Placeholder, SPQS Universe

The Science of Placeholder, Pt.4

I have always felt that nuclear power was our future, because the power of the atom is undeniable.  But power that great needs to be respected, controlled, and very carefully monitored.  The current tragedy in Japan is a fair enough example of that, but the Three Mile Island and Chernobyl disasters should have been more than enough.

Fine, everyone knows that fission is dangerous and finicky, but if you treat it with the respect and care it deserves, meltdowns, coolant leaks, and gas explosions can usually be avoided.  And again, as the current tragedy in Japan has reminded us, if you build a reactor in an earthquake zone, you should make a point of earthquake-proofing it.  And if that cannot be reliably done to protect against the worst-case-scenario, then you should consider an alternative source of power.

Fusion reactors are a much better option, but unfortunately, they are still only experimental.  The proposed designs are similar in principle to fission-based power plants, but the primary hold-up is sustaining a thermonuclear reaction long enough to produce a reliable source of energy.  The two best approaches to confinement of thermonuclear reactions available today with present technology are magnetic and inertial.

The largest magnetic-confinement fusion reactor currently under construction is the ITER tokamak in Cadarache, France.  It is worth looking into: iter.org

The largest operational inertial-confinement fusion reactor is the NIF.  It uses lasers to ignite the tritium-deuterium mix.  You can check it out here: lasers.llnl.gov

As for the safety of fusion reactors over fission reactors, Wikipedia has a remarkably good summary with cogent points.  It is available here: en.wikipedia.org/wiki/Fusion_reactor#Safety_and_the_environment but I will also quote the first section of it for your benefit in case the article is ever tampered with or moved (all the links within the quote point back to relevant articles on wikipedia).

Accident potential

There is no possibility of a catastrophic accident in a fusion reactor resulting in major release of radioactivity to the environment or injury to non-staff, unlike modern fission reactors. The primary reason is that nuclear fusion requires precisely controlled temperature, pressure, and magnetic field parameters to generate net energy. If the reactor were damaged, these parameters would be disrupted and the heat generation in the reactor would rapidly cease. In contrast, the fission products in a fission reactor continue to generate heat through beta-decay for several hours or even days after reactor shut-down, meaning that melting of fuel rods is possible even after the reactor has been stopped due to continued accumulation of heat (Fukushima I incidents demonstrated the problems that can rise in a fission reactor due to beta decay heating even days after SCRAM, an emergency shutdown of the fission reactor).

There is also no risk of a runaway reaction in a fusion reactor, since the plasma is normally burnt at optimal conditions, and any significant change will render it unable to produce excess heat. In fusion reactors the reaction process is so delicate that this level of safety is inherent; no elaborate failsafe mechanism is required. Although the plasma in a fusion power plant will have a volume of 1000 cubic meters or more, the density of the plasma is extremely low, and the total amount of fusion fuel in the vessel is very small, typically a few grams. If the fuel supply is closed, the reaction stops within seconds. In comparison, a fission reactor is typically loaded with enough fuel for one or several years, and no additional fuel is necessary to keep the reaction going.

In the magnetic approach, strong fields are developed in coils that are held in place mechanically by the reactor structure. Failure of this structure could release this tension and allow the magnet to “explode” outward. The severity of this event would be similar to any other industrial accident or an MRI machine quench/explosion, and could be effectively stopped with a containment building similar to those used in existing (fission) nuclear generators. The laser-driven inertial approach is generally lower-stress. Although failure of the reaction chamber is possible, simply stopping fuel delivery would prevent any sort of catastrophic failure.

Most reactor designs rely on the use of liquid lithium as both a coolant and a method for converting stray neutrons from the reaction into tritium, which is fed back into the reactor as fuel. Lithium is highly flammable, and in the case of a fire it is possible that the lithium stored on-site could be burned up and escape. In this case the tritium contents of the lithium would be released into the atmosphere, posing a radiation risk. However, calculations suggest that the total amount of tritium and other radioactive gases in a typical power plant would be so small, about 1 kg, that they would have diluted to legally acceptable limits by the time they blew as far as the plant’s perimeter fence.[12]

The likelihood of small industrial accidents including the local release of radioactivity and injury to staff cannot be estimated yet. These would include accidental releases of lithium, tritium, or mis-handling of decommissioned radioactive components of the reactor itself.

— Wikipedia.org, “Fusion Power” Pt. 3.1

As you can see, fusion reactors are much, much safer than fission reactors, and meltdowns are effectively impossible.  And once tritium containment is perfected so none whatsoever leaks into the atmosphere, it will be the cleanest, safest, and most abundant source of energy ever known to humanity.

We must not forget atomic batteries either.  They’re called batteries because they are portable, self-contained sources of energy, but in actuality they should be called nuclear-decay generators.  They represent a highly customizable technology, and currently can be made as small as a penny (for liquid semiconductor atomic batteries)—select your energy requirements, match it to an appropriate isotope, and stick it in the most efficient package for your needs.  Betavoltaic cells are one great option.  They rely on beta-decay, so don’t need much shielding at all.  The isotopes they use generally have really low alpha and gamma radiation, so even if you break them open (which is still a dumb idea, but I’m just saying), the harm is minimal.  And the best part?  We can customize atomic batteries to suit our current needs, swap out the chemical batteries and pop in an atomic, and we suddenly have mobile devices that never need to be charged.  Just swap the battery once the half-life of the isotope expires.  For some, that can be as high as 140 years (even longer, if your energy requirements are lower than normal, and the decay product of the isotope continues to produce enough of an electric charge).  The isotopes keep decaying at high energies for centuries.  The problem is actually not with them, but with the semiconductor material.  It breaks down over time, as the decay particles pass through it to produce a charge.  Obviously, liquid semiconductors are better than solid, and will last substantially longer.  This sort of technology will allow for stable, long-use portable power, in basically any environment, and at least 90% of the components (including all of the reaction mass) can be recycled.

Now that I’ve talked a little about the current options for nuclear power, I can get on to my actual point.  The use of nuclear power and propulsion in Placeholder.

 

(Spoiler Alert!  The rest of this post discusses technical details of Placeholder’s plot and primary characters.)

Nuclear Energy in the SPQS Universe:

The political system of the SPQS is (obviously) imperialistic with a transnationalist economy.  The military controls the civilian government, and education is restricted to military personnel.  Furthermore, higher education is restricted to Officers.  The best that a civilian can expect in this world is grade school (elementary), plus some trade school in their teenage years.  Every citizen of the SPQS is given rigorous personality, aptitude, and IQ tests throughout their childhood, plus a final placement test shortly before their twelfth birthday.  This is a very nasty system and means no freedom for anybody, not even the privileged Officer-class.  The Military government controls all resources, all supply lines, all employment, all education, and even all religions.  But it is functional, insofar as the safety and welfare of the human race as a whole is taken care of, and communist-style rationing isn’t necessary because a transnational military government has full control over nuclear energy (and weapons), and doesn’t have to answer to anybody.

Any functional government has to also promote loyalty within its citizenry; while a military government can often be cruel and cover it up with propaganda, it’s actually easier to play nice with the people who can’t get up to much trouble in the first place.  Your average citizen actually wants safety and comfort above freedom and education, as sad as that may seem to some.  So long as they are ultimately left to live their life in peace, have their needs and comforts attended to, and can find some amusement to distract them from their work (even if they happen to love their work), then society as a whole will remain stable.

Now, this point is important.  Nuclear power is perceived as dangerous, and has to be treated with respect and care.  Who better to be the stewards of the atom than our soldiers?  They are disciplined, sharp, used to an undue amount of stress that would make a normal person crack, and ultimately, extremely responsible individuals with a great respect for authority.  They are also willing to lay down their lives for a greater cause—a fact most civilians can’t even appreciate.  With specific training in nuclear engineering, they are the perfect candidates to work in a reactor.  So having nuclear power exclusively in the hands of the military might not be such a bad thing.  It would certainly boost public confidence in nuclear power.

Of course, even if the people didn’t like it, a military government could impose it’s own ideals on society.  With enough propaganda, anything is possible.  And a space age society needs nuclear power.  Nothing else is even close to good enough.

I also mentioned a lack of restrictions.  Allow me to elaborate.  There are certain aspects of nuclear energy that are currently unavailable to the general public, and even unavailable to our militaries and research institutions.  Thanks to the Partial Test Ban Treaty of 1963, the Nuclear Non-proliferation Treaty of 1968, and the Comprehensive Nuclear-Test-Ban Treaty of 1996 (which has not yet entered into force), our options for maximizing the beneficial uses of nuclear energy are severely limited.  Inertial confinement fusion is one workaround (which is a stipulation that the US is trying to enforce for the CTBT before ratifying it), because it allows simulation without the need for actual thermonuclear detonation.  But still, any hope of launching a nuclear pulse propulsion rocket, whether from orbit or from earth, was completely crushed by the partial test ban, and only further enforced by the later two treaties.  For feasible interplanetary and interstellar exploration and colonization, we need nuclear pulse propulsion at the very least.  There’s no way around that.  Chemical rockets are too inefficient, wasteful, and expensive to support a successful, active space program.  But that’s what we’re stuck with.  The SPQS has no such restrictions.  They control all nuclear energy, fuels, and weapons, so they can use them to their best ends.  And seriously, what use does a universal-military-government have for nuclear weapons?  They might maintain a stockpile, just in case, but in that situation at least 99% of nuclear R&D would go into power and propulsion tech.

Right now, the only real limitation on atomic batteries is the expense in making them.  NASA uses them when they have to.  They’re a good, reliable, long-term source of energy to power their space probes.  And they’ll certainly come in handy on manned missions to Mars (if NASA ever gets around to doing it).  But as any technology, now that we have it, it will be improved over time and the costs will go down as they become mass-produced.  Right now, atomic batteries are very much ‘special use’, and complete overkill for most purposes.  But as our mobile technology is steadily improved, and power requirements keep raising, the move from chemical to atomic batteries will be a natural one.  Obviously, in the SPQS Universe, atomic batteries are used exclusively, because even the ‘simplest’ devices have advanced AI systems that require multicore processing in a modular computing environment.  Also, they have moved entirely from electronics to optronics (except for a few select people who also have access to quantum computers), and optical computers are only more energy efficient when kept entirely self-contained.  Powering a ship-wide optical computer network with several supercomputer cores is actually very energy taxing, especially when many of the systems are constantly running and all of them need to be kept cooled (in addition to all the other electrical draws from life support, mechanics, internal and external sensors, etc., etc.).  It’s worth the cost though; optical cores are a big step up from our current processing capabilities, and don’t need much of a refinement to the logic behind it (whereas with quantum computers, it’s a whole new science; everything has to be redesigned from the ground up, to harness the unique properties of quantum systems).

Lastly, the SFS Fulgora is outfitted with two fission reactors; instead of hard water, they use an inert pressurized gas to drive the turbines.  The primary reactor is always running, whereas the secondary reactor is only used during peak times when strain needs to be taken off the primary.  The reactors have no connection with the nuclear pulse propulsion rocket, except for powering the systems which make it work.  Most of the electrical power is needed for the MRD, computer systems, and lab equipment.

 

Nuclear Propulsion in the SPQS Universe:

I’ve already talked a bit about Nuclear Pulse Propulsion, but there are other options.  I’ve only focused on nuclear pulse propulsion because that is what the SFS Fulgora is outfitted with.  Within Placeholder, it’s considered barebones backwards tech.  The SFS Fulgora is stuck with it simply because it was the cheapest practical option to meet mission requirements.

I should also mention why the SFS Fulgora needs a rocket in addition to the MRD—after all, it has a jump drive, so why does it need traditional propulsion at all, beyond simple ion drives for shuffling around local space?  Simply put, since they designed the MRD with Relativistic M-Theory in mind, the MRD can only be used to merge two ‘level’ points within spacetime: interstellar space.  The calculated ‘gravity wells’ caused by a star’s gravitational field are strongest within the heliosphere, and thus according to Relativistic M-Theory, are heavily warped regions of spacetime.  When a REZSEQ is performed between two disparate gravity wells, the object itself is reintegrated with massive distortion because of the errors introduced in the calculation of spacetime by the 4n model.  This problem is overcome when Konrad reprograms the MRD with his 11n model, allowing him to jump between stable orbits of planets.  But that is a unique capability of his ship (until the SOLCOM Celestine Corps catches up with him and reverse engineers his work).  Until he reprograms the MRD, though, the SFS Fulgora has to be piloted out of the solar system, beyond the heliopause to level space.  The ship can then only be jumped to a location beyond the heliosphere of another system, and piloted into it.  This requires a robust means of propulsion, to cover distances of up to 100 AUs within 3 months.  No mean feat, let me tell you.  But a nuclear pulse propulsion rocket is capable of achieving velocities upwards of .1c (10% of the speed of light).  After that, acceleration peters out.  The shaped nuclear charges no longer detonate quickly enough or produce enough of an effect to add any additional acceleration.  ie., you’re just wasting fuel at that point.

There are better nuclear rockets, of course.  For example, there are some good designs for fusion rockets and antimatter-catalyzed nuclear propulsion.  But since the SFS Fulgora is supposed to be a low-budget research vessel (without even a proper artificial gravity system), I thought it unlikely that they would go ahead with a top-notch antimatter or plasma-based propulsion system.

 

Radiation Shielding:

Anytime you start dealing with nuclear energy and/or propulsion in spaceship design, you have to think about shielding the crew from it.  But the truth is, most of the harmful radiation astronauts face is from cosmic radiation, not the reactors or engines they might some day get.  Granted, any extra radiation from these sources would only make matters worse, but my point is only that radiation shielding is already an essential aspect of spacecraft design for extended missions.

My solution for the SPQS Universe is the new and exciting field of meta-materials.  It has so much potential that I couldn’t leave it out—but it also requires its own post.  Suffice it to say for now, that I used a choice selection of metamaterials for radiation-shielding.  Combine that with more traditional means of radiation shielding for the reactor and nuclear rocket, and you have a safe and happy crew, unencumbered with radiation sickness and sterility, even on the longest of space voyages.

 

I suppose that about covers it.  My main points have been to identify the risks involved with nuclear energy, but also show how in the ‘right’ hands (emphasis on quote-unquote), it’s actually the cleanest form of energy we have.  It just needs to be respected.  Naturally, we need to have an invested commitment in perfecting fusion technology, so we can start building safer and cleaner reactors; but even fission, when managed properly, is cleaner than coal or natural gas, and is normally much less detrimental to the environment than hydro dams or windmills.  People who build and run fission reactors need to understand that you can’t cut corners with nuclear engineering, because a meltdown is as bad as a dirty bomb.  But again, if they’re built to standard, and managed with vigilance, they are exactly what we need to step into the future we’ve always dreamed of.

And as far as Placeholder and the SPQS Universe is concerned, I made my future history dominantly atomic because it’s still the best source of energy we have.  Maybe someday we’ll discover something better, but every other avenue that’s been explored requires more energy input than we can get back (such as with the models for antimatter-based power plants).  But you never know.

In my next post, I’ll deal with the new field of meta-materials.  It’s an especially exciting topic, since it’s such a new field that it hasn’t gotten much treatment in science fiction yet.  And in the SPQS Universe, it’s fundamental to just about everything.

— the Phoeron

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