Document: NUREG-0800
Document ID: b761625e-90fd-41e3-a3ae-acaea1aabf84
Document Type: srp
Title: should still be met.
Source: NUREG-0800
Source URL: https://www.nrc.gov/docs/ML0520/ML052070476.pdf
Revision Date: 2023-06
Chapter: 6
Section ID: 6.5.1
CFR Part: 
CFR Title: 

Content:
of iodine released from the core during an accident as predicted in recent source term research. In Regulatory Guide 1.4, the chemical form of iodine is specified to be predominantly elemental iodine (91 percent), with 5 percent assumed to be particulate iodine. However, in draft NUREG-1465, "Accident Source Terms for Light-Water Nuclear Power Plants," the staff concluded that iodine entering the containment from the reactor core is composed of at least 95 percent cesium iodide in particulate form with no more than 5 percent as iodine (I) and hydrogen iodide (HI). Once within the containment, highly soluble cesium iodide will readily dissolve in water pools forming iodide in solution and will deposit onto the interior surfaces. The staff also indicated that without pH control, large fractions of iodine dissolved in water pools in ionic form will be converted to elemental iodine and will be released into the containment atmosphere if the pH is less than 7. On the other hand, if the pH is maintained at 7 or above, very little (less than 1 percent) of the dissolved iodine will be converted to elemental iodine. The SRP review procedures (step III.1.a) indicate that the ice condenser system is considered ineffective for organic iodide and particulate iodine removal. No changes were initiated to this SRP Section based upon the information provided in the Final SER for the CE 80+ because the information was from a draft NUREG- 1465 and no final staff position or guidance is presented. However, the staff should consider the implications of the new source term research on the effectiveness of the ice condenser as a fission product removal system. The evaluation should consider the change in fraction of particulate iodine released to the containment atmosphere and the fact that highly soluble cesium iodide (particulate) will readily dissolve and only a small fraction will be converted to elemental iodine if the pH is maintained at 7 or above. The acceptance criteria for the