Since NASA’s announcement of Project Prometheus, plans for robust nuclear space systems were in the offing. The nuclear space community has been elated with renewed interest. Project Prometheus’s existence for public announcements initially were muted due to an unfortunate Columbia shuttle mishap.

Project Prometheus with a tentative budget for 2004 as requested includes $93 million dollars and a total expenditure of $ 2.07 billion spreads over 5 years is an attempt to recover 30 years worth of lost ground in the field of active nuclear fission reactor use in space for power and propulsion. The recent attempts of a flock of Mars probes to eventually land in 6-7 months on the planet taking advantage of rare celestial mechanics making it possible its proximity to Earth alignment. The stakes of bumping into an answer of life’s existence elsewhere in the Solar system could take on new urgency. NASA’s fledging use by “Dusting off” the shelve, tested nuclear technology is no accident. Faced with the potential in peek public curiosity about space, requires leaps in nuclear technology in space to provide added power in round trip transport propulsion capabilities. Power for communications and on-site solar independent, resilient temperature extreme power units for sustained safe exploration to and from distant locations.

Space and the Solar system in a young public’s eye with the discovery, life forms on Earth pop up in the most inconspicuous places, can hope space is not just a gigantic lifeless void once thought. But a reservoir and conduit for inoculating life’s sentient processes and its possible beneficial medicinal properties to us.

PROMETHEUS UNCHAINED TO WORK IN SPACE IN PEACE

Missions requiring continued exploration and commercialization in space need investment dollars in new high performance nuclear technologies. This is too important an endeavor to justify it languishing in obscurity as information too sensitive to pass onto a reasonable public who ultimately must finance and support its use. I asked Victoria Friedensen, Special Assistant Nuclear Systems Initiative, Office of Space Science, NASA. What she meant by a co-authored abstract publication for the STAIF 2003 conference entitled: “Implementing a Managed Approached to Risk Communication” she essentially said, "The approach will cover risk communication, education and outreach, and media relations; disseminate consistent, accurate, quality information on the benefits of the scientific knowledge enabled by space nuclear power: provide for proactive, cooperative engagement with a broad range of potential stakeholders including environmental and social justice organizations; and includes technology education-oriented outreach programs and materials." To date there hasn’t been a real proactive approach to “reach out” to the public about nuclear space other than a NASA space science website and a few public announcements to the news media.

Another problem is unfair environmental criticism with a political agenda in academia such as, Dr. Michio Kaku professor of nuclear physics at City University of New York. He notes, nuclear fission’s use in space is somehow dangerous, unwise politically and incorrect.

The real story ultimately, is the continuing saga of a species using the necessary tools in seeking understanding and survival as in numerous past noble quests; to land humans on the moon. The use of nuclear reactor systems in space should be about hard science and be above petty politics. Either for public, private and educational investments for its important use in space.

HELP TO POWER OUR IMAGINATIONS INTO SPACE

Although “Project Prometheus” at first blush gives us a welcomed impression that passive natural isotope decay RTG with Stirling power conversion (PC) and updated variant SNAP 10A, TOPAZ reactor technology or reactor core fueled UO2 driven close loop heat pipe is exclusive to NEP nuclear electric technology. The plan so far falls short on human and direct lander and return robotic mission benefits of scale. No one should doubt its initial intention as NASA’s desire to make in roads into nuclear use in space. As on Earth we also should be mindful that fission nuclear reactor power in space has a range of electrical potential energy production from watts, kilowatts, to megawatts and unlike Earth reactors can be made to produce a specific impulse in seconds of 500 to 3000, a thrust-to-weight ratio of .01:10. High enough power and thrust to haul systems keeping humans and robotics warm, comfy and safe on long voyages to outer planets.

One promising concept is Nuclear Thermal Propulsion (NTP) employed by a system called MITEE pronounced, “Mighty” (Miniature Reactor Engine) and its electrical variant MITEE-B (Miniature Reactor Engine-Bimodal) represent part of the MITEE family of compact ultra light weight nuclear thermal propulsion engines for planetary transport for exploration and commercialization of space.

Basic NTP systems had their start in the early ‘50’s with extensive testing in the U.S. and the former Soviet Union, which ran on into the mid ‘70’s. These early versions of the NTP rocket were bulky and equipped with graphite as a moderator making them heavy and non-competitive compared with chemical propulsion due to a low thrust-to-weight ratio at ground launch. The U.S. carried out successful ground tests of the NERVA system but no flight test were ever conducted.

The U.S. worked on NERVA but stopped the program in the ‘70’s because of a lack of direction and increased criticism by an environmental lobby. Russia continued work on NERVA type engine till its program terminated in the ‘80’s.  All programs completed successful goals.

BRIEF RESENT HISTORY: “Starting in the late 1980’s the U.S. DOD/SNTP (Department of Defense/Space Nuclear Thermal Propulsion) program undertook the development of a much smaller and lighter 2^nd generation nuclear rocket based on the Particle Bed Reactor (PBR).

The PBR used ⁷LiH (lithium 7 hydride) moderator with very high power density (30 MW/Liter) particle bed fuel elements. The PBR engine power was 1000MW, Isp 1000 sec, thrust 220,000 N and total mass 800kg, including turbo pump and auxiliaries. When the SNTP program stopped in 1993 at the end of the Cold War, the PBR component had been extensively tested and validated, with high power nuclear testing of PBR fuel elements assemblies as the planned next step. The PBR, which was a major step forward in reducing the size and weight of nuclear thermal propulsion engines, is still too heavy for today’s lightweight missions.” ¹

THE MITEE FAMILY OF NUCLEAR ROCKETS

“A family of compact, ultra lightweight nuclear thermal propulsion engines is described based on the MITEE concept. The MITEE engine consists of a clustered assembly of individual beryllium pressure tubes (typically 37 or 61 tubes for the complete engine) each of which contains an outer annular Li-7 hydride moderator zone, with an inner annular nuclear region. Cold hydrogen propellant flows radially inwards through the ~1 cm thick fuel region, where it is heated to a temperature of 3000 K or more. The hot hydrogen then flows longitudinally along the central channel to a small exit nozzle at the end of the pressure tube, through which it exits to space, providing thrust. The nuclear fuel region is composed of a multi-layer roll (typically 20 sheets) set of perforated tungsten/UO₂ metal matrix composite sheets (developed for the 710 engine in the 1960's) through which the hydrogen propellant flows.

Four different MITEE design approaches are described:

1. U-235 fueled baseline design that achieves an Isp of 1000 sec., with a thermal power of 75 MW and total engine weight of 200kg (including 50% contingency).

2. Ultralight MITEE engines utilizing high performance nuclear fuels (80 kg engine weight with U-233 and 50 kg with Am-242 m).

3. A low pressure (~I atm) MITEE engine that dissociates ~40% of the H₂ propellant to monatomic H, achieving an Isp of ~1300 sec.

4. A hybrid electro-thermal engine in which electric power generated by expansion of hot high pressure H₂ propellant in a turbine is used to further heat hot low pressure hydrogen from the reactor. The hybrid engine achieves temperatures of ~4000 K, with almost complete dissociation of the H₂ propellant, and an lsp of ~l600 seconds.

 New and important unique missions enabled by MITEE are described, including Europa sample return, a Pluto orbiter/lander and sample return, ultra high velocity (>100 km/sec.) spacecraft for travel to 200 AU and beyond MITEE development requirements are discussed. An in-space demonstration of the baseline MITEE engine could be carried out in approximately 6 years.” ²

The newer nuclear engine approach MITEE proposed by PUT Incorporated:

“The MITEE is similar to the PBR in terms of having the propellant flow radially through annular fuel elements, and the use of lightweight, high neutronic efficient lithium 7 hydride as the moderator. However, MITEE is significantly different from the PBR in two major respects:

1. The MITEE reactor utilizes an array of individual pressure tubes, each having its own fuel elements, moderator region and outlet nozzle, rather than a single common pressure vessel and nozzle.

2. The MITEE fuel element is composed of a multi-sheet annual roll of tungsten metal matrix-UO₂ composite material, instead of a packed bed of small carbide fuel particles. The metal sheets are perforated by many small holes, through which the propellant flows.

The baseline engine is taken as a starting point for further improvements and modifications to MITEE, which lead to even greater performance capability.

For greater performance:

I. Use of alternate nuclear fuels (U-233 and Am-242m) to further shrink the size and weight of the MITEE reactor

2. Operation at lower coolant pressures (e.g.,1 atm or less) and higher temperatures (e.g., 3200 K) to dissociate a substantial fraction of the diatomic hydrogen propellant into H atoms, thereby increasing Isp.

3. Generation of electric power using a compact turbo-generator to expand hot high pressure hydrogen. The lower pressure exhaust hydrogen is then reheated to high temperature in the MITEE reactor (in separate pressure tubes from these that heat the high pressure hydrogen). The outlet hot low pressure hydrogen is then further heated by an electrical discharge using the generated electrical energy to increase the fraction of hydrogen that dissociates to H atoms, further increasing Isp.” ¹

ADDED MITEE ENGINE PERFORMANCE FEATURES

“Dissociation of diatomic hot hydrogen propellant to monatomic hydrogen atoms results in a substantial increase in specific impulse because the effective molecular weight of the heated propellant becomes much less.

At 0.4 atmosphere and 3200K, for example, the H atom fraction is 37% and increases to 53% at 3400K. Although such temperatures are only a few hundred degrees below the melting point of tungsten, there appear to be no chemical compatibility problems between the fuel elements and hydrogen, and in the very low pressure drop MITEE configuration, minimal mechanical stress on the solid fuel sheets. Accordingly, operating MITEE engines at low pressure has the potential for substantial dissociation of the hydrogen propellant, with a consequent significant increase in specific impulse.” ³ 

“A second approach to increasing reactor power is a different flow geometry for the reactor core. In Figure 10, the baseline geometry is termed a "uni-core" geometry, in which all of the outlet coolant exits through the bottom end of the fuel element.

A "split-core" geometry is also possible. In this geometry, the core is split into upper and lower halves. lnlet coolant flows into each of the core halves through passages on the midplane of each half. The hot outlet coolant first flows out through the ends of the fuel elements at the top and bottom of each of the core halves, then radially outwards to channels between the two core halves and the reactor reflector, and finally to a chamber below the lower core half, which in turn leads to the engine nozzle.

This split-core geometry increases the high Mach number flow area by a factor of 4, as compared to the uni-core geometry. This occurs because there are four outlets per equivalent fuel element (2 outlets for the upper half core and 2 for the bottom half) as compared to 1 for the uni-core. 

The split-core arrangement is less efficient neutronically than the uni-core, since it requires an empty annular channel between the core and reflector, and a gap between the upper and lower core halves. However, the thickness of these channels are small compared to the core dimensions, and are not anticipated to pose a major penalty on the size and weight of the MITEE engine.” ⁴ 

“Material temperature limits on the solid fuel elements in the monatomic hydrogen MITEE engine still constrain the total enthalpy that can be imparted to the hydrogen coolant, together with the degree of dissociation. This, in turn, limits the specific impulse available using the monatomic MITEE engine. 

However, it is possible to increase the enthalpy and dissociation of the outlet hydrogen beyond the values imposed by the temperature limits of the monatomic engine, using electric energy to further heat the hydrogen propellant after it exits from the reactor. This electrical energy can be generated by expansion of hot high pressure hydrogen propellant through a turbo-generator. The exhaust low pressure hydrogen from the turbo generator is then reheated to high temperature in the MITEE reactor, and finally, further heated by the electrical energy from the turbo-generator. 

This approach, termed the hybrid electro-thermal MITEE engine, can considerably increase the specific impulse of the output hydrogen propellant.  

Two hybrid options for MITEE have been examined:

1.Once-through open cycle

2.Recuperated recycle” ⁵

 MITEE ENGINE AT A BARGAIN PRICE 

Prices reflect best estimates values:

• The development cost of the MITEE engine: $800 million.

• The development cost of the MITEE-B engine: $1 billion.

• Unit production cost of each MITEE engine after development: $40 million.

• Unit production cost of each MITEE-B engine after development: $60 million. 

Considering increased access in space, comparison to NASA pegged expense launching latest Rover mission to Mars: $800 million.

FEATURE INTERVIEW

Three engineers formed Plus Ultra Technologies (PUT) in 1995 translated from the latin "Plus Ultra" means "Ever Forward". James R. Powell Sc.D in Nuclear Engineering, George Maise Ph.D in Aerospace and Mechanical Sciences, John C. Paniagua Ph.D in Mechanical Engineering.

As a group of real world experienced engineers in the field of nuclear space science they stand behind their statement, "Only when significant reductions in the cost of space flight are realized will space exploration flourish."

In an age of shrinking expectations, civil impropriety and wavering space ventures this unique company gives us a notion that indeed, "Fortune rewards the bold".

After searching the internet for information "Plus Ultra" stood out. I decided to contact Dr. Maise who helped me arrange an interview with Dr. Powell conducted end of May 2003.

The following is an excerpt of our conversation:

BB: Doctor Powell, I would like to thank you for granting nuclearspace.com this opportunity to talk with you. You are President of Plus Ultra Technologies Inc. Could you explain your company and what it is involved in?

JP: Yes...it's a group of three people who were part of the team that started and worked on the last nuclear space program that the United States carried out. This was the Space Nuclear Thermal Propulsion (SNTP) Program that was aimed at producing a small nuclear rocket, the PBR (Particle Bed Reactor) for use in defense applications. The program started in late 80's and went on until about 1993. It was funded by the Defense Department (DOD) and the Space Defense Initiative (SDI). Some of the principals in that effort were myself, George Maise and John Paniagua. The program was closed down in 1993. A few years afterwards we got together and started working on, a derivative of the PBR  Rocket which would be useful for planetary robotic exploration. We then formed Plus Ultra Corporation to further these efforts and have been at it for the last five years. It's a small subchapter 'S' company. Besides ourselves, we have consultants and work with other people. Our main goal is to develop nuclear space propulsion and power systems that would be useful for space exploration.

BB: One risk assessment study, ("An examination of emerging In-space Propulsion Concepts for One-Year Crewed Mars Missions" by Dennis G. Pelaccio, Gerald A. Rauwolf, Gaspare Maggio, Saroj Patel, Kirk Sorensen) of a round trip Mars human mission (beginning year 2018) based on risk criteria: In-space environment crew exposure, propulsion system crew hazards, system degradation, system complexity, ground and spacecraft hazards, in-space assembly complexity and safety, crew transfer, abort option/capabilities, disposal requirements.

Comparing propulsion type options with mission:

| Chemical | BNTR (Bimodal Nuclear Thermal Rocket same as BNTP) | High power-NEP (Nuclear Electric Propulsion) | VASIMR (Variable Specific Impulse Magnetoplasma Rocket) | Momentum Tether | SEP (Solar Electric Propulsion) | SEP Chemical |

They elected BNTR as a most attractive option as a mature technology, modest Initial mass at LEO (low earth orbit) of 685 metric ton with 32 launches required. Could you comment on its findings?

JP: Yes, I think generally that is true. Nuclear is in our view the preferred option, not just because it's potentially the lightest weight in LEO, but also because it gets you there fast. Outwards times in space are about 90 days with a high performance nuclear engine and trip times back about 150 -160 days at favorable opportunities. That's considerably faster than say, chemical or the other propulsion options  and it's a system that we think can be developed fairly soon. A lot of technology already exists out there that can be drawn on to get the actual operating system. There is an additional advantage besides shorter trip time.

One of the things we've been looking at, is the possibility of robotically manufacturing the supplies that you would need for a Manned Mars expedition by landing a small autonomous nuclear factory unit on the, North Polar Cap. You've got all the materials there you need to make a really wide range of products; using exposed water, ice and the CO2 atmosphere  and a fairly lightweight 'Factory Unit'. You could make the hydrogen propellant for your return trip, oxygen for breathable air and fuels like methane and methanol. You could even make plastics from CO2, and Hydrogen. You could even grow food.

A lot of the materials that you would normally think of bringing from Earth to Mars for an expedition could actually be waiting there just under the ice when you land. So, when we think of a nuclear system, you can already have assured stockpiles of supplies at a Mars base on the Northern Polar Cap when you land, including sub-surface ice habitats to protect you from cosmic radiation. This further reduces the mass in LEO needed for a Manned Mars Mission. So, in that sense, nuclear is even more powerful than just a one-on-one comparison as a propulsion system.

BB: I ask out of curiosity, how would your surface plant/s avoid flooding of reactor by melted ice with water and any surrounding contamination?

JP: What we propose is having a small water cooled nuclear reactor that would melt its way down through the ice and operate in a melt pool below the surface. This gets into an area that is not nuclear rocket propulsion but really nuclear power. One of the things we've found in our studies is that a very attractive nuclear power option for space application has been overlooked. A really simple nuclear electric power system for both space and surface power that could be based on existing reactor fuels like those developed for the DOD. For example, you can have a very small reactor, maybe about 40 cm in diameter, that's critical and would employ existing nuclear fuels. It would use water coolant and operate in a small sub-surface cavity surrounded by water for shielding.

We have found that steam/water cycle reactors for space applications actually have as good or better performance than gas cooled reactors.

BB: I read some of your papers, you seem to be a 'fan' of water use for cooling that's a bit of a change from reading other people's work; they don't really like water (used as coolant).

JP: I know...and I've been trying to figure out why, using water you can get a very light weight space reactor power system that weighs only a few kilograms per kilowatt. I think it's because people thought there would be zero G problems with a two phase flow. There really aren't if you design your system right. It's one of those not invented things; people get a certain mindset and stick with it.

BB: Most people tend to lead sedentary lives, to most space is still an aberration since so few humans actually experience space as a destination. How would your concept in the design of MITEE (mini reactor engine) with an ISP of ~1000 seconds, weighing 140 kg, the length of a 50cm facilitate adequate propulsion and could it be scaled up to produce 25klbf (kilopound force) or 111N (newtons) expelling mass quantities of super heated H2 at super sonic speeds to haul human missions to outer planets?

JP: The original size of the PBR reactor for the defense applications was 1000MW and it was not much bigger than the present MITEE. It was designed to produce 44,000lb of thrust, with a total weight of something like 500 kilograms.

The reason we scaled down in size to MITEE from the original PBR was the idea, that if you're going to have nuclear propulsion systems in space. The best way is to develop a system that can be used for very small light weight robotic planetary missions. You can then build on that to bigger systems. Then you can say, " When we're ready to do human missions we can easily scale it up and get more powerful units." But you have to get systems in place early.

BB: Could you explain, when missions to outer planets for example; Jovian moons may last as much as +7 years (round trip) how would an NTP-B (Nuclear Thermal Propulsion-Bimodal) type reactor who's monteburns fuel burn-up 'end of life' or a spent reactor core's lifespan ends at that time, warrant disposal in space?

Is there a difference with respect to end-of-life of a reactor using identical fuel (for example; U-235) and fuel weight used in a closed NEP system vs an open NTP system?

JP: I don't see any fundamental difference. Both types can be designed to have adequate fuel life times.

BB: "End of life", burn-up depending on the reactor make-up, doesn't it have a "Shelf life"?

JP: People tend to say a reactor is a reactor is a reactor.

There's actually very large differences from the radioactive inventory point of view. A typical nuclear rocket would have a radioactive inventory that was about at 1 part in 10⁶ of what a standard commercial reactor would have at the end of its life.

In fact a typical nuclear rocket mission would only produce a few Curies of Cesium and Strontium which are the most troublesome radioactive isotopes. Put that in the context of what we now have on Earth, which is something like 10 billion Curies of Cesium in the radioactive spent fuel in storage pools and something like 100 million Curies already in the biosphere. In a typical NTP mission you would produce only 10 Curies of Cesium. So, it's very small and it's way out in space.

BB: There is disposal sites (Sun, Jupiter, subsoil storage, etc.) in space that can deal with that.

JP: Right. As to the difference between NTP and Nuclear Electric Propulsion in terms on inventory. I don't think either one would have a problem. The NEP would have a lot more radioactive inventory, maybe a factor of 1000 more than an NTP, because it burns at a lower power but, burns for a lot longer time. However, from a disposal point of view either system doesn't trouble me at all.

BB: Can you use any reactor cooling radiators structures as high/low gain reflector antenna disks to facilitate communications on outer planet spacecraft?

JP: I hadn't thought of that, it seems like a reasonable idea...Yeah, I wouldn't see any reason - why not?

As long as they're metal and most of them are. We've looked at Beryllium and Aluminum for example. They could easily be an antenna. That would be a nice dual use application.

BB: As far as maintenance operations in space, can MITEE-B core be 'changed out' with a fresh core block and fuel inserted into a new core to begin the process over again? Can that be done robotically?

JP: Yes, I think so...One of the features we designed into the MITEE is that instead of being a single pressure vessel it's a bunch of individual small "Pressure tubes" which are closely packed so that they form a complete reactor. Each "Pressure tube"- there might be 61 in a reactor assembly - could be individually removed. So you not only have the option of 'changing out' the whole reactor system, you also have the option of changing out a failed tube. In fact we looked at the reactivity effect on the reactor, if one of those "Pressure tubes" were to fail and that particular tube shut down, the reactor could still be critical and keep operating. At some future time a robotic system could replace that failed "Pressure tube". Meanwhile, however the reactor could go on operating.

BB: When a "Pressure tube" region of the reactor, when a single one is shut down for whatever reason, does that automatically shut down the NEP portion of the Helium cooling system?

JP: Yes...You would close the flow portion to that tube, but the other tubes would continue to operate.

BB: That would go too.

JP: Right...Now, in fact it's a little bit more complicated. What would happen if it failed? If it failed by, for example; an over heat situation. The Uranium fuel would blow out the nozzle leaving an empty tube for that particular "Pressure tube". You would 'close off' the inlet and outlet Helium connections to that particular "Pressure tube". The rest of the reactor would continue to function.

BB: When you mention water, I quess you use a conventional steam cycle style...Is this a Rankine thermocyle PC (power conversion) system (turbine turning PC for electricity)?

JP: Right. It's a Rankine cycle with super heat. In a Rankine cycle you have a phase change. The water vapor that comes off as steam could be expanded as a saturated vapor as it's done now in Light Water Reactors, or it could be super heated to higher temperatures, which yields a higher thermal efficiency this is done in coal burning plants.

BB: What sort of computerized sensoring system would you be using, meaning how would you monitor your reactor?

JP: Basically, you monitor the power level. You could do it in either of two ways, either by monitoring the temperature of the gas coming out, or by monitoring the neutron and gamma flux from the reactor to give a precise measure of the total power.

So, like all reactors you have a system, that controls the reactivity of the reactor. When you start the reactor you make it slightly super critical. The power builds up exponentially over a period which is defined by how much super criticality there is in the reactor. When the reactor reaches its desired power level you trim back the control system so that, the criticality constant (Keff ) is just equal to 1. The reactor then stays at constant power thereafter.   

For a nuclear rocket you would probably bring its power up over the space of several seconds. In the PBR rocket mission requirement was to bring the power up from cold start to full power in 2 seconds. That was a real challenge, but we figured out a control strategy to do that.

In space exploration you're not driven so much by mission requirements to rapidly respond. You probably would, bring the power up slowly to warm up the reactor over the space of several minutes to (maybe 1000th of final power). You would then ramp it up over 10 or 15 seconds to full power. I don't think there would be any problem in doing that.

BB: I didn't notice any reactor control rods, drums etc. in any reads do you need it?

JP: Oh, we need it. We never got into that level of detail in the MITEE design. We did detailed design of control systems in the PBR program, however.

BB: Do you use Boron?

JP: No, we used rare earth poisons like Gadolinium or Europium, which are often used in reactors. We had a special, "Rotating shutter" control rod. This is a fine technical detail - but it's interesting. The control rods normally in reactors move axially up and down into and out of the core. There are control reflectors where you have poison on one side of a rotating drum and a moderator on the other side which you could also use . We had a "Rotating Shutter" control rod which was inside the core. Think of say, 3 or 4 nested segmented cylinders with poison region lines along them. If these poison lines are positioned one behind the other as you go inwards on these cylinders the effect on reactivity is fairly limited. Then when you rotate each cylinder so that instead of lining up, the poison lines form a continuous shell, then it's a much more powerful neutron absorber. So, with a very small rotational movement you can cause reactivity swings of several percent.

BB: Can you give us a sense how reliable your reactor is under hundreds of thermal cycles without damage meaning shutdown and start-ups.?

JP: Sure, I'll go back to the nuclear fuel we are proposing for the [MITEE] which is the cermet fuel that was developed during the 60's as part of an AEC program. It used small UO2 particles dispersed in a Tungsten (W) metal matrix. Similar fuels have been fabricated for many years in very large volumes for reactors on Earth. To give you an idea of the toughness of this tungsten cermet fuel, it was exposed for 100 thermal cycles to full temperature and down again in hydrogen and there was no problem. They also ramped it at rates of 10,000K per second up and down and there was no problem.

BB: Uh...10,000K ?

JP: Yes...It was done in a 'treat' pulse reactor in the Idaho National Engineering and Environmental Laboratory (INEEL). 

You pulse the reactor and...BANG ! You get a very intense burst of neutrons. When they tested this fuel in the Treat Reactor, its temperature climbed at the rate of 10,000K per second. They did this several times on these fuels and didn't have any problems.

So, it's a very, very rugged fuel.

I'll give you another example; in the Particle bed Reactor (PBR) fuel elements, we had the HTGR type fuel particles between two porous "Frits" - made of metal " or graphite (we used various combinations of these "Frits"). We would heat the elements (they were full sized) to 2500K and then pass hydrogen propellant through them and cool them at the rate 10,000K per second at a power density of 30 megawatts per liter. We did that twenty seven times on an element and never had a failure. So, you can make these fuel elements incredibly rugged.

BB: Whoa !!

kelvin/centigrade conversion temperature:

0°K= -273.150°C absolute zero

2.7°K = -270.45°C ~ normal space temperature.

0°C = 273.15°K ~ H20 freeze

100°C  = 373.15°K ~ H20 boil

3000°K= 2,726.85°C

5800°K= 5526.85 °C ~ Sun surface

3700°K= ~ melting point of W (tungsten)

BB: As of late the government has decided to revive efforts of peaceful nuclear use in space for propulsion and power with NASA director O'Keefe announcing Project Prometheus with a tentative budget for '04 as requested includes $93 million for this initiative, and $2.07 billion over five years. How could this public money investment effect Plus Ultra Technologies?

JP: Well, we're a small business. We're certainly not at the stage where we can take on a big project on our own. We would hope to have both small business contracts and also team with some larger company that wanted to use the kind of technology we are proposing for a large scale program. In that case we would assist in the development, but the larger company would take the lead.

BB: Do you think overall job growth in aerospace be better served with small business and established companies as contractors all under a group or consortium, a need to "group task" for young and old companies to work together i.e. "Space Nuclear Reactor System Groups" as main contractors for power and propulsion systems. Meaning do you think NASA is doing enough to farm out contracts to young small business? Would you mind Plus Ultra Technologies working with a Pratt & Whitney etc. in direct development?

JP: No, I wouldn't have any problem with that at all. It's a good policy to draw in the smaller companies for new ideas.

BB: Well...companies like Pratt & Whitney, could care less now about nuclear propulsion and power in space. They're more concerned with their Earth bound "Coleman camper lighter" style kerosene, hydrogen/oxygen burning [rocket engines] stuff. Though there's maybe some public monies thrown their way.

I don't know why they have this aversion to nuclear power. I would think they would like to work with a company like Plus Ultra Technologies.

JP: If you really going to explore the solar system you need nuclear propulsion. There's just no other way out. Chemical propulsion, as we've seen for the last 30 years, is very limited in what it can do.

BB: One chief complaint from the nuclear space community is that funding for implementation of nuclear propulsion and power in space is sporadic and dependent on who's in power in Washington; unlike other successful NASA space programs of the past. Do you have any thoughts on why this is so?

JP: Yes,I think that's true. I think the basic problem seems to be that NASA hasn't really formulated its future missions, let's say, for the next twenty years, in a broader context. They're doing Mars Rover and things like that and those are very worthwhile. But we need bigger missions. The 'Big' mission 40 years ago was going to the Moon. We focused our energies and said, we're going to do it; and we did it successfully. Then we had the Space Station and so forth. But they haven't focused on what they are going to do in a 'Big' way for the next 25 years. Once they do that, I think they will decide they need much better propulsion capabilities and that will result in sustained development.

BB: I agree with you there.

BB: Maybe you can refresh my memory a bit...Is there an public exhibition, a space nuclear rocket museum of these engines, if even as models? If not, what do you think of having some traveling road show of nuclear power and propulsion make the rounds at air & space shows, schools, universities so the general public can relate to Project Prometheus: NASA nuclear space initiative and companies like yours involved in its development?

JP: Well, there's some for example; like NERVA. I think they have NERVA [rocket] engines at Los Alamos in their museum.

BB: But it's not a traveling "road show" of nuclear power and propulsion to make the rounds at Air & Space Shows, schools, universities etc.

JP: Right, there's no such exhibit, I don't think there's anything in the Smithsonian. That would be a nice exhibit.

BB: Nuclear propulsion and power in space is very under represented in the public's eyes they have no idea of the potential. That's where the confusion lay when critics talk about it, because people just don't know about it.

BB: NASA's revolutionary aerospace systems concepts (RASC) program identifying new mission approaches and defining the technologies required for the accomplishment of those missions, technologies like yours. One such human mission proposal requires the creation of microgravity for the trips to lucrative Jovian moons. How would your reactor handle 'Tumbling' or 'Wobbling' producing 1/8th artificial gravity as required as this spacecraft travels through space?

JP: I don't think there would be any problem in handling 'Tumbling' or anything like that. There is nothing loose in the reactor. It's very tightly mechanically constructed. I don't see any problems at all.

BB: Is there business investment exposure for a "Nuclear space transport industry" of stock offerings for an investor's portfolio?

JP: I don't know of any.

BB: In your youth, how did you get involved in this field and endeavor?

JP: I started in Brookhaven National Laboratory (BNL) out of graduate school in Nuclear engineering, I was MIT's (Massachusetts Institute of Technology) first doctoral student in nuclear engineering under Manson Benedict. I joined the Nuclear Engineering Department in Brookhaven in '56. In those early days in Brookhaven, and a lot of national labs around the country, you had a great deal of freedom in what you could work on.You don't see that kind of freedom these days. People are very constrained. In order to be funded you have to part of a work break down structure with an infinite number of milestones that are micromanaged to death.

Our funding for the whole department was done by the chairman. In April he would write a one page letter to the AEC saying how much money he wanted next year. So, as a result you could do many different and interesting things, a lot of which wasn't micromanaged.

One of the things I was working on was non-equilibrium plasma conversion, MHD generators for reactors to make them more efficient. I also was working on a space power system using a "Liquid Cesium" piston instead of a mechanical turbine. I did a lot of work on Rayleigh Taylor instabilities, built MHD generator models and tested them and so on. That got me interested in space propulsion. I stopped working on space systems after the NERVA program ended. Then, I did a lot of work on Fusion Reactors. I then came back in the '80's to the question. How do you get a really small high power density reactor ?

The answer, is you make the fuel elements out of packed beds of very small HTGR (High Density) fuel particles so you get a large heat transfer area per unit volume. We proposed this at the Air Force Rocket Lab and we did some nice work there. SDI they started a major program  on the PBR nuclear rocket. The $200 million dollar program involved: Grumman, Babcock & Wilcox, Sandia, Hercules, Garrett and a couple other companies. We made a lot of progress during the five, six years on the program. We developed very high temperature fuels and materials, built reactors and tested hardware. We were on the path to ground test an engine that would have been much smaller than NERVA. When the Cold War ended, however the program was shutdown.

So, there was a hiatus of several years. Toward the later part of the '90's we then proposed the small MITEE reactor for robotic exploration of space.

So NASA has come back to nuclear propulsion and it seems like they're serious.

But as you say, will it follow through or will it be another on again, off again program - I don't know.

BB: What do you think of some of these other space nuclear propulsion systems within the fission fuel category for example: Gas core nuclear rocket (GCNR), Salt or Gallium molten core reactor rocket engines? Do you think they need more work, are they feasible in the near term?

JP: I think they can definitely work. But I believe the important goal is to get out there [in space] with an operating system, and not make the goals too long term. Because if you them very long term - what happens?

It always seems to happen in these long term programs is that after awhile the public and the funders loose interest and the funding stops. So, we need a near term system that can do a lot of useful things. People will see that it works you then can build on that to more advanced systems like GCNR rocket engines, which ultimately have a lot of promise. That's the reason we're concentrating on the MITEE system we're proposing. There is a lot of technology base out there. We feel that MITEE can be built and implemented in a few years, rather than putting it off another 10, 15, 20 years while you work on it. That's a prescription for failure.

BB: NASA has recently described in it's Orbital science website a system with the acronym SAFE reactor and they describe a mission for it called JIMO .

Are you going to wait for this mission to happen and chalk up its success?

JP: I think Nuclear Electric (NEP) propulsion, which the SAFE reactor and JIMO are part of is a worthwhile goal. But the exploration 'Benefits' that NEP would yield will be fairly constrained. You won't be able to land on moons or planets, you won't be able to return samples and you won't for example, like our "Jupiter Flyer" be able to make it into a nuclear ramjet and fly in the atmosphere of Jupiter to collect atmospheric data. So, I believe NTP can really get  more of the major 'Benefits' that you really want out of space exploration. Like answering the question; is there life on Europa? Which means you have to land on the surface and go down through the ice cap to the Undersea ocean there.

BB: What is your nearest development, can you give me a date?

JP: A system application?

BB: If NASA were to show-up at your store for "Nuclear rockets" to pull off the shelve to use.

JP: I think by 2010 you could have a system that was going to Jupiter to land on Europa. My view that is the highest priority of them all is a mission to Europa, to land on the surface, go through the ice cap and see if there is any life in the sub - surface ocean.

There's increasing reason to believe that life might be found on Europa. I was reading in a recent issue of Science News that life may automatically forms in conditions in deep oceans at hydrothermal vents. There's good reason to believe that's what really happened on Earth. The chemistry and conditions down there are just about right for making primitive microbes. If that's true, chances are the same thing happened on Europa. That would really, really be a "Grab you and hold your attention" type mission.

BB: Yeah, no doubt Jovian moons could serve as a human outpost - for me.

Mars is a target to at least have a human mission.

JP: Oh Yes... I certainly think there could be colonies on Mars, You have the right resources - water, ice and CO2 to have a colony on the North Polar Cap . But from the standpoint of the knowledge point of view, if I had to think about the most important thing about the solar system, I'd want to know if there was life under the ice sheet on Europa, or the other moons of Jupiter.

BB: How do you answer critics that point to nuclear use in space as incompatible with life on earth affecting everything from communications, weather and the odd pet owner's concern pets will soil their homes (chuckle)?

JP: There's no connection (chuckle). I mean you're very far away from Earth. They will be launched in a completely cold, non-radioactive condition and you only start these reactors up in very high orbit where there is no chance it will ever reach Earth at least for many, many thousands of years. By that time the very small amount of radioactive materials have long since decayed.

So, if people really want to worry there're a lot more important things to worry about than space power reactors or nuclear space propulsion units. I would worry about unguarded nuclear material in Russia for example. That's a much more serious problem - people should concentrate on that.

BB: Well...thank you very much Dr. Powell and I noticed your website is full of information and I urge readers to go visit website Plus Ultra Technologies Inc.

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