• Can't trust the government - they lied about the weapons' fallout.
• This is all part of a militaristic program, turning Idaho into a one-stop shopping place for weapons
  (citing both INL and Mountain Home Air Force Base). Next INL will be making nuclear weapons?
• One woman said her father had worked at ORNL, Hanford and INL and died at age 42.
  She blamed his work on his contamination.
• Uranium has been found in animals in Idaho.
• What about a terrorist plane crashing into the building?
• One person likened DOE employees to Nazis exterminating the Jews commenting, "...They're just doing their jobs."
• The European Space Agency (ESA) uses solar cells, why can't NASA?

• Reactor Mass at first glance mod systems appear to have mass advantage over a fast system. This advantage occurs because the fuel inventory could be reduced significantly (assumed same enrichment used) and because the fuel accounts for a large fraction mass in fast-spectrum space reactors. The actual mass saving would depend on how well the moderating material (most likely hydrogen) could be placed in the core geometry. Mod systems have a lower neutron flux because the fission X-section is higher and a smaller neutron leakage fraction both factors could help to reduce shielding mass. Also lower neutron flux will cause less material damage. So structures could be made thinner thus lower mass. Gamma shielding mass will depend on several factors. Mod systems may have larger gamma source emerging from the core (zirconium or yttrium provide some shielding in moderator in-core components) because there will probably be less high-Z material in the core and more capture gammas. Fast reactors will have more gamma in the shield and ex-core components because of higher neutron flux. So no general conclusion can be drawn for gamma shield mass until specific applications can be studied. The most important contributor to system mass is temperature, so even though the reactor and shield might be physically lighter for a mod system, it may not provide a lighter spacecraft if the reactor operation temperature of the spacecraft is lower (radiator waste heat cooling fin system mass ).
• Reactor Temperature only hydrogen could be an effective moderator. Hydrogen slows down neutrons far more efficiently than any other atom because its mass is essentially that same a neutron. The primary difficulty with using hydrogen or hydrogenous material is hydrogen retention over the life of the mission. No established technology can hold hydrogen at temperatures >1000K, and fro a long periods of time. Yttrium hydride is a potential material, but a very optimistic temperature limit of ~1100K and for a long duration mission the temperature limit might be even lower. Zirconium hydride is a more established moderator material, but it's temperature limit is more than 100K lower than Yttrium hydride. Fuel forms (metal hydrides) with hydrogen are established, such as UZrH, but its max. temperature is between 900K and 1000K. The other option is to attempt to cool the moderating material, which adds a extra level of complexity to the reactor system which would add substantial risk in cost, schedule and reliability. Adding a second cooling mechanism, whether pumped or HP driven and integrating it into the system would be very difficult. So a simple, low technical risk moderated reactor will require an operating temperature <1000K and possibly much lower. The temperature issue would be the largest obstacle to using a mod reactor for a mission that requires a low-system alpha # (system mass per electrical power output). If you combine either low power conversion efficiency and/or low radiator temperature it makes it hard to design a low-alpha system if the reactor temperature is limited to below 1000K. For missions where alpha can be relaxed, the radiator area is not critical, or there are other reasons to keep material temperatures low (like in low power surface operation reactors), this temperature limit is not as significant.
• Lifetime the impact of moderation on lifetime is dependant on many factors. If the system lifetime is limited by fast fluence, then a thermal system has an advantage because fast flux is lower. Fluence does not appear to be a life-limiting factor for most potential space reactors concepts. It depends on the choice of materials used and reactor requirements. If system lifetime is limited by fuel burnup, then the amount of fuel in the reactor is fixed by the burnup limit and the mod system will lose the potential mass advantage provided by less fuel. This might be the case for several space reactor application since fuel burnup database is very limited. The biggest lifetime issue encountered might be moderator lifetime technology selected for moderation and operating temperature and fluence.

Technical Risk: Its important to minimize technical risk in any first-of-a-kind engineering system.

• Complexity in a mod system appears much greater than for a fast system on several levels. Added complexity propagates through the entire program, design, development, fabrication, analysis, testing and system integration thus adding to program development risk.
• Experience considerably more experience exist with small moderated reactors than with small fast reactors. The question is, how much applies to space reactor applications? Water moderated cores may have significantly different neutronic behavior than cores where the moderator is in solid form as in zirconium hydride or yttrium hydride because water density changes can dominate feedback. Reactors fueled with UZrH (uranium zirconium hydride) can provide much better experience base, although if a space reactor uses a moderator external to the fuel, there could be significant differences as well as solid moderator materials generally have been designed and used for very short lifetimes compared with space reactor applications. Space reactor operational experience in the U.S. is largely limited to moderated SNAP, whereas Russian experience involves both fast spectrum (RORSAT) and moderated (TOPAZ) reactors. Any experience can be valuable because near-term space reactors of the future will be very different from any reactor ever operated before and complexity and testing issues may contribute to technical risk more than experience or lack thereof.
• Testing for any premier space reactor design testing is important. Testing issues are significantly different fast spectrum systems come out better in ease of testing. the increased level of uncertainly or potential unknowns means that moderated systems may require a larger and more complex test program than a fast reactor program. However the moderated spectrum have one advantage in this area currently more capability exists to test materials in moderated spectrum than in fast spectrum. Mod reactors are available in the US for irradiation testing whereas fast spectrum in pile testing currently is limited to; a.) placing samples in moderated-spectrum reactors, b.) placing samples in an accelerator-driven test facility the drawback here is of a high-energy (>20MeV) neutron spectrum trail, c.) placing samples in foreign fast reactors [this is the best near-term technical solution, but the drawback of negotiating to use foreign resources on a project that wishes to restrict foreign involvement.]
• Cost and development time most factors point toward fast spectrum system as being lower cost and easier to develop.

Safety and Safeguards there could be many differences in safety and safeguards between fast-spectrum and moderated space reactors.

• Safety likely the largest fraction of safety risk of any space reactor program will be associated with potential nuclear-powered ground tests (note: a large fraction of a very small safety risk is still a very small safety risk). A fast spectrum system should require less and/or simpler nuclear operational testing as would be the testing path would be known from reactor behavior adding to confidence this could reduce the overall probability of a safety issue. The best safety case would be to design a system that could in confidence develop without a nuclear powered ground test, but this would be a significant challenge (less so for a fast-spectrum system compared to a mod system). The other major aspect of space reactor nuclear safety is transport and launch accident safety. Fast reactor systems have two advantages; 1) the fast spectrum system requires less excess criticality because of the temperature defect (change in reactivity from ambient to operating temperature). This reduced excess criticality results in a smaller Delta-k between nominal and flooded conditions, which is an easier condition to meet. 2) given the nature of material neutron X-sections, a faster spectrum can take better advantage of an intrinsic safety ( i.e.,no moving parts) approach. Core materials, such as Nb-1Zr and rhenium, have very low cross sections in the fast spectrum region but moderately large cross sections in the epithermal region. Intrinsic safety offers, high reliability and robust safety approach. If a thermal system could be designed to be fully or overly moderated, it would have an advantage, but would be impractical for this size of reactor. One area where a mod system has an advantage is that the fission yield should be substantially lower for accidental criticality event than for a fast system.
• Safeguards is essentially the only area where a moderated system could have a clear advantage. Mod systems can use a lower quality U235 either in less highly enriched uranium (HEU) or potentially a lower enriched fuel. The only potential advantage would be if a system could be designed that used lower-enriched fuel. It might be very hard to design and develop a 'practical' space reactor with 20% enriched fuel. However, there appears to be significant safeguards advantage if the reactor can be designed with 50% enriched fuel and reduce costs and schedule implications of safeguarding fuel.

REACTOR APPLICATIONS

• Power for NEP Missions will call for high temperature (>1000K), long-life (>10yr.), low alpha (mass/power), vacuum/micro-g environment, shadow/spot component shielding and several other requirements. High temperature is often the most important parameter for NEP missions because of how it impacts overall system alpha, most importantly power conversion efficiency and heat rejection temperature. Fortunately, operation is assumed to occur in a vacuum environment, which allows high temperature refractory metals to be considered. Temperature is the key variable to performance.The strong emphasis on low-system alpha also tends to lead toward higher powers for NEP missions (>100kWe).
• Surface power missions. Reactors that will need to operate on Moon and Mars, the requirements will call for relatively low temperatures (<1000K), short lifetime (<10 yr.), thick shields,compatibility with atmosphere and relatively low power (<100kWe). Temperature should be kept low to allow materials to be used that are compatible with whatever atmosphere encountered; also alpha is not too important for surface system. Mass is important for launch and landing, but not for acceleration, for crewed missions, the power for a reactor module might be only in the range of 25-to-50 kWe, and robotic mission could have powers <5kWe. The potential need to surround the reactor with substantial shielding would favor a more compact reactor with a lower flux. Based on generic requirements and the discussion above there is no clear advantage for either a fast or mod reactor, The development risk may be smaller for a fast-spectrum system, but performance could be better and/or programmatic risk (e.g. safeguards) could be lower for a moderated system.

Conclusion: Unless safeguards becomes the dominant program risk design factor, a fast spectrum reactor appears better suited for the majority of space reactor applications. However, in some cases, such as low power (<100kWt) surface reactor, a moderated spectrum could provide a better approach.

~~+++~~

• Development in advanced Radioisotope Power Systems (RPS's).
• Studying advanced nuclear power and propulsion.
• Start up of the first Prometheus flight program the Jupiter Icy Moons Orbiter (JIMO) and its nuclear-electric propulsion (NEP) system.
• Research in nuclear power systems as a means to provide auxiliary power for spacecraft in transit for example, life-support and other spacecraft systems operations. The required power in support of activities on the surface of Moon and Mars.
• Exploring the use of much larger nuclear power systems in support of NTR (Nuclear Thermal Rocketry) and NEP (Nuclear Electric Propulsion) systems for human exploration activities beyond the Earth-Moon system.

NASA asked the the NRC for a two point study.

1. Identify high-priority space science objectives that could be uniquely enabled or greatly enhanced by the development of advanced spacecraft nuclear power and propulsion.
2. Make recommendations for an advanced technology development program for future space science missions employing nuclear power and propulsion capabilities.

The National Research Council has tackled the first point in this report. They used goals and priorities from their own previous decadal survey's for solar system exploration, solar and space physics, astronomy and astrophysics. These predate the creation of Project Prometheus they feel the scientific community consensus they embody make them compelling guides to identification of high-priority science activities in their respective disciplines. The report found that none of the missions identified in the decadal survey state as priorities for implementation in the coming decade explicitly require NEP technology. But these reports are not all silent on the need for and use of nuclear space power and propulsion systems. Both the solar system exploration and space physics surveys also call for the reopening of RPS production lines and NASA assign high priority to NEP development. The most recent astronomy and astrophysical survey make no recommendation concerning the use of nuclear power and propulsion systems.

When dealing in contributions of nuclear power and propulsion to the space sciences. The Solar/Space Physics and Solar System Exploration (SSP/SSE) communities seem far more in favor of nuclear potential in space than Astronomy and Astrophysics (AA) communities, excluding some possibilities for nuclear use to service e.g, Binary-Star Gravitational Telescope and Solar Gravitational Telescope.The AA community feels that serious issues...e.g, the effects of man made intrusions to scientist's "free space" medium of high-energy particles like gamma rays and waste heat from nuclear reactors on sensitive astronomical detectors skew results. Reminiscent of picky concerns the community has over city light and electromagnetic frequency pollution debates of the past.
The SSP/SSE communities want nuclear power and propulsion NEP/NTR and RPS to service such missions as:

• Solar Coronal Cluster
• Long-lived Venus lander
• Long-lived Mars network
• Jupiter Magnetosphere multiprobe mission
• Cryogenic Comet Sample-Return mission
• Titan Express/Interstellar Pioneer
• Neptune-Triton System Explorer
• Solar System Disk Explorer
• Interstellar Observatory

So, the NRC has made primary finding and recommendations; "Nuclear power and propulsion technology appear, in general, to have great promise and may, in some senses, be essential for addressing space science goals in future decades." They also raise concern over "scientific utility" NASA's ability in current nuclear research and development in its technological approach and integration of a new class of large, heavy and potentially very expensive nuclear missions into its diverse and healthy mix of current missions.

Specific recommendations include the following:

• Nuclear power and propulsion technologies appear, in general, to have great promise and may in some senses, be essential for addressing important space science goals in future decades. This is particularly true for the fields of solar and space physics and solar system exploration, and especially  so with respect to near -to- mid-term applications of RPS systems.
• NASA should expand the development and application of RPS technologies.
• Nuclear propulsion technologies will likely be used initially for moving relatively large scientific payloads(~1000s of Kilograms) to destinations in the outer solar system and beyond and extremely large payloads (~10,000s Kilograms) in support of human exploration activities in the inner solar system. Alternative technologies, such as NTR and bimodal systems may provide a more cost effective means of transport to the outer solar system and beyond.
• NASA should commission detailed, comprehensive studies-supported by external independent reviews and the broad participation of the space science and technology communities to examine feasibility of developing space nuclear propulsion technologies with reduced transit times and costs, in order to get the greatest benefit for the NASA community.
• Cost of developing advanced power and propulsion technologies must not preclude diversity of other space science missions recommended.
• Essential NASA communicate clearly and openly with the public regarding the potential benefits and challenges posed by the use of nuclear space power and propulsion. The agency and its partners must avoid the denial of risks and neglect of impacts, or perception thereof. NASA adopt a very proactive stance and role in the management and integration and future foreseeable processes of assessment and decision making that will undoubtedly influence public opinion concerning environmental and safety risks associated with the use of nuclear power and propulsion systems in space.
• With regard to fission reactors are likely to be useful in providing long term power for human activities on the surface of the Moon and Mars. Surface power are in practice likely to be very different from shipboard reactors and will require separate development programs. NASA should reexamine the technology goals of Project Prometheus for both human and robotic propulsion requirements.
• NEP/NTR class spacecraft are inherently massive and as such, will require either in-space assembly following multiple launches on the largest launch vehicles currently available, or a single launch on a new heavy-lift booster. A new heavy-lift launch capacity would potentially enable new classes of space science missions. [nasa CEV/lunar plan]
• Nuclear space science should be in service to: provide fraction of payload launch for general space science, power Deep Space Network Grid & Planetary Data System, provide radiation-hard components/radiation-tolerant detectors and contamination mitigation for instruments.

As noted previous foreign government and organizations with expertise in the field of nuclear space science could go along way in improving cooperation and success in a project of this magnitude. In fact this is already being done on fusion reactor research in France (ITER). Institutes like Rand Corporation and the Club of Rome could lend assistance to a "Space Nuclear Commission" structure that would benefit each member. Mega projects in space need wide support technically and financially in order to succeed.

BALANCE FOR SUCESS BETWEEN PRIVATE INDUSTRY AND GOVERNMENT IN SPACE

 NASA is finding a tough road ahead in fiscal budget woes and its flights of the space Shuttle. It seems to rivet an eager public to learn about the trials and tribulations of working a spacecraft launch system in constant upgrade and repair, fortunately return to flight STS 141 was a successful flight. Not what was envisioned or the best light for an agency that is suppose to be about a renewed spirit of discovery, inspiration and exploration following the Shuttle Columbia mishap.
  Still according to a CBS/Gallup poll, "Americans continue to show solid support for NASA's plans to explore, discover and understand our universe by returning the Space Shuttle to flight, completing the International Space Station, and sending robot probes and humans to the Moon, Mars and beyond. " They offer that almost 3/4 (77%) of the American public want to support a new plan for space exploration that would include a stepping-stone approach to return the space shuttle to flight, complete assembly of the space station, build a replacement for the shuttle, go back to the Moon and then on to Mars and beyond. The problem it seems is Americans don't seem to want to pay for mega projects that create infrastructure in space or in education or transportation because it goes against what has been preached for years, "If it doesn't have quick pay off's in my lifetime... don't bother with support ". In fact the same poll says, "When it comes to NASA's budget, almost three-fourths (73%) of American adults surveyed think NASA's budget should remain at its present level (36%) or be increased (37%)."

 

  Some private operations in space have some success Space Adventures Ltd. is a company that has and is offering the opportunity to get involved in a big way and you don't have to be a member of an elite trained official astronaut corps, just the finances, energy and will to be the ultimate space aficionado to experience the space environment. These are welcomed measures, but in reality only a concerted effort by both private industry and government will spaceflight be open to more people than what is currently allowed. In order for this to happen major steps in building systems that can provide moving in comfort and safety large numbers of trained people to a Lunar or Martian destination as well as provide habit for temporary and permanent stays requires nuclear facilities be built on the ground and in-space infrastructure to accomplish. Currently this can't be done any other way without the use and development of space nuclear science and technology in fission, fusion and antimatter disciples in science. We need to be taking steps toward development now. No one is more aware of the future that nuclear potential brings to the table to open vistas for people of our solar system than CEO of Space Adventures Ltd. Eric Anderson.

I recently had a chat with Mr. Anderson this summer.

Bruce: Welcome Mr. Anderson to nuclearspace.com you are president and CEO of Space Adventures, Ltd., the only company to have sent paying passengers to space by arranging orbital flights for space tourists to the ISS and your company now wants to expand its influence into providing Lunar excursions. Space travel aficionados, no doubt admire the effort and energy that Space Adventures applies to flight preparation, training and arranging flights for individuals who qualify. As you say, "Space travel is a form of Exploration." Realistically speaking 'Destination' and the 'Travel the experience' are metrics that people understand as worth the risk and investment.
As you know with respect to space power and propulsion we still live in an era of the "Horse and Buggy" in a "Supersonic Age". The world's leading government space faring agencies including our own are finding it hard to garner support from their respective Public.
NASA at the moment is suffering the consequences of decisions made long ago to stand by an aging launch system that experiences unpredictability, it makes for exciting press, but its not the type of attention space faring agencies crave. They would like missions to be associated with solar system science understanding, predictability in transport for humans and the attitude they can accomplish the near impossible. Private space venture interests such as yours are inextricably tied to the success and failure of government owned space systems performance. Major infrastructure building such as advanced optic communication deep space grid and most importantly the means of providing power and propulsion to bridge our solar system remain the subject of reports and proclamation, but short on realistic budget and preparation for projects that aim to address the necessities of a robust vision in space.
The use of nuclear power and propulsion remains controversial, but unavoidable in the near term to service this wider vision in space.
What position do you take with regard to this technology for use in space, and what can a space travel agency do with its industry and government partners to bring back that sense of excitement in space travel and exploration to the general public?

Mr. Anderson: My position is that all available options should be explored in terms of developing the infrastructure, technologies and energy systems to enable the human expansion into and the development of space. I can not see the scenario that does not include nuclear energy in the long run for that goal. There simply aren't other types of energy that could be used in a manner as efficiently or as beneficial as nuclear energy both in terms of the long term power requirements and even propulsion technology for space travel. Solar energy is wonderful, but the energy density of solar electrical power is dependent on proximity to solar light and storage capability. Any spacecraft propelled by solar energy would take a long time to travel to a planet which is not true for nuclear energy to power a spacecraft with nuclear thermal energy which is the least efficient nuclear reaction. The real key is that fifty to a hundred years from now or maybe less is finding ways to utilize fusion energy, to contain it to harness the power of fusion because that's nature's most efficient way of converting mass into energy... we'll see if these things come to pass. Of course, we're never going to get there unless we start somewhere. In terms of short term projects, I'm totally in favor of advanced research using nuclear energy and demonstration technologies that use nuclear power rockets from low Earth orbit to deep space. Trying ways to contain the element of fusion energy, going to the Moon looking for Heluim 3...I think it's great !

Bruce: Some of our readers have raised and interesting question. Would it be legal to have a privately funded and controlled nuclear reactor in space? For example, if Burt Rutan were to construct a craft in orbit that was powered by nukes, would there be anything illegal about it?
If we are to colonize space meaning, civilians living in space... eventually we are going to need nuclear powered private vehicles (non-NASA, non-USAF, non-USN).
Personally, I'd find it hard to criticize the NRC in light of their excellent record of licensing and monitoring safe operating U.S. nuclear power plants despite rare innocuous incidences... that said, U.S. companies that build nuclear reactor plants complain that complying with NRC regulations toward approval for licensing comes at a high cost. Delays in licensing the federal nuclear repository at Yucca Mountain and excessive non-proliferation guidelines that shape U.S. laws with regard to reprocessing and re-cycling spent nuclear fuel in an effort not just to separate and store, but to use waste of high level radiation and "Tranuranic Waste Actinides" for fuel in nuclear fast spectrum reactor power plants to generate electricity. Measures that bring nuke fuel cycles to closure toward shorter half life isotopes and thus relieve the burden of filling Yucca Mountain with high level radiation waste.
Would you be in favor of space nuclear technology in providing advances to U.S. industry and in government participation to offset these financial costs so in the future private U.S. companies wishing to provide services in space would be licensed to safely operate a space nuclear fast spectrum reactor for power and propulsion?

Mr. Anderson: I think, much like other advanced projects that private companies undertake that have the potential to be dangerous and/or critical for national security is certainly feasible and should be allowed, but it has to be overseen by an appropriate group of regulators. You don't want rouge nuclear companies playing around with energy or nuclear material in space or on Earth...you don't want anybody doing that. Certainly Boeing builds missiles, Lockheed builds warplanes lots of companies contribute components that are "Hot Potatoes" nevertheless they're also important to defense and exploration for a lot of things. Energy companies have the right to use technologies to drill thousands of feet into the Earth doing so being environmentally responsible. These are issues we can overcome. Private companies should absolutely be permitted to participate given their threshold of capability and credibility.

Bruce: Some months ago the American Academy of Arts and Sciences published a study entitled: "United States Space Policy Challenges and Opportunities" it noted four barriers to U.S. progress in space science and exploration: the strict regulation of satellite exports as munitions under the State Department rules, a projected shortfall in the science and engineering workforce, unrealistic plans for NASA’s future space missions that neglect the important role of science, and faltering international cooperation on existing and planned space missions. These barriers, according to the papers authors, George Abbey and Neal Lane, will have to be overcome if the United States space program is to succeed. They urge the United States to strive for a “balanced program of commerce, science, exploration, national security and shared international partnerships.”
On the point, "Projected shortfall in the science and engineering workforce." When it comes to educating and training young people for this expanded vision in space activity. Faced with cutbacks in science education for example, at NASA, deficiencies in the Department of education's policy of "No child left behind". How would you reverse this trend to give young people career options toward science in non-offensive pursuits rather than ones that stress war and conflict since the paper draws the conclusion, “...A paradoxical picture of high ambition and diminishing commitment.” ?

Mr. Anderson: The way I would reverse this trend is through three points:

1.) To continue to do things that generate positive publicity and public opinion for space exploration that inspire people to show that one day people will be able to go to space themselves as private citizens. That's inspirational. That's the kind of inspiration that gets kids to study more science and technology to get into those types of fields.
2.) To provide opportunities for students to work with us. We have intern programs were people come and work for us every summer.
3.) Promote the participation of youth in our programs themselves. The outer space tourist programs on Earth like, "Zero Gravity Flights", jet rides to the edge of space, spaceflight club memberships and to promote this not only to the existing adult market, but to the youth market as well. So people can get a taste of what's out there in the future...right now.

Bruce: Thank you very much Mr. Anderson for this interview.

USE OF SPACE NUCLEAR SCIENCE SAGA WILL CONTINUE

So, the question begs an answer. Is space nuclear science any closer to mission in space? No one can say for sure officially if a premier fission space reactor in either NEP/NTR or bimodal form for civilian use is closer to mission in space. One glaring fact remains if we are in this corner of the universe members of the only sentient master tool makers with reason and intellect continue to delay its full use in the near term in space. It may make the difference between a vacant view of an undiscovered solar system or a vibrant solar system in full bloom to a human diaspora making it possible to bridge other stellar systems that hold the promise of human habitability.