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:
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 for values equal to or greater than ten per hour. is to be s s limited to 20 per hour to prevent extrapolation beyond the existing data for boric acid solutions with a pH of 5 (References 816 and 1117) . For 31 values less than ten per hour, analyses using a more sophisticated s expression are recommended. (2) Elemental iodine removal during recirculation of sump solution p 3hFE 2VD 6.5.2-13 DRAFT Rev. 3 - April 1996 The sump solution at the end of injection is assumed to contain fission products washed from the reactor core as well as those removed from the containment atmosphere. The radiation absorbed by the sump solution, if the solution is acidic, would generate hydrogen peroxide (Reference 1220) in sufficient amount to react with both iodide and iodate ions and 32 raise the possibility of elemental iodine re-evolution (Reference 518) . 33 For sump solutions having pH values less than 7, molecular iodine vapor should be conservatively assumed to evolve into the containment atmosphere (Reference 1513) . 34 Information on the partition coefficients for molecular iodine can be found in References 159, 1610, and 1713. The equilibrium partitioning 35 of iodine between the sump liquid and the containment atmosphere is examined for the extreme additive concentrations determined in Section III.1.a.(2), in combination with the range of temperatures possible in the containment atmosphere and the sump solution. The reviewer should consider all known sources and sinks of acids and bases (e.g., alkaline earth and alkali metal oxides, nitric acid generated by radiolysis of nitrogen and water, alkaline salts or lye additives) in a post-accident containment environment. The minimum iodine partition coefficient determined for these conditions forms the basis of the ultimate iodine