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:
e forecasts are at variance with other forecasts submitted by the applicant, the bases for the differences should be provided. Although conservative estimates are sometimes required to ensure that the consequences of accidents are acceptable, realistic estimates will be adequate for the normal effluent release evaluations required by 10 CFR Part 50, Appendix 1. c. Existing Studies Many studies of the effects of water resource development schemes have been completed in great detail. For example, many large river basins have been studied by the Corps of Engineers and others. These existing studies, with only minor modifications for plant water use, may be used directly. 7. SEDIMENT UPTAKE AND TRANSPORT MODELS The ability of suspended and bottom sediments to absorb and adsorb radioactive nuclides from solution is recognized as contributing to important pathways to man through the sediment's ability to concentrate otherwise dilute species of ions. The pathways are by direct contact with the populace and by transfer to the aquatic food chain. Sorption by sediments is also an important mechanism for reducing the area of influence of plant releases. The state of the art in sediment-related effects is not as advanced as in other engineer ing disciplines. For this reason, and until reliable models become available, the staff will rely on existing field studies and the staff's and consultants' experience to determine the conservatism or reasonableness of the applicant's analyses and results. If the applicant elects to take credit for the removal of certain ions from the surface waters by sediment uptake, extensive verification of the techniques used will be necessary because of the lack of existing verified generalized models. The applicant's models will be evaluated based on their adherence to physical principles and their proven reliability in simulating prototype data. Models will be compared, in terms of physical principles, to those listed in the references, in