Years ago in the Golden Days of MegaTraveller, power plant discussions abounded on the early version of the Web. I gleaned the following from the TML and thought I'd post it here to add some discussion points. I'm not saying this is the answer to how power plants work but it did come in useful in a couple of my campaigns for some players who thought the details were "good enough for play". We also used the assumption that most of the hydro fuel was used for cooling dumps.
Traveller Tech Brief: Nuclear Fusion Reactor System
Original Author: J. Duncan Law Green
Modifications to Original Article: David Smart
Additional Ideas Taken from Discussions by: Peter Brenton, Tom Lane, Doug Sinclair, Jim Choate, Eric Freitas, Garry Ward
------------------------------------------------------------
Abstract
This article will attempt to set out, in some detail, the anatomy of fusion reactor systems in Traveller (more specifically, those used as starship power plants), the fusion reactions they use, their most common failure modes, and the methods and expected results of sabotaging power plants.
Regular or Super Unleaded?
The standard Traveller references on power plants (the Starship Operator’s Manual published by Digest Group Publications being the most instructive) state that the fusion reactor is fueled by "hydrogen." What they fail to state is that there are three different isotopes of hydrogen, with quite different abundances and nuclear properties. These are:
1H (Protium): Stable (non radioactive.) Consisting of one proton and one electron, protium is by far the most abundant isotope in the Universe.
2H (Deuterium): Stable. Consisting of one proton, one neutron, and one electron, Deuterium is present to an abundance of approximately one part in 5,000 in "natural" hydrogen extracted from seawater.
3H (Tritium): Radioactive. Decays to Helium 3 by proton emission with a half life of 12.5 years. Consisting of one proton, two neutrons, and an electron, Tritium's natural abundance is negligible it has to be "manufactured"
by a variety of possible routes.
Current research on fusion power production is concentrating on deuterium deuterium, deuterium tritium, or deuterium Helium 3 fusion, as these require the lowest plasma energies. At first, this suggested that Traveller power plants were standard deuterium tritium reactors, but further examination of Traveller texts has ruled this out. The reasons for this are detailed below.
Wot? No Tritium?
The first reservation is based on the health and security hazards involved in handling large quantities of radioactive material such as tritium. Starport scenarios make no mention of the necessity of shielding fuel lines or storage tanks! Also, tritium is important in the manufacture of "clean" or laser triggered fusion warheads one would think it is the Imperium's interest to regulate the sale and supply of tritium.
Second, there is a serious problem with wilderness refueling, whether it be from oceans, gas giants, or Oort clouds. The references state that purification plants are intended to remove "trace" impurities which may interfere with the operation of the reactor. For a deuterium fueled reactor, however, 4,999 parts in 5,000 of the fuel intake is impurity." Ships without a purification plant would be in serious trouble.
Third, the scenario "Wrong Way Valve" in Challenge #31 specifically states that a starship's fuel tanks are filled with ordinary water. (It makes no mention of the repeated electrolysis necessary for deuterium separation.)
Thus, it is clear that Traveller fusion reactors are remarkable devices which can be fueled by "natural" hydrogen (primarily protium.) I say remarkable, because the plasma energy and magnetic confinement requirements for protium fusion (via the "proton proton" chain, as in the center of the Sun) are several orders of magnitude greater than those for other types of fusion. It seems the only way to duplicate this process is to construct a reactor the size of a small star! However, there is still hope ....
C, NO Other Way
As stated previously, it is believed that the sun produces energy by fusing protium via the "proton proton" chain. Some giant stars fuse hydrogen by a different route, known as the "CNO catalytic cycle", so called because isotopes of carbon, nitrogen, and oxygen participate in the nuclear reaction, lowering the plasma energy sufficiently for it to become a practicable proposition. The CNO catalyst is not consumed in the reaction, and only relatively small amounts are necessary to produce sustainable fusion. Details of the cycle are shown on the next page.
12C + 1H > 13N + y
13N + 1H > 14O + y
14O > 14N + e+ + y
14N + 1H > 15O + y
15O > 15N + e+ + y
15N + 1H > 12C + 4He
Note that the reaction results in the creation of Carbon/Helium-based “ash” (12C + 4He). The buildup of carbon/helium ash is slow, but if it isn’t removed on a regular basis it can cause the energy output to drop, as fewer reactions are occuring. Also, in a fusion reactor, the biggest problem is ablative effects on the inner surface of the reactor vessel from the high-velocity impacts of the particles that escape the magnetic bottle. Removal of the ash and relining of the reactor vessel are usually accomplished during annual maintenance.
Anatomy of a Traveller Fusion Reactor
All starship power plants possess a small "purification" plant known as an HHSU (Heavy Hydrogen Separation Unit.) This unit partially separates the deuterium from a small volume of the fuel. The deuterium enriched fuel is used when the reactor is in "warm start" or "park" mode. Because the reactor uses deuterium deuterium fusion in "warm start" and CNO fusion in normal operation, it is known as a split cycle or twin cycle reactor.
The components of a starship reactor system are discussed below.
1. Containment Vessel: A highly rigid vessel typically constructed of superdense metal, inlaid with superconducting field coils. Spherical in shape, it uses inertial-electrostatic confinement to contain and heat the hydrogen plasma.
2. Ignition Capacitors: Supply the initial energy pulse to establish the magnetic fields and heat the plasma.
3. NFE Modulator: The Nuclear Force Enhancement Modulator combines the reverse effects of a nuclear damper with a point node to manipulate the weak nuclear forces, allowing enhancement of these forces and, therefore, the H + H fusion reaction.
4. Power Transfer Circuit: Alpha particles from the fusing plasma are passed through a high-efficiency thermionic diode system consisting of multiple “absorption” layers, directly producing electric power.
5. Thermal Transfer Circuit: Containment vessel cooled by liquid sodium or high pressure argon. System links through at least two heat exchanger loops to hull radiator strips. Turbine generators in coolant circuit produce supplementary power and low pressure steam for ship systems.
6. Helium Purge Circuit: Removes waste helium from containment system. May be discarded or retained for ship's cryogenic systems.
7. HHSU: See above.
8. Deuterium Warm Start Reservoir: ("Ignition module".) Holds the supply of deuterium enriched fuel prior to warm start of the reactor.
9. Catalyst "Scavenge" Circuit: Maintains level of CNO catalysts in containment vessel.
10. CNO Catalyst Reservoir: ("Sustainer Module".) Holds the supply of CNO catalyst when the reactor is at "warm start", or powered down.
Failure Modes and Sabotage Opportunities (Or: I thought you checked the sustainer module..)
Containment Failure: There are sufficient failsafes built into the field coil system that a catastrophic failure of the magnetic bottle is highly unlikely. The "ball lightning" bottle configuration tends to be self sustaining for short periods ...meaning that the sphere of plasma can punch its way out of the containment vessel if the coil system fails.
To sabotage the field coil system:
Formidable, Engineering, Electronics, 10 min (Hazardous, Fateful)
Conversely, the magnetic bottle may be too small, or the catalyst level too high for the fuel volume being injected...in which case a thermonuclear explosion will result. To achieve this, the majority of the reactor control firmware must be rewritten, and the diagnostic circuitry disabled.
To rewrite the reactor control firmware to cause an explosion:
Impossible, Computer, Engineering, 18 min (hazardous)
NFE Modulator Malfunction: If the Modulator malfunctions, it can destabilize the fusion reaction, causing power losses or power spikes. This, in turn, can damage ship circuitry. Because of the failsafes built into the module’s firmware, the NFE Modulator normally can’t dramatically increase the strong nuclear force. Indeed, any power input approaching the level required to cause a runaway fusion reaction has an 80% chance of destroying the unit’s circuitry and causing a powerplant shutdown. However, careful manipulation of its power input can result in a nuclear force enhancement capable of overloading the magnetic bottle. Malfunctions may require the module to be recalibrated or completely replaced.
To calibrate the modulator:
Formidable, Engineering, Edu, 30 min (uncertain)
Requires specialized tools and software available at any Class A/B starport.
To replace the modulator:
Difficult, Engineering, 30 min (uncertain)
If successful, the module must then be calibrated.
To manually manipulate the modulator’s power input:
Impossible, Engineering, Edu, 30 min (hazardous, fateful)
Coolant Failure: In the event of a partial or complete coolant failure, the reactor should flip to warm start or power down automatically. If the ship is in flight, the computer will offer an override option to the crew but the consequences
of reactor overheat are highly unpredictable. You have been warned.
Deuterium Failure: If the deuterium separator or reservoir fail, the reactor will not cold start. Period. A potential saboteur may decide to remove the ignition module to cripple an enemy starship. On a small starship (under 500 tons),
the ignition module is typically 40cm x 20cm x 15cm and weighs 16 kg.
To remove ignition module:
Formidable, Engineering, Dex, 30 sec (hazardous, uncertain)
Referee: Task is difficult if reactor design is familiar to engineer.
On Some Truth, diagnostic circuit is triggered.
Catalyst Failure: If the catalyst scavenge circuit fails, or the sustainer module is removed, interesting things can happen. The reactor will appear to operate normally at full power, but sometime between 15 seconds and 20 minutes after power up it will flip back to warm start without warning and will not restart. This can be troublesome if the ship happens to be a couple of kilometers up in the air at the time. On small starships, the sustainer module is typically 25cm by 12cm by 10cm and weighs 6 kg.
To remove sustainer module:
Formidable, Engineering, Dex, 40 sec (Hazardous)
Referee: As ignition module above.
Thermionic Diodes - A Side Note
Thermionic diodes work off the principle of thermionic emission, that is, the emission of negative ions and electrons (which are also negative) from a hot object. A thermionic diode consists of two semiconductive ceramo-polymer plates, with a certain distance separating them, contained within a vacuum. The front plate (closest to the thermionic source) collects the electrons onto its area, while the rear plate gets none, thus setting up a current source with the front plate supplying the electrons and the rear supplying niches for those electrons. There are, basically, no moving parts.
.........................................Front/Rear Conductive Plates
.......--o..............--o..............|.......|
.................--o.......................|.......|
...............Electrons...................-.......+
--------- End of Brief ---------
Well, there you have it. As I alluded to above, it was good enough for adding fun details and plot points for a group of non-scientist players. Although we did assume most of the hydro was used for heat dumping, we never took the time to work out about how much was used for heat dumps and how much was actually fuel..we wanted to have fun, not work, and it never became an issue during game play. I am curious, though, if anyone else actually did work up the numbers..or a reasonable facsimile.
By the way, the people listed above were not members of any of my gaming groups but were contributors to the TML conversations on power plant tech.
Traveller Tech Brief: Nuclear Fusion Reactor System
Original Author: J. Duncan Law Green
Modifications to Original Article: David Smart
Additional Ideas Taken from Discussions by: Peter Brenton, Tom Lane, Doug Sinclair, Jim Choate, Eric Freitas, Garry Ward
------------------------------------------------------------
Abstract
This article will attempt to set out, in some detail, the anatomy of fusion reactor systems in Traveller (more specifically, those used as starship power plants), the fusion reactions they use, their most common failure modes, and the methods and expected results of sabotaging power plants.
Regular or Super Unleaded?
The standard Traveller references on power plants (the Starship Operator’s Manual published by Digest Group Publications being the most instructive) state that the fusion reactor is fueled by "hydrogen." What they fail to state is that there are three different isotopes of hydrogen, with quite different abundances and nuclear properties. These are:
1H (Protium): Stable (non radioactive.) Consisting of one proton and one electron, protium is by far the most abundant isotope in the Universe.
2H (Deuterium): Stable. Consisting of one proton, one neutron, and one electron, Deuterium is present to an abundance of approximately one part in 5,000 in "natural" hydrogen extracted from seawater.
3H (Tritium): Radioactive. Decays to Helium 3 by proton emission with a half life of 12.5 years. Consisting of one proton, two neutrons, and an electron, Tritium's natural abundance is negligible it has to be "manufactured"
by a variety of possible routes.
Current research on fusion power production is concentrating on deuterium deuterium, deuterium tritium, or deuterium Helium 3 fusion, as these require the lowest plasma energies. At first, this suggested that Traveller power plants were standard deuterium tritium reactors, but further examination of Traveller texts has ruled this out. The reasons for this are detailed below.
Wot? No Tritium?
The first reservation is based on the health and security hazards involved in handling large quantities of radioactive material such as tritium. Starport scenarios make no mention of the necessity of shielding fuel lines or storage tanks! Also, tritium is important in the manufacture of "clean" or laser triggered fusion warheads one would think it is the Imperium's interest to regulate the sale and supply of tritium.
Second, there is a serious problem with wilderness refueling, whether it be from oceans, gas giants, or Oort clouds. The references state that purification plants are intended to remove "trace" impurities which may interfere with the operation of the reactor. For a deuterium fueled reactor, however, 4,999 parts in 5,000 of the fuel intake is impurity." Ships without a purification plant would be in serious trouble.
Third, the scenario "Wrong Way Valve" in Challenge #31 specifically states that a starship's fuel tanks are filled with ordinary water. (It makes no mention of the repeated electrolysis necessary for deuterium separation.)
Thus, it is clear that Traveller fusion reactors are remarkable devices which can be fueled by "natural" hydrogen (primarily protium.) I say remarkable, because the plasma energy and magnetic confinement requirements for protium fusion (via the "proton proton" chain, as in the center of the Sun) are several orders of magnitude greater than those for other types of fusion. It seems the only way to duplicate this process is to construct a reactor the size of a small star! However, there is still hope ....
C, NO Other Way
As stated previously, it is believed that the sun produces energy by fusing protium via the "proton proton" chain. Some giant stars fuse hydrogen by a different route, known as the "CNO catalytic cycle", so called because isotopes of carbon, nitrogen, and oxygen participate in the nuclear reaction, lowering the plasma energy sufficiently for it to become a practicable proposition. The CNO catalyst is not consumed in the reaction, and only relatively small amounts are necessary to produce sustainable fusion. Details of the cycle are shown on the next page.
12C + 1H > 13N + y
13N + 1H > 14O + y
14O > 14N + e+ + y
14N + 1H > 15O + y
15O > 15N + e+ + y
15N + 1H > 12C + 4He
Note that the reaction results in the creation of Carbon/Helium-based “ash” (12C + 4He). The buildup of carbon/helium ash is slow, but if it isn’t removed on a regular basis it can cause the energy output to drop, as fewer reactions are occuring. Also, in a fusion reactor, the biggest problem is ablative effects on the inner surface of the reactor vessel from the high-velocity impacts of the particles that escape the magnetic bottle. Removal of the ash and relining of the reactor vessel are usually accomplished during annual maintenance.
Anatomy of a Traveller Fusion Reactor
All starship power plants possess a small "purification" plant known as an HHSU (Heavy Hydrogen Separation Unit.) This unit partially separates the deuterium from a small volume of the fuel. The deuterium enriched fuel is used when the reactor is in "warm start" or "park" mode. Because the reactor uses deuterium deuterium fusion in "warm start" and CNO fusion in normal operation, it is known as a split cycle or twin cycle reactor.
The components of a starship reactor system are discussed below.
1. Containment Vessel: A highly rigid vessel typically constructed of superdense metal, inlaid with superconducting field coils. Spherical in shape, it uses inertial-electrostatic confinement to contain and heat the hydrogen plasma.
2. Ignition Capacitors: Supply the initial energy pulse to establish the magnetic fields and heat the plasma.
3. NFE Modulator: The Nuclear Force Enhancement Modulator combines the reverse effects of a nuclear damper with a point node to manipulate the weak nuclear forces, allowing enhancement of these forces and, therefore, the H + H fusion reaction.
4. Power Transfer Circuit: Alpha particles from the fusing plasma are passed through a high-efficiency thermionic diode system consisting of multiple “absorption” layers, directly producing electric power.
5. Thermal Transfer Circuit: Containment vessel cooled by liquid sodium or high pressure argon. System links through at least two heat exchanger loops to hull radiator strips. Turbine generators in coolant circuit produce supplementary power and low pressure steam for ship systems.
6. Helium Purge Circuit: Removes waste helium from containment system. May be discarded or retained for ship's cryogenic systems.
7. HHSU: See above.
8. Deuterium Warm Start Reservoir: ("Ignition module".) Holds the supply of deuterium enriched fuel prior to warm start of the reactor.
9. Catalyst "Scavenge" Circuit: Maintains level of CNO catalysts in containment vessel.
10. CNO Catalyst Reservoir: ("Sustainer Module".) Holds the supply of CNO catalyst when the reactor is at "warm start", or powered down.
Failure Modes and Sabotage Opportunities (Or: I thought you checked the sustainer module..)
Containment Failure: There are sufficient failsafes built into the field coil system that a catastrophic failure of the magnetic bottle is highly unlikely. The "ball lightning" bottle configuration tends to be self sustaining for short periods ...meaning that the sphere of plasma can punch its way out of the containment vessel if the coil system fails.
To sabotage the field coil system:
Formidable, Engineering, Electronics, 10 min (Hazardous, Fateful)
Conversely, the magnetic bottle may be too small, or the catalyst level too high for the fuel volume being injected...in which case a thermonuclear explosion will result. To achieve this, the majority of the reactor control firmware must be rewritten, and the diagnostic circuitry disabled.
To rewrite the reactor control firmware to cause an explosion:
Impossible, Computer, Engineering, 18 min (hazardous)
NFE Modulator Malfunction: If the Modulator malfunctions, it can destabilize the fusion reaction, causing power losses or power spikes. This, in turn, can damage ship circuitry. Because of the failsafes built into the module’s firmware, the NFE Modulator normally can’t dramatically increase the strong nuclear force. Indeed, any power input approaching the level required to cause a runaway fusion reaction has an 80% chance of destroying the unit’s circuitry and causing a powerplant shutdown. However, careful manipulation of its power input can result in a nuclear force enhancement capable of overloading the magnetic bottle. Malfunctions may require the module to be recalibrated or completely replaced.
To calibrate the modulator:
Formidable, Engineering, Edu, 30 min (uncertain)
Requires specialized tools and software available at any Class A/B starport.
To replace the modulator:
Difficult, Engineering, 30 min (uncertain)
If successful, the module must then be calibrated.
To manually manipulate the modulator’s power input:
Impossible, Engineering, Edu, 30 min (hazardous, fateful)
Coolant Failure: In the event of a partial or complete coolant failure, the reactor should flip to warm start or power down automatically. If the ship is in flight, the computer will offer an override option to the crew but the consequences
of reactor overheat are highly unpredictable. You have been warned.
Deuterium Failure: If the deuterium separator or reservoir fail, the reactor will not cold start. Period. A potential saboteur may decide to remove the ignition module to cripple an enemy starship. On a small starship (under 500 tons),
the ignition module is typically 40cm x 20cm x 15cm and weighs 16 kg.
To remove ignition module:
Formidable, Engineering, Dex, 30 sec (hazardous, uncertain)
Referee: Task is difficult if reactor design is familiar to engineer.
On Some Truth, diagnostic circuit is triggered.
Catalyst Failure: If the catalyst scavenge circuit fails, or the sustainer module is removed, interesting things can happen. The reactor will appear to operate normally at full power, but sometime between 15 seconds and 20 minutes after power up it will flip back to warm start without warning and will not restart. This can be troublesome if the ship happens to be a couple of kilometers up in the air at the time. On small starships, the sustainer module is typically 25cm by 12cm by 10cm and weighs 6 kg.
To remove sustainer module:
Formidable, Engineering, Dex, 40 sec (Hazardous)
Referee: As ignition module above.
Thermionic Diodes - A Side Note
Thermionic diodes work off the principle of thermionic emission, that is, the emission of negative ions and electrons (which are also negative) from a hot object. A thermionic diode consists of two semiconductive ceramo-polymer plates, with a certain distance separating them, contained within a vacuum. The front plate (closest to the thermionic source) collects the electrons onto its area, while the rear plate gets none, thus setting up a current source with the front plate supplying the electrons and the rear supplying niches for those electrons. There are, basically, no moving parts.
.........................................Front/Rear Conductive Plates
.......--o..............--o..............|.......|
.................--o.......................|.......|
...............Electrons...................-.......+
--------- End of Brief ---------
Well, there you have it. As I alluded to above, it was good enough for adding fun details and plot points for a group of non-scientist players. Although we did assume most of the hydro was used for heat dumping, we never took the time to work out about how much was used for heat dumps and how much was actually fuel..we wanted to have fun, not work, and it never became an issue during game play. I am curious, though, if anyone else actually did work up the numbers..or a reasonable facsimile.
By the way, the people listed above were not members of any of my gaming groups but were contributors to the TML conversations on power plant tech.
