Document: NUREG-0800
Document ID: bcc615f1-3f65-4757-994f-88cc8fe800d5
Document Type: srp
Title: should still be met.
Source: NUREG-0800
Source URL: https://www.nrc.gov/docs/ML0520/ML052070473.pdf
Revision Date: 2023-06
Chapter: 6
Section ID: 6.5.1
CFR Part: 
CFR Title: 

Content:
es an exemption from existing regulations that require the use of TID 14844 (Reference 7).23 b. The removal of fission products from the containment atmosphere by the spray is considered a first-order removal process. The removal coefficient (lambda) for each of the sprayed regions of the containment is computed. Removal coefficients representing time-dependent wall plate-out are also calculated. The coefficients for spray removal and wall plate-out are summed. The removal lambdas are input parameters of a computer model for dose calculation. c. Fission Product Cleanup Models The reviewer estimates the area of the interior surfaces of the containment building which could be washed by the spray system, the volume flow rate of the system (assuming single failure), the average drop fall height and the mass-mean diameter of the spray drops, from inspection of the information in the SAR. The effectiveness of a containment spray system may be estimated by considering the chemical and physical processes that could occur during an accident in which the system operates. Models containing such considerations are reviewed on case-by-case bases. NUREG/CR-5966 (Reference 14) provides a method for review of containment spray models and evaluating the effectiveness of the spray design in the removal of fission products from the containment atmosphere. This model is used in conjunction with the fission product release assumptions in NUREG-1465. 24 In the absence of detailed models, the following simplifications may be used: Experimental results (References 816, 917, and 1119) and computer simulations 25 of the chemical kinetics involved (Reference 1011) show that an important 26 factor determining the effectiveness of sprays against elemental iodine vapor is the concentration of iodine in the spray solution. Experiments with fresh sprays having no dissolved iodine were observed to be quite effective in the scrubbing of elemental iodine even at a pH as low as 5 (References 916 and