|Founded||Santa Fe, New Mexico, USA|
|Key people||Robert E. Prince, CEO
David Carlson, COO/Chief Nuclear Officer
Gen4 Energy, Inc (formerly Hyperion Power Generation, Inc.) is a privately held corporation formed to construct and sell several designs of relatively small (70 MW thermal, 25 MW electric) nuclear reactors, which they claim will be modular, inexpensive, inherently safe, and proliferation-resistant. According to news coverage, these reactors could be used for heat generation, production of electricity, and other purposes, including desalinization.
- 1 Revised 2009 design: uranium nitride fueled, lead-bismuth cooled reactor
- 2 Previous 2008 design: self-regulating, uranium hydride reactor
- 3 Current Competing Designs
- 4 References
- 5 External links
Revised 2009 design: uranium nitride fueled, lead-bismuth cooled reactor
Hyperion announced in November 2009 that, despite their continued intentions to pursue the self-moderated uranium hydride reactor, urgent customer needs for a rapidly licenseable and deployable reactor are causing them to choose another LANL design for initial commercialization. They are moving forward with a more conventional Generation IV reactor design: a uranium nitride fueled, lead-bismuth cooled reactor. Using a liquid-metal-cooled fast reactor should speed the time to commercialization over the more revolutionary uranium hydride, self-modulating design that had previously been publicly discussed.
Fuel and Coolant Selection
According to Hyperion, the uranium nitride fuel incorporated in the design is generally similar in physical characteristics and neutronics to the standard ceramic uranium oxide fuel that is used at present in modern light water nuclear reactors. However, it has certain beneficial traits - higher thermal conductivity - and thus less retained heat energy - that make it preferable over oxide fuels when used at temperature regimes that are greater than the 250 to 300 °C (482 to 572 °F) temperatures found in light water reactors. By operating at higher temperatures, steam plants can operate at a higher thermal efficiency. The presentation by Hyperion at the ANS 2009 conference mentions the use of the Doppler inherent negative temperature coefficient of reactivity in this reactor as a means of control. Nuclear scientist Alexander Sesonske avers that nitride fuels have both received very little development (as of 1973) and seem to have a very favorable combination of physical properties - especially in fast reactors. Whether this carries over to lead-bismuth cooled reactors is a question not answered in the reviewed literature, though the Soviet Union has worked with this type of reactor before in naval service; in particular, the Alfa class submarine - well known in the West for its high speed operation - was driven by such a lead-bismuth reactor which is known to have worked very effectively.
The Hyperion module has sufficient fuel for 3650 full power days at 70 MWth, is capable of load following, and is meant to be built in pairs; one module can be at power, while another can be under installation or uninstallation at the same time, ensuring reliable supply of electricity.
Thermal Hydraulics, Energy Production and Extraction
Hyperion plans to use natural circulation of the lead-bismuth coolant through the reactor module as a means of primary cooling. Coolant temperatures within the primary loop should be approximately 500 °C (932 °F). Powered intermediate heat exchangers, also using lead-bismuth coolant, are located within the reactor and run an intermediate loop going to a third ex-reactor heat exchanger (the steam generator), where heat is transferred to the working fluid, heating it to approximately 480 °C (896 °F). Two schemes of power generation exist at this point: either using superheated steam or supercritical carbon dioxide to drive Rankine cycle or Brayton cycle turbines. In addition to the classical use of power generation, further uses for the heated working fluid can include desalinization, process heat, and district heating and cooling.
The thermal hydraulics of the lead-bismuth reactor are dictated by the high heat capacity and unique properties of the lead-bismuth eutectic coolant. This coolant has several extremely beneficial properties for a reactor: it is opaque to gamma radiation, but transparent to neutron flux; it melts easily at a low temperature, but does not boil until an extremely high temperature is reached; it does not greatly expand or contract when exposed to heat or cold; it has a high heat capacity; it will naturally circulate through the reactor core without pumps being required - whether during normal operation or as a means of residual decay heat removal; and it will solidify once decay heat from a used reactor has dropped to a low level.
Hyperion intends to pursue the licensing of the uranium nitride, lead-bismuth small reactor with the U.S. Nuclear Regulatory Commission (NRC), though the firm's deployment schedule - the target date for deployment will be by the end of 2013 - as well as indications from senior personnel within Hyperion indicates that perhaps the reactor will bypass the normal NRC process for commercial reactors - as it takes many years - and will instead be initially deployed by the U.S. Department of Energy or the U.S. Department of Defense, not subject to NRC regulation, or that Hyperion will seek a 10CFR50.21 Class 104 Research and Development reactor license from the NRC. As of May 2010[update] Hyperion expects to apply to the NRC for regulatory approval "within a year."
Possibilities for manufacture in nations other than the United States have also been mentioned as a way to overcome the NRC's lesser agility in responding to the commercial introduction of unique and innovative features of this reactor design. In particular, Hyperion plans to manufacture reactors in the United Kingdom, which has demonstrated recent national leadership in the field of nuclear energy, while a yet to be announced nation in Asia is targeted for manufacture as well.
As of September 2010[update], the company announced an agreement with Savannah River Nuclear Solutions, operator of the Savannah River National Laboratory in Aiken, South Carolina, for the development of a demonstration site, intended for testing and licensing purposes, at Savannah River. 
Previous 2008 design: self-regulating, uranium hydride reactor
In 2008 and 2009, Hyperion planned to initially commercialize a small, modular self-regulating, uranium hydride reactor, based on a design by Dr. Otis G. Peterson, formerly of Los Alamos National Laboratory, (with United States patent application #11/804,450) for a unique modular nuclear reactor design that Peterson developed while working for LANL.  According to the U.S. Nuclear Regulatory Commission, Dr. Peterson has licensed the pending patent to Hyperion Power Generation, Inc.
In November 2008, the Nuclear Regulatory Commission (NRC) indicated that investigation of the design is not expected to begin until February 2009 and that they expect "that it will take significant time to ensure safety requirements."
As of September 2009[update], Hyperion expected to sell 4,000 units of the "2008-design" version of its Hyperion Power Module, at an estimated US$25–30 million each, and expected to ship its first unit in June 2013, before the company moved on to a second-design in 2009. In early 2009, the company had more than 100 orders for the "2008-design", with plans to build manufacturing facilities in the United States, the United Kingdom, and Asia.
Current Competing Designs
- Hyperion Power Generation Inc. Announces Change of Company Name to Gen4 Energy, Inc., 13 March 2012, BusinessWire
- Hyperion launches U2N3-fuelled, Pb-Bi-cooled fast reactor, 20 November 2009, Nuclear Engineering International
- Hyperion Power Module (HPM), Nuclear Regulatory Commission filing February 10, 2010, accessed 2010-03-10.
- Adams, Rod; Rudin, Forrest; Trapp, TJ; (2010-01-21). "The Atomic Show #148: Hyperion Power Module Update (Audio Interview)". The Atomic Show. Adams Atomic Engines, Inc./The Podcast Network. Retrieved 2010-01-24.
- Campagna, Mark S.; COO, CNO, Hyperion Power Generation (2009-11-18). "Presentation (PDF format)". American Nuclear Society Meeting 2009 (Denver, Colorado, USA: Hyperion Power Generation). pp. 6, 8.
- Sesonske, Alexander (1973-11). "7.161". In Technical Publications Department, ORNL, Oak Ridge, Tennessee. Nuclear Power Plant Design Analysis (1st ed.). Technical Information Center, Office of Information Services, U.S. Atomic Energy Commission. p. 373. ISBN 0-87079-009-9. Retrieved 2009-11-29.
- Small Nuclear Reactors Are Becoming Big Business: The race is on to develop refrigerator-size reactors that could power small towns or plants, Business Week, 2010-05020, accessed 2010-05-24.
- "Reactor may be heading to SRS". Aiken Standard. 9 September 2010. Retrieved 2010-09-17.
- "Hyperion demo for Savannah River". World Nuclear News. 10 September 2010. Retrieved 2010-09-17.
- John Vidal; Nick Rosen (2008-11-09). "Mini nuclear plants to power 20,000 homes; £13m shed-size reactors will be delivered by lorry". The Observer (London, UK). Retrieved 2008-11-20.
- "Compact Reactor Technology Deemed Outstanding by Federal Laboratory Consortium". Los Alamos National Laboratory. October 3, 2008. Retrieved 2009-05-22.
- Peterson, Otis G. (2008-03-20). "Patent Application 11/804450: Self-regulating nuclear power module". United States Patent Application Publication. United States Patent and Trademark Office, Federal Government of the United States, Washington, DC, USA. Retrieved 2009-09-05.
- "NRC: Hyperion". Advanced Reactors (webpage). United States Nuclear Regulatory Commission, Federal Government of the United States, Beltsville, MD, USA. Retrieved 2009-09-05.
- PhysOrg news about Hyperion's uranium hydride reactor
- "Interview with John Deal, Hyperion Power Generation". techrockies.com. September 22, 2008. Retrieved 2009-05-22.
- Fridge-Sized Nuclear Reactors to Tap $135 Billion Power Market, 17 May 2010, Bloomberg
- "Hyperion to build small reactor assembly facility in the UK". Nuclear Engineering International. 1 October 2009. Retrieved 2009-10-01.