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:
ically integrated two-dimensional equations of mass and momentum conservation: aU aU aU•S g(2 + V 2 ) S+ U -- + V -8 -f g 1 1 + x -9 Ch2H .av +3V + VA+ fu --gi+ -j- MAV+ (21) 7Fa y + Ch• 2H1 at ax ay)+• ,) where Ch is the Chezy coefficient; f is the Coriolis parameter; H is the depth from water surface to bottom; (U,V) are the vertically averaged x and y component velocities; C Is the water surface location above an undisturbed level datum; and TX sTy are the x and y component surface stresses. The resulting velocity field then becomes the advective mechanism in the following vertically averaged conservation equation for the dissolved constituent concentration C: C + (HUC) + - (HVC) (HKx 'C +2- (HKy -C (5 C ax a y a" -1 By+• • -HC(2 where Kx and Ky are the dispersion coefficients in the indicated directions. 1.113-15 The Eraslan model, on the other hand, requires synthesis of the flow field from current , measurements. Use of this technique requires a careful analysis of the flow data to ensure that the resulting velocity field conserves mass. The velocity field is then applied to the integral form of the conservation equation for the dissolved constituent in question (donor cell method) (Ref. 37). b. Oceans Modeling techniques for estimating radionuclide transport in ocean coastal waters are simi lar to those applicable to near-shore waters in the Great Lakes. The primary differences in behavior between the two systems results from the greater temporal and spatial variability in flow occurring in ocean coastal waters. This variability results primarily from two factors. The first and more readily defined factor is the major influence of astronomical tidal currents, which are negligibly small in the Great Lakes. The second factor, whose effects are important but much more difficult to quantify, Is the influence of meteorological driving forces. These forces include the direct effects of both meso-scale and synoptic-scale wind systems and the indirect