Document: NUREG-0800
Document ID: 808cea66-69b8-4f91-9fb2-62b3b99bc87a
Document Type: srp
Title: NUREG-0800
Source: NUREG-0800
Source URL: https://www.nrc.gov/docs/ML0523/ML052340579.pdf
Revision Date: 2023-06
Chapter: 3
Section ID: 3
CFR Part: 
CFR Title: 

Content:
e the severity of this gradient by limiting the rise in temperature to an acceptable level. Procedures for determining seismic loads on the primary shield wall are reviewed in accordance with Standard Review Plan Section 3.7.2. Loss of coolant accident loads that are applicable to the primary shield wall include a different pressure created across the reactor cavity by a pipe break in the vicinity of the reactor nozzles. Such a transient pressure may act on the entire cavity or on portions thereof. Procedures for determining such pressures are reviewed by the Containment Systems Branch (CSB). Other loss of coolant accident loads that apply are those transmitted to the wall through the reactor supports including pipe rupture reaction forces which may induce simultaneous shear forces, torsional moments, and bending moments at the base of the wall. Further, the elevated temperature within and around the primary shield created by the accident may produce transient thermal gradients across the thick wall. Design and analysis procedures for such accident effects are accordingly reviewed. iii. Secondary Shield Walls The secondary shield walls surrounding the primary loops and supporting the operating floor should be designed for loads similar to those applicable to the primary shield wall includ- ing loads of fluid jets from a postulated break of a primary pipe which can impinge on these walls. The analytical tech- niques utilized for these walls are reviewed including their structural framing and behavior under loads. Where elasto- plastic behavior is assumed and the ductility of the walls is relied upon to absorb the energy associated with jet loads, the procedures and assumptions are reviewed with particular empha- sis on such areas as modeling techniques; boundary conditions, force-time functions, and assumed ductility. For the time- dependent differential pressure, however, elastic behavior is required and the methods of determining an equivalent static load are