Document: NUREG-0800
Document ID: 0b1da184-7029-4886-9101-d5e6755a79ad
Document Type: srp
Title: Revision 4 - March 2007
Source: NUREG-0800
Source URL: https://www.nrc.gov/docs/ML0708/ML070850324.pdf
Revision Date: 2023-06
Chapter: 10
Section ID: 10
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Content:
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 "once through" flow designs, have generally not reported 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 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. B. BRANCH TECHNICAL POSITION In CP and COL application reviews, the staff expects the applicant to provide the following design capability and verification: Top-Feed Steam Generator Designs To eliminate or reduce possible water hammer in the feedwater system: BTP 10-2-3 Revision 4 - March 2007 1. Prevent or delay water draining from the feed ring following a drop in steam generator water level by means such as top discharge J-Tubes and limiting feed ring seal assembly leakage. 2. Minimize