Castle Bravo

1954 U.S.thermonuclear weapon test in the Marshall Islands

castle bravo was the first in a series of high – yield thermonuclear weapon design test conduct by the United States at bikini Atoll , Marshall Islands , as part ofOperation castle.Detonated on 1 March 1954, the device remains the most powerful nuclear device ever detonated by the United States andthe first lithium deuteride-fueled thermonuclear weapon tested using the teller-Ulam design.^[1][2] castle bravo’s yield was 15 megatons of tNt [Mt] (63 PJ), 2.5 times the predicted 6 Mt (25 PJ), due to unforeseen additional reactions involving lithium-7,^[3] which is led lead to radioactive contamination in the surround area .^[4]

Fallout, the heaviest of which was in the form of pulverized surface coral from the detonation, fell on residents of Rongelap andUtirik atolls, while the more particulate andgaseous fallout spread around the world.theinhabitants of the islands were evacuated only three days later andsuffered radiation sickness.twenty-three crew members of the Japanese fishing vessel Daigo Fukuryū Maru (“Lucky Dragon No.5”) were also contaminated by the heavy fallout, experiencing acute radiation syndrome, including the death six months later of Kuboyama Aikichi, the boat’s chief radioman.theblast incited a strong international reaction over atmospheric thermonuclear testing.^[5]

thebravo Crater is located at 11 ° 41′50″N 165 ° 16′19″E /11.69722°N 165.27194°E /11.69722 ; 165.27194.theremains of the castle bravo causeway are at 11°42′6″N 165 ° 17′7″E /11.70167°N 165.28528°E /11.70167 ; 165.28528.

thecastle bravo device was house in a cylinder that weigh 23,500 pound ( 10,700   kg ) andmeasure 179.5 inch ( 456   cm ) in length and53.9 inch ( 137   cm ) in diameter .^[3]

theprimary device is was was aCObRA deuterium – tritium gas – boost atomic bomb made by Los Alamos Scientific Laboratory , a very compact MK 7 device .this boost fission device had been test in theUpshot-Knothole Climax event andyielded 61 kilotons of tNt [kt] (260 tJ) (out of 50–70 kt expected yield range) .It was considered successful enough that the planned operation series Domino, designed to explore the same question about a suitable primary for thermonuclear bombs, could be canceled.^[8]: 197 theimplosion system is was was quite lightweight at 900   lb ( 410   kg ) , because it eliminate the aluminum pusher shell around the tamper^{[Note 1]} andused the more compact ring lenses,^{[note 2]} a design feature shared with the Mark 5, 12, 13 and18 designs.theexplosive material of the inner charges in the MK 7 was changed to the more powerful Cyclotol 75/25, instead of the Composition b used in most stockpiled bombs at that time, as Cyclotol 75/25 was denser than Composition b andthus could generate the same amount of explosive force in a smaller volume (it provided 13 percent more compressive energy than Comp b) .^{[9]: 86 :   91} thecomposite uranium – plutoniumCObRA core was levitated in a type-D pit.CObRA was Los Alamos ‘ most recent product of design work on the ” new principle ” of the hollow core .^{[8]:   196} A copper pit liner is prevented encase within the weapon – grade plutonium inner capsule prevent Dt gas diffusion into the plutonium , a technique first test inGreenhouse Item.^[8]: 258 theassembled module weighed 1,840 lb (830 kg), measuring 30.5 in (770 mm) across.It was located at the end of the device, which, as seen in the declassified film, shows a small cone projecting from the ballistic case.this cone is the part of the paraboloid that was used to focus the radiation emanating from the primary into the secondary.^[10]

deuterium andlithium

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thedevice was called SHRIMP, andhad the same basic configuration ( radiation implosion ) as theivy Mike wet device, except with a different type of fusion fuel.SHRIMP used lithium deuteride ( lid ) , which is solid at room temperature ;ivy Mike used cryogenic liquid deuterium (D₂), which required elaborate cooling equipment.castle bravo was the first test by the United States of a practical deliverable fusion bomb, even though the tX-21 as proof-tested in the bravo event was not weaponized.thesuccessful test rendered obsolete the cryogenic design used by ivy Mike andits weaponized derivative, the JUGHEAD, which was slated to be tested as the initial castle Yankee.It also used a 3.7-inch-thick (9.5 cm) 7075 aluminum ballistic case.Aluminum was used to drastically reduce the bomb’s weight andsimultaneously provided sufficient radiation confinement time to raise yield, a departure from the heavy stainless steel casing (304L or MIM 316L) employed by other weapon-projects at the time.^{[8]: 54 : 237 [11]}

theSHRIMP was at least in theory andin many critical aspect identical in geometry to therunt andrunt II device later proof – fire incastle Romeo andcastle Yankee respectively.On paper it was a scaled-down version of these devices, andits origins can be traced back to 1953.theUnited States Air Force indicated the importance of lighter thermonuclear weapons for delivery by the b-47 Stratojet andb-58 Hustler.Los Alamos National Laboratory responded to this indication with a follow-up enriched version of the runt scaled down to a 3/4 scale radiation-implosion system called the SHRIMP.theproposed weight reduction (from tX-17’s 42,000 pounds (19,000 kg) to tX-21’s 25,000 pounds (11,000 kg)) would provide the Air Force with a much more versatile deliverable gravity bomb.^[8]: 237 thefinal version tested in castle used partially enriched lithium as its fusion fuel.Natural lithium is a mixture of lithium-6 andlithium-7 isotopes (with 7.5% of the former) .theenriched lithium used in bravo was nominally 40% lithium-6 (the remainder was the much more common lithium-7, which was incorrectly assumed to be inert) .thefuel slugs varied in enrichment from 37 to 40% in ⁶Li, andthe slugs with lower enrichment were positioned at the end of the fusion-fuel chamber, away from the primary.thelower levels of lithium enrichment in the fuel slugs, compared with the ALARM CLOCK andmany later hydrogen weapons is were , were due to shortage in enrich lithium at that time , as the first of theAlloy Development Plants (ADP) started production in late 1953.^[12]: 208 thevolume of LiD fuel used was approximately 60% the volume of the fusion fuel filling used in the wet SAUSAGE anddry runt I andII devices, or about 500 liters (110 imp gal; 130 U.S. gal),^{[note 3]} corresponding to about 390 kg of lithium deuteride (as LiD has a density of 0.78201 g/cm³) .^{[13]:   281} themixture cost about 4.54 USD/g at that time.thefusion burn efficiency was close to 25.1%, the highest attained efficiency of the first thermonuclear weapon generation.this efficiency is well within the figures given in a November 1956 statement, when a DOD official disclosed that thermonuclear devices with efficiencies ranging from 15% to up about 40% had been tested.^{[8]:   39} Hans bethe reportedly stated independently that the first generation of thermonuclear weapons had (fusion) efficiencies varying from as low as 15% to up about 25%.

thethermonuclear burn would produce (like the fission fuel in the primary) pulsations (generations) of high-energy neutrons with an average temperature of 14 MeV through Jetter’s cycle.

• theSHRIMP shortly before installation in its shot cab

• SHRIMP’s parabolic projection

• SHRIMP‘s cylindrical end

• shot – cab installation ofSHRIMP device , with human for scale

theJetter cycle is a combination of reactions involving lithium, deuterium, andtritium.It consumes lithium-6 anddeuterium, andin two reactions (with energies of 17.6 MeV and4.8 MeV, mediated by a neutron andtritium) it produces two alpha particles.^[14]

thereaction would produce high-energy neutrons with 14 MeV, andits neutronicity was estimated at ≈0.885 (for a Lawson criterion of ≈1.5) .

possible additional tritium for high – yield

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AsSHRIMP, along with the runt I andALARM CLOCK, were to be high-yield shots required to assure the thermonuclear “emergency capability,” their fusion fuel may have been spiked with additional tritium, in the form of ⁶Lit.^[12]: 236 All of the high-energy 14 MeV neutrons would cause fission in the uranium fusion tamper wrapped around the secondary andthe spark plug’s plutonium rod.theratio of deuterium (and tritium) atoms burned by 14 MeV neutrons spawned by the burning was expected to vary from 5:1 to 3:1, a standardization derived from Mike,^[12] while for these estimations, the ratio of 3:1 was predominantly used in ISRINEX.theneutronicity of the fusion reactions harnessed by the fusion tamper would dramatically increase the yield of the device.

SHRIMP‘s indirect drive

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bravo SHRIMP device shot-cab

Attached to the cylindrical ballistic case was a natural-uranium liner, the radiation case, that was about 2.5 cm thick.Its internal surface was lined with copper that was about 240 μm thick, andmade from 0.08-μm thick copper foil, to increase the overall albedo of the hohlraum.^{[15][16][0.08 μm?? – verification needed]} Copper possesses excellent reflecting properties, andits low cost, compared to other reflecting materials like gold, made it useful for mass-produced hydrogen weapons.Hohlraum albedo is a very important design parameter for any inertial-confinement configuration.A relatively high albedo permits higher interstage coupling due to the more favorable azimuthal andlatitudinal angles of reflected radiation.thelimiting value of the albedo for high-z material is reach when the thickness is 5–10   g / cm², or 0.5–1.0 free paths.thus, a hohlraum made of uranium much thicker than a free path of uranium would be needlessly heavy andcostly.At the same time, the angular anisotropy increases as the atomic number of the scatterer material is reduced.therefore, hohlraum liners require the use of copper (or, as in other devices, gold or aluminium), as the absorption probability increases with the value of z_eff of the scatterer.there are two sources of X-rays in the hohlraum: the primary’s irradiance, which is dominant at the beginning andduring the pulse rise; andthe wall, which is important during the required radiation temperature’s (t_r) plateau.theprimary emits radiation in a manner similar to a flash bulb, andthe secondary needs constant t_r to properly implode.^[17] this constant wall temperature is dictated by the ablation pressure requirements to drive compression, which lie on average at about 0.4 keV (out of a range of 0.2 to 2 keV)^{[Note 4]}, corresponding to several million kelvins.Wall temperature depended on the temperature of the primary’s core which peaked at about 5.4 keV during boosted-fission.^{[20]: 1–11 [18]:   9} thefinal wall-temperature, which corresponds to energy of the wall-reradiated X-rays to the secondary’s pusher, also drops due to losses from the hohlraum material itself.^{[15][Note 5]} Natural uranium nails, lined to the top of their head with copper, attached the radiation case to the ballistic case.thenails were bolted in vertical arrays in a double-shear configuration to better distribute the shear loads.this method of attaching the radiation case to the ballistic case was first used successfully in the ivy Mike device.theradiation case had a parabolic end, which housed the CObRA primary that was employed to create the conditions needed to start the fusion reaction, andits other end was a cylinder, as also seen in bravo’s declassified film.

thespace between the uranium fusion tamper,^{[note 6]} andthe case formed a radiation channel to conduct X-rays from the primary to the secondary assembly; the interstage.It is one of the most closely guarded secrets of a multistage thermonuclear weapon.Implosion of the secondary assembly is indirectly driven, andthe techniques used in the interstage to smooth the spatial profile (i.e.reduce coherence andnonuniformities) of the primary’s irradiance are of utmost importance.this was done with the introduction of the channel filler—an optical element used as a refractive medium,^{[21]:   279} also encountered as random-phase plate in the ICF laser assemblies.this medium was a polystyrene plastic foam filling, extruded or impregnated with a low-molecular-weight hydrocarbon (possibly methane gas), which turned to a low-z plasma from the X-rays, andalong with channeling radiation it modulated the ablation front on the high-z surfaces; it “tamped”^{[Note 7]} the sputtering effect that would otherwise ” choke ” radiation from compress the secondary .^{[Note 8]} thereemitted X-rays from the radiation case must be deposited uniformly on the outer walls of the secondary’s tamper andablate it externally, driving the thermonuclear fuel capsule (increasing the density andtemperature of the fusion fuel) to the point needed to sustain a thermonuclear reaction.^{[23]: 438–454} (see Nuclear weapon design) .this point is above the threshold where the fusion fuel would turn opaque to its emitting radiation, as determined from its Rosseland opacity, meaning that the generated energy balances the energy lost to fuel’s vicinity (as radiation, particle losses) .After all, for any hydrogen weapon system to work, this energy equilibrium must be maintained through the compression equilibrium between the fusion tamper andthe spark plug (see below), hence their name equilibrium supers.^[24]: 185

SHRIMP device delivered via truck awaiting installation

Since the ablative process takes place on both walls of the radiation channel, a numerical estimate made with ISRINEX (a thermonuclear explosion simulation program) suggested that the uranium tamper also had a thickness of 2.5 cm, so that an equal pressure would be applied to both walls of the hohlraum.therocket effect on the surface of tamper’s wall created by the ablation of its several superficial layers would force an equal mass of uranium that rested in the remainder of the tamper to speed inwards, thus imploding the thermonuclear core.At the same time, the rocket effect on the surface of the hohlraum would force the radiation case to speed outwards.theballistic case would confine the exploding radiation case for as long as necessary.thefact that the tamper material was uranium enriched in ²³⁵u is primarily base on the final fission reaction fragment detect in the radiochemical analysis , which conclusively show the presence of²³⁷U, found by the Japanese in the shot debris.^[25]: 282 thefirst-generation thermonuclear weapons (MK-14, 16, 17, 21, 22 and24) all used uranium tampers enriched to 37.5% ²³⁵U.^[25]: 16 theexception to this was the MK-15 zOMbIE that used a 93.5% enriched fission jacket.

thesecondary assembly

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In a similar manner to the earlier pipes filled with a partial pressure of helium, as used in the ivy Mike test of 1952, the 1954 castle bravo test was likewise heavily instrumented with Line-of-Sight (LOS) pipes, to better define andquantify the timing andenergies of the x-rays andneutrons produced by these early thermonuclear devices.^[26][27] One of the outcomes of this diagnostic work resulted in this graphic depiction of the transport of energetic x-ray andneutrons through a vacuum line, some 2.3 km long, whereupon it heated solid matter at the “station 1200” blockhouse andthus generated a secondary fireball^[28][29]

thesecondary assembly was the actual SHRIMP component of the weapon.theweapon, like most contemporary thermonuclear weapons at that time, bore the same codename as the secondary component.thesecondary was situated in the cylindrical end of the device, where its end was locked to the radiation case by a type of mortise andtenon joint.thehohlraum at its cylindrical end had an internal projection, which nested the secondary andhad better structural strength to support the secondary’s assembly, which had most of the device’s mass.A visualization to this is that the joint looked much like a cap (the secondary) fitted in a cone (the projection of the radiation case) .Any other major supporting structure would interfere to radiation transfer from the primary to the secondary andcomplex vibrational behavior.With this form of joint bearing most of the structural loads of the secondary, the latter andthe hohlraum-ballistic case ensemble behaved as a single mass sharing common eigenmodes.to reduce excessive loading of the joint, especially during deployment of the weapon, the forward section of the secondary (i.e.the thermal blast/heat shield) was anchored to the radiation case by a set of thin wires, which also aligned the center line of the secondary with the primary, as they diminished bending andtorsional loads on the secondary, another technique adopted from the SAUSAGE.^{[23]: 438–454} thesecondary assembly was an elongated truncated cone.From its front part (excluding the blast-heat shield) to its aft section it was steeply tapered.tapering was used for two reasons.First, radiation drops by the square of the distance, hence radiation coupling is relatively poor in the aftermost sections of the secondary.this made the use of a higher mass of the then scarce fusion fuel in the rear end of the secondary assembly ineffective andthe overall design wasteful.this was also the reason why the lower-enriched slugs of fusion fuel were placed far aft of the fuel capsule.Second, as the primary could not illuminate the whole surface of the hohlraum, in part due to the large axial length of the secondary, relatively small solid angles would be effective to compress the secondary, leading to poor radiation focusing.by tapering the secondary, the hohlraum could be shaped as a cylinder in its aft section obviating the need to machine the radiation case to a parabola at both ends.this optimized radiation focusing andenabled a streamlined production line, as it was cheaper, faster andeasier to manufacture a radiation case with only one parabolic end.thetapering in this design was much steeper than its cousins, the runt, andthe ALARM CLOCK devices.SHRIMP ‘s tapering andits mounting to the hohlraum apparently made the whole secondary assembly resemble the body of a shrimp.thesecondary’s length is defined by the two pairs of dark-colored diagnostic hot spot pipes attached to the middle andleft section of the device.^{[Note 9]} these pipe sections were 8+5⁄8 inches (220 mm) in diameter and40 feet (12 m) long andwere butt-welded end-to-end to the ballistic case leading out to the top of the shot cab.they would carry the initial reaction’s light up to the array of 12 mirror towers built in an arc on the artificial 1-acre (0.40 ha) shot island created for the event.From those pipes, mirrors would reflect early bomb light from the bomb casing to a series of remote high-speed cameras, andso that Los Alamos could determine both the simultaneity of the design (i.e.the time interval between primary’s firing andsecondary’s ignition) andthe thermonuclear burn rate in these two crucial areas of the secondary device.^{[8]: 63 : 229}

this secondary assembly device contained the lithium deuteride fusion fuel in a stainless-steel canister.Running down to the center of the secondary was a 1.3 cm thick hollow cylindrical rod of plutonium, nested in the steel canister.this was the spark plug, a tritium-boosted fission device.It was assembled by plutonium rings andhad a hollow volume inside that measured about 0.5 cm in diameter.this central volume was lined with copper, which like the liner in the primary’s fissile core prevented Dt gas diffusion in plutonium.thespark plug’s boosting charge contained about 4 grams of tritium and, imploding together with the secondary’s compression, was timed to detonate by the first generations of neutrons that arrived from the primary.timing was defined by the geometric characteristics of the sparkplug (its uncompressed annular radius), which detonated when its criticality, or k_eff, transcended 1.Its purpose was to compress the fusion material around it from its inside, equally applying pressure with the tamper.thecompression factor of the fusion fuel andits adiabatic compression energy determined the minimal energy required for the spark plug to counteract the compression of the fusion fuel andthe tamper’s momentum.thespark plug weighed about 18 kg, andits initial firing yielded 0.6 kilotonnes of tNt (2.5 tJ) .then it would be completely fissioned by the fusion neutrons, contributing about 330 kilotonnes of tNt (1,400 tJ) to the total yield.theenergy required by the spark plug to counteract the compression of the fusion fuel was lower than the primary’s yield because coupling of the primary’s energy in the hohlraum is accompanied by losses due to the difference between the X-ray fireball andthe hohlraum temperatures.^[18] theneutrons entered the assembly by a small hole^{[Note 10]} through the ≈28 cm thick ²³⁸U blast-heat shield.It was positioned in front of the secondary assembly facing the primary.Similar to the tamper-fusion capsule assembly, the shield was shaped as a circular frustum, with its small diameter facing the primary’s side, andwith its large diameter locked by a type of mortise andtenon joint to the rest of the secondary assembly.theshield-tamper ensemble can be visualized as a circular bifrustum.All parts of the tamper were similarly locked together to provide structural support andrigidity to the secondary assembly.Surrounding the fusion-fuel–spark-plug assembly was the uranium tamper with a standoff air-gap about 0.9 cm wide that was to increase the tamper’s momentum, a levitation technique used as early as Operation Sandstone anddescribed by physicist ted taylor as hammer-on-the-nail-impact.Since there were also technical concerns that high-z tamper material would mix rapidly with the relatively low-density fusion fuel—leading to unacceptably large radiation losses—the stand-off gap also acted as a buffer to mitigate the unavoidable andundesirable taylor mixing.

boron was used at many location in this dry system ; it is has has a high cross – section for the absorption of slow neutron , which fission²³⁵U and²³⁹Pu, but a low cross-section for the absorption of fast neutrons, which fission ²³⁸U.because of this characteristic, ¹⁰b deposited onto the surface of the secondary stage would prevent pre-detonation of the spark plug by stray neutron from the primary without interfere with the subsequent fissioning of the²³⁸U of the fusion tamper wrapping the secondary.boron also played a role in increasing the compressive plasma pressure around the secondary by blocking the sputtering effect, leading to higher thermonuclear efficiency.because the structural foam holding the secondary in place within the casing was doped with ¹⁰b ,^{[8]:   179} the secondary was compressed more highly, at a cost of some radiated neutrons.(thecastle Koon MORGENStERN device is use did not use¹⁰b in its design; as a result, the intense neutron flux from its RACER IV primary predetonated the spherical fission spark plug, which in turn “cooked” the fusion fuel, leading to an overall poor compression.^[8]: 317) theplastic’s low molecular weight is unable to implode the secondary’s mass.Its plasma-pressure is confined in the boiled-off sections of the tamper andthe radiation case so that material from neither of these two walls can enter the radiation channel that has to be open for the radiation transit.^[12]

bravo detonation andfireball.

thedevice was mounted in a “shot cab” on an artificial island built on a reef off Namu Island, in bikini Atoll.A sizable array of diagnostic instruments were trained on it, including high-speed cameras trained through an arc of mirror towers around the shot cab.

thedetonation took place at 06:45 on 1 March 1954, local time (18:45 on 28 February GMt) .^[3]

When bravo was detonated, within one second it formed a fireball almost 4.5 miles (7.2 km) across.this fireball was visible on Kwajalein Atoll over 250 miles (400 km) away.theexplosion left a crater 6,500 feet (2,000 m) in diameter and250 feet (76 m) in depth.themushroom cloud reached a height of 47,000 feet (14,000 m) anda diameter of 7 miles (11 km) in about a minute, a height of 130,000 feet (40 km) and62 mi (100 km) in diameter in less than 10 minutes andwas expanding at more than 160 meters per second (580 km/h; 360 mph) .Asa result of the blast, the cloud contaminated more than 7,000 square miles (18,000 km²) of the surrounding Pacific Ocean, including some of the surrounding small islands like Rongerik, Rongelap, andUtirik.^[31]

castle bravo mushroom cloud a few seconds after detonation

In terms of energy released (usually measured in tNt equivalence), castle bravo was about 1,000 time more powerful than the atomic bomb that was drop on Hiroshima during World War II .castle bravo is the sixth large nuclear explosion in history , exceed by the soviet test oftsar bomba at approximately 50 Mt, test 219 at 24.2 Mt, andthree other (test 147, test 173 andtest 174) ≈20 Mt Soviet tests in 1962 at Novaya zemlya.

Diagram of tritium bonus provided by Lithium-7 isotope

theyield of 15 (± 5) Mt^[32] was triple that of the 5 Mt predicted by its designers.^{[3][23]:   541} thecause of the higher yield was an error made by designers of the device at Los Alamos National Laboratory.they considered only the lithium-6 isotope in the lithium deuteride secondary to be reactive; the lithium-7 isotope, accounting for 60% of the lithium content, was assumed to be inert.^{[23]:   541} It was expected that the lithium-6 isotope would absorb a neutron from the fissioning plutonium andemit an alpha particle andtritium in the process, of which the latter would then fuse with the deuterium andincrease the yield in a predicted manner.Lithium-6 indeed reacted in this manner.

It was assume that the lithium-7 would absorb one neutron , produce lithium-8 , which decay ( through beta decay into beryllium-8 ) to a pair of alpha particle on a timescale of nearly a second , vastly long than the timescale of nuclear detonation .^[33] However, when lithium-7 is bombarded with energetic neutrons with an energy greater than 2.47 MeV, rather than simply absorbing a neutron, it undergoes nuclear fission into an alpha particle, a tritium nucleus, andanother neutron.^[33] Asa result, much more tritium was produced than expected, the extra tritium fusing with deuterium andproducing an extra neutron.theextra neutron produced by fusion andthe extra neutron released directly by lithium-7 decay produced a much larger neutron flux.theresult was greatly increased fissioning of the uranium tamper andincreased yield.^[33]

Summarizing, the reactions involving lithium-6 result in some combination of the two following net reactions:

¹n +⁶Li →³H + ⁴He +4.783 MeV

⁶Li +²H → 2 ⁴He +22.373 MeV

but when lithium-7 is present, one also has some amounts of the following two net reactions:

⁷Li +¹n →³H + ⁴He +¹n

⁷Li +²H → 2 ⁴He +¹n +15.123 MeV

this resultant extra fuel (both lithium-6 andlithium-7) contributed greatly to the fusion reactions andneutron production andin this manner greatly increased the device’s explosive output.thetest used lithium with a high percentage of lithium-7 only because lithium-6 was then scarce andexpensive; the later castle Union test used almost pure lithium-6.Had sufficient lithium-6 been available, the usability of the common lithium-7 might not have been discovered.^{[citation is needed need]}

theunexpectedly high yield of the device severely damaged many of the permanent buildings on the control site island on the far side of the atoll.Little of the desired diagnostic data on the shot was collected; many instruments designed to transmit their data back before being destroyed by the blast were instead vaporized instantly, while most of the instruments that were expected to be recovered for data retrieval were destroyed by the blast.

In an additional unexpected event, albeit one of far less consequence, X-rays traveling through line-of-sight (LOS) pipes caused a small second fireball at Station 1200 with a yield of 1 kiloton of tNt (4.2 tJ) .

high level of fallout

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thebravo fallout plume spread dangerous levels of radioactivity over an area over 280 miles (450 km) long, including inhabited islands.thecontour lines show the cumulative radiation exposure in roentgens (R) for the first 96 hours after the test.^[34][35] Although widely published, this fallout map is not perfectly correct^[36]

thefission reactions of the natural uranium tamper were quite dirty, producing a large amount of fallout.that, combined with the larger than expected yield anda major wind shift, produced some very serious consequences for those in the fallout range.In the declassified film Operation castle, the task force commander Major General Percy Clarkson pointed to a diagram indicating that the wind shift was still in the range of “acceptable fallout”, although just barely.

thedecision to carry out the bravo test under the prevailing winds was made by Dr.Alvin C.Graves, the Scientific Director of Operation castle.Graves had total authority over detonating the weapon, above that of the military commander of Operation castle.Graves appears in the widely available film of the earlier 1952 test “ivy Mike”, which examines the last-minute fallout decisions.thenarrator, the western actor Reed Hadley, is filmed aboard the control ship in that film, showing the final conference.Hadley points out that 20,000 people live in the potential area of the fallout.He asks the control panel scientist if the test can be aborted andis told “yes”, but it would ruin all their preparations in setting up timed measuring instruments.In Mike, the fallout correctly landed north of the inhabited area but, in the 1954 bravo test, there was a large amount of wind shear, andthe wind that was blowing north the day before the test steadily veered towards the east.

Inhabited islands affected

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Radioactive fallout was spread eastward onto the inhabited Rongelap andRongerik atolls, which were evacuated^[37] 48 hour after the detonation .^[38] In 1957, the Atomic Energy Commission deemed Rongelap safe to return, andallowed 82 inhabitants to move back to the island.Upon their return, they discovered that their previous staple foods, including arrowroot, makmok, andfish, had either disappeared or gave residents various illnesses,^[39] andthey were again removed.^[40] Ultimately, 15 islands andatolls were contaminated, andby 1963 Marshall Islands natives began to suffer from thyroid tumors, including 20 of 29 Rongelap children at the time of bravo, andmany birth defects were reported.^{[medical citation is needed need]} theislanders received compensation from the U.S.government, relative to how much contamination they received, beginning in 1956; by 1995 the Nuclear Claims tribunal reported that it had awarded $43.2 million, nearly its entire fund, to 1,196 claimants for 1,311 illnesses.^[38] A medical study, named Project 4.1, studied the effects of the fallout on the islanders.^[38]

Map show point ( X ) where contaminated fish were catch or where the sea was find to be excessively radioactive .b=original “danger zone” around bikini announced by the U.S.government.W=”danger zone” extended later.xF= position of theLucky Dragon fishing boat .NE, EC, andSE are equatorial currents

Although the atmospheric fallout plume drifted eastward, once fallout landed in the water it was carried in several directions by ocean currents, including northwest andsouthwest.^[41]

A Japanese fishing boat, Daigo Fukuryū Maru (Lucky Dragon No.5), came in direct contact with the fallout, which caused many of the crew to grow ill due to radiation sickness.One member died of a secondary infection six months later after acute radiation exposure, andanother had a child that was stillborn anddeformed.^[42] this resulted in an international incident andreignited Japanese concerns about radiation, especially as Japanese citizens were once more adversely affected by US nuclear weapons.^[23]: 542 theofficial US position had been that the growth in the strength of atomic bombs was not accompanied by an equivalent growth in radioactivity released, andthey denied that the crew was affected by radioactive fallout.^[42] Japanese scientists who had collected data from the fishing vessel disagreed with this.

Sir Joseph Rotblat, working at St bartholomew’s Hospital, London, demonstrated that the contamination caused by the fallout from the test was far greater than that stated officially.Rotblat deduced that the bomb had three stages andshowed that the fission phase at the end of the explosion increased the amount of radioactivity a thousand-fold.Rotblat’s paper was taken up by the media, andthe outcry in Japan reached such a level that diplomatic relations became strained andthe incident was even dubbed by some as a “second Hiroshima”.^[43] Nevertheless, the Japanese andUS governments quickly reached a political settlement, with the transfer to Japan of $15.3 million as compensation,^[44] with the surviving victims receiving about ¥ 2 million each ($5,550 in 1954, or about $63,000 in 2024) .^[45] It was also agreed that the victims would not be given Hibakusha status.

In 2016, 45 Japanese fishermen from other ships sued their government for not disclosing records about their exposure to Operation castle fallout.Records released in 2014 acknowledge that the crews of 10 ships were exposed but under health-damaging levels.^[46] In 2018 the suit was rejected by the Kochi District Court, who acknowledged the fishermen’s radiation exposure but could not “conclude that the state persistently gave up providing support andconducting health surveys to hide the radiation exposure”.^[47]

thedevice’s firing crew was located on Enyu island, variously spelled as Eneu island, as depicted here

bomb test personnel take shelter

[edit]

Unanticipated fallout andthe radiation emitted by it also affected many of the vessels andpersonnel involved in the test, in some cases forcing them into bunkers for several hours.^[48] In contrast to the crew of theLucky Dragon No.5, who did not anticipate the hazard andtherefore did not take shelter in the hold of their ship, or refrain from inhaling the fallout dust,^[49] the firing crew that triggered the explosion safely sheltered in their firing station when they noticed the wind was carrying the fallout in the unanticipated direction towards the island of Enyu on the bikini Atoll where they were located, with the fire crew sheltering in place (“buttoning up”) for several hours until outside radiation decayed to safer levels.”25 roentgens per hour” was recorded above the bunker.^[48][50]

US Navy ships is affected affect

[edit]

theUS Navy tanker USS patapsco was at Enewetak Atoll in late February 1954.patapsco lacked a decontamination washdown system, andwas therefore ordered on 27 February, to return to Pearl Harbor at the highest possible speed.^[51] A breakdown in her engine systems, namely a cracked cylinder liner, slowed patapsco to one-third of her full speed, andwhen the castle bravo detonation took place, she was still about 180 to 195 nautical miles east of bikini.^[51] patapsco was in the range of nuclear fallout, which began landing on the ship in the mid-afternoon of 2 March.by this time patapsco was 565 to 586 nautical miles from ground zero.thefallout was at first thought to be harmless andthere were no radiation detectors aboard, so no decontamination measures were taken.Measurements taken after patapsco had returned to Pearl Harbor suggested an exposure range of 0.18 to 0.62 R/hr.^[51] total exposure estimates range from 3.3 R to 18 R of whole-body radiation, taking into account the effects of natural washdown from rain, andvariations between above- andbelow-deck exposure.^[51]

International incident

[edit]

thefallout spread traces of radioactive material as far as Australia, India andJapan, andeven the United States andparts of Europe.though organized as a secret test, castle bravo quickly became an international incident, prompting calls for a ban on the atmospheric testing of thermonuclear devices.^[52]

A worldwide network of gummed film stations was established to monitor fallout following Operation castle.Although meteorological data was poor, a general connection of tropospheric flow patterns with observed fallout was evident.there was a tendency for fallout/debris to remain in tropical latitudes, with incursions into the temperate regions associated with meteorological disturbances of the predominantly zonal flow.Outside of the tropics, the Southwestern United States received the greatest total fallout, about five times that received in Japan.^[53]

Stratospheric fallout particles of strontium-90 from the test were later captured with balloon-borne air filters used to sample the air at stratospheric altitudes; the research (Project Ashcan) was conducted to better understand the stratosphere andfallout times, andarrive at more accurate meteorological models after hindcasting.^[54]

thefallout from castle bravo andother testing on the atoll also affected islanders who had previously inhabited the atoll, andwho returned there some time after the tests.this was due to the presence of radioactive caesium-137 in locally grown coconut milk.Plants andtrees absorb potassium as part of the normal biological process, but will also readily absorb caesium if present, being of the same group on the periodic table, andtherefore very similar chemically.^[55] Islanders consuming contaminated coconut milk were found to have abnormally high concentrations of caesium in their bodies andso had to be evacuated from the atoll a second time.

theAmerican magazine Consumer Reports warn of the contamination of milk with strontium-90 .^[56]

theSoviet Union had previously used lithium deuteride in its Sloika design (known as the “Joe-4” in the U.S.), in 1953.It was not a true hydrogen bomb; fusion provided only 15–20% of its yield, most coming from boosted fission reactions.Its yield was 400 kilotons, andit could not be infinitely scaled, as with a true thermonuclear device.

theteller–Ulam-based “ivy Mike” device had a much greater yield of 10.4 Mt, but most of this also came from fission: 77% of the total came from fast fission of its natural-uranium tamper.

castle bravo had the greatest yield of any U.S.nuclear test, 15 Mt, though again, a substantial fraction came from fission.In the teller–Ulam design, the fission andfusion stages were kept physically separate in a reflective cavity.theradiation from the exploding fission primary brought the fuel in the fusion secondary to critical density andpressure, setting off thermonuclear (fusion) chain reactions, which in turn set off a tertiary fissioning of the bomb’s ²³⁸U fusion tamper andcasing.Consequently, this type of bomb is also known as a “fission-fusion-fission” device.theSoviet researchers, led by Andrei Sakharov, developed andtested their first teller–Ulam device in 1955.

thepublication of the bravo fallout analysis was a militarily sensitive issue, with Joseph Rotblat possibly deducing the staging nature of the castle bravo device by studying the ratio andpresence of tell-tale isotopes, namely uranium-237, present in the fallout.^[57] this information could potentially reveal the means by which megaton-yield nuclear devices achieve their yield.^[58] Soviet scientist Andrei Sakharov hit upon what the Soviet Union regarded as “Sakharov’s third idea” during the month after the castle bravo test, the final piece of the puzzle being the idea that the compression of the secondary can be accomplished by the primary’s X-rays before fusion began.

theShrimp device design later evolved into the Mark 21 nuclear bomb, of which 275 units were produced, weighing 17,600 pounds (8,000 kg) andmeasuring 12.5 feet (3.8 m) long and58 inches (1.5 m) in diameter.this 18-megaton bomb was produced until July 1956.^[59] In 1957, it was converted into the Mark 36 nuclear bomb andentered into production again.

Page 36 from the Project 4.1 final report, showing four photographs of exposed Marshallese.Faces blotted out for privacy reasons.

Following the test, the United States Department of Energy estimated that 253 inhabitants of the Marshall Islands were impacted by the radioactive fallout.^[60] this single test exposed the surrounding populations to varying levels of radiation.thefallout levels attributed to the castle bravo test are the highest in history.^{[61][failed verification]} Populations neighboring the test site were exposed to high levels of radiation resulting in mild radiation sickness of many (nausea, vomiting, diarrhea) .theunexpected strength of the detonation, combined with shifting wind patterns, sent some of the radioactive fallout over the inhabited atolls of Rongelap andUtrik.Within 52 hours, the 86 people on Rongelap and167 on Utrik were evacuated to Kwajalein for medical care.^[62] Several weeks later, many people began suffering from alopecia (hair loss) andskin lesions.^[63]

theexposure to fallout has been linked to increase the likelihood of several types of cancer such as leukemia andthyroid cancer.^[64][65] therelationship between iodine-131 levels andthyroid cancer is still being researched.there are also correlations between fallout exposure levels anddiseases such as thyroid disease like hypothyroidism.Populations of the Marshall Islands that received significant exposure to radionuclides have a much greater risk of developing cancer.^[65]

there is a presumed association between radiation levels andfunctioning of the female reproductive system.^[66]

thecastle bravo detonation andthe subsequent poisoning of the crew aboard Daigo Fukuryū Maru led to an increase in antinuclear protests in Japan.It was compared to the bombings of Hiroshima andNagasaki, andthe castle bravo test was frequently part of the plots of numerous Japanese media, especially in relation to Japan’s most widely recognized media icon, Godzilla.^[67] In the 2019 filmGodzilla: King of the Monsters, castle bravo becomes the call sign for Monarch Outpost 54 located in the Atlantic Ocean, near bermuda.^{[citation is needed need]}

theDonald Fagen song “Memorabilia” from his 2012 album Sunken Condos mentions both the castle bravo andivy King nuclear tests.^[68]

In 2013, the Defense threat Reduction Agency published castle bravo: Fifty Years of Legend andLore.^[36] thereport is a guide to off-site radiation exposures, a narrative history, anda guide to primary historical references concerning the castle bravo test.^[36] thereport focuses on the circumstances that resulted in radioactive exposure of the uninhabited atolls, andmakes no attempt to address in detail the effects on or around bikini Atoll.^[36]

Notes

1. ^ In the Mark 7 HE system , the irregularities is were in the implosion front were relatively small render the pusher component unnecessary .^[9]: 60
2. ^ Ring Lenses were used in conjunction with 1E23 type bridge-wire detonators.thering lenses reduced weapon’s external diameter by making the HE layer thinner, andtheir simultaneity of shock wave emergence was considerably higher compared to previous hyperboloid lenses, enabling better andmore accurate compression (LA-1632, table 4.1) .At the same time, since the high explosive layer was thinner it was less opaque for the X-rays emitted by the pit.^{[9]: 86 : 98}
3. ^ both SAUSAGE andthe two runts (SAUSAGE’s “lithiated” versions) had fusion fuel volumes of 840 liters.SAUSAGE used an 840-liter version of a cryogenic vessel developed for the PANDA committee (PANDA was SAUSAGE’s unclassified name) andin part by the National bureau of Standards (see more information here) .this vessel fits the description of Richard Rhodes in Dark Sun (p.490) andMike’s fusion fuel volume assumed by Andre Gsponer andJean-Pierre Hurni in their paper “thephysical principles of thermonuclear explosives, inertial confinement fusion, andthe quest for fourth generation nuclear weapons”, p.68.
4. ^ this temperature range is compatible with a hohlraum filling made of a low-z material because the fission bomb’s tamper, pusher andhigh-explosive lenses as well as interstage’s plastic foam strongly attenuate the radiation emitted by the core.thus, X-rays deposited into the hohlraum liner from primary’s interface with the interstage (i.e.the primary’s outer surface) were “cooler” than the maximum temperature of a fission device.^{[18]: 25 [19]}
5. ^ these losses were associated with material’s properties like back-scattering, quantum tunneling, exitance etc.^[15]
6. ^ tamper is the metal cladding encasing the secondary, andit is also termed pusher; both terms can be used interchangeably
7. ^ Not to be confused with the function of the fusion tamper
8. ^ Sputtering is the manifestation of the underdense plasma corona of the ablating hohlraum andthe tamper surfaces.^[22] It is a problem also shared with (see tokamak), that has to do with the ablated heavy particles; For a hydrogen weapon, these particles are blown-off high-z granular particles (made off uranium of Pb–bi eutectic; the selected material depends on the “cocktail”, or high-z element mixture, of the hohlraum design to tailor its opacity), which fly inside the radiation channel andabsorb radiation or reflect it, hampering radiation “ducting”.^{[21]:   279}
9. ^ both the ballistic case andhohlraum were perforated in these points so that light emanating from the nuclear components could travel unobstructed to the recording station.A slight drop in yield was expected because of those apertures, much like in the Mike test.^[23] thehot-spot openings, similar to the “starburst” diagnostics in hohlraums used in inertial confinement fusion (ICF) indirect drive experiments,^[30] caused local radiation decoupling andhence poor radiation reflection by the hohlraum.Radiation decoupling in turn reduced locally the efficiency of the ablation process on the surface of secondary’s tamper, destabilizing implosion by a small degree.Nevertheless, even minor instabilities during ablation amplified the already dreaded taylor mixing.
10. ^ thecylindrical hole was plugged with ¹⁰b-doped paraffin wax to time the neutrons’ arrival.^[8]

Citations

1. ^ “Operation castle”.nuclearweaponarchive.org.retrieve23 September 2017.
2. ^ Rowberry, Ariana (30 November 2001) .”castle bravo: theLargest U.S.Nuclear Explosion”.brookings Institution.retrieve23 September 2017.
3. ^^{a b c d} “Operation castle”.nuclearweaponarchive.org.17 May 2006.retrieve20 May 2016.
4. ^ Hughes EW; Molina MR; Abella MKIL; Nikolić-Hughes I; Ruderman MA (30 July 2019) .”Radiation maps of ocean sediment from the castle bravo crater”.proceeding of the National Academy of sciences.116 (31): 15420–15424.bibcode:2019PNAS..11615420H.doi:10.1073 / pnas.1903478116.PMC 6681739.pmid   31308235 .
5. ^ Foster, John bellamy (2009) .theEcological Revolution: Making Peace with the Planet.Monthly Review Press.p. 73.
6. ^ Danneskiold, Jim (14 April 2005) .”Operation castle tests focus of 20 April panel discussion”.Los Alamos National Laboratory.archived from the original on 7 May 2009 .
7. ^ Johnston, Louis; Williamson, Samuel H.(2023) .”What Was the U.S.GDP then?”.MeasuringWorth.retrieve30 November 2023. United States Gross Domestic Product deflator figures is follow follow theMeasuringWorth series .
8. ^^{a b c d e f g h i j} Hansen, Chuck (1995) .sword of Armageddon.Vol .  III.retrieve28 December 2016.
9. ^^{a b c} Glasstone, Samuel (1954) .LA-1632 : Weapons Activities of Los Alamos Scientific Laboratory.Vol. Part I.
10. ^ “theNuclear Weapon Archive – A Guide to Nuclear Weapons”.nuclearweaponarchive.org.retrieve23 September 2017.
11. ^ Sutherland, Karen (2004) .density of Steel.retrieve28 December 2016.
12. ^^{a b c d} Hansen, Chuck (1995) .sword of Armageddon.Vol .  III.retrieve20 May 2016.
13. ^ Holian, Kathleen S.(1984) .t-4 Handbook of Material Properties Data bases.Vol. Ic.
14. ^ “Dangerous thermonuclear Quest: thePotential of Explosive Fusion Research for the Development of Pure Fusion Weapons”, p.4.
15. ^^{a b c} Pruitt (1963) .”High Energy X-Ray Photon Albedo”.Nuclear Instruments andMethods.27 (1): 23–28.bibcode:1964NucIM..27…23P.doi:10.1016/0029-554X(64)90131-4.
16. ^ bulatov andGarusov (1958) .⁶⁰Co and¹⁹⁸Au γ – ray albedo of various material.
17. ^ Current trends in International Fusion Research Proceedings of the third Symposium.2002.
18. ^^{a b c} thephysical principles of thermonuclear explosives, inertial confinement fusion, andthe quest for fourth generation nuclear weapons.2009.
19. ^ https://nuclearweaponarchive.org/Nwfaq/Nfaq4-4.html.^{[dead link‍]}
20. ^ Pritzker, Andreas; Hälg, Walter (1981) .”Radiation dynamics of nuclear explosion”.zeitschrift für Angewandte Mathematik und Physik.32 (1): 1–11.bibcode:1981zaMP…32….1P.doi:10.1007/bF00953545.S2CID 122035869.
21. ^^{a b} benz, Arnold (1992) .Plasma Astrophysics; Kinetic Processes in Solar andStellar Coronae.
22. ^ Lindl, John (1992) .”Progress toward Ignition andburn Propagation in Inertial Confinement Fusion”.Physics today.45 (9): 32–40.bibcode:1992Pht….45i..32L.doi:10.1063/1.881318.
23. ^^{a b c d e f} Rhodes, Richard (1 August 1995) .Dark Sun: theMaking of the Hydrogen bomb.Simon & Schuster.ISbN 978-0-68-480400-2.LCCN 95011070.OCLC 456652278.OL 7720934M.Wikidata Q105755363 – via Internet Archive.
24. ^ Hansen, Chuck (1995) .sword of Armageddon.Vol. II.retrieve20 May 2016.
25. ^^{a b} Hansen, Chuck (1995) .sword of Armageddon.Vol. IV.retrieve20 May 2016.
26. ^ “Operation CAStLE Commander’s Report”.12 May 1954 – via Internet Archive.
27. ^ “Declassified U.S.Nuclear test Film #34 0800034 – Project Gnome – 1961.6:14 minutes”.Youtube.31 October 2007.Archived from the original on 21 December 2021.
28. ^ “How Archive Data Contribute to Certification.Fred N.Mortensen, John M.Scott, andStirling A.Colgate”.Archived from the original on 23 December 2016.retrieve23 December 2016.
29. ^ “LANL: Los Alamos science: LA science No.28”.12 June 2007.Archived from the original on 12 June 2007.
30. ^ Cook, R.C.; Kozioziemski, b.J.; Nikroo, A.; Wilkens, H.L.; bhandarkar, S.; Forsman, A.C.; Haan, S.W.; Hoppe, M.L.; Huang, H.; Mapoles, E.; Moody, J.D.; Sater, J.D.; Seugling, R.M.; Stephens, R.b.; takagi, M.; Xu, H.W.(2008) .”National Ignition Facility target design andfabrication” ( PDF ).Laser andParticle beams.26 (3): 479.bibcode:2008LPb….26..479C.doi:10.1017/S0263034608000499.
31. ^ titus, A.Costandina (2001) .bombs in the backyard: Atomic testing andAmerican Politics.Reno: University of Nevada.
32. ^ “Commander task Group 7.1 Eniwetok to U.S.AEC”.National Security Archive.6 March 1954.retrieve1 March 2024.
33. ^^{a b c} Parsons, Keith M.; zaballa, Robert A.(2017) .bombing the Marshall Islands: A Cold War tragedy.Cambridge University Press.pp. 53–56.ISbN 978-1-108-50874-2.
34. ^ Glasstone, Samuel (1962) .theEffects of Nuclear Weapons.U.S.Department of Defense, U.S.Atomic Energy Commission.p. 462. (Dose given in roentgens in the 1962 ed.)
35. ^ Glasstone, Samuel; Dolan, Philip J.(1977) .theEffects of Nuclear Weapons (3rd ed.).U.S.Department of Defense, U.S.Atomic Energy Commission.p. 437.ISbN 978 – 0 – 318 – 20369 – 0. (Dose given in rads in 1977 ed.)
36. ^^{a b c d} Kunkel, thomas; Ristvet, brian (25 January 2013) .”castle bravo: Fifty Years of Legend andLore” ( PDF ).Albuquerque, NM: Defense threat Reduction Agency.Archived ( PDF ) from the original on 10 March 2014.retrieve20 May 2016.
37. ^ “Les cobayes du Dr Folamour”.Le Monde (in French) .22 June 2009.retrieve20 May 2016.
38. ^^{a b c} “Nuclear Issues”.Archived from the original on 24 April 2016.retrieve20 May 2016.
39. ^ Smith-Norris, Martha (2016) .Domination andResistance: theUnited States andthe Marshall Islands during the Cold War.University of Hawai’i Press.ISbN 978-0-8248-5814-8.
40. ^ “theGhost Fleet of bikini Atoll”.Mystery of Old World Cultures.11 October 2009.A&E television Networks.Military History Channel.Archived from the original on 2 April 2019.retrieve20 May 2016.
41. ^ Sevitt, S.(23 July 1955) .”thebombs”.theLancet.266 (6882): 199–201.doi:10.1016/s0140-6736(55)92780-x.PMID 13243688.
42. ^^{a b} Oishi, Matashichi; Maclellan, Nic (2017), “thefisherman”, Grappling with the bomb, britain’s Pacific H-bomb tests, ANU Press, pp. 55–68, ISbN 978-1-76046-137-9, JStOR j.ctt1ws7w90.9
43. ^ Keever, beverly Deepe (25 February 2004) .”Shot in the Dark”.Honolulu Weekly.Archived from the original on 12 July 2011.retrieve20 May 2016.theJapanese government andpeople dubbed it “a second Hiroshima” andit nearly led to severing diplomatic relations
44. ^ “50 Facts About U.S.Nuclear Weapons”.thebrookings Institution.August 1996.Archived from the original on 19 July 2011.retrieve20 May 2016.
45. ^ Hirano, Keiji (29 February 2004) .”bikini Atoll H-bomb damaged fisheries, created prejudice”.Chugoku.Archived from the original on 29 April 2013.retrieve20 May 2016.
46. ^ “Fishermen Sue Japan for Hiding Records of Fallout From US Nuclear tests”.AbC News.10 May 2016.retrieve20 November 2023.
47. ^ “Former fishermen lose H-bomb damages suit linked to bikini Atoll tests U.S.conducted in 1954”.theJapan times.21 July 2018.
48. ^^{a b} Clark, John C.(July 1957) .Robert Cahn (ed.) .”trapped by Radioactive Fallout” ( PDF ).Saturday Evening Post.retrieve20 May 2016.
49. ^ Hoffman, Michael (28 August 2011) .”Forgotten atrocity of the atomic age”.Japan times.p. 11.retrieve20 May 2016.
50. ^ Ely, Dave.”Operation castle: bravo blast”.dgely.com.Archived from the original on 22 October 2013.retrieve25 August 2013.
51. ^^{a b c d} Newton, Richard G.; Cuddihy, George J.(September 1985) .Human Radiation Exposures relate to Nuclear Weapons Industries.Albuquerque, New Mexico: Inhalation toxicology Research Institute, Lovelace biomedical & Environmental Research Institute.p. 109.
52. ^ DeGroot, Gerard (2004) .thebomb: A Life.London: Jonathan Cape.pp. 196–198.ISbN 978 – 0 – 224 – 06232 – 9.
53. ^ List, Robert J.(17 May 1955) .World-Wide Fallout from Operation castle (Report) .doi:10.2172/4279860.OStI 4279860.retrieve20 May 2016.
54. ^ Machta, Lester; List, Robert J.(1 March 1959) .Analysis of Stratospheric Strontium⁹⁰ Measurements.Journal of Geophysical Research (Report) .OStI 4225048.
55. ^ Winter, Mark.”Caesium biological information”.WebElements Periodic table of the Elements.retrieve20 May 2016.
56. ^ Nash, Gary b.; et al.(2007) .theAmerican People: Creating a Nation anda Society (6th ed.) .New York: Longman.ISbN 978-0-205-80553-2.^{[page needed]}
57. ^ braun, Reiner (2007) .Joseph Rotblat: Visionary for Peace.Wiley-VCH.ISbN 978 – 3 – 527 – 40690 – 6.
58. ^ Geer, Lars-Erik De (1991) .”theRadioactive Signature of the Hydrogen bomb” ( PDF ).science & Global Security.2 (4) .Gordon andbreach science Publishers: 351–363.bibcode:1991S&GS….2..351D.doi:10.1080/08929889108426372.retrieve22 February 2016.
59. ^ Strategic Air Command History Development of Atomic Weapons 1956, pp.29, 39
60. ^ Lauerman, John F.; Reuther, Christopher (September 1997) .”trouble in Paradise”.Environmental Health Perspectives.105 (9): 914–917.doi:10.2307/3433870.JStOR 3433870.PMC 1470349.PMID 9341101.
61. ^ “Fallout Radiation And Growth”.thebritish Medical Journal.1 (5496): 1132.1 January 1966.doi:10.1136/bmj.1.5496.1132-a.JStOR 25407693.PMC 1844058.PMID 20790967.
62. ^ “theLegacy of U.S.Nuclear testing andRadiation Exposure in the Marshall Islands”.U.S.Embassy in the Republic of the Marshall Islands.15 September 2012.retrieve8 July 2024.
63. ^ “Radioactive Fallout in the Marshall Islands”.science.122 (3181): 1178–1179.1 January 1955.bibcode:1955Sci…122.1178..doi:10.1126/science.122.3181.1178.JStOR 1749478.PMID 17807268.
64. ^ Jorgensen, timothy J.(2017) .Strange Glow: theStory of Radiation.Princeton University Press.ISbN 978-0-691-17834-9.
65. ^^{a b} Simon, Steven L.; bouville, André; Land, Charles E.(1 January 2006) .”Fallout from Nuclear Weapons tests andCancer Risks: Exposures 50 years ago still have health implications today that will continue into the future”.American Scientist.94 (1): 48–57.doi:10.1511/2006.57.982.JStOR 27858707.retrieve8 July 2024.
66. ^ Grossman, Charles M.; Morton, William E.; Nussbaum, Rudi H.; Goldberg, Mark S.; Mayo, Nancy E.; Levy, Adrian R.; Scott, Susan C.(1 January 1999) .”Reproductive Outcomes after Radiation Exposure”.Epidemiology.10 (2): 202–203.doi:10.1097/00001648-199903000-00024.JStOR 3703102.PMID 10069262.
67. ^ brothers, Peter H.(2009) .Mushroom Clouds andMushroom Men: theFantastic Cinema of Ishiro Honda.AuthorHouse.
68. ^ Donald Fagen – Memorabilia, retrieve31 October 2018

bibliography