Document: NRC Regulatory Guide
Document ID: 5ec01b96-5209-446f-95b3-7342d73ba086
Document Type: regulatory_guide
Title: Design, Inspection, and Testing Criteria for Air Filtration and Adsorption Units of Post-Accident Engineered-Safety-Feature Atmosphere Cleanup Systems in Light-Water-Cooled Nuclear Power Plants + HISTORY - HISTORY 12/2011 – DG-1274 , Proposed Revision 4 10/2000 – DG-1102 , Proposed Revision 3 (Rev. 4)
Source: NRC Regulatory Guide Division 1
Source URL: https://www.nrc.gov/docs/ML1124/ML11244A045.pdf
Revision Date: 2023-06
Chapter: 
Section ID: RG-1.52
CFR Part: 
CFR Title: 

Content:
mination Efficiencies Methyl Iodide Penetration Acceptance Criterion for Representative Sample 2 inches Elemental iodine 95% Penetration ≤2.5% when tested in accordance with ASTM D-3803-1991 (R2009) (Ref. 15) Organic iodide 95% 4 inches or greater Elemental iodine 99% Penetration ≤0.5% when tested in accordance with ASTM D-3803-1991 (R2009) (Ref. 15) Organic iodide 99% a The activated carbon, when new, should meet the specifications of Regulatory Position 4.k of this guide. b Multiple beds (e.g., two 2-inch beds in series) should be treated as a single bed of aggregate depth. It is advantageous when series beds are located in separate housings and individually in-place leak tested. This aids in mixing the challenge agent and contributes to the accuracy of the test results. NOTES: (1) Credited decontamination efficiencies (a portion of which includes bypass leakage) are based on a 0.25-second residence time per 2-inch bed depth. (2) Organic iodide and elemental iodine are the forms of iodine that are expected to be absorbed by activated carbon during a DBA. Organic iodide is more difficult for activated carbon to adsorb than elemental iodine. Therefore, the laboratory test to determine the performance of the activated carbon adsorber is based on organic iodide. Methyl iodide is the organic form of iodine that is used in the laboratory test. (3) This table provides acceptable decontamination efficiencies and methyl iodide test penetrations of used activated carbon samples for laboratory testing. Laboratory tests are conducted in accordance with ASTM D3803-1991 (R2009) (Ref. 15). Tests are conducted at a temperature of 30 degrees Celsius and a relative humidity of 95 percent, with the exception that a relative humidity of 70 percent is used when the air entering the carbon adsorber is maintained at less than or equal to 70-percent relative humidity. (4) See Appendix I to ASME N509-2002 (Ref. 11) for the definition of a representative sample. Testing should be