Document: NUREG-0800
Document ID: a4637484-a66d-4066-b2e7-77b0ea7d3187
Document Type: srp
Title: 2.
Source: NUREG-0800
Source URL: https://www.nrc.gov/docs/ML0520/ML052070601.pdf
Revision Date: 2023-06
Chapter: 10
Section ID: 10.4.9.16
CFR Part: 
CFR Title: 

Content:
ing have introduced steam generators of the preheat type, wherein the majority of feedwater enters the steam generator at the bottom through a preheater section. The potential for condensation-induced water hammer in preheat steam generators was studied by BNL and reported in NUREG/CR-1606, "An Evaluation of Condensation-Induced Water Hammer in Preheat Steam Generators," June 1980. This report, citing the lack of definitive experimental and analytical results, recommended full-scale verification tests to demonstrate the absence of damaging water hammer in preheat steam generators and connecting feedwater piping (i.e., preoperational tests). B&W steam generators, which are a "once through" flow designs, have generally not reported 99 water hammer occurrence. However, in May 1982, several B&W plants (following inservice inspection) reported damaged internal auxiliary feedwater headers and support structures. The cause was attributed to steam pocket collapse. The internal auxiliary feed ring design concept is similar to CE & W top-feed ring concepts which have experienced water hammer before corrective design measures were implemented. For these B&W plants, the OTSGs are being 10.4.7-13 DRAFT Rev. 4 - April 1996 modified to return to the previous design using auxiliary feedwater injection manifolds which are external to the steam generator. The staff believes that SGWH evidence and studies performed to date warrant the establishment of design guidelines for steam generators and the associated piping. Guidelines have been developed that may be used to reduce the probability of a damaging steam-condensation-induced water hammer, particularly for the Westinghouse and Combustion Engineering PWR designs which use top-feed steam generators. BRANCH TECHNICAL POSITION In CP and OL application reviews, the staff requires the applicant to provide the following design capability and verification: Top-Feed Steam Generator Designs To eliminate or reduce possible water hammer in the