Document: NRC Regulatory Guide
Document ID: e75bce6f-d094-4709-bb7c-545c8bf5ad94
Document Type: regulatory_guide
Title: Atmospheric Relative Concentrations for Control Room Radiological Habitability Assessments at Nuclear Power Plants (Rev. 0)
Source: NRC Regulatory Guide Division 1
Source URL: https://www.nrc.gov/docs/ML1526/ML15268A488.pdf
Revision Date: 2023-06
Chapter: 
Section ID: RG-1.194
CFR Part: 
CFR Title: 

Content:
ion 3.2.4.8 has "horizontal" and "vertical" interposed. These terms related to is determining a x!O value for large louvered panels or large openings on vertical walls (e.g., railway doors on BWR Mark I plants). • Equation 10 seemed to be in error because it did not result in the correct units for x!O (s/m3 instead of s-1m-3). This issue can be resolved by replacing the integral in the denominator by the average control room intake flow rate over the period 0 to T seconds. • The diffusion coefficients used in Equation 10 should be representative of instantaneous releases instead of continuous releases. • Equation 10 should use z (receptor elevation) and h (source height) instead of h (difference between z and h). The current approach in Equation 10 essentially assumes either z or h are at ground level, which tends to be conservative and consistent with ARCON96 (but inconsistent with EXTRAN). • This RG and RG 1.183 should be in alignment. • Other minor known editorial, formatting, and content changes are known; however, these changes have not been documented for inclusion in this review. 2. What is the impact on internal and external stakeholders of not updating the RG for the known issues, in terms of anticipated numbers of licensing and inspection activities over the next several years? • There is no impact of not correcting the interposed terms in Section 3.2.4.8. The item has limited application. No known license amendments or changes are pending or anticipated relative to this issue. The staff reviewing any applications or amendments that would use this section of the RG is aware of the problem and would identify any applications that could use the process incorrectly. • There is minimal impact of not correcting Equation 10. The staff reviewing any applications or amendments that would use this section of the RG is aware of the problem and would identify any applications that could use the process incorrectly. 3. What is an estimate of the level of