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Hyperion Unveils Design of its Small Modular Nuclear Reactor, the Hyperion Power Module

At the recent Annual Winter Conference of the American Nuclear Society in Washington, and simultaneously at the “Powering Toward 2020” conference in London, England, Hyperion Power Generation Inc. revealed the design for the first version of its Hyperion Power Module (HPM), a small modular nuclear reactor (SMR) that it intends to have licensed and manufactured at facilities in the United States, Europe, and Asia.

The HPM is a compact (approx. 1.5m wide x 2.5m tall), sealed and self-contained, simple-to-operate nuclear power reactor, euphemistically referred to by the company as a “fission battery”. Over its 7-10 year operational life, the HPM will deliver 70 MW of thermal energy, or approximately 25 MWe. Each module will cost $50 million; initial deliveries, slated to begin in the second half of 2013, are being scheduled, the company says.

The reason for the low electrical efficiency (36% of 70 MWt) is that the steam loop does not run through the inside of the reactor, for simplicity and safety, the company says.

The HPM is small enough to be manufactured en masse and transported in its entirety via ship, truck, or rail, and is intended to be buried underground for its operational life, after which it will be dug up and refueled at Hyperion.

The US Department of Energy is supporting the development and deployment of SMRs for the domestic market, and plans to establish an SMR program, with a target of FY2011. DOE defines an SMR as producing less than 350 MWe.

The DOE groups SMR technology into three categories: LWR-based designs; non-LWR designs; and Advanced Reactor Concepts and Technologies. The HPM falls into that last category, as do designs and concepts from a few other vendors in the same general power range as the HPM.

Advanced SMR (<350 MWe) Vendor Designs & Concepts
CompanyProductPower rating
Brookhaven Technology Group Global Energy Module (GEM50) 10 MWe
Westinghouse-Toshiba Toshiba 4S (Super Safe, Small and Simple) 10 MWe
Hyperion Power Generation HPM 25 MWe
Sandia National Laboratory Sodium-cooled Fast Reactor 100 MWe
General Electric Power Reactor Inherently Safe Module (PRISM) 311 MWe
TerraPower Traveling Wave Reactor (TWR) 350 MWe

The first version of the HPM is a uranium nitride (U2N3)-fueled, lead-bismuth (Pb-Bi)-cooled, fast reactor. This will include all of the company’s original design criteria, but is expected to take less time for regulators to review and certify than the initial concept of a uranium hydride-fueled reactor created by Dr. Otis Peterson during his tenure at Los Alamos National Laboratory, according to Hyperion CEO John “Grizz” Deal.

We have every intention of producing Dr. Peterson’s uranium hydride-fueled reactor; it is an important breakthrough technology for the nuclear power industry. However, in our research of the global market for small, modular nuclear power reactors—aka SMRs—we have found a great need for the technology. Our clients do not want to wait for regulatory systems around the globe, to learn about and be able to approve a uranium hydride system. A true SMR design, that delivers a safe, simple and small source of clean, emission-free, robust and reliable power is needed today—not years from now. As we construct and deploy this launch design, we will continue to work towards licensing Dr. Peterson’s design.

—John Deal

This initial design for the company’s small, modular, nuclear power reactor (SMR) is the first of several that have been under co-development with staff from Los Alamos National Laboratory.

Nuclear Engineering International reports that:

  • The HPM uses 24 assemblies of uranium nitride fuel, and 18 control rods. The center of the core is hollow so that boron carbide marbles could be dropped in the center to shut down the reactor in an emergency.

  • The U2N3 fuel is 20% enriched and set in HT-9 cladding tubes. Flowing around the pins is liquid Pb-Bi coolant. Quartz is used as a radial reflector. A gas plenum is at one end of the 2-3m long fuel pins.

  • Two sets of boron carbide control rods keep the reactivity of the core under control.

  • The hot (500 °C) coolant transfers its heat through an intermediate heat exchanger to another lead-bismuth loop, through another intermediate heat exchanger to a tertiary circuit with an undisclosed fluid, and then through a third heat exchanger to water (at about 200 °C).

Hyperion Power’s market goals include the distribution of at least 4,000 of its transportable, sealed, self-contained, simple-to-operate fission-generated power units.




These are very interesting. However, I think Americans would be more accepting of fewer larger reactors vs. more smaller ones.


Thermal electric generation uses huge amounts of water, whether they produce CO2 or not. That is the next challenge and cost that will limit the use of nuclear energy.

Henry Gibson

These units do not need to consume any water. They can if they were operated like old steam locomotives. They also can if some water were evaporated to cool the consenser water as many steam power plants do. Many steam power plants pump cold water into their system from a river or lake or ocean and pump it right back again. They do use but they do not "use up" the water. Many people try to make this later use of water into a big issue because they do not understand that the water can and is returned to be used by cities and farms or to flow into the sea. The water in such lakes or streams is not heated substantially and cools off soon most of the time. Before humans were on the earth the water flowed uselessly down the streams and was wasted in the seas.

Cogeneration avoids the need for this cooling water. No natural gas should be burned for electricity except in cogeneration units at homes or businesses. TATA should now build a cheap cogeneration unit, The TATA NANOCOGEN.

There is very little difference between many small reactors at one location than one large one except enormous increases in reliabilility and redundantcy. As many as are needed can be shut down to deal with low load. If one of ten needs repair or refueling or replacement, then nine are still functional. Three of the four reactors at Chernobyl were restarted and operated for many years after the one exploded because operators disabled the safety systems until too late.

Thousands of people are employed at a large reactor site and many small reactors at the same site would not greatly increase the labor needed because of automation.

The first of two reactors at Three Mile Island was put back into service after modifications were made so that it did not fail as the second one did. One explanation of the Three Mile island failure was that it was rushed into service to get tax credits that year. A valve actualy did fail, but after that and before that many mistakes were made. It was obviously too big. Four smaller ones would have been less costly in spite of low efficiency. Several large steam turbines have failed and their high efficiency would never have made up the losses of the failure that took months or years to repair. Infact, the losses may have been so high that the higher efficiency of all such turbines together may not have made up the losses.

Steam power turbine builders have forgotten that redundantcy may be better than efficiency. Efficiency has not been the concern of the solar energy industry since the solar cell was invented; convenience has been the driving force with some emphasis on hope for more efficient solar cells. If the solar electricity business were concerned with efficiency, then large arrays of solar cells would not be sold anymore, and the parabolic small systems of Infinia would be promoted for small homes and businesses and the larger ones for large scale production. Mass production of the Infinia type machine can reduce its costs greatly. It actually may be too large. A solar sterling system gives very high efficiency compared to solar cells.

As it is in solar energy, efficiency is not very important in the fission industry, and only about one pecent of the energy available in natural uranium is used in the US. Carlo Rubbia proposed the thorium fueled Energy Amplifier fission reactor and in the cost analysis, the cost of the fuel was a very small part, less than one part in twenty, of the production cost of the electricity. Even Coal represents only about a fourth of the cost of electricity from coal fired power plants.

The change away from hydride is disappointing. Actually the electrical efficiency is not a concern if the reactor were used for steam heating. Many such units could be buried about a hundred feet below any part of NewYork city and feed the steam system to save a lot oc CO2. The fact that hot water rises or other means can be used to bring the heat from a depth where a Chernobyl explosion would not disrupt pedestrians. Foam glass can be used as a very long life protector and insulator of steam pipes and can be made from recycled glass.

Individual large buildings anywhere can use one of more of this size of energy converter to provide for both heating and cooling. Units, ordinarily used for geothermal electricity, may be used by these buildings to make some electricity as well. ..HG..

Henry Gibson

Even the power plants that have large amounts of vapour rising in the air do not use as much water as some farms nearby, and much of the cooling comes from air not water. ..HG..

Bill Young

This reactor design has not yet been submitted to the NRC. The designs currently before the NRC are, in reality, updates of existing light water reactors in service throughout the US. The designs currently before the NRC are taking 3 or more years to get approval. This design is far more challenging than a conventional LWR, despite its small size.

If they are going to be making deliveries starting in 2013, it will be to markets outside the US and without NRC design certification. A US based company trying to market an uncertified design is not a gold plated business plan.



This is a fascinating development in nuclear power. It solves one of the main objections to NP: the outrageous development costs (billions over budget and yrs behind schedule).
The anti-nuke crowd must take an open minded look at this.


Hopefully someday we'll be able to solve the nuclear waste problem. I'd like to see it taken up into space via the space elevator the Japanese and others are working on, then sent into the sun with the nuclear powered ship the russians are working on.




Actually, maybe nuclear waste can someday be beamed/elevated into space via lasers, and also beamed into the sun with similar lasers...beam all the space junk around earth into the sun while they're at it.

John L.

"The HPM is small enough to be manufactured en masse and transported in its entirety via ship, truck, or rail..."

...which means, it's only a matter of time before somebody steals one for mischief.


If you want to dispose of nuclear waste how about encapsulating in a manner capable of keeping it intact for an extended period of time and then bury it in a non-volcanic section of a subduction plate. Descending at 2" a year it will take a long time for the material to work its way back out again.


The advantage of much smaller nuclear reactors is that they can be mass produced at a much lower cost and installed very close to where the power is required, limiting loss and the use of very expensive long power lines.

Aluminium and steel (and similar) plants could have their own on-site small nuclear power plants and not even be connected to the national grid.

A few well located underground N-plants could supply all the power a small/medium city need without overhead cables. The face of America would change without all those power lines, poles and towers.

However, the not in my backyard fight will last a few centuries in the land of the 10 million lawyers and lobbies.


Owing to the multiple heatexchangers and design constraints the thermal efficiency @ ~ mid 30% is pathetic.

On theft safety issues, the co says "Why would anyone want to steal this? It's like stealling a piece of the sun"

Sounds more than enough reason for some, having seen some things in my day.
"Shh! dont speak too loudly" "everyone will want one"


OOPS! "the thermal efficiency" should read electrical efficiecy (36%)


OOPS! "the thermal efficiency" should read electrical efficiecy (36%)



Lets hope the water and pumps hold up for the cooldown phase. Then grt it back to the factory before it heats up again.

"which weighs 50 tons, would operate like a battery: it would be slotted into place in a power station built by an undisclosed partner company, connected, and generate power continuously for seven to 10 years without refuelling. Then it would be disconnected and left to cool down for up to two years (with water) before being removed and returned to the factory for dismantling"
------And refurbishing Arn.


The question now (in addition to all the other questions already asked in these comments), if this is adopted, is:
Is there enough fissile material for everyone?

I saw EDF's then CEO (Pierre Gadonneix) say that fissile material as it is needed in current generators ( most of the time U235 ) is already in scarce supply. If nuclear energy was to be used increasingly, there wouldn't be enough of it.
But he also said that work was being done on 3rd generation reactors (in terms of fuel) that could use U238 and not U235 as fuel. He seemed confident they would be up and running in 2035, but how confident can one be for research in 3 decades?


Sandia's sodium-cooled fast reactor could use U-238 (with a starter load of reclaimed reactor plutonium), but not Hyperion.  Hyperion is a thermal-spectrum reactor and requires U-235 or U-233.  I expect that it would take some time to design a Hyperion based on the thorium-uranium cycle, so U-235 is it for now.

Hyperion is going to have a huge market in areas dependent upon oil for electric generation (like Hawaii).  Oahu could use a few dozen Hyperions (~1.3 GW peak consumption) or ten or so of the Sandia reactors.  Hyperion would also play well where there are industrial consumers of low-pressure steam.  A $1/watt steam supply good for 7 years comes to a bit over 1.6¢/kWh for heat, or under $5/mmBTU.  That's competitive with natural gas, and no market risk.


This this be as successful as the
Ford Nucleon

jeff r

We should consider what will happen when and if Hyperion and any of their customers go bankrupt and aren't around to dig up/recycle/decommission these units. Say a steel mill buys one, goes bankrupt, it sits in a brownfield for a few decades--whose responsibility is it? Then say there's no Hyperion to deal with taking it back. Is it now the DOE's problem? Do they even know it's there? Imagine more decades pass, etc. Perhaps a terrorist group finally digs it up when no one's looking. Is there anything worth stealing or processing inside? Anything dangerous at all? That should be the question. Maybe someone here can answer it. If not, then I'm fine with it.

We can at least keep track of the nuclear power stations in the world, precisely because they *can't* fit on a flatbed truck. Thousands of these units in private hands scattered all over the world may not sound that bad now, but think a hundred years ahead when we could easily have lost track of them all, just like we no longer know where all the former gold mines are that are leaking arsenic into the groundwater in California. The whole proposition seems pretty dubious to me, especially when there are simpler alternatives, like solar approaching a dollar a watt.


All spent nuclear fuel in the USA belongs to the US government, by law.  (The DOE is supposed to take possession of it and dispose of it in Yucca mountain, but Harry Reid has made that impossible.  Not to mention that the repository is too small, and throwing away uranium and actinides is a bad idea.)

The spent fuel from Hyperions will still have a very large fraction of U-235, so it will be feasible to extract it (e.g. by fluorine volatilization) and just blend it with natural or depleted uranium to make 5-6% fuel for larger light-water reactors.  (The process doesn't have to end there.  The spent fuel from LWRs is still about 1% U-235, which is more than potent enough to run a CANDU.  Practically all of the uranium in US SNF could be extracted, converted to oxide and sold to Canada as CANDU fuel.)

Solar at a dollar a watt has many virtues, but

  1. it costs quite a bit more than that installed,
  2. it doesn't produce at night, and
  3. the seasonal production curve is wrong for northern areas.
Nuclear's virtues are complementary.

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