Document: NRC Regulatory Guide
Document ID: f4c5fb1d-efb9-4168-9804-5ad3f6f64d06
Document Type: regulatory_guide
Title: Reporting Procedure for Mathematical Models Selected To Predict Heated Effluent Dispersion in Natural Water Bodies
Source: NRC Regulatory Guide Division 4
Source URL: https://www.nrc.gov/docs/ML0037/ML003739535.pdf
Revision Date: 2023-06
Chapter: 
Section ID: RG-4.4
CFR Part: 
CFR Title: 

Content:
ng plume size. The MAT should indicate if recirculation is fesaible for the prototype and whether the models can simulate this process. Substantiation for the entry should be presented in the text. f. Surface Heat Tresfer. Every thermal discharge plume which is bounded by the water surface experiences heat loss to the atmosphere. Since the quantity of heat dissipated in such a manner varies directly with the surface area of the plume, surface heat transfer is largely a far-field phenomenon. The simplest, most direct approach for estimating surface heat transfer employs the excess temperature concept, which requires the adoption of an empirical surface heat transfer coefficient and often an equilibrum temperature. Under such circumstances, the range of pertinent coefficients and temperatures applicable to the prototype should be specified in the MAT, and the coefficient's functional form, if any, should appear in the text. An alternative method for modeling surface heat transfer may be adopted, provided the method is described in detail. N. Moda/Chauacteriltta This section of the MAT supplies no additional information for understanding thermal dispersion by the prototype. However, in order to expand the basis for differentiation among models, the functional propertiet of each model should be included for completeness. a. Fiad. The dispersion field to which the model applies should'be specified in the MAT by the following number code: (1) Near-field (2) Intermediate-field (3) Far-field (4) Complete-field b. Dimenion. This entry identifies the spatial properties of the model solution. The directions are defined consistent with those previously utilized in the table. The Regulatory staff puts no constraint on the number of dimensions to which a model applies. c. Mathematical Approach. The solution technique utilized by each model should be specified by the following number code: (I) Phenomenological (2) Analytical (3) Finite Difference (4) Integral (5) Finite Element