281:, then optionally to nitride, and then to oxide. Gallium is then mostly removed from the solid oxide mixture by heating at 1100 °C in a 94% argon 6% hydrogen atmosphere, reducing gallium content from 1% to 0.02%. Further dilution of plutonium oxide during the MOX fuel manufacture brings gallium content to levels considered negligible. A wet route of gallium removal, using
117:δ phase Pu–Ga is still thermodynamically unstable, so there are concerns about its aging behavior. There are substantial differences of density (and therefore volume) between the various phases. The transition between δ-phase and α-phase plutonium occurs at a low temperature of 115 °C and can be reached by accident. Prevention of the
69:. The δ phase is the least dense and most easily machinable. It is formed at temperatures of 310–452 °C at ambient pressure (1 atmosphere), and is thermodynamically unstable at lower temperatures. However, plutonium can be stabilized in the δ phase by alloying it with a small amount of another metal. The preferred alloy is 3.0–3.5
150:
electrons, and can be disrupted by increased temperature or by presence of suitable atoms in the lattice which reduce the available number of 5f electrons and weaken their bonds. The alloy is denser in molten state than in solid state, which poses an advantage for casting as the tendency to form
162:
is required at the temperature just below the δ–ε phase transition, so gallium atoms can diffuse through the grains and create homogeneous structure. The time to achieve homogenization of gallium increases with increasing grain size of the alloy and decreases with increasing temperature. The
245:
Plutonium alloys can be produced by adding a metal to molten plutonium. However, if the alloying metal is sufficiently reductive, plutonium can be added in the form of oxides or halides. The δ phase plutonium–gallium and plutonium–aluminium alloys are produced by adding
125:
However, the phase change is useful during the operation of a nuclear weapon. As the reaction starts, it generates enormous pressures, in the range of hundreds of gigapascals. Under these conditions, δ phase Pu–Ga transforms to α phase, which is 25% denser and thus more
174:
of plutonium then allows rough identification of its origin, manufacturing method, type of the reactor used in its production, and rough history of the irradiation, and matching to other samples, which is of importance in investigation of
113:
More modern pits are produced by casting. Subcritical testing showed that wrought and cast plutonium performance is the same. As only the ε-δ transition occurs during cooling, casting Pu-Ga is easier than casting pure plutonium.
297:
During the
Manhattan Project (1942-1945), the maximum amount of diluent atoms for plutonium to not affect the explosion efficiency was calculated to be 5 mol.%. Two stabilizing elements were considered,
121:
and the associated mechanical deformations and consequent structural damage and/or loss of symmetry is of critical importance. Under 4 mol.% gallium the pressure-induced phase change is irreversible.
306:. However, only aluminium produced satisfactory alloys. But the aluminium tendency to react with α-particles and emit neutrons limited its maximum content to 0.5 mol.%; the next element from the
206:
Ga (ζ'-phase) within α phase, with the corresponding dimensional and density change and buildup of internal strains. The decay of plutonium however produces energetic particles (
163:
structure of stabilized plutonium at room temperature is the same as unstabilized at δ-phase temperature, with the difference of gallium atoms substituting plutonium in the
97:
good castability; since plutonium has the rare property that the molten state is denser than the solid state, the tendency to form bubbles and internal defects is decreased.
176:
1206:
218:
with only a modest amount of ζ' phase present, which explains the alloy's unexpectedly slow, graceful aging. The alpha particles are trapped as interstitial
805:
1489:
233:, which has significantly faster decay rate, to the alloy increases the aging damage rate by 16 times, assisting with plutonium aging research. The
758:
624:
146:. Addition of gallium causes the bonds to become more even, increasing the stability of the δ phase. The α phase bonds are mediated by the
222:
atoms in the lattice, coalescing into tiny (about 1 nm diameter) helium-filled bubbles in the metal and causing negligible levels of
138:
Plutonium in its α phase has a low internal symmetry, caused by uneven bonding between the atoms, more resembling (and behaving like) a
524:
106:
Stabilized δ-phase Pu–Ga is ductile, and can be rolled into sheets and machined by conventional methods. It is suitable for shaping by
1199:
400:
333:
310:
of elements, gallium, was tried and found to be satisfactory. The early atomic bomb design secrets passed to the
Soviets by spy
798:
250:
to molten gallium or aluminium, which has the advantage of avoiding dealing directly with the highly reactive plutonium metal.
314:
included the gallium trick for stabilizing phases of plutonium, and thus the first Soviet atomic bomb used this alloy also.
588:
1484:
1192:
640:
425:
53:, the component of a nuclear weapon where the fission chain reaction is started. This alloy was developed during the
170:
The presence of gallium in plutonium signifies its origin from weapon plants or decommissioned nuclear weapons. The
791:
502:
1494:
1417:
1279:
828:
1479:
1409:
1354:
1297:
1289:
1266:
1127:
1120:
266:
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158:
and gallium-poor grain boundaries. To stabilize the lattice and reverse and prevent segregation of gallium,
66:
1455:
1436:
1305:
1103:
993:
188:
159:
1342:
1313:
1079:
972:
896:
1370:
1067:
1021:
1001:
956:
891:
562:
50:
766:
1362:
1215:
980:
964:
886:
274:
223:
215:
164:
694:"Method for plutonium-gallium separation by anodic dissolution of a solid plutonium-gallium alloy"
358:
202:
During aging of the stabilized δ alloy, gallium segregates from the lattice, forming regions of Pu
1250:
1245:
1055:
1050:
870:
478:
455:
171:
1337:
1321:
1284:
1271:
1237:
1229:
1045:
1037:
814:
620:
614:
278:
88:
54:
1147:
931:
851:
570:
528:
118:
1159:
1091:
1009:
988:
912:
865:
860:
447:
286:
404:
337:
262:, the majority of gallium has to be removed as its high content could interfere with the
566:
207:
147:
17:
226:; the size of bubbles appears to be limited, though their number increases with time.
110:
at about 400 °C. This method was used for forming the first nuclear weapon pits.
1473:
230:
127:
70:
734:
714:
282:
107:
574:
154:
Gallium tends to segregate in plutonium, causing "coring"—gallium-rich centers of
1382:
693:
311:
307:
211:
155:
592:
647:
94:
low susceptibility to corrosion (4% of the corrosion rate of pure plutonium),
944:
379:
303:
270:
234:
42:
672:
263:
259:
214:
nuclei) that cause local disruption of the ζ' phase, and establishing a
936:
613:
Moody, Kenton James; Hutcheon, Ian D.; Grant, Patrick M. (2005-02-28).
479:"Modelling the Lattice Parameter of Plutonium Aluminium Solid Solution"
299:
139:
74:
46:
1184:
273:) and with migration of fission products in the fuel pellets. In the
219:
783:
550:
715:"First Nuclear Weapons: Nuclear Weapons Frequently Asked Questions"
237:
supercomputer aided with simulations of plutonium aging processes.
143:
38:
646:. Amarillo National Resource Center for Plutonium. Archived from
525:"Plutonium: Aging Mechanisms and Weapon Pit Lifetime Assessment"
277:, the pits are converted to oxide by converting the material to
1188:
787:
527:. The Minerals, Metals & Materials Society. Archived from
673:"Gallium in Weapons-Grade Plutonium and MOX Fuel Fabrication"
759:"The drama of plutonium - Nuclear Engineering International"
426:"Scientists tackle long-standing questions about plutonium"
380:"Optical Pyrometry on the Armando Subcritical Experiment"
336:. Nuclear Engineering International. 2005. Archived from
551:"Reversible expansion of gallium-stabilized δ-plutonium"
1448:
1429:
1402:
1330:
1259:
1222:
1119:
924:
905:
879:
844:
821:
289:is another way to separate gallium and plutonium.
591:. Science and Technology Reviews. Archived from
258:For reprocessing of surplus warhead pits into
1200:
799:
641:"Gallium Interactions with Zircaloy Cladding"
549:Wolfer, W. G.; Oudot, B.; Baclet, N. (2006).
8:
151:bubbles and internal defects is decreased.
1207:
1193:
1185:
1116:
806:
792:
784:
589:"U.S. Weapons Plutonium Ages Gracefully"
187:There are several plutonium and gallium
322:
328:
326:
80:Pu–Ga has many practical advantages:
7:
523:Martz, Joseph C.; Schwartz, Adam J.
359:"Italian Stallions & Plutonium"
84:stable between −75 and 475 °C,
403:. centurychina.com. Archived from
67:several different solid allotropes
25:
27:Alloy used in nuclear weapon pits
671:Toevs, James W.; Beard, Carl A.
382:. Los Alamos National Laboratory
1490:Low thermal expansion materials
501:Edwards, Rob (19 August 1995).
1:
735:"Dr Smith goes to Los Alamos"
575:10.1016/j.jnucmat.2006.08.020
446:Hecker, Siegfried S. (2000).
1121:Organogallium(III) compounds
555:Journal of Nuclear Materials
1511:
448:"Plutonium and Its Alloys"
428:. innovations-report. 2006
254:Reprocessing into MOX fuel
616:Nuclear forensic analysis
334:"The drama of plutonium"
229:Addition of 7.5 wt.% of
248:plutonium(III) fluoride
189:intermetallic compounds
65:Metallic plutonium has
31:Plutonium–gallium alloy
18:Plutonium-gallium alloy
740:. RESONANCE. June 2006
503:"Fissile Fingerprints"
102:Use in nuclear weapons
285:, is also possible.
1485:Plutonium compounds
1216:Plutonium compounds
763:www.neimagazine.com
567:2006JNuM..359..185W
293:Development history
216:dynamic equilibrium
51:nuclear weapon pits
769:on 9 November 2021
456:Los Alamos Science
407:on January 7, 2010
172:isotopic signature
1467:
1466:
1182:
1181:
1178:
1177:
815:Gallium compounds
626:978-0-8493-1513-8
279:plutonium hydride
269:(gallium attacks
177:nuclear smuggling
134:Effect of gallium
89:thermal expansion
55:Manhattan Project
16:(Redirected from
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1209:
1202:
1195:
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1117:
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765:. Archived from
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477:Darby, Richard.
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401:"Plutonium (Pu)"
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119:phase transition
21:
1510:
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1504:
1503:
1501:
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1495:Nuclear weapons
1470:
1469:
1468:
1463:
1459:
1449:Plutonium(VIII)
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1421:
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505:. New Scientist
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287:Electrorefining
256:
243:
208:alpha particles
205:
198:
194:
185:
136:
104:
73:(0.8–1.0 wt.%)
63:
28:
23:
22:
15:
12:
11:
5:
1508:
1506:
1498:
1497:
1492:
1487:
1482:
1480:Gallium alloys
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1260:Plutonium(III)
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938:
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906:Gallium(I,III)
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561:(3): 185–191.
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1430:Plutonium(VI)
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1401:
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1381:
1379:
1369:
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1331:Plutonium(IV)
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1223:Plutonium(II)
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1187:
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653:on 2012-03-02
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619:. CRC Press.
618:
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595:on 2013-02-17
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531:on 2016-03-03
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275:ARIES process
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231:plutonium-238
227:
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224:void swelling
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56:
52:
48:
44:
40:
36:
32:
19:
1403:Plutonium(V)
925:Gallium(III)
771:. Retrieved
767:the original
762:
753:
742:. Retrieved
729:
718:. Retrieved
709:
698:. Retrieved
688:
677:. Retrieved
666:
655:. Retrieved
648:the original
635:
615:
608:
597:. Retrieved
593:the original
583:
558:
554:
544:
533:. Retrieved
529:the original
518:
507:. Retrieved
496:
485:. Retrieved
472:
461:. Retrieved
454:
441:
430:. Retrieved
420:
409:. Retrieved
405:the original
395:
384:. Retrieved
374:
363:. Retrieved
353:
342:. Retrieved
338:the original
296:
283:ion exchange
257:
244:
228:
201:
186:
169:
153:
137:
124:
116:
112:
108:hot pressing
105:
79:
64:
34:
30:
29:
880:Gallium(II)
822:Gallium(-V)
696:. frepatent
312:Klaus Fuchs
308:boron group
212:uranium-235
1474:Categories
845:Gallium(I)
773:5 February
744:2010-01-25
720:2010-01-25
700:2010-01-25
679:2010-01-25
657:2010-01-25
599:2010-01-25
535:2010-01-25
509:2010-01-25
487:2010-01-25
463:2010-01-25
432:2010-01-25
411:2010-01-25
386:2010-01-25
365:2010-01-25
344:2010-01-25
318:References
241:Production
195:Ga, and Pu
191:: PuGa, Pu
49:, used in
361:. jeffrey
304:aluminium
271:zirconium
235:Blue Gene
167:lattice.
160:annealing
87:very low
43:plutonium
267:cladding
264:fuel rod
260:MOX fuel
148:5f shell
128:critical
61:Overview
37:) is an
563:Bibcode
300:silicon
142:than a
140:ceramic
75:gallium
47:gallium
1002:Ga(CN)
994:Ga(OH)
675:. IEEE
623:
220:helium
156:grains
1418:XePuF
1371:Pu(IO
1343:Pu(NO
1148:Ga(CH
1092:Ga(CH
1010:Ga(NO
738:(PDF)
651:(PDF)
644:(PDF)
482:(PDF)
451:(PDF)
183:Aging
144:metal
71:mol.%
39:alloy
35:Pu–Ga
1383:Pu(C
1306:PuBr
1298:PuCl
1267:PuAs
1251:PuSi
1246:PuSe
1160:Ga(C
1128:Ga(C
1096:COO)
1051:GaSb
1038:GaPO
965:GaCl
957:GaBr
932:GaAs
913:GaCl
897:GaTe
892:GaSe
866:GaBr
861:GaCl
775:2022
621:ISBN
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1314:PuI
1290:PuF
1285:PuB
1280:PuP
1272:PuH
1238:PuB
1230:PuH
1046:GaP
1026:(SO
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981:GaI
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