Document: NRC Regulatory Guide
Document ID: c9ebcbb0-96c4-4d29-be51-5acae9cc858a
Document Type: regulatory_guide
Title: Estimating Aquatic Dispersion of Effluents from Accidental and Routine Reactor Releases for the Purpose of Implementing Appendix I (Rev. 1)
Source: NRC Regulatory Guide Division 1
Source URL: https://www.nrc.gov/docs/ML0037/ML003740390.pdf
Revision Date: 2023-06
Chapter: 
Section ID: RG-1.113
CFR Part: 
CFR Title: 

Content:
Steady-State Concentrations in Completely Mixed and Plug-Flow Models ....... 1.113-31 10 Plug-Flow Model ............................................................ 1.113-32 11 Partially Mixed Model ...................................................... 1.113-33 12 Concentration in Partially Mixed Case ...................................... 1.113-35 13 Lumped Parameter Stratified Reservoir Model ............................... 1.113-36 14 Buildup of Radioisotopes in Completely Mixed Model (Normalized) .... ....... 1.113-39 15 Dimensionless Time To Reach 99% of Steady-State Concentration in Completely Mixed Case ................................................. 1.113-40 16 Typical Schematic Diagram of a River Basin ................................. 1.113-42 17 Effect of Flow Averaging Period on Normalized Concentration ................ 1.113-43 iv A. INTRODUCTION Section 20.106, "Radioactivity in Effluents to Unrestricted Areas," of the Commission's regulations in 10 CFR Part 20, "Standards for Protection Against Radiation," establishes limits on concentrations of radioactive material in effluents to unrestricted areas. Paragraph 2 0.1(c) of 10 CFR Part 20 states that, in addition to complying with the limits set forth in that part, licensees should make every reasonable effort to maintain releases of radioactive materials in effluents to unrestricted areas as far below the limits specified as is reasonably achievable (ALARA). Section 50.34a, "Design Objectives for Equipment to Control Releases of Radioactive Mate rial in Effluents - Nuclear Power Reactors," of 10 CFR Part 50, "Licensing of Production and Utilization Facilities," sets forth design objectives for equipment to control releases of radioactive effluents from light-water-cooled nuclear power reactors. Section 50.36a, "Tech nical Specifications on Effluents from Nuclear Reactors," of 10 CFR Part 50 further provides that, in order to keep power reactor effluent releases as low as is reasonably achievable,