Project Atlantis: A Design of the Nuclear Power Supply for an Undersea City
Authors: Atkinson G.D. , Coltharp W.D. , Gramates R.D. , Oelkers E.D. , Roberts D.A. , Waid K.R. , Gage S.J. , Koen B.V. 
Published: October 2008

Abstract.
In order to provide the power necessary to sustain a city of 20,000 people 600 feet below the surface of the ocean, it is proposed to use four nuclear power plants. Each of the 500 Mwth, gas cooled, uranium-thorium fueled, thermal reactor. The power requirements for the city include oxygen production, carbon dioxide removal, and fresh water production, as well as electrical power and heating. A 100% overload has been allowed for industrial and agricultural applications.

Authors' Note.
Project Atlantis was a six semester hour design course for graduate students in the Nuclear Engineering Program of the Mechanical Engineering Department of the University of Texas at Austin. The following paper represents a synopsis of the final report presented by the six graduate students to their advisors.
"In one day and one night of unprecedented upheaval, with earthquakes and floods like none ever witnessed by man before, the entire army of Athens was swallowed up by the earth, and simultaneously the whole island of Atlantis disappeared utterly beneath the waves of the Ocean."Plato's Dialogue "TIMAEUS"c. 400 B.C.SCOPE OF DESIGN
The goal of this project was to design a nuclear power plant system which would furnish the complete power requirements for a city of 20,000 people located under the ocean on the continental shelf of the united States. The continental shelf is usually defined as that portion of the U.S. coastline with an ocean depth of 600 feet or less. At the maximum depth the city would be subjected to a pressure of 275 psia and an ambient water temperature of about 40°F.
In order to move freely between the city and the ocean floor it will be necessary to maintain the living and working quarters of the city at ambient pressure. To prevent nitrogen narcosis, the inhabitants of the city will breathe a mixture of helium, nitrogen, and oxygen. Because of the higher thermal conductivity of the helium, it will be necessary to maintain an ambient temperature in the city of about 80° F to insure "shirt-s leeve" comfort. Other special environmental considerations are:Use of water for neutron and gamma-ray shielding.contamination of seawater by neutron activation or fission product release.Use of seawater as a low temperature sink for heat rejection.Flooding of the reactor core.The corrosive nature of seawater.
The power required from the reactor has been determined as follows (see Fig. 1):Air conditioningventilation-2000 ft 3 /hrperson, 1 Mwe.CO2 removal-IOO watts/ person by electrodialysis, 2 Mwe.O2 makeup-2 Ibs/personday by electrolysis, 6 Mwe.Non-industrial electrical: lighting, communications, entertainment, etc.-35Mwe.Industrial electrical 175 Mwe.Fresh water production 130 Mwth.Heating-240 Mwth.
The choice of a nuclear reactor to provide this power was made in order to satisfy the requirements of reliability and independence from surface supply lines.
Supplied with sufficient power, air, and water, the city represents a permanent, self-sufficient, undersea habitation. The most probable use of such a city, in the near future, would be to support rotating teams of scientific and technical personnel conducting advanced and extended experiments.