Document: NRC Regulatory Guide
Document ID: 42f2dcf0-38ba-4f75-84d4-e60f4bbf9162
Document Type: regulatory_guide
Title: Assessment of Abnormal Radionuclide Discharges in Ground Water to the Unrestricted Area at Nuclear Power Plant Sites Appendix-Simple Ground Water Model for Estimating Offsite Tritium Activity Flux + HISTORY - HISTORY 12/2015 – DG-4025-Proposed New Guide
Source: NRC Regulatory Guide Division 4
Source URL: https://www.nrc.gov/docs/ML1523/ML15237A388.pdf
Revision Date: 2023-06
Chapter: 
Section ID: RG-4.25
CFR Part: 
CFR Title: 

Content:
ns for each block and for each time period for which there is a tritium activity measurement. e. Calculate the tritium-activity flux across each block by multiplying the tritium activity concentration for each block by the bulk water flux for each block using the following equation: Q୨ൌC୨ൈQw୨ equation A-3 where ܳ௝ is the tritium activity flux for block ݆, pCi/day; and ܥ௝ is the tritium activity concentration of block ݆, pCi/liter. f. Sum up for each time period (e.g., monthly), the tritium activity fluxes to obtain a total tritium-activity flux (e.g., total monthly tritium-activity flux for the transect). 8. Average the totals if interested in an average activity flux across the transect for a longer time period (such as annual). 9. To estimate the total tritium-activity discharging to the accessible environment, estimate the time of travel from the transect to the boundary of the accessible environment, and reduce the total tritium-activity discharge from radioactive decay for this incremental additional travel time. DG-4025, Appendix Page 1 Table 1. Overview of the example Table 2. Plan view of the transect showing location of the facility, the transect, ground water flow direction and location of a large body of water DG-4025, Appendix, Page 2 DG-4025, Appendix, Page 3 Table 3. Vertical transect illustrating the hydrostratigraphy and the location of the monitoring wells. DG-4025, Appendix, Page 4 Table 4. Monitoring data showing tritium concentration DG-4025, Appendix, Page 5 Table 5. Activity flux through each transect block [pCi/day] DG-4025, Appendix, Page 6 Table 6. Total transect activity flux