Document: NUREG-0800
Document ID: 2df7cc71-18c8-408a-a8b1-e2b0def18569
Document Type: srp
Title: and 6.2.1.1.B.
Source: NUREG-0800
Source URL: https://www.nrc.gov/docs/ML0523/ML052340767.pdf
Revision Date: 2023-06
Chapter: 6
Section ID: 6.2.1
CFR Part: 
CFR Title: 

Content:
steady-state flow rate of approximately 40,000 cfm), an effi- ciency of 30% per pass for elemental iodine is assigned. The system is considered ineffective for organic iodide and parti- culate iodine removal. For designs different from those of 0. C. Cook and Sequoyah plants, reconsideration of the system efficiency is required. The reviewer should consult References 5, 6, and 7 when evaluating the iodine removal efficiency of the ice condenser. Reference 6, in particular, should be considered if time-dependent removal efficiencies are used. Reference 8 provides useful background information. Removal efficiencies of time-varying air-steam mixtures or flow rates should conserva- tively account for factors that affect their time dependencies (e.g., fan capacity, fan activation time, natural circulation rates). b. Iodine Scrubbing Function It is not feasible to specify the exact time of the fission product release following a postulated loss-of-coolant accident. In addition, the flow rates and air-steam fractions of the flow through the ice condenser vary significantly during and imme- diately following the accident. For radiological dose calcula- tions, therefore, the following conservative assumptions are made: (1) If a 30% iodine removal efficiency is used, the iodine removal effectiveness of the ice condenser commences with the establishment of a steady-state air-steam flow. Steady flow is assumed to start with the operation of the post- accident mixing fans. A single failure of one of the fans is assumed. (2) The initial concentration of iodine is assumed uniform throughout the entire containment. (3) The effectiveness of the ice condenser as an iodine removal system is assumed to cease with the meltout of the first ice bed. c. Upper Compartment Spray Credit Plants designed with an upper compartment spray system may claim credit for such. Containment spray systems are reviewed under SRP Section 6.5.2. d. Evaluation The iodine removal effectiveness and the degree