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:
ne 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 1119) . However, 27 w KwA/V s 6KgTF VD DRAFT Rev. 3 - April 1996 6.5.2-12 solutions having dissolved iodine, such as the sump solutions that recirculate after an accident, may revolatilize iodine if the solutions are acidic (References 511 and 1018) . Chemical additives in the spray solution have no significant effect 28 upon aerosol particle removal because this removal process is largely mechanical in nature. (1) Elemental iodine removal during spraying of fresh solution During injection, the removal of elemental iodine by wall deposition may be estimated by Here, is the first-order removal coefficient by wall deposition, A is the w wetted surface area, V is the containment building net free volume, and K is a mass-transfer coefficient. All available experimental data are w conservatively enveloped if K is taken to be 4.9 meters per hour w (Reference 138, page 17). 29 During injection, the effectiveness of the spray against elemental iodine vapor is chiefly determined by the rate at which fresh solution surface area is introduced into the containment building atmosphere. The rate of solution surface created per unit gas volume in the containment atmosphere may be estimated as (6F/VD), where F is the volume flow rate of the spray pump, V is the containment building net free volume, and D is the mass-mean diameter of the spray drops. The first-order removal coefficient by spray, , may be taken to be s where K is the gas-phase mass-transfer coefficient, and T is the time of g fall of the drops, which may be estimated by the ratio of the average fall height to the terminal velocity of the mass-mean drop (Reference 1421) . 30 The above expression represents a first-order approximation if a well-mixed droplet model is used for the spray efficiency. The expression is valid