Document: NUREG-0800
Document ID: 848ab24d-ac9b-4ec5-85ff-099e13b769c3
Document Type: srp
Title: CONTAINMENT SPRAY AS A FISSION PRODUCT CLEANUP SYSTEM
Source: NUREG-0800
Source URL: https://www.nrc.gov/docs/ML0601/ML060150001.pdf
Revision Date: 2023-06
Chapter: 6
Section ID: 6.5.2
CFR Part: 
CFR Title: 

Content:
n at the end of injection is assumed to contain fission products washed from the reactor core and removed from the containment atmosphere. If the solution is acidic, the radiation absorbed by the sump solution generates enough hydrogen peroxide (Reference 19) to react with both iodide and iodate ions and make elemental iodine reevolution possible (Reference 17). For sump solutions having pH values less than 7, molecular iodine vapor should be conservatively assumed to evolve into the containment atmosphere (Reference 12). Information on the partition coefficients for molecular iodine is given in References 12, 9, and 8. The equilibrium partitioning of iodine between the sump liquid and the containment atmosphere is examined for the extreme additive concentrations reviewed in Section III.1.a.(2), combined with the range of possible temperatures in the containment atmosphere and the sump solution. The reviewer should consider all known sources and sinks of acids and bases in a postaccident containment environment (e.g., alkaline earth and alkali metal oxides, nitric acid generated by radiolysis of nitrogen and water, alkaline salts or lye additives). The minimum iodine partition coefficient determined for these conditions forms the basis of the ultimate iodine decontamination factor in the staff’s analysis (described in Subsection III.4.d). (3) Organic iodides It is conservative to assume that organic iodides are not removed by either spray or wall deposition. Radiolytic destruction of iodomethane may be modeled, but the model must also consider radiolytic production (Reference 11). Engineered safety features designed to remove organic iodides are reviewed on a case-by-case basis. 6.5.2-13 Rev. 3 - December 2005 (4) Particulates The first-order removal coefficient for particulates, 8p, can be determined by the method described in Reference 13, or estimated by: where h is the spray drop fall height, V is the containment building net free volume, F is the spray flow,