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:
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, and E/D is the ratio of a dimensionless collection efficiency E to the average spray drop diameter D. Since the removal of particulate material chiefly depends on the relative sizes of the particles and the spray drops, it is convenient to combine parameters that cannot be known (Reference 7). It is conservative to assume E/D to be 10 per meter initially (i.e., 1% efficiency for spray drops of 1 millimeter in diameter), changing abruptly to 1 spray drop per meter after the aerosol mass has been depleted by a factor of 50 (i.e., 98% of the suspended mass is 10 times more readily removed than the remaining 2%). d. The iodine decontamination factor, DF, is defined as the maximum iodine concentration in the containment atmosphere divided by the concentration of iodine in the containment atmosphere at some time after decontamination. The DF for the containment atmosphere achieved by the containment spray system is determined by the following equation (Reference 14): where H is the effective iodine partition coefficient, Vs is the volume of liquid in containment sump and sump overflow, and Vc is the containment building net free volume less Vs. The effectiveness of the spray in removing elemental iodine is presumed to end when the maximum elemental iodine DF is reached. This value cannot exceed 200. Because the removal mechanisms for organic iodides and particulate iodines are significantly different from and slower than the mechanisms for elemental iodine, there is no need to limit the DF for organic iodides and particulate iodines. For reviews under 10 CFR Part 52, the reviewer should follow the above procedures to verify | that the design set forth in the safety analysis report, and as applicable, site interface | requirements, and combined license action items, meet the