Document: NUREG-0800
Document ID: 5cb19e99-a561-4571-92e5-2933a6181985
Document Type: srp
Title: CONTAINMENT SPRAY AS A FISSION'PRODUCT CLEANUP SYSTEM
Source: NUREG-0800
Source URL: https://www.nrc.gov/docs/ML0523/ML052340761.pdf
Revision Date: 2023-06
Chapter: 6
Section ID: 6.5.2
CFR Part: 
CFR Title: 

Content:
be transferred automatically from the injection mode to the recirculation mode to ensure continuous operation until the design objectives of the system have been achieved. In all cases, the operating period should not be less than two hours. Additives to the spray solution may be initiated manually or automatically, or may be stored in the containment sump to be dissolved during the spray injection period. b. Coverage of Containment Building Volume In order to ensure full spray coverage of the containment building volume, the following should be observed: (1) The spray nozzles should be located as high in the containment building as practicable to maximize the spray drop fall distance. (2) The layout of the spray nozzles and distribution headers should be such that the cross-sectional area of the containment building covered by the spray is as large as practicable and that a nearly homogeneous distribution of spray in the containment building space is produced. Unsprayed regions in the upper containment building and, in particular, an unsprayed annulus adjacent to the containment building liner should be avoided wherever possible. (3) In designing the layout of the spray nozzle positions and orien- tations, the effect of the post-accident atmosphere should be considered, including the effects of post-accident conditions that result in the maximum possible density of the containment atmos- phere. c. Promotion of Containment Building Atmosphere Mixing Because the effectiveness of the containment spray system depends on a well-mixed containment atmosphere, all design features enhancing post-accident mixing should be considered. 6.5.2-3 Rev. 2 - December 1988 d. Spray Nozzles The nozzles used in the containment spray system should be of a design that minimizes the possibility of clogging while producing drop sizes effective for iodine absorption. The nozzles should not have internal moving parts such as swirl vanes, turbulence promoters, etc. They should not have