Document: NUREG-0800
Document ID: 9e3f4564-4ddf-4369-b699-a42709a80b66
Document Type: srp
Title: CONTAINMENT SPRAY AS A FISSION PRODUCT CLEANUP SYSTEM
Source: NUREG-0800
Source URL: https://www.nrc.gov/docs/ML0701/ML070190178.pdf
Revision Date: 2023-06
Chapter: 6
Section ID: 6.5.2
CFR Part: 
CFR Title: 

Content:
ter than 10 per hour. λs must be limited to 20 per hour to prevent extrapolation beyond the existing data for boric acid solutions with a pH of 5. For λs values less than 10 per hour, analyses using a more sophisticated expression are recommended. ii. Elemental iodine removal during recirculation of sump solution The sump solution 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 to react with both iodide and iodate ions and make elemental iodine reevolution possible. For sump solutions having pH values less than 7, molecular iodine vapor should be conservatively assumed to evolve into the containment atmosphere. 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 6.5.2-13 Revision 4 - March 2007 forms the basis of the ultimate iodine decontamination factor in the staff’s analysis (described in Subsection III.4.d). iii. 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. Engineered safety features designed to remove organic iodides are reviewed on a