| Abstract: | This paper investigates the horizontal responses of the reactor internals to a 14 inch safety injection nozzle break, which is expected to cause the largest loads of the branch line pipe breaks defined for a nuclear power plant. It examines the effects of two forcing terms, reactor vessel motions and internal hydraulic loads, and suggests a new procedure which can be used for tributary pipe break analysis. The analysis result confirms the applicability of the suggested procedure to small size tributary pipe break analysis. Also, this paper calculates the horizontal responses of the reactor internals to a 3 inch pressurizer spray line nozzle break, which is the only one remaining on the primary side after leak-before-break evaluation, and secondary side pipe breaks such as main steam line and economizer feedwater line. The responses are compared with those of safe shutdown earthquake to show that seismic loads with a conservative margin may be used for the pipe break loads in the preliminary design. |
