Larger individual plant capacity, increased 
greatly from earlier years, makes nuclear electric 
power more economically competitive. Nuclear 
fuel costs are lower than fossil fuel costs in a 
growing number of locations. The equipment to 
generate electricity is very expensive, whether 
conventional or nuclear. Planners for undersea 
operations also will have to take such factors as 
size, distance from shore, and weather conditions 
into account when considering the costs of their 
projects. 
b. Studies Several studies have been made by 
industry and government to determine the phys- 
ical and economic feasibility of placing a nuclear 
reactor with its power generating plant on the U.S. 
Continental Shelf. One such study made by the 
University of California, Davis Campus, described, 
as an example, advantages and disadvantages of 
such a system in the New York area. 
The first consideration was reactor safety. The 
radiation shield usually found on dry land reactors 
would be replaced by the water surrounding the 
pressure vessel. To be safe, a minimum of about 
100 feet of water between the top of the vessel 
and the surface had been set; this put the bottom 
on which the reactor is placed at about 150 feet. 
The additional 50 feet of water overburden would 
act to reduce the spread of radioactive debris in 
the unlikely event of an accident involving the 
core. 
The oceanographic characteristics of the sea 
south and southeast of Long Island were very 
important from a viewpoint of currents as well as 
climatic conditions. 
More important for their potential to damage 
underwater structures are the large number of 
storms and hurricanes in this area. However, when 
a storm has reached as far north as New York, it 
has usually diminished substantially in intensity. 
Except for the largest storms, little disturbance is 
produced at depths greater than 200 feet. 
Interference with the maritime and fishing 
industries was considered. The reactor must not 
impede existing shipping lanes, and the fishing 
industry must not be affected by contamination of 
fish near the reactor. Further, system design plans 
have provided for a possible nuclear accident or 
explosion. 
VI-214 
c. Plant Design Two basic designs were exam- 
ined, both dependent on the not-so-obvious fact 
that nuclear reactors do not need air to operate. 
The first design places the reactor with the heat 
exchangers on the ocean floor. The power- 
producing turbines and generators are above the 
water surface, resting on a platform with founda- 
tions in the sea bottom. A vertical pipe carries the 
superheated steam from the reactor to the tur- 
bines. 
The second design calls for both the reactor and 
electrical system on the sea floor. While the 
reactor can operate in a liquid environment, the 
turbines and generators require a gaseous envelope 
to function properly. Hence, a caisson must be 
built around the power-producing unit. If the gas 
pressure inside is the same as the hydrostatic 
pressure outside, the structure need support only 
the pressure difference between the top and the 
bottom of the caisson or pressure vessel, allowing a 
shell structure of considerable cost saving. 
A platform with foundations on the sea floor 
must be built for the first design, in which the 
generating station is above the surface. At depths 
of 150 to 300 feet, it is possible to build this 
structure using modern offshore oil platform 
technology. 
A compact system of turbines and generators 
will be arranged on the platform located immedi- 
ately above the reactor so the platform legs can 
support the steam-carrying pipes. The turbines and 
generators are of conventional design, requiring a 
minimum of maintenance. The steam cycle is 
closed, the steam of lower temperature and pres- 
sure returning to a condenser located on the sea 
floor. Having concentric pipes, carrying the hot 
steam upward within the innermost pipe, reduces 
heat losses to the sea. 
In the second design, the turbine-generator 
system is installed underwater beside the reactor, 
eliminating the platform. The gaseous environment 
in a caisson allows personnel to enter regularly to 
operate the system, to perform maintenance, and 
to respond to accidents. They can stay indefi- 
nitely, inconvenienced only by the prescribed 
decompression cycle when returning to the sur- 
face. Alternatively, the entire plant may be oper- 
ated by remote control, personnel entering only 
occasionally for regular maintenance or in case of 
accident. 
