Radionuclide battery

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Activity measurements on the radioisotope generator intended for Cassini-Huygens in the Kennedy Space Center

A radionuclide battery , also radioisotope generator , isotope battery , atomic battery converts the thermal energy or the beta radiation of the spontaneous nuclear decay of a radionuclide into electrical energy . It gets its energy from radioactive decay , not from a nuclear fission with a subsequent chain reaction , and is therefore to be distinguished from nuclear reactors .

If only the thermal energy of the decay is used, one speaks of RTG (for radioisotope thermoelectric generator ).

Radionuclide batteries are generally small, compact, and have no moving parts. They are autonomous, maintenance-free and can supply electrical energy for years to decades.


Sectional view through a RHU heating element

The decay of a radionuclide creates thermal energy and radiation . The heat can either be used directly for heating ( Radioisotope Heating Unit, RHU ) or converted into electrical energy with the help of a converter. The various radionuclides that can be used are listed below, as well as the possibilities of generating electrical energy from decay heat or from beta radiation .

The radionuclide in the RTG is arranged in such a way or present in such a small amount that the critical mass for igniting a chain reaction is not reached even with isotopes of transuranium elements .

Radionuclide heating element

It is used as a heating element on board space probes and rovers to protect the electronic equipment from the cold in the sun's shadow or in the outer solar system. For example, they were used on board the Lunochod (Polonium) and Cassini-Huygens (PuO 2 ). A RHU, as provided by the US Department of Energy for American space missions, contains 2.7 g of “fuel” (PuO 2 ). This plutonium dioxide pellet is surrounded by a shell made of a platinum-rhodium alloy, which is in an insulation made of graphite and this in turn is in a thermal insulation made of the same material. The entire RHU is a 3.2 cm × 2.6 cm capsule, which delivers a thermal output of approx. 1 W with a total mass of approx. 40 g. A radionuclide heating element is therefore not a radionuclide battery for generating electrical energy .

Power generation

When it comes to generating electrical energy, thermoelectric generators (see also below in the converter chapter ) are most often used today. They work without moving parts and are therefore wear-free and well suited for their area of ​​application (long-life space probes remote from the sun). The efficiency is only 3 to 8 percent. The Peltier elements used therein for energy conversion require the greatest possible temperature difference to generate electricity. Therefore, one side is heated by the radioactive preparation, the other side radiates heat into the environment over a large area with high emissivity and is thus cooled.

Alternatives are in the development stage. The most promising of these is the AMTEC generator (alkali metal-thermal-electrical converter, see below). It was originally intended to be used on the New Horizons space probe, but a thermoelectric generator (type GPHS-RTG) was chosen for financial reasons.

Compared to nuclear reactors , radionuclide batteries also have a worse mass-performance ratio. The fuel consumption is independent of whether electrical power is drawn or not. In the case of radioisotopes with a short half-life, the energy output drops quickly. Therefore, an excess of fuel must always be carried, which requires higher costs and heavier shielding.

Partial section view of an ASRG (Advanced Stirling Radioisotope Generator)

Stirling generator

In an “Advanced Stirling Radioisotope Generator” (ASRG), the heat from the radioisotope is used to operate a Stirling engine , which in turn drives a generator to generate electricity. At around 28 percent, the efficiency of the Stirling engine is much higher than that of thermocouples, which means that much more electrical energy can be generated with the same amount of radionuclide.

The disadvantage of the ASRG is the use of moving parts that can lead to failure.

No ASRG has yet been used.

Actually used and theoretically conceivable fuels

To ensure that an RTG does not lose too much of its performance during its service life, the radionuclide used should have a half-life that is a factor of 2 to 5 greater than the maximum operating time, which is a few decades for normal missions. In space travel, the radionuclide has to give off a sufficient amount of energy in order to achieve a high heat output in relation to its mass and volume. On the other hand, a thin shield must be sufficient so that the RTG does not become too heavy. Therefore beta emitters are not well suited because of the release of bremsstrahlung , gamma emitters and nuclides with a high spontaneous fission rate due to the release of gamma rays and neutrons. For a sufficiently large specific heat output, the half-life should not be unnecessarily long. Otherwise too much of the radionuclide would be required, which would make the RTGs too heavy for a reasonable launch mass. In the case of interstellar probes, alpha emitters with a half-life of up to 10,000 years would be used.

For applications on earth, the shielding mass and the power density are often less important, but the price of the radionuclide is. This is why beta emitters are also used in RTGs on Earth. However, the decay products (in the entire decay series ) of the selected nuclide must also not emit radiation that is too penetrating. Some isotopes from nuclear waste from nuclear power plants can be used, such as 90 Sr, 137 Cs, 144 Ce, 106 Ru, or 241 Am. However, a reprocessing plant is necessary to obtain them . Other fuels first have to be produced in a laborious manner, which sometimes even requires several passes through a reprocessing plant, for example 210 Po, 238 Pu or 244 cm. 244 cm costs approximately US $ 160,000 / g.

Radionuclides suitable for radionuclide batteries are as follows:

Decay fuel Specific
power a (W / g)
Melting point of the
fuel (° C)
060 Co 0005.27 β , γ metal 018.9 heavy 1480
090 Sr 0028.78 β, β SrTiO 3 002.31 heavy 1910
106 Ru 0001.02 β, β metal 070.0 heavy 2310
137 Cs 0030.17 β, γ CsCl or glass 000.60 heavy 0646 / - b
144 Ce 0000.78 β, β, γ CeO 2 062.6 heavy 2190
147 pm 0002.62 β Pm 2 O 3 001.23 medium 2130
210 Po 0000.38 α GdPo 141 easy 1630
238 Pu 0087.7 α PuO 2 000.568 easy 2250
242 cm 0000.45 α Cm 2 O 3 122 medium 1950
244 cm 0018.1 α Cm 2 O 3 002.84 medium 1950
241 On 0432.2 α AmO 2 000.112 medium 2000
243 On 7513 c α, β, α AmO 2 000.010 c ≥ medium 2000
a Power related to the mass of the nuclide, which related to the mass of the fuel is correspondingly lower
b Temperature not specified for glass
cEffective half-life and heat of decay of the decay series 243 Am → 239 Np → 239 Pu → 235 U
(in steady state)
Cobalt 60 Co
is generated by neutron bombardment of 59 Co and disintegrates with a half-life of 5.26 years with beta decay first into an excited state of 60 Ni * and then with the emission of high-energy gamma radiation into the ground state of this nuclide. 60 Co is used, among other things, for the sterilization or preservation of food, for material testing (radiographic testing) and in cancer therapy ("cobalt cannon"). When used in a radioisotope battery, a very thick shield would therefore be necessary.
Strontium 90 Sr
is a waste product in nuclear reactors and is a beta emitter with a half-life of 28.78 years. The decay energy is 0.546 MeV . This beta radiation releases bremsstrahlung in the surrounding material during braking . The decay product yttrium 90 Y releases even harder beta radiation at 2.282 MeV, which leads to even stronger bremsstrahlung. Therefore 90 Sr needs a much thicker shield than an alpha emitter .
An advantage can be that it only decays to stable zirconium 90 Zr via the mentioned intermediate stage ( 90 Y with 64.10 hours half-life) and the radiation of the fuel of an RTG has dropped to a harmless value after about 900 years (instead of hundreds of thousands to Millions of years over a long chain of decay like transuranic elements ). 90 Sr can be recovered in large quantities in reprocessing and is used in RTGs on Earth, where the mass of the shield is not as critical as it is in space travel.
Ruthenium 106 Ru
accrues as a waste product in nuclear reactors and is a beta emitter , which decays to rhodium 106 Rh with a half-life of 373.6 days , which leads to a rapid loss of power in the isotope battery. It has a high power density and a high melting point of 2310 ° C. As the beta radiation emitted in turn releases bremsstrahlung, thick shielding is required. The decay product 106 Rh is also a beta emitter and decays to stable palladium 106 Pd with a half-life of 29.80 seconds with the emission of hard beta radiation, which leads to intense bremsstrahlung.
Cesium 137 Cs
is a waste product in nuclear reactors and has a half-life of 30.17 years. It requires more complex shielding for the radiation than an alpha emitter , as it emits beta radiation and the decay product barium 137m Ba is a strong gamma emitter .An advantage can be that it only decays to a stable 137 Ba via the mentioned intermediate stage ( 137m Ba with 2.55 minutes half-life) and not via a long decay chain as in the case of the transuranic elements. 137 Cs can be recovered in large quantities from reprocessing.
Cerium 144 Ce
also occurs as a waste product in nuclear reactors and has a good power density. However, the half-life of 284.9 days is usually too short for applications. It is also a beta emitter and therefore releases bremsstrahlung. The decay product praseodymium 144 Pr decays further to neodymium 144 Nd with a half-life of 17.28 minutes through beta decay , whereby it releases even harder bremsstrahlung. The 144 Nd decays through alpha decay with an extremely long half-life of 2.29 quadrillion years to the stable Cer 140 Ce.
Promethium 147 pm
is a beta emitter and has a relatively short half-life of 2.62 years. It is primarily used in the context of beta voltaics to generate energy, and continues to be used, among other things, as a stimulating beta emitter in luminous numbers in clocks and in cold light sources in signal systems. It is a waste product in nuclear reactors and can be recovered during reprocessing. Promethium 147 Pm decays to Samarium 147 Sm, which in turn decays to stable Neodymium 143 Nd through alpha decay with a very long half-life of 106 billion years .
Polonium 210 Po
is generated by neutron bombardment of 209 Bi. At 141 W / g, it has the highest power density and, as an alpha emitter, only needs a low level of shielding. Since the half-life is low at 138.376 days, it was only used in the RHU of Lunochod , as the mission duration there was sufficiently short. It decays to the stable lead isotope 206 Pb.
Pellet made of
plutonium dioxide glowing due to decay energy - the pellet in the photo emits 62 W in the form of heat.
Plutonium 238 Pu
is specifically manufactured for use in radionuclide batteries. It is used in most space RTGs. Typical generators for space probes are filled with ceramic plutonium dioxide (PuO 2 ) in the form of solid blocks. It is chemically stable, insoluble in water, does not atomize and has a higher melting point than metallic plutonium. The heat output of the fuel resulting from radioactive decay is around 500 W / kg.
238 Pu is an alpha emitter with a low spontaneous fission rate and therefore low neutron and gamma emissions with a half-life of 87.7 years. The relatively long half-life (= several decades of use of the RTG) and low emission of radiation that is difficult to shield mean that only the thinnest radiation shielding of the nuclides mentioned here is required. A quantity of 300 g of 238 Pu provides after thermoelectric conversion with about 8% efficiency, for example, about 11 W electrical power, i.e. about 933 kWh electrical energy within 10 years  .
Curium 242 cm
has the second highest energy density and a very short half-life of 162.8 days. Its production is complex and very expensive. It breaks down directly to 238 Pu and is only mentioned here for the sake of completeness.
Curium 244 cm
must be incubated in nuclear reactors and has a half-life of 18.1 years. It is an alpha emitter, but its spontaneous fission rate and thus the neutron and gamma radiation is higher than that of 238 Pu, so the shielding must be thicker. Its half-life is much shorter, so an RTG with it would have a much shorter period of use.
Americium 241 Am
arises from beta decay of 241 Pu, which is incubated in small quantities in nuclear reactors . With a half-life of 432.2 years, it would be suitable for RTGs that have to deliver electrical energy not just for decades, but for centuries. However, americium is not a pure alpha emitter, but emits large amounts of relatively soft gamma radiation when it decays, because only about 0.35% of all 241 Am atoms give the entire decay energy to the alpha particle. The neutron emission is higher than with 238 Pu. Therefore RTGs with this isotope would need a slightly thicker shield than those with 238 Pu filling.
Americium 243 Am
arises from the beta decay of the plutonium 243 Pu, which is produced in very small quantities by nuclear reactors . With a half-life of 7,370 years, it would be suitable for RTGs with a service life of around 5,000 years.


Several principles come into question or have been tested for energy conversion:

Scheme of a thermoelectric converter
Thermoelectric generator
(English. radioisotope thermoelectric generator , RTG for short ) a radionuclide generates heat and operates a thermoelectric generator , similar to a Peltier element ( Seebeck effect or inverse Peltier effect ). This type of isotope generator is the most common. It contains one or more radioactive heating elements that are inserted directly into the radioisotope generator. The radioisotope generator consists of a metal cylinder in the wall of which the thermocouples are embedded. It has cooling fins on its outer wall in order to give off the heat generated by the heating elements and thus to produce the temperature difference necessary for the operation of the thermocouples. The efficiency is 3 to 8 percent.
Thermionic generator
it uses the glow emission of electrons from a glow cathode heated by the radionuclide . Efficiency around 10 to 20 percent, but high temperatures of at least around 750 ° C are necessary.
Thermophotovoltaic generator
it uses the infrared radiation of the radionuclide , which heats up to the point of embers, and converts it into electricity with photodiodes, similar to solar cells . The efficiency is initially around 20 to 30 percent, but they degrade fairly quickly when operated with radionuclides due to radiation damage.
Betavoltaic batteries
they convert beta radiation in a semiconductor, similar to a photodiode, directly into electrical current. The problem here is the poor efficiency, which is around 7 percent. The subject is the subject of research by the USAF. The heat of decay does not play a role here.
Alkali metal-thermal-electrical converter
(English alkali-metal thermal to electric converter , or AMTEC for short ). It uses components from the sodium-sulfur battery . The structure is similar to a fuel cell : Sodium vaporized by the heat of the radionuclide is pressed through a solid electrolyte made of aluminum oxide ceramic. Since the ceramic only conducts Na + ions, the electron has to flow to the other end of the ceramic via a consumer. There, sodium ions and electrons combine and are liquefied in a condenser. The liquid sodium is transported to the evaporator with the help of a magnetohydrodynamic pump and the cycle starts all over again. The efficiency is 15 to 25 percent, in the future up to 40 percent is considered possible.
Stirling engine
(English stirling radio isotope generator , short SRG ). The heat generated by the radioisotopes drives a Stirling engine. Its efficiency (20 to 30 percent) is higher than that of thermoelectric elements, but in contrast to thermoelectric or AMTEC converters, it uses moving parts. The Advanced Stirling Radioisotope Generators developed in the meantime have not yet been used. Because of the risk posed by the moving parts of the generators, NASA plans to test them first on an inexpensive mission before using them on an expensive mission.



One of the radioisotope generators for Cassini-Huygens

In space travel , RTGs are used for power supply and RHUs for heating. Beyond the orbit of Mars , until recently (now beyond Jupiter ), the radiation from the distant sun was no longer sufficient to cover the energy requirements of the probes with solar cells of practicable size. In addition, the gas planets (especially Jupiter) are surrounded by so strong radiation belts that the solar cells are degraded or destroyed too quickly . RTGs are currently the only generators that are light and reliable enough to be integrated into a probe and that can deliver power for a long enough period. All space probes that were sent to the planet Jupiter or further up to 2010 , such as Pioneer 10 , Pioneer 11 , Voyager 1 , Voyager 2 , Galileo , Ulysses , Cassini and New Horizons , were therefore equipped with isotope batteries. The Juno space probe, launched in 2011, uses solar cells in Jupiter's orbit . However, this is only possible because the planned polar orbit of the probe lies largely outside the radiation belt. The planned " Jupiter Icy Moons Explorer " , which emerged from the Europa Jupiter System Mission , will also use solar cells, since the moon Ganymede is located outside of Jupiter's strong radiation belt. The "Jupiter Europa Orbiter" of the abandoned Europa Jupiter System Mission, on the other hand, should use RTGs, since the moon Europa is closer to Jupiter within the radiation belt. The Rosetta space probe , which examined the Churyumov-Gerasimenko comet until 2016, also used solar cells, although it has now moved further away from the Sun than Jupiter. However, the main part of the mission took place when the comet was in its eccentric orbit near the perihelion (and thus near the sun). So there was enough energy available during the actual mission on the comet. It must also be taken into account here that ESA has not yet developed any RTGs, but is considering developing and building RTGs that should be ready in the 2020s. Americium 241 Am is expected to be used as the radionuclide .

The automatic measuring stations ( ALSEP ) set up on the moon by the Apollo astronauts in the early 1970s also obtained their energy from isotope batteries in order to be able to work continuously.

The lander of the Chinese lunar probe Chang'e-3 has an RTG on board so that it can continue to work during the 14-day lunar night.

With military satellites, the smaller size compared to solar cells plays a role, as well as the greater insensitivity to radiation. Satellites orbiting in a low orbit ( LEO ) are slowed down by the high atmosphere , small dimensions are particularly important here.

Russia (or the Soviet Union) also used RTGs in both civil and military missions, but in space travel tended to focus on nuclear reactors ( RORSAT ). Very little has been published about Soviet / Russian activities, so the following list is US dominated. However, it can be assumed that the USSR used RTGs at least as often.

Space applications of RTGs
year Surname mission number
electrical power
per RTG in W (start)
1958 SNAP-1 Deleted in 1958 ? 144 Ce 500
1958 SNAP-1A 1958 soil test ? 125
1961 SNAP-3 Transit 4A 1 238 Pu 002.7
1961 SNAP-3 Transit 4B 1 002.7
1963 SNAP-9 Transit 5BN-1 1 025th
1963 SNAP-9 Transit 5BN-2 1 025th
1965 Orion-1 Cosmos 84 1 ? ?
1965 Orion-1 Cosmos 90 1 ?
1965 SNAP-17 Communications satellite , deleted ? 090 Sr 025th
1966 SNAP-11 Surveyor (deleted), soil test ? 242 cm 025th
1969 SNAP-29 USAF ? 210 Po 400
1969 SNAP-19B3 Nimbus B 2 238 Pu 028.2
1969 SNAP-19B3 Nimbus III 2 028.2
1969 SNAP-27 EALSEP 1 075
1969 SNAP-27 ALSEP A1 1 075
1970 SNAP-27 ALSEP B 1 075
1971 SNAP-27 ALSEP C 1 075
1971 SNAP-27 ALSEP A2 1 075
1972 SNAP-19 Pioneer 10 4th 040
1972 SNAP-27 ALSEP D 1 075
1972 Transit RTG Triad 1 1 ? ?
1972 SNAP-27 ALSEP E 1 238 Pu 075
1973 SNAP-19 Pioneer 11 4th 040
1975 SNAP-19 Viking 1 2 043
1975 SNAP-19 Viking 2 2 043
1976 MHW-RTG LES-8 2 154
1976 MHW-RTG LES-9 2 154
1977 MHW-RTG Voyager 2 3 158
1977 MHW-RTG Voyager 1 3 158
1989 GPHS-RTG Galileo 2 290
1990 GPHS-RTG Ulysses 1 280
1996 RTG fishing rod Mars 96 4th N / A
1997 GPHS-RTG Cassini-Huygens 3 285
2006 GPHS-RTG New Horizons 1 240
2011 MMRTG Curiosity 1 110
2013 ? Chang'e-3 1 238 Pu ?


Before there were small and long-lasting batteries, RTGs based on 238 Pu were used to power pacemakers . Such cardiac pacemakers were also implanted in Germany between 1971 and 1976. They contained 200 mg of plutonium.

Before that, the company Biotronik had already produced a pacemaker that used the beta voltaic principle to generate energy on the basis of beta decay of 147 μm.

RTGs were used to supply lighthouses and lighting in remote regions of the USSR . With around 1000 pieces, 90 Sr generators of the Beta-M type were used most frequently . Some of them are still in operation today.



In the early days of space travel, RTGs were only built with little shielding. The shield was designed to adequately protect the satellite's instruments from radiation from the radioisotope. Since protective measures against cosmic radiation were in place anyway , it was rather easy to implement. The RTGs of the time were not designed for atmospheric re-entry ; rather, they were built in such a way that they should burn up in the atmosphere in the event of an accident. The fuels would thus have spread over a large area as dust and then fall-out. The resulting radioactive pollution from an RTG unit (maximum 8 kg of fuel) was considered to be negligible in view of the nuclear weapons tests taking place around the world and the amount of radioactive material released and produced as a result (several 1000 tons). Accidents involving satellites with nuclear reactors instead of radionuclide batteries as an energy source, such as the Soviet Kosmos 954 , led to a far greater level of radioactive contamination.

In October 1963, the Treaty on the Prohibition of Nuclear Weapons Tests in the Atmosphere, in Space and Underwater came into force. The ionizing radiation quickly went back worldwide.

On April 21, 1964, the Able Star upper stage of a Thor DSV2A Able Star launcher that was supposed to launch the Transit 5BN-3 and Transit 5E-3 satellites into space. The satellites re-entered the earth's atmosphere, with the SNAP-9A radionuclide battery of Transit 5BN-3 burning up at an altitude of about 50 km, releasing the 238 Pu with an activity of 629 T Bq (17,000 Curie ). It can still be measured worldwide today.

General Purpose Heat Source

Due to the change in the image of nuclear technology in the 1960s and 70s and the above-mentioned crash, RTGs also moved into the focus of politics and the public. From now on, maximum security was the top priority. Since then, all RTGs have been designed to allow the rocket to re-enter and explode on the launch pad, which, however, drastically deteriorated the mass-performance ratio and drove up costs. The following is the structure of a modern GPHS-RTG (General Purpose Heat Source - Radioisotope Thermoelectric Generator) to illustrate the safety measures, they were used at Cassini-Huygens , New Horizons , Galileo and Ulysses :

Sectional view of the finished GPHS RTG
  1. The fuel (plutonium dioxide) is filled in iridium blocks to protect against corrosion .
  2. Two fuel blocks are filled into a small graphite cylinder, separated from one another by a membrane and screwed together (Graphite Impact Shell).
  3. Two of these graphite cylinders are inserted in parallel into a larger graphite block, which is screwed on and secured against unscrewing (Aeroshell).
  4. Nine of these blocks are stacked on top of each other and fixed against each other.
  5. The resulting assembly is inserted into a cylinder that contains the thermal transducers; this is followed by a partition (midspan heat source support), then another stack.
  6. The wall containing the thermoelectric converters is insulated.
  7. Are outside the radiators of aluminum attached and a relief valve for discharging from the alpha particles resulting helium .

The finished unit weighs approx. 57 kg, of which 7.8 kg are fuel. The security concept works as follows: When the atmosphere re-enters, the aluminum radiators burn up, the thermal insulation protects the interior until it burns up too. The graphite blocks (Aeroshell) survive the re-entry. If they hit the surface, they break and release the graphite cylinder (Graphite Impact Shell). On land, the remains can now be recovered locally, as the graphite blocks fall as a unit. The segmentation is intended to increase safety in the event of damage before re-entry. Rescue is not planned in the event of an impact in the sea. The graphite cylinders go under immediately. Graphite is very resistant to corrosion. If the cylinders are damaged after several decades, the fuel is still surrounded by a layer of iridium , the most corrosion-resistant element.

The functioning of these safety measures has been proven with Nimbus B and Apollo 13 . The Thorad-SLV2G Agena-D rocket from Nimbus B and the secondary payload SECOR 10 had to be blown up shortly after the launch. The fuel capsules of the two SNAP 19 RTG from Nimbus B held tight despite the rocket explosion and could be recovered from the sea in front of Vandenberg Air Force Base . The 238 Pu was reused in Nimbus 3. When the Apollo 13 lunar module burned up in the earth's atmosphere near the Fiji islands, a SNAP-27 RTG was on board and fell into the Tonga trench . No 238 Pu could be found in subsequent air and water measurements: the container obviously withstood the impact.


A Soviet-made RTG on the
Kola peninsula

Because of the large amount of radioactive material, its use in the successor states of the USSR is seen as problematic. 1007 radioisotope generators were manufactured there between 1976 and the 1990s. They were designed for uses such as powering remote lighthouses or military radio relay stations, with large amounts (up to over 100 kg) of radioactive material, mostly 90 strontium , being used due to the high power requirements of these applications and the low efficiency of power generation . The 90 Sr was used by the RTGs in the compound strontium titanate or as a component of borosilicate glass .

All of these devices come from the Soviet era and have now exceeded their projected service life. Due to the slow dismantling and disposal by the responsible authorities, the incomplete documentation of the types and locations and the mostly inadequate security of these systems, there were releases of radiating material through corrosion and in particular through metal theft until at least 2006.

It was reported from Georgia that in 2001 two lumberjacks found the abandoned components of two isotope batteries from former mobile military radio systems in forests, warmed themselves with them at night and then had to be treated in a hospital for severe symptoms of radiation sickness. Corresponding reports were sent to the IAEA. Strong protective requirements were required for the subsequent evacuation. In Georgia, the IAEA and the Georgian government are actively looking for so-called orphan emitters ("ownerless emitters"), as serious radiation damage has already occurred. In addition to the RTGs containing 90 Sr , these are primarily 137 cesium sources from military and agricultural use.

By 2012, the 1007 Russian radioisotope generators had been collected with the help of France, Norway, Canada, France and the USA. The radioisotope generators were then stored at DalRAO near Vladivostok and at RosRAO near Moscow . The remaining radioisotope generators that are still in existence are also to be collected in the coming years, so that from 2025 there will no longer be any RTGs on Russian territory. Three Russian radioisotope generators are missing in the Arctic .

Patients who still have an RTG-operated pacemaker are registered centrally and the RTG unit is safely recycled after death. Of the 284 registered German patients, two were still alive in 2010 and one unit (or patient) is considered missing in Cambodia.


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Web links

Commons : Radioisotope generator  - collection of images, videos and audio files
Commons : Stirling Radioisotope Generator  - Collection of images, videos and audio files

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