Document: NUREG-0800
Document ID: 29fa664a-a42c-4ff0-8ae1-3798f7f23c23
Document Type: srp
Title: TURBINE MISSILES
Source: NUREG-0800
Source URL: https://www.nrc.gov/docs/ML0520/ML052070373.pdf
Revision Date: 2023-06
Chapter: 3
Section ID: 3.5.1.3
CFR Part: 
CFR Title: 

Content:
ility components in the relation where P2ij ( j j,max ) ( max ) DRAFT Rev. 3 - April 1996 3.5.1.3-12 EQUATION DELETED P = Total probability for incurring damage which exceeds the criteria described in subsection II, per turbine year. N = Total number of distinct turbine missile sources per turbine generator unit, usually identified with the number of low pressure wheels. P = Probability for turbine failure leading to the ejection of missiles due to the 1i i type of turbine failure. th P = 6 x 10 per turbine year for design over speed failures. 11 -5 P = 4 x 10 per turbine year for destructive overspeed failures (Ref. 4). 12 -5 P = The strike probability with respect to a barrier between the turbine and the 2ij target. In case of multiple barriers, it is equivalent to the probability for striking the final barrier between the turbine and the target. The j - index refers to the j wheel on the turbine rotor. th P = The probability for damaging the target. This can be either due to primary 3ij missile penetration of a barrier or due to the generation of secondary missiles (e.g., scabbing in concrete), or both. It should be noted that in the case of multiple barriers the value of P will be determined by a combination of geometric considerations, missile deflections, and intermediate barrier penetration estimates (Ref. 5). The usual procedure is to estimate the portion of the total solid angle associated with each ejected missile that is subtended by the target in question. If there are no intermediate barriers, or if all barriers up to the final barrier are penetrated independently of missile state (i.e., energy, impact orientation) then P can be 2ij approximated by where = Azimuthal angle subtended by the target with the respect to j the j(th) wheel. = Maximum azimuthal angle range of fragment trajectories ejected j,max from the j(th) wheel. = 10 for inner wheels 0 fij M m 1 (All missile states that penetrate the mth barrier )ij (Total number of possible missile states