Document: NUREG-0800
Document ID: dfb421c6-cf9c-447e-ab71-dd0426ce50e5
Document Type: srp
Title: TURBINE MISSILES
Source: NUREG-0800
Source URL: https://www.nrc.gov/docs/ML0523/ML052340523.pdf
Revision Date: 2023-06
Chapter: 3
Section ID: 3.5.1.3
CFR Part: 
CFR Title: 

Content:
.3. b. The effect of fracture toughness properties on the failure probability of the low pressure turbine wheels is reviewed by the MTEB. c. The turbine overspeed protection system and its testing are evaluated by the MEB (turbine steam valve reliability) and the PSB (tripping and overspeed sensing systems). d. The identification of plant essential systems to be protected against turbine missiles is reviewed by the ASB. 4. For Construction Permit applications docketed prior to 11/15/76 and to all Operating License reviews, a summary should be prepared of the following items: a. Identification of all safety-related targets vulnerable to turbine missiles. b. MTEB findings regarding turbine disc and rotor integrity and inservice inspection program. c. When appropriate, SEB evaluation of credit for missile barriers. d. PSB findings regarding turbine overspeed protection system. e. A general value impact assessment of localized missile shielding (CP's and .OL's) and/or system relocation (CP's only). f. Identification of additional plant requirements, if any. 5. High trajectory turbine missiles are characterized by their nearly vertical trajectories. Missiles ejected more than a few degrees from the vertical, either have sufficient speed such that they land offsite, or their speeds are low enough so that their impact on most plant structures 3.5.1.3-6 Rev 2 - July 1981 is not a significant hazard. The probability of a high trajectory turbine missile landing within a few hundred feet from the turbine is on the order of 10-7 per square foot of horizontal target area. Consequenty the risk from high trajectory turbine missiles is insignificant unless.the vulnerable target area is on the order of 104 square feet or more. IV. EVALUATION FINDINGS The reviewer verifies that sufficient information has been provided and that the review and calculations support conclusions of the following types: 1. The staff concludes that the turbine missile risk for the proposed plant design is