Document: NUREG-0800
Document ID: fb538e14-08a0-4d3f-a974-8170cbfe0b5b
Document Type: srp
Title: ASME CODE CLASS 1, 2, AND 3 COMPONENTS,
Source: NUREG-0800
Source URL: https://www.nrc.gov/docs/ML0523/ML052340603.pdf
Revision Date: 2023-06
Chapter: 3
Section ID: 3.9.3
CFR Part: 
CFR Title: 

Content:
Rules for the Design of Safety Valve installations" (Reference 6). Additionally, the following criteria are applicable: (1) Where more than one valve is installed on the same run pipe, the sequence of valve openings to be assumed in analyzing for the stress at any piping location should be that sequence which is estimated to induce the maximum instantaneous value of stress at that location. (2) Stresses should be evaluated, and applicable stress limits should be satisfied for all components of the run pipe and connecting systems and the pressure relief valve station including supports and all connecting welds between these components. (3) In meeting the stress limit requirements, the contribution from the reaction force and the moments resulting from that force should include the effects of the Dynamic Load Factor or should use the maximum instantaneous values of forces and moments for that location as deter- mined by the dynamic hydraulic/structural system analysis. This requirement should be satisfied in demonstrating satisfaction of all design limits at all locations of the run pipe and the pressure relief valve for Class 1, 2, and 3 piping. A Dynamic Load Factor (DLF) of 2.0 may be used. in lieu of a dynamic analysis to determine the DLF. The SAR must also include a description of the calculational procedures, computer programs, and other methods to be used in the analysis. The analysis must include the time history or equivalent effects of changes of momentum due to fluid flow changes of direction. The fluid states considered must include postulated water slugs where water seals are used and subcooled or saturated liquid if such fluid can be discharged under postulated transient or accident conditions. Plants utilizing suppression 3.9.3-4 Rev. 1 - July 1981 pools shall also consider the applicable pool dynamic loads on the safety 1 relief valve system. Stress computations and stress limits must be in accord with applicable rules of the Code. 3. Component