Adams Atomic Engines, Inc. AND Romawa, B. V.
Close cooperation between Romawa, B. V. and Adams Atomic Engines, Inc. began in June of 1994, when Gulian Crommelin, Captain, Royal Netherlands Navy (retired) read "Submarine Engines of the Future" in the Naval Institute Proceedings. An engine that combined nuclear energy with modern gas turbine machinery seemed to the career naval engineer to be the natural next step in the progression of ship board power plants that began with the tiny, wood and coal burning steam piston engine that propelled the original Savannah more than 100 years ago. Capt. Crommelin formed Romawa B. V. to promote the development of the concept in the Netherlands and other parts of the European Community.
In September of 1995 the two companies signed a memorandum of understanding formalizing their relationship. This MOU defines areas of cooperation including marketing and promotion, design and technology sharing. In the Netherlands, Romawa's efforts have sparked the NEREUS project.
The NEREUS Project
NEREUS is an acronym derived from the project title: A Naturally Safe, Efficient, Reactor, Easy to operate, Ultimately simple and Small. (NEREUS is the god of shipping in Greek mythology.)
Early in the spring of 1996, a consortium of Dutch companies involved in nuclear technology began a pre-feasibility study of the NEREUS concept under the chairmanship of the Ministry of Economic Affairs. One design that is being studied includes a 20 MW pebble bed reactor and an intercooled, recuperated gas turbine that will produce 8 MW of electrical power. The system will operate for three years without refueling.
THE CHALLENGEto make the Netherlands the market leader, within an integrating Europe, of a type of advanced energy generating installation in a limited power range, based on well-proven inherent safe gas-cooled reactor in combination with a direct driven gas turbine with free power turbine, designed and extensively tested by Research and Development organizations, Engineering Universities and Industries in the Netherlands and suitable for:
Heat/power generating installations
Stand-alone energy generation
Stand-alone heat generation
Power generation on board ships
Neutron production for medical purposes Incorporating aspects the Dutch are famous for:
Low through life costing
Easy to monitor and control
A minimum of on-site maintenance
Transportable in a sealed container
Assembled, tested and maintained in a dedicated workshop
Lifecycle managed from a central pooling system
Low noise and vibration levels
Rugged and straight forward in handling. In other words, marinized
Frequently Asked Questions about NEREUS
What is a nuclear gas turbine?
- A gas turbine operating with moderate temperatures and pressures in which the combustion section has been replaced by an adapted gas cooled reactor.
- It is, from a historical point of view in power generation, the next logical step.
- In more detail: It is an installation that uses nuclear fission energy to heat a gas. This gas, with a temperature of 850 C, rotates a gas turbine, that pumps the gas through the reactor and heat exchangers. After the turbine, which drives the compressor, the gas drives a free-power turbine attached to a generator.
What can a nuclear gas turbine be used for?
- Power/heat generation
- Stand alone electricity generation
- A combination of all of the above
- Ship propulsion
- Nuclear materials production
In other words, the same applications that are known today.
Is the idea new?
The idea has been discussed ever since people thought about ways to use nuclear energy for peaceful purposes. Although several gas-cooled reactor types are in use or have been used, the improvements in nuclear fuel, gas turbine technology, heat exchangers, electro-magnetic bearings and radioactive waste treatment have now made the above installation feasible.
What are some of the key features of the NEREUS concept?
This is an engineering project based on a combination of well-proven technologies such as:
- Inherently safe gas-cooled nuclear reactor
- Usage of inert helium with the following advantages:
- Does not get activated by neutrons
- No corrosion
- Excellent heat transfer characteristics
- It cannot decompose
- Leaks are easy to detect by spectrometry
- Graphite moderator protected by coatings against influences from outside (fire, corrosion):
- Improved fuel use efficiency
- Usage of thorium as fuel
- High strength at high temperatures
- Cycle enhancements
- Reactor inlet recuperator
- Compressor intercooler
- Gas-water heat exchangers (water pressure is lower than gas pressure)
- Gas flow control system
- Engine-health monitoring systems
- Remote condition and performance control
- Gas turbine characteristics
- Radial compressors
- axial turbines
- Free-power turbine, driving a helium-cooled generator
- Electro-magnetic bearings
- Zero air pollution
- Inexpensive fuel
- No intake air filtration
- No air intake and funnel restrictions
- Low weight installation
- No fuel treatment plant
- No lubrication oil treatment plant
- Reduced maintenance
- Great endurance
- Low through life costing
What about the fuel and the radioactive waste?
Instead of fuel pins coated with metal alloys as are common in light water reactors, the fuel for high temperature gas reactors can be formed by ceramic materials. In the most common type of High Temperature Reactor (HTR) fuel, tiny particles of nuclear fuel are coated with three or four layers of coatings which are impenetrable to fission products up to a temperature of 2000 celsius. About 20,000 particles, bonded with graphite are massed together to form a spherical fuel element with a diameter of about 6 centimeters. The high temperature reactor for the NEREUS project might contain 100,000 or more of these fuel elements.
The core will be designed in such a way that the highest temperature possible in the core, even under accident conditions will be less than the temperature at which the fuel coatings will release fission products. This design limiting temperature is even farther from the point at which the fuel elements will melt since they are formed with graphite, a material that does not melt until it reaches a temperature of more than 3000 celsius.
Because the HTR fuel has excellent retention characteristics for its radioactive fission products, it is well suited for long-term storage after use. It also facilitates a shift to a thorium fuel cycle, which shows a great deal of promise.
What about reactor safety?
The reactor design will be based on a well-proven gas-cooled reactor design used in Germany, which has been in operation for more than 20 years. By an optimal choice of nuclear process parameters the safety can be guaranteed by:
- Reactor power control by a negative temperature coefficient. At a decrease of power, when the flow of the cooling fluid will decrease, the activity of the neutrons will slow down as a result of the increased temperature in the reactor. (Contrary to the Chernobyl accident, where an increasing temperature led to an increasing power)
- The removal of decay-heat in a natural way in the event of a breakdown in the cooling system of the reactor. (Contrary to the accident at Three Mile Island where a loss of cooling led to a partial melting of the core.)
- Under all circumstances, the fission products will be contained in fuel elements because the maximum temperature will be well below the material failure point.
In other words, the reactor safety of a High Temperature Reactor with a pebble-type fuel and a negative temperature coefficient, is guaranteed by the construction of the fuel pebbles and the combination of types of fuel and does not depend upon automatic and/or human controlled systems.
I am intrigued. How can I find out more?
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