at least 8.3 kg-m (60 ft-lbs). A minimum of three C specimens should be tested in accordance 18 v with specification ASTM A-370. 2. Fracture Toughness The low-pressure turbine disk forged or welded rotor fracture toughness properties are 19 acceptable if in compliance with the following criteria: The ratio of the fracture toughness (K ) of the diskrotor material to the maximum Ic tangential stress at speeds from normal to design overspeed should be at least two 10 mm (2 in), at minimum operating temperature. Bore stress calculations should 20 include components due to centrifugal loads, interference fit, and thermal gradients. Sufficient warmup time should be specified in the turbine operating instructions to assure DRAFT Rev. 2 - April 1996 10.2.3-4 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 diskrotor to establish the K value at Ic normal operating temperature. b. Testing of the actual material of the turbine diskrotor with an instrumented Charpy machine and a fatigue precracked specimen to establish the K (dynamic) Ic value at normal operating temperature. If this method is used, K (dynamic) shall Ic be used in lieu of K (static) in meeting the toughness criteria above. Ic c. Estimating of K values at various temperatures from conventional Charpy and Ic tensile data on the diskrotor material using methods presented by J.