Guest Feature: Micro Nuclear Reactors and Fast Maritime Freight Transportation

In his treatise entitled Competing for the Future, one of America’s leading professors of business and management Dr C.K. Prahalad used the term “ convergence of technologies” as being at the basis of many new innovations. A convergence of very different technologies led to the development of the hovercraft and the convergence of an aircraft and an occurrence that pilots regarded as a nuisance, led to the development of ground effect flight. When operating over water, both hovercraft and wing-in-ground effect craft are classified as maritime vehicles and need to be built to maritime structural standards.

While hovercraft and wing-in-ground effect showed some promise for long-distance commercial freight transportation, both technologies consumed excessive amounts of hydrocarbon fuel. The convergence of high fuel cost and high fuel consumption has restricted the use of the “above-water” maritime technologies to very specialized short-distance services. However, ongoing technological innovation in a totally unrelated area of energy generation may offer some future promise to the future development of super-sized hovercraft, large catamaran hydrofoil craft and equally large wing-in-ground effect craft that may enter trans-oceanic freight transport service.

Micro Nuclear Power:

Companies such as Hyperion Energy, NuScale Power and Toshiba Energy Systems have developed of micro-nuclear reactors that can raise enough steam to generate 10MW to 25MW of electrical output. High-speed maritime craft that travel above the water surface can benefit from water pick-up technology developed for water bomber aircraft. Water bombers re-load by flying close to the surface of a lake or a wide river, to allow purposefully designed pick-up tubes to submerge below water surface to scoop water into on-board tanks. An identical stream of water can provide the cooling water for the condenser of a micro nuclear reactor.

It is technically possible to develop a super-size high-speed maritime craft that will travel between a few inches to several feet about the water surface and use micro-nuclear-steam power. A steam turbine could drive the propulsion fan taken from a turbofan engine, it could drive over-sized aero-propellers normally used on helicopters or it could even drive through a reduction gear to the pump of a water-jet propulsion system. Companies such as General Electric and their counterparts in China are developing high-temperature nuclear power where reactors are cooled by a highly compressed gas such as helium or carbon dioxide.

Steam-Free Nuclear:

Nuclear research in China has dispensed with water-cooled condensers, ducting the stream of super-heated highly pressurized gas directly into a power turbine. The Chinese research is focused on developing super-sized, externally heated, closed-cycle gas turbine engines that use either helium or carbon dioxide. Researchers in China and Japan are currently exploring gas-cooled micro-nuclear power using smaller scale versions of these engines in which the power turbine(s) may drive turbo-compressor(s) as well as propulsion fans or aero-propellers plus a small electrical generator. A stream of water may cool the exhaust gas prior to it being recycled.

Future development in gas-cooled micro-nuclear reactors could evolve into the propulsion systems for future super-sized hovercraft, trans-oceanic twin-hull hydrofoils and super-sized wing-in-ground effect craft. While using uranium-based fuel would cause security concerns, nuclear powered maritime craft would only travel along designated routes and be designed to automatically or by remote control, to ‘jettison’ the reactor into the ocean during an emergency or hijacking attempt. Remotely controlled submarines could later retrieve the jettisoned reactor. However, researchers are exploring future application of alternative types of nuclear fuel that may be able to sustain the operation of a micro-reactor. 

Uranium-Free Nuclear:

Alternatively, research is under way in China, India and even Japan that involves the fission of thorium. Given the vast amount of thorium that occurs quite naturally in China, researchers are focuses on developing thorium based, high-temperature, gas-cooled nuclear reactors. Micro versions of such technology could find future application in maritime propulsion given thorium’s extreme low levels of radiation and ability to repeatedly re-process thorium for continued use. Given that thorium cannot be used in a weapon, the use of thorium-based future maritime nuclear propulsion would likely lessen security concerns in many nations.

Besides the research in China, there has been early research into radiation-free nuclear power that involves the fusion of lithium and hydrogen. A micro-version of such technology in the range of 10MW to 25MW may be possible some 10 to 20-years in the future and be applicable in several maritime transportation purposes. However, practical application of either high-temperature, thorium-fission micro-reactor or radiation-free fusion power generation technology may be 10 to 20-years into the future. Future large freight vessels that float on the ocean or that ride just above its surface would incur lower fuel/energy costs when using non-hydrocarbon fuel.

Terminals:

Hovercraft and wing-in-ground effect craft can literally ride up over a beach or coastal ramp, on to paved roadway. A ramp built at a main seaport could allow super-size hovercraft access to the terminal to interchanging cargo with trains, trucks and ships. Airports such as Hong Kong, Tokyo and San Francisco are built next to the ocean coast. A ramp built over the beach between seawater and paved runway would allow super-size wing-in-ground effect craft access into the freight section of airports, along with future ‘blended-body’ or ‘flying wing’ freight aircraft that may carry double the payload of existing airplanes.

Both super-size hovercraft and equally large wing-in-ground effect craft could share the same coastal terminals as future freight aircraft. Except that nuclear powered maritime vessels that ‘sail’ just above the water surface could carry many times the payload as their much smaller, high-flying hydrocarbon powered counterparts. While the hovercraft would exert very gentle pressure on the ground surface, wing-in-ground effect craft would require a large number of wheels to ride on paved surface. Like amphibious craft, they may also float on water at other terminals. While en route, both craft may skim above land that separated 2-bodies of water.

Routes:

High-speed maritime craft would operate trans-Pacific routes between East Asian or Eastern Australian terminals and west coast North and South American terminals. Such craft could operate between East Coast South American terminals and terminals located on the Bay of Bengal or Western Australia, with a possible stop at South Africa. There may be a market across the North Atlantic between Western Europe and East Coast North and South America. While high-speed maritime craft would bypass the Panama and Suez Canals, there may be market potential on a trans-Arctic route between East Asian terminals and Western European terminals.

Towing:

Ships have towed barges and lighter-than-air ships while speedboats and hydrofoil craft have towed gliders. Super-sized hovercraft could tow new generation lighter-than-air ships that may include fuselage-mounted wind turbines to provide electrical power. Alternatively, the towing line may carry a coaxial power cable. An innovation from Voith involves a rotating vertical cylinder mounted ahead of a rudder to provide a moving boundary layer that re-directs the water stream to the rear-side of the rudder. It greatly improves rudder performance and the same technology may be applied to the wings attached of slow moving, airborne towed units.

A transversely mounted rotating cylinder has been applied to the upper surface of an experimental winged aircraft, to provide a powerful boundary layer affect on that upper surface while the air stream flows through an extreme angle. The rotating cylinder can allow an aircraft to take off, fly and ‘land’ at low speed that allows a fast-moving water-bound craft to tow it. With future research and development, wing-in-ground effect craft could tow large passenger gliders across sections of ocean while offering competitive ticket prices compared to commercial aircraft powered by hydrocarbon fueled engines and that burn expensive fuel.

Future Design:

A Singaporean company called Hoverbarge is currently designing heavy-lift hovercraft technology. Future development in micro-nuclear power may provide the power plant to allow larger versions such technology, possibly extended-length variants that include a hinge articulation to operate extended voyages. Future research would need to assure that the craft would negotiate severe ocean wave conditions. High-speed, twin-hull catamaran ferries operate inter-island ferry services in the Canary and Hawaiian Islands. There may be scope to include hydrofoils into the hull design to assure higher operational speed over extended distances through severe ocean conditions.

While a Korean company has demonstrated a 50-seat wing-in-ground effect craft that can take-off (and land) on water, hobby builders have explored numerous design possibilities that allow the craft to ‘sail’ at higher elevation above the water surface. Ongoing refinements to craft and ‘wing’ design may eventually assure that wing-in-ground effect craft may better cope with ocean wave conditions. The underside of such craft may include retractable hydrofoils built beneath buoyant ‘twin-hull’ pontoons to allow take-off and ‘landing’ on water. Future development of large size wing-in-ground effect craft would depend on the availability of suitable (nuclear) power plant.

Conclusions:

Ongoing research in high-temperature, gas-cooled, thorium fueled micro nuclear and also in radiation-free nuclear power generation could result in a power plant that may be applied to conventional and high-speed civilian maritime propulsion. Such power plants would likely become feasible as future oil prices rise in response to increased demand in developing countries.

Harry Valentine is a frequent contributor to the MarEx newsletter and can be reached at [email protected] for comments.