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:
stem. The dynamic structural response due to BWR safety relief valve discharge into the suppres- sion pool is also considered. The design of safety and relief valve systems is reviewed with respect to the load combinations imposed on the safety or relief valves, upstream piping or header, downstream or vent piping, system supports, and BWR suppression pool discharge devices such as ramsheads and quenchers. The load combinations should identify the most severe combination of the applicable loads due to internal fluid weight, momentum and pressure, dead weight of valves and piping, thermal load under heatup, steady state and transient valve operation, reaction forces when valves are discharging (thrust, bending, and torsion), seismic forces, and dynamic forces due to BWR safety relief valve discharge into the suppression pool as applicable. The reaction loads due to discharge of loop seal water slugs and subcooled or saturated liquid under transient or accident conditions shall also be included as valve discharge loads. The structural response of the piping and support system is reviewed with particular attention to the dynamic or time-history analyses employed in evaluating the appropriate support and restraint stiffness effects under dynamic loadings when valves are discharging. Where the use of hydraulic snubbers is proposed, the snubber performance characteristics are reviewed to assure that their effects have been considered in the analyses under steady state valve operation and repeti- tive load applications caused by cyclic valve opening and closing during the course of a pressure transient. 3. Component Supports The review of information submitted by the applicant includes an evaluation of Code Class 1, 2, and 3 components supports. The review includes an assessment of design and structural integrity of the supports. The review addresses three types of supports: plate and shell, linear, and component standard types. All the component supports of these three