A Caltech Library Service

Hydraulic modeling of thermal outfall diffusers for the San Onofre nuclear power plant

Koh, Robert C. Y. and Brooks, Norman H. and List, E. John and Wolanski, Eric J. (1974) Hydraulic modeling of thermal outfall diffusers for the San Onofre nuclear power plant. California Institute of Technology , Pasadena, CA. (Unpublished)

[img] PDF - Submitted Version
See Usage Policy.


Use this Persistent URL to link to this item:


Various hydraulic model tests were performed in connection with the design and performance of the offshore thermal outfalls for the San Onofre Nuclear Generating Station (jointly owned by the Southern California Edison Company and the San Diego Gas and Electric Company)near San Clemente, California. These include model investigations of: (i) the multiple port discharges for the proposed Units 2 and 3, (ii) the existing submerged single outlet from Unit 1, (iii) the discharge of heated water from the Units 2 and 3 intakes during heat treatment, and (iv) hydraulic characteristics of discharge ports. On the basis of these investigations, the diffusion structure for each of the proposed new units was designed to be 2500 feet long aligned perpendicular to shore. The diffuser for Unit 3 will extend from 3500 to 6000 feet from shore, and that for Unit 2 from 6000 to 8500 feet from shore. Each diffuser will have 63 discharge nozzles aimed offshore (±25° from the pipe axis, 20° above horizontal). The momentum of the discharge produces and offshore drift of the diluted warm-water plume. The maximum temperature rise on the surface caused by the discharge was found to decrease with increasing longshore current speed, and the discharge momentum from the jets was effective in preventing significant re-entrainment in the event of reversing or low currents. Although the California thermal discharge requirements specify a maximum surface temperature increase of 4°F (beyond 1000 feet from the discharge structure), the laboratory target maximum was established at 2.5°F, to account for possible model-prototype differences and unmodeled effects. The hydraulic model studies showed that the proposed outfall design meets the laboratory target value for a variety of possible longshore current conditions; therefore, it is predicted that the prototype outfall operation will meet the California thermal discharge requirements.

Item Type:Report or Paper (Technical Report)
Additional Information:Final Report to the Southern California Edison Company. Work performed under SCE P.O. No. T2062905. The writers wish to acknowledge the valuable assistance of many members of the staff of the W. M. Keck Laboratory of Hydraulics and Water Resources. We make particular mention of Elton Daly, Joe Fontana, Carl Green and Bill Stone for their efforts in the erection and instrumentation of the basin and models; Max Irvine, Phil Roberts, and Noks Kotsovinos, graduate research assistants; Robert Stecher, Mafred Chu and Bruce Bennett, undergraduate assistants; and Pat Rankin and Arvilla Stanton for their assistance in the typing and preparation of this report. Particular thanks are also due to Martin Leonard for his assistance during the final confirming tests. Mr. Ken Meddock of the Southern California Edison Company also participated part time and provided liaison with the Southern California Edison Company.
Group:W. M. Keck Laboratory of Hydraulics and Water Resources
Funding AgencyGrant Number
Southern California EdisonT2062905
Record Number:CaltechKHR:KH-R-30
Persistent URL:
Usage Policy:You are granted permission for individual, educational, research and non-commercial reproduction, distribution, display and performance of this work in any format.
ID Code:26008
Deposited By: Imported from CaltechKHR
Deposited On:24 Dec 2009
Last Modified:21 Dec 2020 18:41

Repository Staff Only: item control page