From the standpoint of ship safety, assurance of sufficient power to
maintain steerage and maneuverability is the principal requirement of
the propulsion plant. To this end, duplication of machinery and power
sources on the SAVANNAH has been carried to the fullest practicable
degree. An electric “take-home” motor is installed for emergency
operation. Developing 750 hp (nominal), it is coupled to one of the
high-speed pinions in the reduction gear. A quick-connect coupling
permits engagement in less than 2 minutes. In addition, a temporary
supplementary startup steam plant is installed in No. 7 hold. This plant
is capable of developing 2,000 shp ahead and about 1,750 shp astern,
using the main propulsion unit; in emergencies this steam plant may be
used in lieu of the take-home motor. Using forced circulation boilers,
it can, like the take-home motor, be brought on the line in about 2
minutes. In case of a reactor plant failure, the stored heat in the
reactor system will be available during the interim period, so that at
no time will the SAVANNAH be without power to the shaft.
From the standpoint of conventional ship operation, the SAVANNAH is
designed and constructed to the highest degree of operational safety.
Reactor safety is ensured by the heavy steel containment shell
surrounding the reactor system. This shell is designed to withstand the
pressure surge from the hypothetical example, “maximum credible
accident,” used in nuclear reactor analysis. Thus, any internal accident
will be contained within the reactor containment shell and no hazardous
amount of radioactivity can escape to the environment.
Protection of the containment complex from ship accidents was studied in
detail in establishing the SAVANNAH’s design criteria. In particular,
ship collisions were carefully reviewed and methods developed to predict
structural damage to vessels struck in collision as a function of speed
and displacement of the vessels involved. On the basis of the data
obtained from these studies, the SAVANNAH is designed and constructed to
withstand, without damage to the nuclear reactor compartment, any
collision with any of the ships making up 99 percent of the world’s
merchant fleet.