NS Savannah

NS Savannah (1962)

NS Savannah, first nuclear powered merchant ship. 596 feet long, 78 feet wide, 29 feet draft and capable of 24 knots speed. Designed for 30 passenger cabins and 7 cargo holds. It was named after the first ship to use steam in crossing the Atlantic (1818). In 1955, President Eisenhower initiated an “Atoms for Peace” program that resulted in creation of the NS Savannah. The ship sailed around the world to demonstrate the peaceful application of nuclear power. The ship was successful in demonstrating safe use of nuclear power but it was not a commercial success. The costs of operating the ship were higher than a conventional ship, the cargo capacity and revenue was less

Power was provided by a pressurized water reactor designed by Babcox and Wilcox. It generated 74 megawatts thermal energy and used slightly enriched uranium (enriched in the U-235 isotope) for fuel. The reactor and steam generator provide steam to a conventional steam turbine. The ship has a single propeller shaft with an emergency motor connected to the shaft. If normal power is lost an emergency diesel generator could propel the ship. The ship is currently (2020) defueled and laid up as a museum ship in Baltimore MD.

Launching at New York Shipyard

Properties of Atoms - Prior to 1900, much was known about chemical properties of atoms but little was known about internal makeup of the atoms. Chemical properties deal with the orbital electrons. Nuclear properties deal with the internal nucleus of atoms.

History (prelude to self sustaining nuclear fission)

1869 – Periodic Table of Elements (Mendeleev)

1900 – discovery of radioactivity (Curies)

1904 – equation for mass - energy equivalence proposed by Albert Einstein, Energy = Mass x Velocity of Light squared.

1914 – mass and positive charge at the center of the atom (Rutherford)

1932 – neutron discovered (Chadwick)

1938 – nuclear fission (Meitner/Frisch)

1942 – first self-sustaining chain reaction at University of Chicago graphite pile (Fermi)

Shell-atomic-model-shell-shells-electron

Nuclear Fission Fundamental Definitions

Atom – the smallest constituent unit of matter that has properties of its chemical element.

Nuclear Fission – The splitting of an atom nucleus into nuclei of lighter atoms with the release of energy.

Self-Sustaining – the number of neutrons available for fission is constant with time.

Exothermic – reaction that liberates heat.

Fission - If a neutron is captured in a U-235 atom nucleus, the resulting nucleus is unstable and splits apart into two nuclei of approximately equal weight. The split atom also gives off about 2.5 (average) neutrons plus about 200 MEV of energy, mostly in the form of heat. To control the reaction, one and only one of the neutrons produced in fission must go on and cause another fission. That means that the fission reaction is self-sustaining. If more than one neutron is produced in the reaction, the reaction is supercritical and the fission rate will increase with time. If less than one neutron is produced, the reaction rate is subcritical and will decrease with time.

Fuel - The fuel (U-235) is in the form of sintered pellets of uranium dioxide stacked in a stainless steel tube. Each pellet is about half an inch in diameter and half an inch long. The tubes are arranged in a bundle to make a 8 inch square elements, 32 elements make up a reactor core 62 inches in diameter and 66 inches high. In the core, the tubes are surrounded by water to absorb the heat generated by fission.

This illustration shows a fuel subassembly for a bigger reactor than Savannah but the general arrangement is the same.

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This illustration is for a fuel assembly that is bigger than NS Savannah reactor assembly but the general arrangement is the same.

Reactor Core Design - The Savannah core has 21 neutron absorbing control rods to absorb neutrons and control the reactor. The reactor designers challenge is to design a core that:

does not leak excessive neutrons,

does not contain materials that absorb too many neutrons in non-fuel atoms,

controls the average speed of neutrons in the core,

limit temperature in the core by heat removal,

control fission rate through control rods.

NS Savannah nuclear reactor core cross sectional view

NS Savannah reactor coolant system showing coolant pumps, boiler or steam generator and reactor.

My Savannah Bride

Upon graduating from Massachusetts Maritime Academy in 1960 I became employed with Texaco`s Marine Department as a 3rd assistant engineer on board various tank vessels. I sailed for 3 years delivering a variety of petroleum based products to Gulf and East Coast ports from Texas to Maine.

In 1963 Marad [The US Maritime Administration (the vessel`s owner)] awarded the general agent/operating contract for the NS Savannah to American Export Isbrandtsen Lines at which time I applied for and was accepted into their Reactor Operator training program.

After successful completion of the program I received a Reactor Operator`s license issued by the USAEC [US Atomic Energy Commission (the predecessor to today`s NRC) (Nuclear Regulatory Commission)] This license was added as an endorsement to my Marine Engineer`s License issued by the US Coast Guard.

Between training and sailing, I remained with the NS Savannah for 2 years. During this period, one of our ports of call was Oslo Norway. As was the custom, we were tied up in the heart of downtown Oslo thereby affording maximum exposure and encouraging visitors to tour the vessel.

One such visitor was a young lady from a local office who had seen the Savannah from her office window and decided to visit/tour the ship during her lunch hour … and as they say the rest is history. We were married approximately 1 year later and, therefore, she had now become my “Savannah Bride”.

Now that I was married I decided to make a major career change by transitioning from ocean going employment to land based employment as I did not want to be away from my family for extended periods of time. We eventually settled in New Hampshire and raised our family together with no regrets.

I believe most people have a defining experience in their life and for me it was my time with the NS Savannah. I will forever treasure the friendships and the memories that were made.

Name withheld