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112-619: October Revolution Island (Russian: остров Октябрьской Революции, ostrov Oktyabrskoy Revolyutsii ) is the largest island of the Severnaya Zemlya group in the Russian Arctic . It is named after the October Revolution which led to the former Russian Empire becoming a Socialist country. The area of this island has been estimated at 14,170 km (5,470 sq mi) making it the 59th largest island in

224-428: A multi-mission radioisotope thermoelectric generator (MMRTG) in which the thermocouples would be made of skutterudite , a cobalt arsenide (CoAs 3 ), which can function with a smaller temperature difference than the current tellurium -based designs. This would mean that an otherwise similar RTG would generate 25% more power at the beginning of a mission and at least 50% more after seventeen years. NASA hopes to use

336-433: A "foreign object". A common route of production (whether accidental or deliberate) is neutron irradiation of Bi , the only naturally occurring isotope of bismuth . It is this accidental production that is cited as an argument against the use of lead-bismuth eutectic as a coolant in liquid metal reactors. However, if a sufficient demand for polonium-210 exists, its extraction could be worthwhile similar to how tritium

448-568: A factor of 1 – (1/2) , which is 0.787%, per year. One example is the MHW-RTG used by the Voyager probes . In the year 2000, 23 years after production, the radioactive material inside the RTG had decreased in power by 16.6%, i.e. providing 83.4% of its initial output; starting with a capacity of 470 W, after this length of time it would have a capacity of only 392 W. A related loss of power in

560-456: A further shielding against neutron radiation . As lead, which is an excellent shielding material against gamma rays and beta ray induced Bremsstrahlung , is not a good neutron shield (instead reflecting most of them), a different shielding material would have to be added in applications where neutrons are a concern. Most RTGs use Pu, which decays with a half-life of 87.7 years. RTGs using this material will therefore diminish in power output by

672-425: A half-life of 87.7 years, reasonable power density of 0.57 watts per gram, and exceptionally low gamma and neutron radiation levels. Pu has the lowest shielding requirements. Only three candidate isotopes meet the last criterion (not all are listed above) and need less than 25 mm of lead shielding to block the radiation. Pu (the best of these three) needs less than 2.5 mm, and in many cases, no shielding

784-603: A higher voltage. RTGs and fission reactors use very different nuclear reactions. Nuclear power reactors (including the miniaturized ones used in space) perform controlled nuclear fission in a chain reaction . The rate of the reaction can be controlled with neutron absorbing control rods , so power can be varied with demand or shut off (almost) entirely for maintenance. However, care is needed to avoid uncontrolled operation at dangerously high power levels, or even explosion or nuclear meltdown . Chain reactions do not occur in RTGs. Heat

896-491: A larger number of such units have been deployed both on the ground and on the ocean floor than have been used on spacecraft, with public regulatory documents suggesting that the US had deployed at least 100–150 during the 1970s and 1980s. In the past, small "plutonium cells" (very small Pu-powered RTGs) were used in implanted heart pacemakers to ensure a very long "battery life". As of 2004 , about ninety were still in use. By

1008-426: A much lower neutron emission rate for the oxide; this can be accomplished by a gas phase O 2 exchange method. Regular production batches of PuO 2 particles precipitated as a hydroxide were used to show that large production batches could be effectively O 2 -exchanged on a routine basis. High-fired PuO 2 microspheres were successfully O 2 -exchanged showing that an exchange will take place regardless of

1120-565: A series of lighthouses built by the Soviet Union inside the Arctic Circle . Safe use of RTGs requires containment of the radioisotopes long after the productive life of the unit. The expense of RTGs tends to limit their use to niche applications in rare or special situations. The RTG was invented in 1954 by Mound Laboratories scientists Kenneth (Ken) C. Jordan (1921–2008) and John Birden (1918–2011). They were inducted into

1232-420: A similar effect of dispersion by physically grinding the inert matrix into a fine dust. RTGs pose a risk of radioactive contamination : if the container holding the fuel leaks, the radioactive material may contaminate the environment. For spacecraft, the main concern is that if an accident were to occur during launch or a subsequent passage of a spacecraft close to Earth, harmful material could be released into

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1344-856: A small base at Golomyanny – the western end of Sredniy Island , off October Revolution Island's western coast. From there they made multiple surveying-trips into the interior and to the coastlines of the larger islands. The first detailed map drawn by the expedition's cartographers showed Severnaya Zemlya divided into four main islands. Geographic features of the territory were named after communist organisations, events, and personalities. With reference to Severnaya Zemlya Ushakov wrote: I have seen God-forsaken Chukotka Peninsula , blizzard-ridden Wrangel Island , twice visited fog-enshrouded Novaya Zemlya , and I have seen Franz Josef Land with its enamel sky and proud cliffs garbed in blue, hardened glacial streams, but nowhere did I witness such grimness or such depressing, lifeless relief... The Graf Zeppelin flew over

1456-478: A steady source of power. Most have no protection, not even fences or warning signs, and the locations of some of these facilities are no longer known due to poor record keeping. In one instance, the radioactive compartments were opened by a thief. In another case , three woodsmen in Tsalendzhikha Region, Georgia found two ceramic RTG orphan sources that had been stripped of their shielding; two of

1568-584: Is 965 m (3,166 ft) Mount Karpinsky, the summit of the Karpinsky Glacier, an ice dome on October Revolution Island. The Red Army Strait separates Komsomolets Island from October Revolution Island and the broader Shokalsky Strait Bolshevik Island from October Revolution Island. Both straits connect the Kara Sea in the west with the Laptev Sea in the east. This archipelago encloses

1680-467: Is a thermoelectric device that can convert thermal energy directly into electrical energy using the Seebeck effect . It is made of two kinds of metal or semiconductor material. If they are connected to each other in a closed loop and the two junctions are at different temperatures , an electric current will flow in the loop. Typically a large number of thermocouples are connected in series to generate

1792-402: Is a pure alpha-emitter and does not emit significant gamma or X-ray radiation, the shielding requirements are as low as those for Pu. While the short half-life also reduces the time during which accidental release to the environment is a concern, polonium-210 is extremely radiotoxic if ingested and can cause significant harm even in chemically inert forms, which pass through the digestive tract as

1904-538: Is almost equal parts Cs-135 and Cs-137, plus significant amounts of stable Cs-133 and, in "young" spent fuel, short lived Cs-134. If isotope separation , a costly and time-consuming process, is to be avoided, this has to be factored in, too. While historically RTGs have been rather small, there is in theory nothing preventing RTGs from reaching into the Megawatt thermal range of power. However, for such applications actinides are less suitable than lighter radioisotopes as

2016-406: Is commonly used as strontium titanate in RTGs, which increases molar mass by about a factor of 2. Furthermore, depending on the source, isotopic purity may not be obtainable. Plutonium extracted from spent nuclear fuel has a low share of Pu-238, so plutonium-238 for use in RTGs is usually purpose-made by neutron irradiation of neptunium-237 , further raising costs. Caesium in fission products

2128-829: Is described by material from the Middle and Upper Ordovician deposits of the Strojnaya River, after which it was named. Loganellia grossi , Paralogania consimilis , Thelodus calvus and Shielia multispinata were found in the younger Wenlock deposits of the Silurian . Conodonts were also collected from October Revolution Island. Aphelognathus sp. is dated to the Middle-Upper Ordovician, while Panderodus and Ozarkodina were discovered in Rhuddanian , Lower Silurian period. The island

2240-459: Is economically recovered from the heavy water moderator in CANDUs . Americium-241 is a candidate isotope with much greater availability than Pu. Although Am has a half-life of 432 years, which is about five times longer than that of Pu and could hypothetically power a device for centuries, missions with more than 10 years were not the subject of the research until 2019. The power density of Am

2352-491: Is funded, the goal would be to set up automation and scale-up processes in order to produce an average of 1.5 kg (3.3 lb) per year by 2025. Strontium-90 has been used by the Soviet Union in terrestrial RTGs. Sr decays by β emission, with minor γ emission. While its half life of 28.8 years is much shorter than that of Pu, it also has a lower decay energy with a power density of 0.46 watts per gram. Because

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2464-537: Is located at the far northwestern end of the archipelago. This island is quite detached from the whole Severnaya Zemlya group. It is also its northernmost island and before modern climate warming it was fully in the region of permanent sea ice . This island is almost entirely covered by the Schmidt Ice Cap . Owing to its exposed position, the climate in the Schmidt Island's area is much colder than in

2576-642: Is located on the southwestern edge of the Karpinsky glacier. To the east and south of the island are the large Matusevich Fjord and the smaller Marat Fjord . They, together with the lake, encircle the Karpinsky ice cap. Cape October is located in the northern part of the island facing the Red Army Strait. Ostrov Vysokiy is an islet located in a small bay on October Revolution Island's southwest shores. Bolshevik Island (Russian: о́стров Большеви́к , pronounced [ˈostrəv bəlʲʂɨˈvʲik] )

2688-464: Is most likely that they melted through the glacier and were pulverized, whereupon the Pu–Zr alloy fuel oxidized soil particles that are moving in a plume under the glacier. Many Beta-M RTGs produced by the Soviet Union to power lighthouses and beacons have become orphaned sources of radiation. Several of these units have been illegally dismantled for scrap metal (resulting in the complete exposure of

2800-548: Is needed in a Pu RTG, as the casing itself is adequate. Pu has become the most widely used fuel for RTGs, in the form of plutonium(IV) oxide (PuO 2 ). However, plutonium(IV) oxide containing a natural abundance of oxygen emits neutrons at the rate of roughly 2.3 × 10  n/sec/g of plutonium-238. This emission rate is relatively high compared to the neutron emission rate of plutonium-238 metal. The metal containing no light element impurities emits roughly 2.8 × 10  n/sec/g of plutonium-238. These neutrons are produced by

2912-433: Is only one-fourth that of Pu, and Am produces more penetrating radiation through decay chain products than Pu and needs more shielding. Its shielding requirements in a RTG are the third lowest: only Pu and Po require less. With a current global shortage of Pu, Am is being studied as RTG fuel by ESA and in 2019, UK's National Nuclear Laboratory announced the generation of usable electricity. An advantage over Pu

3024-504: Is produced through spontaneous radioactive decay at a non-adjustable and steadily decreasing rate that depends only on the amount of fuel isotope and its half-life. In an RTG, heat generation cannot be varied with demand or shut off when not needed and it is not possible to save more energy for later by reducing the power consumption. Therefore, auxiliary power supplies (such as rechargeable batteries) may be needed to meet peak demand, and adequate cooling must be provided at all times including

3136-441: Is simple by the standards of nuclear technology : the main component is a sturdy container of a radioactive material (the fuel). Thermocouples are placed in the walls of the container, with the outer end of each thermocouple connected to a heat sink . Radioactive decay of the fuel produces heat. It is the temperature difference between the fuel and the heat sink that allows the thermocouples to generate electricity. A thermocouple

3248-514: Is spacecraft power supply. Several generations of RTG design have been used for probes that traveled far from the Sun, rendering solar panels impractical. As such, they have been used for Pioneer 10 and 11 ; Voyager 1 and 2 ; Galileo ; Ulysses ; Cassini ; New Horizons ; and are planned for the Dragonfly mission to Titan . RTGs were also used instead of solar panels to power

3360-418: Is that it is produced as nuclear waste and is nearly isotopically pure. Prototype designs of Am RTGs expect 2–2.2 W e /kg for 5–50 W e RTGs design but practical testing shows that only 1.3–1.9 W e can be achieved. Americium-241 is currently used in small quantities in household smoke detectors and thus its handling and properties are well-established. However, it decays to neptunium-237 ,

3472-796: Is the Lia radiological accident in Georgia , December 2001. Strontium-90 RTG cores were dumped behind, unlabeled and improperly dismanteled, near the Soviet-built Enguri Dam . Three villagers from the nearby village of Lia were unknowingly exposed to it and injured; one of them died in May 2004 from the injuries sustained. The International Atomic Energy Agency led recovery operations and organized medical care. Two remaining RTG cores are yet to be found as of 2022. There have been several known accidents involving RTG-powered spacecraft: One RTG,

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3584-646: Is the island with most individual glaciers in Severnaya Zemlya. Next are the islands of Bolshevik with six, Komsomolets with four, Pioneer with two and Schmidt Island with one. The largest glacier is the Academy of Sciences Glacier in Komsomolets, which is also the largest ice cap of Russia —a 5,575 km (2,153 sq mi) and 819 m (2,687 ft) thick ice dome reaching 749 m (2,457 ft) above sea level covering about two-thirds of

3696-507: Is the southernmost and second largest island in the group, located across the Shokalsky Strait from October Revolution Island. The area of this island has been estimated at 11,312 km (4,370 sq mi). Bolshevik Island is mountainous, reaching a height of 935 m (3,068 ft). It houses an Arctic base named Prima near Cape Baranov . Parts of the shore of the island are deeply indented, with Mikoyan Bay in

3808-406: Is unlikely as SrTiO 3 passes through the digestive tract of humans or other animals unchanged, but the animal or human who ingested it would still receive a significant radiation dose to the sensitive intestinal lining during passage. Mechanical degradation of "pebbles" or larger objects into fine dust is more likely and could disperse the material over a wider area, however this would also reduce

3920-634: The Arctic Ocean , the Kara Sea in the west and the Laptev Sea in the east. Severnaya Zemlya was first noted in 1913 and first charted in 1930–32, making it the last sizeable archipelago on Earth to be explored. Administratively, the islands form part of Russia's Krasnoyarsk Krai . In Soviet times there were a number of research stations in different locations, but currently there are no human inhabitants in Severnaya Zemlya, except for

4032-581: The National Inventors Hall of Fame in 2013. Jordan and Birden worked on an Army Signal Corps contract (R-65-8- 998 11-SC-03-91) beginning on 1 January 1957, to conduct research on radioactive materials and thermocouples suitable for the direct conversion of heat to electrical energy using polonium-210 as the heat source. RTGs were developed in the US during the late 1950s by Mound Laboratories in Miamisburg, Ohio , under contract with

4144-745: The Russian Revolution , this island was named in honour of the members of the Komsomol , the "Communist Union of Youth". Off the northwestern shores of Komsomolets Island lies a group of islets known as Ostrova Dem'yana Bednogo . Pioneer Island , Ostrov Pioner in Russian. It is the westernmost of the large islands of the Severnaya Zemlya group and is separated from Komsomolets Island by the Yuny Strait . Pioneer island measures 1,527 km (590 sq mi) in area. This island houses

4256-574: The SNAP-19C , was lost near the top of Nanda Devi mountain in India in 1965 when it was stored in a rock formation near the top of the mountain in the face of a snowstorm before it could be installed to power a CIA remote automated station collecting telemetry from the Chinese rocket testing facility. The seven capsules were carried down the mountain onto a glacier by an avalanche and never recovered. It

4368-464: The Soviet Arctic coast by the late 1980s. Many different types of RTGs (including Beta-M type) were built in the Soviet Union for a wide variety of purposes. The lighthouses were not maintained for many years after the dissolution of the Soviet Union in 1991 . Some of the RTG units disappeared during this time—either by looting or by the natural forces of ice/storm/sea. In 1996, a project

4480-626: The Sr-90 source), fallen into the ocean, or have defective shielding due to poor design or physical damage. The US Department of Defense cooperative threat reduction program has expressed concern that material from the Beta-M RTGs can be used by terrorists to construct a dirty bomb . However, the Strontium titanate perovskite used is resistant to all likely forms of environmental degradation and cannot melt or dissolve in water. Bioaccumulation

4592-676: The Taymyr Autonomous Okrug until this okrug was merged into Krasnoyarsk Krai on 1 January 2007. As of 2021 it belongs to the Taymyrsky Dolgano-Nenetsky District of Krasnoyarsk Krai. There has been a request at the Krasnoyarsk Krai Legislative Assembly to reinstate the former name of Severnaya Zemlya as "Emperor Nicholas II Land" (Russian: Земля Николая II ). This request, however, has been rejected by

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4704-762: The United States Atomic Energy Commission . The project was led by Dr. Bertram C. Blanke. The first RTG launched into space by the United States was SNAP 3B in 1961 powered by 96 grams of plutonium-238 metal, aboard the Navy Transit 4A spacecraft . One of the first terrestrial uses of RTGs was in 1966 by the US Navy at uninhabited Fairway Rock in Alaska. RTGs were used at that site until 1995. A common RTG application

4816-500: The critical mass is orders of magnitude below the mass needed to produce such amounts of power. As Sr-90, Cs-137 and other lighter radionuclides cannot maintain a nuclear chain reaction under any circumstances, RTGs of arbitrary size and power could be assembled from them if enough material can be produced. In general, however, potential applications for such large-scale RTGs are more the domain of small modular reactors , microreactors or non-nuclear power sources. Plutonium-238 has

4928-674: The heat released by the decay of a suitable radioactive material into electricity by the Seebeck effect . This type of generator has no moving parts and is ideal for deployment in remote and harsh environments for extended periods with no risk of parts wearing out or malfunctioning. RTGs are usually the most desirable power source for unmaintained situations that need a few hundred watts (or less) of power for durations too long for fuel cells , batteries, or generators to provide economically, and in places where solar cells are not practical. RTGs have been used as power sources in satellites , space probes , and uncrewed remote facilities such as

5040-456: The ASRG uses a Stirling power device that runs on radioisotope (see Stirling radioisotope generator ) The radioactive material used in RTGs must have several characteristics: The first two criteria limit the number of possible fuels to fewer than thirty atomic isotopes within the entire table of nuclides . Plutonium-238 , curium-244 , strontium-90 , and most recently americium-241 are

5152-561: The BES-5 Buk ( БЭС-5 ) reactor was a fast reactor which used thermocouples based on semiconductors to convert heat directly into electricity *** not really an RTG, the SNAP-10A used enriched uranium fuel, zirconium hydride as a moderator, liquid sodium potassium alloy coolant, and was activated or deactivated with beryllium reflectors Reactor heat fed a thermoelectric conversion system for electrical production. **** not really an RTG,

5264-587: The Center for Space Nuclear Research (CSNR) in 2013 for studies of feasibility. However the essentials are unmodified. RTG have been proposed for use on realistic interstellar precursor missions and interstellar probes . An example of this is the Innovative Interstellar Explorer (2003–current) proposal from NASA. An RTG using Am was proposed for this type of mission in 2002. This could support mission extensions up to 1000 years on

5376-554: The Kara Sea. The Krasnoflotskiye Islands (Russian: Краснофлотские ) extend from north to south in an almost straight line 78°36′N 98°40′E  /  78.600°N 98.667°E  / 78.600; 98.667 . The main islands are Sverdlova – very close to Cape Sverdlov on the coast, Bolshoy – not much larger than the others despite its name, Sredniy and Greben far offshore. All islands are devoid of vegetation. Two small islets named Opasnye , which are also part of this group, lie 35 km (19 nmi; 22 mi) to

5488-784: The Pioneer Glacier. Thelodonti fossils from the Upper Silurian have been found in the island. Off Pioneer Island's southwestern end lies Krupskoy Island . This is a fairly large island, over 20 km (12 mi) in length and about 11 km (6.8 mi) in width. The sound that separates it from Pioneer is only 0.5 km (0.31 mi) in width. This island should not be confused with Pioneer Island in Canada ( 76°57′N 96°57′W  /  76.950°N 96.950°W  / 76.950; -96.950 ). Schmidt Island , measuring 467 km (180 sq mi),

5600-738: The Prima Polar Station near Cape Baranov . The largest glacier in the Russian Federation, the Academy of Sciences Glacier , is located in Severnaya Zemlya. Until recently, ice joined the islands to Eurasia , even at its smallest extent during the late summer melt season, blocking the Northeast Passage between the Atlantic and the Pacific. By the late summer of 2012, however, due to Arctic sea ice decline

5712-411: The RTGs was estimated at 1 in 10. The launch was successful and Cassini–Huygens reached Saturn . To minimize the risk of the radioactive material being released, the fuel is stored in individual modular units with their own heat shielding. They are surrounded by a layer of iridium metal and encased in high-strength graphite blocks. These two materials are corrosion- and heat-resistant. Surrounding

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5824-523: The Russian flag on the shore and named the new territory Tayvay Land (Russian: Земля Тайвай , Zemlya Tayvay ), after the first syllable of each of their icebreakers' names. During the days that followed, Vilkitsky's expedition charted parts of the Laptev Sea coast of what they believed to be a single island. Barely six months later, in early 1914, by order of the Secretary of the Imperial Navy,

5936-578: The Sedov Group. Golomyanniy Meteorological Station , located on the western tip of Sredniy Island at 79°33′N 90°38′E  /  79.550°N 90.633°E  / 79.550; 90.633 , was the wintering site and base of the 1931–32 expedition and has been taking continuous measurements since 1954. An official request has been forwarded to rename Domashnyy Island as Svyatoy Anastasii ( остров Святой Анастасии ), St. Anastasia Island. Located just south of October Revolution Island in

6048-519: The Voyager RTGs is the degrading properties of the bi-metallic thermocouples used to convert thermal energy into electrical energy ; the RTGs were working at about 67% of their total original capacity instead of the expected 83.4%. By the beginning of 2001, the power generated by the Voyager RTGs had dropped to 315 W for Voyager 1 and to 319 W for Voyager 2 . By 2022, these numbers had dropped to around 220 W. NASA has developed

6160-408: The alpha decay from the radioisotope is also used in alpha-neutron reactions with a suitable element such as beryllium . This way a long-lived neutron source is produced. Because the system is working with a criticality close to but less than 1, i.e. K eff < 1, a subcritical multiplication is achieved which increases the neutron background and produces energy from fission reactions. Although

6272-756: The area during its polar flight of July 1931 and recorded some cartographic and meteorological data; Hugo Eckener tried to take pictures of the yet unsurveyed western coast, but it was obscured by fog and clouds. Although German communists had endured suffering under the Third Reich , due to anti-German sentiment caused by the 1941–1945 German-Soviet War in the USSR some features of Severnaya Zemlya that had been previously named in solidarity with German Communism were given Russian or neutral-sounding names, e.g. Cape Unslicht becoming Mys Peschanyy and Proliv Yungshturm becoming Yuny Strait . During

6384-569: The atmosphere; therefore their use in spacecraft and elsewhere has attracted controversy. However, this event is not considered likely with current RTG cask designs. For instance, the environmental impact study for the Cassini–Huygens probe launched in 1997 estimated the probability of contamination accidents at various stages in the mission. The probability of an accident occurring which caused radioactive release from one or more of its three RTGs (or from its 129 radioisotope heater units ) during

6496-526: The base. The places where the glaciers reach the sea contribute to the formation of icebergs. The most active glacier fronts are the eastern side of the Academy of Sciences Glacier at Krenkel Bay as well as its southern side. Another quite active glacier is the Rusanov Glacier on the island of October Revolution with its terminus at Matusevich Fjord . October Revolution, with seven glaciers ,

6608-522: The bones it can significantly damage the bone marrow , a rapidly dividing tissue), it is usually not employed in pure form in RTGs. The most common form is the perovskite strontium titanate (SrTiO 3 ) which is chemically nigh-inert and has a high melting point. While its Mohs hardness of 5.5 has made it ill-suited as a diamond simulant , it is of sufficient hardness to withstand some forms of accidental release from its shielding without too fine dispersal of dust. The downside to using SrTiO 3 instead of

6720-514: The closing of the weather station. Severnaya Zemlya Severnaya Zemlya ( Russian : Сéверная Земля́ , lit.   'Northern Land', pronounced [ˈsʲevʲɪrnəjə zʲɪmˈlʲa] ) is a 37,000 km (14,000 sq mi) archipelago in the Russian high Arctic . It lies off Siberia 's Taymyr Peninsula , separated from the mainland by the Vilkitsky Strait . This archipelago separates two marginal seas of

6832-401: The design on the next New Frontiers mission. Radioactive materials contained in RTGs are dangerous and can even be used for malicious purposes. They are not useful for a genuine nuclear weapon , but still can serve in a " dirty bomb ". The Soviet Union constructed many uncrewed lighthouses and navigation beacons powered by RTGs using strontium-90 ( Sr). They are very reliable and provide

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6944-620: The desired strontium titanate plus carbon dioxide . If desired, the strontium titanate product can then be formed into a ceramic-like aggregate via sintering . Some prototype RTGs, first built in 1958 by the US Atomic Energy Commission, have used polonium-210 . This isotope provides phenomenal power density (pure Po emits 140 W /g) because of its high decay rate , but has limited use because of its very short half-life of 138 days. A half-gram sample of Po reaches temperatures of over 500 °C (900 °F). As Po

7056-710: The eastern side of the island, feed with glaciers the Matusevich Fjord of the Laptev Sea and the Marat Fjord of the Shokalsky Strait . The Karpinsky ice cap reaches a maximum height of 963 m and it is also the highest point in Severnaya Zemlya. In 2015 the Vavilov Glacier accelerated dramatically due to warming. Between 2015 and 2016 the glacier front advanced 4 km and the glacier lost 4.5 km of ice. Other minor ice caps on

7168-415: The end of 2007, the number was reported to be down to just nine. The Mound Laboratory Cardiac Pacemaker program began on 1 June 1966, in conjunction with NUMEC. When it was recognized that the heat source would not remain intact during cremation, the program was cancelled in 1972 because there was no way to completely ensure that the units would not be cremated with their users' bodies. The design of an RTG

7280-476: The energy output is lower it reaches lower temperatures than Pu, which results in lower RTG efficiency. Sr has a high fission product yield in the fission of both U and Pu and is thus available in large quantities at a relatively low price if extracted from spent nuclear fuel . As Sr is a very reactive alkaline earth metal and a so-called "bone seeker" that accumulates in bone-tissue due to its chemical similarity to calcium (once in

7392-439: The first 3.5 minutes following launch was estimated at 1 in 1,400; the chances of a release later in the ascent into orbit were 1 in 476; after that the likelihood of an accidental release fell off sharply to less than 1 in a million. If an accident which had the potential to cause contamination occurred during the launch phases (such as the spacecraft failing to reach orbit), the probability of contamination actually being caused by

7504-549: The graphite blocks is an aeroshell, designed to protect the entire assembly against the heat of reentering the Earth's atmosphere. The plutonium fuel is also stored in a ceramic form that is heat-resistant, minimising the risk of vaporization and aerosolization. The ceramic is also highly insoluble . The plutonium-238 used in these RTGs has a half-life of 87.74 years, in contrast to the 24,110 year half-life of plutonium-239 used in nuclear weapons and reactors . A consequence of

7616-451: The high latitude. The Laptev Sea , where the mighty Lena River steadily expands its large delta, lies to the east of Severnaya Zemlya. The topographic relief of the archipelago is quite smooth, with Neoproterozoic and Palaeozoic sedimentary successions dominating its bedrock geology. Glaciers in the archipelago have a characteristic dome shape with a continuously decreasing surface towards their edges. Ice cliffs are found only at

7728-574: The interior of the island and do not reach the sea. Ostrov Tash is a small island located on Bolshevik's southern shore. Lavrov Island is located off the NE shore and Ostrov Lishniy off its northern tip. Komsomolets Island (Russian: остров Комсомолец ) is the northernmost island of the Severnaya Zemlya group in the Russian Arctic , and the third largest island in the group. It is the 82nd largest island on earth. The northernmost point of

7840-441: The interstellar probe, because the power output would decline more slowly over the long term than plutonium. Other isotopes for RTG were also examined in the study, looking at traits such as watt/gram, half-life, and decay products. An interstellar probe proposal from 1999 suggested using three advanced radioisotope power sources (ARPS). The RTG electricity can be used for powering scientific instruments and communication to Earth on

7952-404: The island between Krenkel Bay in the east and Zhuravlev Bay in the west. The soil of the island is mostly composed of loose loam and sand , a tundra desert scattered with mosses and lichens. The island was first explored and named by the expedition of Georgy Ushakov and Nikolay Urvantsev in 1930–32. In keeping with their scheme of naming the islands after events and movements of

8064-766: The island include the Malyutka Glacier . The Podemnaya River and the Bolshaya River drain to the northwest between the Vavilov and Albanov glaciers, and the Bedovaya and Obryvistaya Rivers drain to the north between the Albanov and Rusanov ice caps. The coast of the island is uneven with rugged coves and headlands. The largest bays of the island are along the northern coast. The Red Army Strait separates October Revolution Island from Komsomolets Island to

8176-515: The island is called the Arctic Cape . This is the launching point for many Arctic expeditions. The area of this island has been estimated at 9,006 km (3,477 sq mi). It rises to a height of 780 m (2,559 ft). Some 65% of the island is covered with glaciers. Komsomolets Island is home to the largest ice cap in Russia, the Academy of Sciences Ice Cap , which covers most of

8288-453: The island is covered with glaciers reaching down into the sea. In the sections free from ice, the vegetation is desert or tundra . The island was first explored and named by the expedition of G.A. Ushakov and Nikolay N. Urvantsev in 1930–32. October Revolution Island houses five domed ice caps; clockwise from north, they are named: Rusanov , Karpinsky , University , Vavilov and Albanov . The Vavilov Meteorological Station

8400-435: The islands, but adverse weather conditions forced them to turn southward when only an hour or two from viewing the archipelago's coastline. In the spring of 1931, Georgy Ushakov , accompanied by the geologist Nikolay Urvantsev , the veteran surveyor Sergei Zhuravlev , and the radio-operator Vasily Khodov , thoroughly surveyed Severnaya Zemlya during a two-year expedition to the archipelago. Ushakov and his team established

8512-448: The largest island, has a land surface of 232 km or 90 sq mi and is at 78°07′N 107°15′E  /  78.117°N 107.250°E  / 78.117; 107.250 . Nuclear-powered lighthouses in the Soviet Union A radioisotope thermoelectric generator ( RTG , RITEG ), sometimes referred to as a radioisotope power system (RPS), is a type of nuclear battery that uses an array of thermocouples to convert

8624-499: The local government for the time being. Severnaya Zemlya comprises four major islands – October Revolution, Bolshevik, Komsomolets, and Pioneer – and around 70 smaller islands, covering a total area of about 37,000 km (14,300 sq mi). It is separated from the Taymyr Peninsula by the Vilkitsky Strait . Komsomolets is separated from Canada 's northernmost point, Cape Columbia , by under 2000 km . Four of

8736-460: The main islands are largely glaciated, October Revolution, Komsomolets, and Pioneer, as well as the smaller Schmidt Island at the northwestern limit. The glacierised area on Bolshevik, the southernmost main island of the group, covers about a quarter of its land's surface. The southmost point of Severnaya Zemlya is Cape Neupokoyev at the SW end of Bolshevik Island. The highest point of the archipelago

8848-472: The most chemically mobile among the actinides. Curium-250 is the isotope with the lowest atomic number that primarily decays by spontaneous fission, a process that releases many times more energy than alpha decay. Compared to plutonium-238, curium-250 provides about a quarter of the power density, but 95 times the half-life (~8300 years vs. ~87 years). As it is a neutron emitter (weaker than californium-252 but not entirely negligible) some applications require

8960-595: The most often cited candidate isotopes, but 43 more isotopes out of approximately 1,300 were considered at the beginning in the 1950s. The table below does not necessarily give power densities for the pure material but for a chemically inert form. For actinides this is of little concern as their oxides are usually inert enough (and can be transformed into ceramics further increasing their stability), but for alkali metals and alkaline earth metals like caesium or strontium respectively, relatively complex (and heavy) chemical compounds have to be used. For example, strontium

9072-527: The native metal is that its production requires energy. It also reduces power density, as the TiO 3 part of the material does not produce any decay heat. Starting from the oxide or the native metal, one pathway to obtaining SrTiO 3 is to let it transform to strontium hydroxide in aqueous solution, which absorbs carbon dioxide from air to become less soluble strontium carbonate . Reaction of strontium carbonate with titanium dioxide at high temperature produces

9184-661: The new discovery was renamed Emperor Nicholas II Land (Russian: Земля Императора Николая II , Zemlya Imperatora Nikolaya II ), after the ruling Emperor Nicholas II of Russia. In 1926, the Presidium of the Central Executive Committee of the USSR renamed the still not fully-explored land Severnaya Zemlya . In May 1928, Umberto Nobile and his crew in the Airship Italia attempted to overfly

9296-589: The north and Solnechny Bay in the south, as well as fjords such as the large Akhmatov Fjord , and the smaller Thaelmann Fjord , Spartak Fjord and Partizan Fjord . Bolshevik Island is comparatively less glaciated than the other islands of Severnaya Zemlya. Only about 30% of the island is covered by glaciers while the coastal plains have a sparse vegetation of moss and lichen . The Leningrad Glacier , Semyonov-Tyan-Shansky Glacier , Kropotkin Glacier , Mushketov Glacier and Aerosyomki Glacier are located in

9408-406: The north and from Pioneer Island in the northwest, while the broader Shokalsky Strait separates it from Bolshevik Island to the south. Both straits connect the Kara Sea in the west with the Laptev Sea in the east. Cape October is located in the northern part of the island facing the Red Army Strait. Fossilized scales of thelodonts have been discovered on this island. Stroinolepis maenniki

9520-563: The north of the 55 km-wide (34 mi) strait between the Kara Sea and the Laptev Sea that they navigated. The archipelago first appeared on the map with the 1913–1915 Arctic Ocean Hydrographic Expedition of the icebreakers Taimyr and Vaigach . The chief organiser and first captain of the Vaygach was officer Aleksandr Vasiliyevich Kolchak of the Imperial Russian Navy . The expedition, privately financed,

9632-473: The northern limits of the Kara Sea on its western shores, together with Novaya Zemlya , located roughly 1,000 km (620 mi) to the southwest. The large rivers Ob and Yenisei , among others, flow from the south into this marginal sea area of the Arctic Ocean, with their abundant waters contributing to a climate with relatively high precipitation despite the prevalent extreme cold temperatures of

9744-505: The number of fissions produced in the RTG is very small (making their gamma radiation negligible), because each fission reaction releases over 30 times more energy than each alpha decay (200  MeV compared to 6 MeV), up to a 10% energy gain is attainable, which translates into a reduction of the Pu needed per mission. The idea was proposed to NASA in 2012 for the yearly NASA NSPIRE competition, which translated to Idaho National Laboratory at

9856-521: The other minor islands the following deserve mention: The Sedov Archipelago, formerly known as Sergey Kamenev Islands , is located just west of October Revolution Island on the Kara Sea side. The main islands of this archipelago are Sredny (the longest island), Domashnyy , Strela , and Figurnyy . Close to the shore of October Revolution Island lies Obmannyy Island and 32 km (20 mi) further offshore southwards lies Dlinnyy Island . These other coastal islands are sometimes included as part of

9968-443: The other three isotopes discussed in this section, Pu must be specifically synthesized and is not abundant as a nuclear waste product. At present only Russia has maintained high-volume production, while in the US, no more than 50 g (1.8 oz) were produced in total between 2013 and 2018. The US agencies involved desire to begin the production of the material at a rate of 300 to 400 grams (11 to 14 oz) per year. If this plan

10080-678: The period of the Cold War (1940s to 1980s), the islands of Severnaya Zemlya continued to be studied by a team of geologists from NIIGA (the Scientific Research Institute of Arctic Geology) in St. Petersburg , (then known as Leningrad). Between 1948 and 1954 a comprehensive geological map was compiled under B. Kh. Egiazarov. Also more accurate maps were drawn by means of cartographic data gathered from aerial-photography surveys. Administratively, Severnaya Zemlya formed part of

10192-412: The permanent ice had reached a record low extent and open water appeared to the south of the archipelago. Although Severnaya Zemlya lies not far off the northern coast of Siberia, cartographers did not formally record it until the 20th century. Earlier explorers deemed that there was a land mass in the general area - note for example the report by Matvei Gedenschtrom and Yakov Sannikov made in 1810 at

10304-487: The pre-launch and early flight phases of a space mission. While spectacular failures like a nuclear meltdown or explosion are impossible with an RTG, there is still a risk of radioactive contamination if the rocket explodes, the device reenters the atmosphere and disintegrates, terrestrial RTGs are damaged by storms or seasonal ice, or are vandalized. Due to the shortage of plutonium-238, a new kind of RTG assisted by subcritical reactions has been proposed. In this kind of RTG,

10416-578: The previous heat treatment history of the PuO 2 . This lowering of the neutron emission rate of PuO 2 containing normal oxygen by a factor of five was discovered during the cardiac pacemaker research at Mound Laboratory in 1966, due in part to the Mound Laboratory's experience with production of stable isotopes beginning in 1960. For production of the large heat sources the shielding required would have been prohibitive without this process. Unlike

10528-458: The probes. One mission proposed using the electricity to power ion engines , calling this method radioisotope electric propulsion (REP). A power enhancement for radioisotope heat sources based on a self-induced electrostatic field has been proposed. According to the authors, enhancements of 5-10% could be attainable using beta sources. A typical RTG is powered by radioactive decay and features electricity from thermoelectric conversion, but for

10640-553: The rest of the archipelago. Schmidt Island was named after the Soviet scientist Otto Schmidt . Close to the main archipelago of Severnaya Zemlya there are a number of smaller islands and archipelagos. There are also many small coastal islands and islets in different locations, such as Krupskoy to the west of Pioneer and Naydenysh (Russian: Найдёныш ) near Cape Anuchin in October Revolution Island. Among

10752-502: The risk of radioactive contamination. Transforming the radioactive material into an inert form reduces the danger of theft by people unaware of the radiation hazard (such as happened in the Goiânia accident in an abandoned Cs-137 source where the caesium was present in easily water-soluble caesium chloride form). However, a sufficiently chemically skilled malicious actor could extract a volatile species from inert material and/or achieve

10864-648: The sake of knowledge, some systems with some variations on that concept are included here. Known spacecraft/nuclear power systems and their fate. Systems face a variety of fates, for example, Apollo's SNAP-27 were left on the Moon. Some other spacecraft also have small radioisotope heaters, for example each of the Mars Exploration Rovers have a 1 watt radioisotope heater. Spacecraft use different amounts of material, for example MSL Curiosity has 4.8 kg of plutonium-238 dioxide . ** not really an RTG,

10976-439: The same, plutonium-238 is around 275 times more toxic by weight than plutonium-239. The alpha radiation emitted by either isotope will not penetrate the skin, but it can irradiate internal organs if plutonium is inhaled or ingested. Particularly at risk is the skeleton , the surface of which is likely to absorb the isotope, and the liver , where the isotope will collect and become concentrated. A case of RTG-related irradiation

11088-410: The shorter half-life is that plutonium-238 is about 275 times more radioactive than plutonium-239 (i.e. 17.3 curies (640  GBq )/ g compared to 0.063 curies (2.3 GBq)/g ). For instance, 3.6  kg of plutonium-238 undergoes the same number of radioactive decays per second as 1 tonne of plutonium-239. Since the morbidity of the two isotopes in terms of absorbed radioactivity is almost exactly

11200-599: The solar-powered option, as used in prior generations of rovers . RTGs were also used for the Nimbus , Transit and LES satellites. By comparison, only a few space vehicles have been launched using full-fledged nuclear reactors : the Soviet RORSAT series and the American SNAP-10A . In addition to spacecraft, the Soviet Union built 1,007 RTGs to power uncrewed lighthouses and navigation beacons on

11312-648: The southwest of Greben Island. The Krasnoflotskiye Islands were first sighted and mapped in August 1932 by the expedition of the All-Union Arctic Institute on the icebreaker Rusanov . There is an Arctic Station in the Krasnoflotskiye Islands (AS-042), which has been operating since 1953. This is a small group including two main islands located in the Laptev Sea, off the far southeastern end of Bolshevik Island. Maly Taymyr ,

11424-406: The spontaneous fission of plutonium-238. The difference in the emission rates of the metal and the oxide is due mainly to the alpha, neutron reaction with the oxygen-18 and oxygen-17 present in the oxide. The normal amount of oxygen-18 present in the natural form is 0.204% while that of oxygen-17 is 0.037%. The reduction of the oxygen-17 and oxygen-18 present in the plutonium dioxide will result in

11536-424: The surface of the island. October Revolution Island (Russian: Остров Октябрьской Революции , Ostrov Oktyabrskoy Revolyutsii ) is the largest island of the Severnaya Zemlya group in the Russian Arctic . The area of this island has been estimated at 14,170 km (5,470 sq mi) making it the 59th largest island in the world. It rises to a height of 965 m (3,166 ft) on Mount Karpinsky . Half

11648-661: The time of their exploration of the New Siberian Islands . Later in the 19th century, Adolf Erik Nordenskiöld during the Vega expedition sailed very close to this land in 1878 but did not notice it. In 1882, the Danish Arctic explorer and naval officer Andreas Peter Hovgaard , leader of the Arctic survey Dijmphna expedition , set himself the goal of discovering land north of Cape Chelyuskin and exploring

11760-589: The two Viking landers, and for the scientific experiments left on the Moon by the crews of Apollo 12 through 17 (SNAP 27s). Because the Apollo 13 Moon landing was aborted, its RTG rests in the South Pacific Ocean , in the vicinity of the Tonga Trench . The Curiosity and Perseverance Mars rover designs selected RTGs to allow greater flexibility in landing sites and longer lifespan than

11872-440: The unknown northeastern limits of the Kara Sea . However, Hovgaard was prevented from accomplishing his objectives after having become trapped in thick ice, and his expedition was unable to reach even the shores of the Taymyr Peninsula . Even at the end of the 19th century, both Nansen's Fram expedition of 1895 and Eduard Toll 's Russian polar expedition of 1900–02 on the ship Zarya failed to note any traces of land to

11984-444: The woodsmen were later hospitalized with severe radiation burns after carrying the sources on their backs. The units were eventually recovered and isolated. There are approximately 1,000 such RTGs in Russia, all of which have long since exceeded their designed operational lives of ten years. Most of these RTGs likely no longer function, and may need to be dismantled. Some of their metal casings have been stripped by metal hunters, despite

12096-432: The world . It rises to a height of 965 m (3,166 ft) on Mount Karpinsky . Half the island is covered with glaciers reaching down into the sea. In the sections free from ice, the vegetation is desert or tundra . October Revolution Island houses five domed ice caps ; clockwise from north, they are named: Rusanov , Karpinsky , University , Vavilov and Albanov . The Rusanov and Karpinsky ice caps, located on

12208-601: Was begun by Russian and international supporters to decommission the RTGs in the lighthouses, and by 2021, all RTGs had been removed. As of 1992, the United States Air Force also used RTGs to power remotely-located Arctic equipment, and the US government has used hundreds of such units to power remote stations globally. Sensing stations for Top-ROCC and SEEK IGLOO radar systems, predominantly located in Alaska , use RTGs. The units use strontium-90 , and

12320-607: Was discovered by Boris Vilkitsky in 1913 during an expedition on behalf of the Russian Hydrographic Service , but its insularity was not proven until 1931, when Georgy Ushakov and Nikolay Urvantsev charted the archipelago during their 1930–1932 expedition. The Vavilov Meteorological Station was operated from 1974 to 1988 on the northern part of the Vavilov Ice Cap. The island had a nuclear-powered lighthouse installed in 1989, shortly after

12432-567: Was launched in 1910 and led by Boris Vilkitsky on behalf of the Russian Hydrographic Service . This venture accomplished its goal of exploring the uncharted areas of the continental side of the Northern Sea Route . On 3 September 1913 (22 August 1913 in the Julian calendar used by Russia at the time), members of Vilkitsky's expedition landed on what is now known as Cape Berg on present-day October Revolution Island . They raised

12544-465: Was operated from 1974 to 1988 on the northern part of the Vavilov Ice Cap. Other minor ice caps on the island include the Mal'yutka Glacier. The Podemnaya River and the Bolshaya River drain to the northwest between the Vavilov and Albanov glaciers, and the Bedovaya and Obryvistaya Rivers drain to the north between Albanov and Rusanov . The largest lake of the island and the entire archipelago, Fiordovoye ,

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