Isotope separation

Atomically precise technology may make radioactivity more controllable (a bit)

Atomically precise technology is likely to make separation of isotopes of an element (same ordinal number same element same chemistry but different mass) much easier.

This is relevant since:

• In the long term radioactive waste can be transmuted away down to zero without spill.
• Legacy radiation spills can be cleaned up a bit better. (note that APT is no no magic wand!)
• Dangerous individuals could make nuclear bombs.

Methods for separation

Sorting atoms by differences in mass instead of differences in chemistry (even if the mass difference is rather tiny) shouldn't be a hard problem for advanced AP systems. Single molecules have already be weighted with tuning forks of today's (2014..2016) technology. A question is how much throughput will be possible.

Possible methods for determining the mass of an atom are:

• de-tuning of a tuning fork
• deflection in E & B fields - densely packed mass spectrometers (Wikipedia: [1])
• necessary centripetal force while spinning
• ...

Limits of the separation capability

Nuclear excitations can have low energies way below the mass equivalent of one whole nucleon or even electron. Thus there is the question how fine compact (e.g. microscale sized) high throughput mass detection sensors will resolve mass. Detecting the presence or non-presence of the mass equivalent of one UV-A quantum in a 100amu nucleus seems very challenging. (TODO: investigate this challenge)

Issues with free flying atoms

Atoms can be sorted by using electric and or magnetic fields to deflect a beam of unsorted atoms that have all the same speed (they are monochromatic). Replicating this method with high throughput in advanced atomically precise processing cells that are as small as possible is a very different problem though. (TODO: investigate this further)

This is related to the topic of "trapped free particles".

Isotope separation in normal operation of advanced gem-gum factories

(TODO: Compare the damage rates stemming from radiation caused by decays of built in atoms to the damage rates stemming from external terrestrial and external cosmic radiation.)

Radiation damage rates with in advanced gem-gum products and factories will be manageable. (Some info in Nanosystems: 6.6. Radiation damage)

• Checking every single atom on radioactivity before usage would very likely sow down the production process noticeably.
• Checking every single atom on radioactivity before usage may not provide much benefit in most practical applications located in earth's average background radiation. (To confirm ...).

If these guesses are right advanced gem-gum factories will not check the used atoms individually for radioactivity in normal usage situations. (Specialized food synthesis devices might be an exception)

(Note: "radioactive" atoms are not permanently radioactive. They are dormant waiting to release a radiation "particle" with some constant likelihood per time interval. When they've released this "particle" they may or may not become an other element and they may or may not become non-radioactive.)

In ultra low radiation environments (where even the massive shielding material has been filtered atom by atom) filtering atom by atom will likely be very beneficial for some exotic experiments. The theoretical extension of product lifetime due to lower radiation induced damage rate caused by the exclusion of radioactive atoms and shielding against external radiation is likely irrelevant since the normal levels can be covered by active self repair anyways.

Effects of the isotope separation capability

Good consequences

Cleaning air and food

Indoor air can be cleaned from (hopefully only naturally occurring) radioactive contents like radon - a noble gas. Spill from nuclear fission accidents like iodine-131, caesium-134 and caesium-137 accumulate in dust too.

If there's radioactive dust particles in the air they collect in air filters. Those dust particles could be evaporated or dissolved (preferably micro-chambers) and radioactive atoms could be brought under control (converted to trapped free particles / brought into machine phase) and separated according to type (element, isotope, nuclear excitation state). Bringing back unordered matter into ordered one is one of the harder problems for APM. See: "Atomically precise disassembly". Similar problem to mining of the lithosphere.

Sayonara to nuclear waste

Getting rid terminally of all the nuclear waste via nuclear transmutation really may become possible.

The process of transmutation is basically about converting radioactive elements to non-radioactive ones faster than they would decay naturally by irradiating them with other forms of radioactivity. This process would technically be possible even with today's crude non AP technology like the recently revived old thorium reactor concepts. (Transmutation will work even better with the massive amounts of neutrons once fusion reactors start working.)

• A real fuel cycle with zero exhaust instead of today's pseudo-"cycle".

The real unsolved problem where non AP technology is bound to fundamentally fail is chemical and especially isotopic separation of the fission products without contamination more and more material and spilling some too.

The isotope separation capability of gem-gum technology would allow to solve the core problem here. Instead of separating with the usual chemical rations (often as low as 10:1) and having the non radioactive stuff still being nuclear waste one can seperate with digital bit error ratios where the non radioactive stuff coming out has far lower radiactivity than even natural background radiation.

Additionally before and after separation one can have an atomically tight (atomically here in the chemical sense as always on this wiki) fuel cycle not releasing a single tritium atom even in the most volatile hydrogen gas form.

• Mechanically safe intermediate short term storage containers (high radiation robust amorphous/metamict inner radiation absorber lining & highly mechanically resilient but more radiation sensitive gem-gem metamaterial shell.)
• Although then not necessary anymore: Ultra long storage container stability via active self repair. (See pages: "Disaster proof" and "Artificial life").

For more info check out the main article: "APM and nuclear technology".

Bad consequences

While Its nice to get rid of all the radioactivity in your breathing air you simultaneously collect high levels of radioactivity in your collection device. High level radiation sources are emerging. Those could be misused by dangerous individuals (security risk).

Really bad consequences

There's plenty of Uranium ore around. What prevents small groups or even individuals from making nuclear bombs is mainly the difficulty of separating the fissile Uranium-235 from the fertile Uranium-238. Currently (2016) the most efficient method to do this is with very large multi stage centrifuge plants. Problematically this kind of isotope separation capability might become desktop scale with atomically precise technology. Obviously this should be regulated. But can it be regulated? Don't panic! Premature and hasty alarmism may cause more damage than the actual problem. For now check the page about Poisons for a minimal discussion on the actual degree of danger.

Other radioactive element isotopes that have a critical mass could potentially be enriched to that point too. (Wikipedia: critical mass). The on average high dilutedness of natural radioactivity (e.g. in air, bananas and whatnot) may make that unpractical though.

Not every radioactive isotope has a critical mass. The most abundant radioactive element is thorium. Its mostly the isotope (²³²Th which has no critical mass. The isotope ²²⁹Th with critical mass is contained only in a small fraction.

Many of the more abundant heavier elements contain a significant fraction of radioactive isotopes Leading the chart are potassium and barium. (TODO: find out what the most abundant and most acessible radioactive isotopes are that have a critical mass)

Other stuff that could be enriched for whatever reason: ¹⁴C, ...

Speculative applications

Creating ultra low radiation environments. By enriching non radioactive isotopes and using exclusively those to build up AP systems one can get rid of internal radiation sources. To get rid of high energy radiation coming from outside (Wikipedia: [2]) big scale isolation facilities may be used. Mountains or in the extreme whole asteroids. There will still be particles penetrating like e.g. neutrinos. Related would be systems for the creation of unprecedented low temperatures to search for yet unkown aspects of (quantum) physics.

ultra high isolation experiments - makroscale superposition and entanglement

Related

• Radiation damage
• APM and nuclear technology

External links

• Wikipedia: Uranium can be drawn from sea water [3]