It's now seven decades since the heyday of British atmospheric nuclear weapons tests (Operation Buffalo, which included a land surface burst at Maralinga, was in 1956), and finally all of the key UK top secret classified nuclear weapon test reports, the Atomic Weapons Research Establishment "AWRE-T" series reports, have been declassified and scanned into PDF form of high quality (I've uploaded them as PDF files to Internet Archive here - there are currently 4,352 downloadable PDF files there, including all key UK and USA nuclear test reports, so they can't simply disappear again under whims of "secrecy" for another 70 odd years, if deemed politically inexpedient by those who hate the deterrence of war and civil defense to mitigate against the failure of deterrence or "demonstration attacks"). One of the most surprising facts is that the completion dates of many declassified UK reports are long after the nuclear tests; for example, the AWRE-T1/75 report on Operation Hurricane nuclear test, Measurement of total integrated heat output by R J Wilson was finally issued, classified Confidential, in May 1975 (over 22 years after the test in 1952!).
"From the moment he became responsible for atomic weapons [May 1947], Penney himself saw the extensive study of the effects of atomic bombs as one of his main jobs. This emphasised the essentially defensive nature of the early British work on atomic weapons; Penney, especially expert as he was in effects, was most anxious about the vulnerability of Britain to atomic bombs exploded on her land, in her harbours or off her coast. From a first preoccupation both with effects and with the first device, the work later expanded. During 1948, the Chiefs of Staff tabled their requirements for 200 bombs by 1957; there was now a firm production order. ... It was Klaus Fuchs, formerly of Los Alamos and now at Harwell, who emphasised from an early date the need for long-term work, despite the need to produce quick answers for a first bomb ... Penney himself ... was known to be convinced from the outset that military application of atomic energy would develop along the lines of thermonuclear reactions - that is, the hydrogen bomb; so much so that Portal thought it necessary to impress on him the undesirability of referring in any detail to the subject until Britain was in a position to start effective work on it."
- Margaret Gowing and Lorna Arnold, Independence and Deterrence: Britain and Atomic Energy, 1945–1952, Volume 2: Policy Execution, Macmillan, 1974, page 443.
The colour photo sequence at the top of this post shows the burning of a British Redbeard nuclear bomb from UK AWRE-T30/63 Experiments with Weapon Type Assemblies - Destruction of Redbeard Mk1 by Fire: "The H.E. was completely consumed in about 12 min. ... the spherical shell of the tamper was probably still complete at the time the H.E. finally burnt out. The temperatures of core and tamper at this time were somewhat less than 100°C ..." (report PDF is linked here). See also AWRE-T27/63 Vixen A Trials Experiments with Implosion Assemblies dispersal of beryllium and uranium (linked here).
The Atomic Weapons Establishment at Aldermaston have now finally also released the masses of fissile materials used in 1956 and 1957 UK nuclear tests, in files titled "Fissile Material Movement Records", which state that the Mosiac G2 nuclear weapon core contained two Ga stabilized (i.e. delta phase) Pu239 shells of 3 kg each, and that 6 fusion "pellets" each containing 0.24 grams of AM (codename for tritium booster) were shipped to Australia by Aldermaston on 15 August 1956, and identify the masses of materials in the various other shells in those externally boosted Mosiac tests, as well as - when read in conjunction with the declassified AWRE-T29/57 Operation Buffalo Weapons Assembly report by G Gallie - proving that weapon core "A1" contained 4.6 kg of delta phase plutonium and was the 15 kt Buffalo-1 "One Tree" weapon test, "A3" contained 6.91 kg of U235 in 7.43 kg of uranium (the remainder being U238) and was the 1.4 kt Buffalo-2 "Marcoo" surface burst, while core "A4" contained 2.0 kg of plutonium, and was the core of the 3 kt Buffalo-3 test, etc. see linked PDF page 7 (document original pagination at page 5):
"A1 The assembly was stripped, the dummy core removed and the fissile core, supplied as required by the RA Assembly Group, inserted. The complete bomb, less firing unit and exploders, was transported in a trailer behind a motor truck from XA1.1 to "One Tree". A2 The assembly was stripped, the dummy core removed and the fissile core, supplied as required by the RA Assembly Group, inserted. The complete bomb, less firing unit and exploders, was transported in a trailer behind a motor truck from XA1.1 to "Breakaway". ... A3 Assembly of this weapon was done in XA1.1. It was transported to "Marcoo" by motor truck without its cartridge. The cartridge was assembled and inserted in the bomb by the RA Assembly Group." (The declassified data on core masses and corresponding bomb yields gives the efficiencies for the bombs; see John Corner's reports AWRE Theoretical Physics Note TPN-102/56, Efficiency, Kilgrams and Kilotons from Non-Thermonuclear weapons, and AWRE-TPN-116/53, Comparison of Fire-Ball and Radio chemical yields. See also Pilgrim's AWRE 17 January 1957 letter to Adams in the UK National Archives, excerpts below, relating the A1-A4 bomb core type numbers to the individual Buffalo nuclear tests, as well as explaining discrepancies between yields based on blast and radiochemistry.)
The fissile shells masses have now been also released for Britain's Pu-U235 composite core H-bomb primary "Tom" tests of 1957: they contained a 3 kg delta phase plutonium core, surrounded by two shells of U235 of 6 kg each, i.e. 12 kg of U235 and 3 kg of Plutonium in total. Real world data are vital to understanding nuclear weapons hazards and countermeasures accurately. This is not a secret to Russia, which has its own nuclear weapons and test data itself. The actual amounts of chemical high explosive in various UK nuclear warheads has also been declassified (see Top Secret UK AWRE Hazards arising from accidental detonation of nuclear warheads containing uranium, linked here; equation on page 1 states the cloud height from M pounds of high explosive is h = 35M0.46 feet, and Table 2 uses this formula to calculate cloud heights of 1850, 520 and 1000 feet, respectively, for nuclear weapons Blue Danube, Red Beard, and Green Grass: anyone can rearrange the formula and then use table 2 to give the high explosives in each weapon). Consequently, safety data have been released, and it is up to Joe Public to make good use of it!
ABOVE: the declassification of UK nuclear warhead design information has now progressed to the point where the fissile materials used in weapons is being openly released, enabling fact-based understanding of the relative merits of different innovations in warhead design by Joe Public, the guys who pay vast sums via their taxes for that deterrent (in the previous post we discussed earlier examples of this for key thermonuclear warhead fissile and fusion material contents). On 8 April 2026, AWRE declassified the fact that the Green Grass U235 implosion warhead used only 65.6 kg of U235, debunking the claim on Wikipedia that it contained over 70 kg! Source: UK AWRE, The hazards arising in an incident involving a fully assembled Green Grass warhead, Top Secret - Atomic, 14 December 1957, PDF is linked here.
UK AWRE has started to declassify its legendary secret nuclear weapons "Theoretical Physics Notes" on nuclear weapons testing effects and warhead design, e.g. see UK AWRE Theoretical Physics Note 112/57 Preliminary Study of gamma dose versus distance results obtained on Operation Grapple by K. Stewart (PDF linked here, declassified 8 April 2026 with redactions, 21 pages). Even the titles and dates of TPN's reveal the rate of progress: TPN 9/56 Yield of a hollow gadget in weapons of various size (1956); TPN 11/56 Elementary theoretical approach to the design of a lensless oval weapon (1956). Other papers include UK AWRE Battlefield Data from Nuclear Weapon Optical Signatures, 7 March 1977 classified "Secret Atomic Principal" (an analysis of French atmospheric nuclear test data), and the following spectacular photos of the 25 kt 300 metres high balloon suspended Antler-3 early time fireball, with the bomb-suspension balloon clearly visible above the fireball and a glowing, expanding "fireball spike" travelling from the fireball up the bomb suspension cable towards the balloon (this photo is taken from the recently declassified Top Secret Atomic UK Eyes Only Operation Antler Preliminary Report), and also the photos of rocket trajectories fired through the Totem 1 and 2 mushroom cloud head and stem to collect reliable samples of fallout determining the crucial particle size distributions in both parts of the cloud (from UK AWRE-B12/55, Operation Totem - Radiochemistry Group Report by F. Morgan):
ABOVE: EMP (then known as radio flash) measured at the Totem-2 nuclear test, Emu Field, Australia in 1953. Detector was 4 miles from ground zero, where the peak electric field strength was -200 v/m at 0.4 microsecond. SOURCE: report AWRE-T11/54, Operation Totem EMP Radio Flash Propagation by F H Wells et al (PDF linked here; they had extensive instrumentation problems to overcome and the close-in EMP measurement amplifier was overloaded, failing for Totem-1). British nuclear test reports are absolutely essential to understand and overcome the problems and limitations with Glasstone's book The Effects of Nuclear Weapons. Truth requires complete technical information, not grossly misrepresentative oversimplifications and omissions of things that were born in secrecy, many decades ago. I will discuss the key information now released in these formerly classified reports in this blog post (some data was extracted from certain reports in the previous post).
"[After the Operation Hurricane ship-based 25 kt nuclear test on 3 October 1952 at Monte Bello] some felt depressed and disappointed. The reality seemed less impressive than the American films they had watched, made with cameras with telephoto lenses and with the sound dubbed so that the bang coincided with the flash."
- Margaret Gowing and Lorna Arnold, Independence and Deterrence: Britain and Atomic Energy, 1945–1952, Volume 2: Policy Execution, Macmillan, 1974, page 493.
Among the large number of newly-released UK Top Secret weapon test reports is a vital high quality scan of Top Secret radiation dose rate histories for a set of remote radiation monitors in different positions around the 1952 Operation Hurricane nuclear test (25 kt weapon centre 9 feet below water line, aboard ship anchored in water 40 feet deep, Monte Bello):
ABOVE: some of the Top Secret classified sets of initial and fallout gamma dose rate time histories for Operation Hurricane, a bomb burst with its centre 9 feet below the waterline, inside a ship, HMS Plym (K271), moored in 40 feet depth of water, 400 yards off Trimouille Island in the Monte Bello group, Western Australia. As shown, the automatic radiation detector station TH47, 1 km directly downwind and on a land station at Trimouille Island, recorded a peak fallout gamma intensity just over 1,000,000 R/hour at 2 minutes after detonation, which decayed to 12,000 R/hour at 1 hour after burst, and to just 330 R/hr at 10 hours. This proves the very short duration of very intense radiation hazards from fallout in such detonations. This nuclear test information is not superseded by abstract theoretical computer models, because nuclear explosion phenomenology is complex for such burst situations. AWRE has now made available a high quality scan of the AWRE-T1/54 report of 1954 which summarizes the physical phenomena (while omitting the Top Secret radiation intensity-time graphs) of Operation Hurricane which shows the time-evolution of the complex physical phenomena, particularly the way that the inverted cone of water and debris (i.e., bottom mud and ship's iron oxide) erupts through the early fireball, rapidly cooling the fireball and thus limiting the observed thermal yield partition to under 2% (we had received a lower quality scan of a declassified photocopy decades ago - I first wrote to AWE Library for this information in the early 1990s, and later uploaded it to internet archive; but the latest higher quality scan photos were finally clear enough to indicate the time-dependent fireball and water cone phenomena):
For comparison of Operation Hurricane's intense early time dose rates to a 5 megaton hydrogen bomb test, Redwing-Tewa in 1956, AWRE has usefully declassified and scanned in its copy of Dr Frank H. Shelton's paper Physical Aspects of Fallout, which was presented at the September 1957 Tripartite Conference (USA-UK-Canada) on Nuclear Weapons Effects, summarizing key results from Operation Redwing fallout studies in 1956. (Note that Shelton was solely responsible for getting the fallout data from the 87% fission dirty 5 megaton Redwing-Tewa test, by pushing - as Technical Director of the U.S. Armed Forces Special Weapons Project - for Tewa to be fired in very shallow water, since others had wanted to detonate it in deep water which alters the close-in fallout distribution. Shelton discusses this briefly in his 1988 and 1992 revised book Reflections of a Nuclear Weaponeer, and there is also extensive declassified documentation of this change in Redwing planning which facilitated a massive increase in fallout documentation in 1956.) Shelton's Physical Aspects of Fallout concisely analyzes and summarizes the implications of all of the preliminary Redwing radiation and fallout reports, stating:
"Salvos of rockets were fired at H + 7 minutes and H + 15 minutes on a number of the Operation REDWING shots. The rockets telemetered to a ground receiving station the gamma radiation dose rate as a function of time along the trajectory. From trajectory information the ionization rate can be correlated with position in space. ... At H + 7 minutes the contours of a given activity per unit volume were concentric toroids, the more intense being in about the lower 1/3 of the cloud and about 1/3 of the distance from the axis to the edge of the visible cloud. The activity per unit volume varied by a factor of about 30 from the most concentrated area to the edge of the cloud and negligible activity was found when rockets traversed the visible stem. At H+ 15 minutes the activity was spread over a larger region and, in particular, activity was generally in the region below the bottom of the visible cloud. Of course this is activity being carried on the larger particles under the influence of gravity. By integrating the activity over space, the total activity accounted for was usually very close to the total fission activity of the bomb at H + 7 minutes and confirmed again that essentially only several percent of the activity is in the stem at early times. ...
"... Throughout the shot atoll various islands were instrumented for fallout. ... Fallout from a detonation of the order of a megaton will begin to arrive on the ground over an area the order of the size of the visible cloud, almost like a blanket at about 15-20 minutes for a large yleld surface burst on an island or presumably on land. Fallout from a shot of the order of a megaton on a barge in water will begin to arrive at the surface at about 30-40 minutes. These times of arrival of the first fallout are of course related to the large particle sizes. ... The radiation rate will build up on the ground under the cloud and reach a peak in about 100 minutes for a detonation of the order of a megaton. The magnitude of the peak will be a function of the fission yield."
Figures below are from Shelton's paper Physical Aspects of Fallout; the first shows fallout build up 14 miles cross-wind from 5 Mt Tewa ground zero, and the second shows the dose rate build up downwind on the deck of a WWII Liberty ship in the fallout. We also include Shelton's comparison of dose rate versus fallout areas graphs scaled to 1 megaton fission from tests of vastly different yield (1.2 kiloton - 5 megatons) and different fission yield tests, and also his graph of local fallout percentage versus scaled height of burst. A key point to emphasise is, the activity versus particle size distribution in surface bursts is not massively dependent on the preshot soil particle size distribution (Small Boy on fine silt at the dried lake bed of Frenchman Flats Nevada in 1962 proved that very small particles silt particles are fused together into much larger fallout particles). Also, the maximum radiation dose rates from fallout are higher for lower yields, where the fallout reaches close-in targets within a couple of minutes, as compared to longer fallout arrival times from higher clouds, e.g. hours for most of the large fallout areas from megaton bursts. Glasstone's decision to give only "theoretical" dose rates for 1 hour regardless of yield (when for high yields, most of the fallout is still airborne and has not even arrived with 1 hour) is entirely misleading. The fallout hazards are severely misunderstood in oversimplified computer models employing the unfused soil particle size distribution. Glasstone obfuscates again by suggesting that fallout arrival time is horizontal distance divided by wind speed; this is approximately correct at very large distances downwind where the doses are low due to decay during the large arrival time, but for the key threat at shorter distances it is false, omitting the time taken for fallout to descend from the higher clouds of higher yield detonations, exaggerating fallout hazards close to those detonations. The Effects of Nuclear Weapons is severely misleading and obstructs understanding.
Now let's move on to the recently declassified UK Atomic Weapons Establishment AWRE paper at the September 1957 Tripartite Conference on weapons effects, J. D. Macdougall, "On the Prediction and Interpretation of Fall-Out Patterns", showing fallout prediction methods for ground and tower bursts at Operation Buffalo, Maralinga, 1956:
"The surface burst was of yield about 1 kiloton [Buffalo-2, 1.4 kt yield Mark I uranium-235 pit], and the best information on the cloud model was obtained from this round mainly because of the large angular shear in the mean wind. The observed fall-out pattern is shown in Figure 1. Figure 2 shows the calculated positions and times of arrival at the ground of particles falling at various speeds from various heights in the cloud. The most striking feature abcut the fall-out pattern is its two lobed nature. ... The fall-out from the main cloud forms the lobe to the NE of the firing site. A thorough analysis of this pattern has been made in order to determine the distribution of activity with height throughout the cloud, and also the distribution of activity with falling velocity at various levels in the cloud."
See Figs 1 and 2, below. Winds below 6,000 feet carried the mushroom cloud's stem towards the north, while the main head of the mushroom cloud was carried towards the east, so from a wind analysis of the detailed fallout pattern, it was possible to analyse precisely how much radioactivity was contained by the stem and how much was in the head of the cloud. It is now clear from this data as well as rocket surveys of mushroom clouds and stems at megaton yield shots in 1956 (report WT-1315 linked here) that the increased updraft effect wind strength and duration for higher yield, megaton sized surface bursts changes the distribution of activity between "stem" and "cloud head"; a low kiloton yield ground burst leaves much of the fallout in the "stem", whereas a megaton range ground burst has enough energy to suck most of the fallout into the main "cloud head", at least at 7 minutes after the 3.53 megatons Zuni coral island 1956 test (at zero plus 15 minutes, the second volley of rockets fired through the cloud containing radiation meters showed that much of that activity was already starting to descend from the bottom of the cloud head). So what is needed to fully understand what is going on is a full hydrodynamic model of the physical phenomena, which will determine the changing partition of fallout activity between stem and cloud head as a function of both yield and time after burst. Ideally, this should also include models of molten fallout particles colliding and coalescing in the stem; large particles ejected from the ground into the fireball at early times from the cratering process are actually falling back while the afterwinds are still strong enough to raise smaller particles, thus producing head-on collisions, so that the fallout activity-size distribution is altered, and the mean sizes are generally much larger, than that of the pre-shot ground zero soil.
That Dacdougall paper at the 1957 Tripartite Conference is clearly based on the longer more detailed UK Atomic Weapons Establishment report AWRE-T25/58, analyzing Operation Buffalo fallout data (linked here). See also the full British fallout patterns from Operation Buffalo: J. J. Rae, AWRE-T49/57, Operation Buffalo Radiation Survey of Ground Deposited Radioactivity, which we uploaded to internet archive, linked HERE (which gives more detailed close-in fallout contours for the surface burst Buffalo-2, and related data on the neutron induced activity versus fission product contributions to the dose rates than the Tripartite paper etc). There is now a better quality scan of AWRE-T49/57 (vital for the detailed fallout patterns near ground zero) here in PDF; see also the aerial survey in report AWRE-T51/57 linked here.
This uranium-238 non-fission neutron capture activity with its easily-shielded very low gamma ray energy (from Np-239 and U-237 during the first few weeks after detonation) is also very important for the dirty U238 pusher design H-bomb, and there is extensive declassified data on the neptunium-239 and also the uranium-237, both of which are emitters of very soft (low energy) gamma rays, in "dirty" H-bombs with U238 pushers, in the declassified fallout reports from various shots at Operation Redwing, as we have previously blogged in detail, see the link here. Uranium-237 is produced by the (n,2n) reaction for high energy thermonuclear fusion neutrons hitting U238 and being captured with immediate double neutron emission; U237 has a half life of 6.75 days, and like neptunium-239, is a very soft gamma emitter which causes the fallout as a whole to have a very low average gamma ray energy, which is easy to attenuate by improvised shelters, for much of the first two week sheltering period; this fact is simply suppressed by Glasstone and disarmament style anti-civil defense cheap shelters propaganda. Please see also the summary tables and graphs on gamma ray spectra from nuclear test fallout containing Np239 and U237 for several designs of nuclear explosives, in our old paper from 2010, an extract of some data debunking CND style anti-nuclear and anti-civil defense fake news, from the 1990 book manuscript Nuclear Weapons Effects Theory, linked here.
ABOVE: after Operation Totem nuclear tests in 1953 provided vital data (report AWRE-T45/54 by Lt. Col. K. Stewart, R.E, PDF linked here) on cloud rise stem updraft and the "skip distance" between crater contamination and the maximum intensity "hotspot" downwind from fallout, AWRE Director Sir William Penney analysed the effect of bomb yield on downwind fallout, predicting a larger skip distance from megaton bursts due to stronger, longer lasting afterwinds in low altitude bursts and surface bursts of higher yields (see PDF of his paper, linked here): this is the hotspot some 50-75 miles downwind observed in patterns of Operation Redwing fallout from 3.5-5 megaton range shots Tewa and Zuni. It is also present in the original RAND Corporation analysis of the hotspot 80-120 miles downwind of 1954 Castle Bravo 15 megaton fallout pattern, which indicated much less local fallout than the traditional Glasstone type extrapolations from ~1 kiloton Nevada surface bursts. Basically, the afterwinds are stronger and last longer for megaton yield bombs, and this increases the upward suction and thus the average time taken for most of the radioactivity to fall back, so that the distance to the downwind hotspot is increased with yield by the straightforward laws of physics, and when the extra fallout decay during this longer fallout time (for most of the deposited activity) is properly included, ironically the overall hotspot fallout danger is reduced as yield increases! The Rongelap islanders and Lucky Dragon tuna trawler on 1 March 1954 were simply caught in a hotspot, unrepresentative of the overall fallout pattern from the Bravo test. Despite this, most of them survived without any shelters at all. The deeper hidden message when propaganda is swept away is that the fallout is really survivable! In low air bursts, the heat hitting the ground directly under a low air burst was filmed (in the 1953 Grable and 1957 Priscilla tests, Nevada) to produce a kind of "second fireball", heating air near ground zero which then rose in the wake of the main toroidal fireball of weapon debris above it. The overall effect is to reduce close-in fallout.
ABOVE: Operation Antler Cobalt-60 tracer fallout map of Maralinga in 1987 (Z + 30 years). The Antler-1 and Antler-2 nuclear tests in 1957 tested neutron activation and dispersal of cobalt-60 and cobalt-59 (which is non-radioactive, but can capture bomb neutrons to become cobalt-60), respectively, and the results debunked Schute's anti-nuclear propaganda mythology (book and film) about cobalt-60 fallout, On The Beach; yes, you can put cobalt-59 into a nuclear weapon and yes it will absorb some of the neutrons and form some cobalt-60. But no, it is chemically refractory (not volatile) in the fireball, so it condenses too fast in the fireball to form fine particles of distant fallout; thus it won't end up concentrating in global fallout to any significant extent, but instead falls out very fast and ends up in relatively large "pellets" scattered close to ground zero. Also, for every neutron absorbed in cobalt-59 to form radioactive cobalt-60 with its 5.24 years half-life, you get out only 2.5 MeV of gamma radiation in the form of two gamma rays of 1.17 and 1.33 MeV energy, respectively, spread out in time over decades (very low dose rate, so you have time to decontaminate before getting a high dose, even if you want to occupy the crater region where the cobalt-60 concentrates). For contrast, using the same neutron to fission U238 gives you about 200 MeV of energy, including over 40 MeV of radiation, received at a relatively higher dose rate (72% of fission products have half lives of less than 24 hours).
Therefore, U238 gives you about 40/2.5 = 16 times as much radioactivity as you can get from cobalt-60 in nuclear weapons, and at a much higher dose rate, quite apart from the fact that its extremely high chemical melting point of 1,495 °C is well above the typical melting point of silicate soil, 1,200 °C, causing cobalt to condense into separate solidified particles before the majority of the fallout carrier! But Glasstone doesn't even mention this fact, any more than the fact that city skylines absorb the thermal radiation more efficiently than air transmission, or the fact that the extremely large ductility of reinforced concrete modern city buildings absorbs and attenuates the blast wave energy rapidly with distance, demolishing his free-field desert based unobstructed terrain fantasy graph data. The 0.93 kiloton Antler-1 shot on September 14, 1957 was the Pixie warhead, and produced 180 large pellets of cobalt containing 4.5 curies of cobalt-60 which fell out locally. Physicist Oliver Harry Turner wrote reports to AWRE on the nature of the cobalt-60 pellets, but the subject was secret, despite its vital debunking of anti-civil defence propaganda from Schute and CND, and the following meeting extract on fallout fractionation at AWRE proves they were aware the cobalt in the nuclear test had been proved to be refractory:
With the exception of Buffalo-1, the 15 kiloton small 71 cm (2 ft 4 inches) diameter Red Beard tactical bomb warhead tested in 1956, British implosion nuclear weapons were bulky 5-feet diameter affairs with heavy U238 reflectors. This changed with Operation Antler in 1957, where much smaller tactical designs were trialled. If you replace U238 with a beryllium reflector, the total mass of pit plus reflector matter for compression is far less, so you need less high explosive to do the compression, so the weapon's mass and diameter is miniaturised. Antler-1 was Britain's first test of a 113 kg very small diameter (less than 50 cm) plutonium implosion system, called Pixie. According to official historian Lorna Arnold's widely ignored book Britain and the H-Bomb, it was placed inside a hydrogen bomb assembly minus the lithium deuteride fusion charge and secondary fission pusher, but with a cobalt neutron tracer apparently to determine the enhanced neutron release from the very compact implosion system (because more neutrons escape when a smaller layer of neutron-absorbing high explosives are around the core). Antler-2 was a 6 kiloton tactical warhead called Indigo Hammer, designed for a surface-to-air missile, while Antler-3, Tom, was Britain's first 25 kt composite-core device, a plutonium pit inside a uranium-235 shell, designed for uses including primary stages for H-bombs.
"... Procedure for Round 1 Pixie. ... An additional requirement for this round was the provisioning of a D. M. Source of Cobalt 60 for use by RC Group. This source travelled out in a lead-lined stecl container above which was mounted a boron carbide shield (see figure C3.1). ... The source container was positioned at the top of the tower as shown on figures 03.2 and 03.3. As a last operation during the firing phase the source was raised to the OUT position by turning the long handle and the tower site then evacuated. ... Procedure for Round 2 Indigo Hammer. ... It was required to provide a non-irradiated cobalt pellet, its position and shielding relative to the weapon being exactly the same as for Round 1. The cobalt pellet was housed inside a boron carbide pot as shown on figure 03.1 and mounted at the top of the tower on a special stand built in IA.10 (see figure C3.4) The lead transit container and operating mechanism were not required as the cobalt pellet was inert."
In Antler-1, the radioactivity of the cobalt-60 was reduced by the explosion because, when cobalt-60 captures a neutron, cobalt-61 is formed, with a half-life of 1.65 hours, decaying into stable Nickel-61! Such claims appear typical ill-informed propaganda. Placing cobalt-60 in a nuclear weapon where it will capture neutrons is a way to convert it rapidly into non-radioactive Ni-61. It was only Antler-2 which actually produced any cobalt-60 during the explosion, when inert cobalt-59 was transformed into radioactive cobalt-60 by neutron capture. However, propaganda lies obfuscate the entire subject. There's a whole disarmament propaganda industry dedicated to spreading disinformation as fear mongering lies, loved by the BBC and other corrupt "fake news" organizations. Once a few "big shot" disarmament anti-nuclear liars have repeated the BS, the BBC then labels it "fact-checked" and suppresses reality like the Nazis' Gestapo used to do. Their idea of "fact-checking" is to find several fake news "sources" repeating the same lies and then to label lies as facts.
This Antler tests cobalt 60 issue came under intense political (not scientific or factual) debate during the McClelland Royal Commission inquiry into the Australian nuclear tests in 1985, but the essential facts were just obfuscated by secrecy, with former head of the Atomic Weapons Tests Safety Committee, Sir Ernest Titterton - who was still alive and had to testify - being labelled a "Dr Strangelove figure" by Judge Jim McClelland. Lord Penney also testified and came under attack, mostly due to excessive secrecy about fallout. Titterton had been on the Manhattan Project at Los Alamos and remained until 12 April 1947, longer than any other member of the British Mission. Titterton is the man filmed in close-up doing the last 10 seconds countdown in the official American film of the Operation Crossroads-Baker underwater shot at Bikini Atoll on 25 July 1946, although his English accent, known by American personnel on the ships as the mysterious "Voice of Abraham," was dubbed over by an American voice for the final version of the soundtrack of the Operation Crossroads film. Titterton emigrated to Australia in 1951 when his former boss, Oliphant (with whom he had developed the cavity magnetron, which produced the first microwave radar beams in WWII and cooked food afterwards) offered him a chair in physics at the Australian National University.
For the full story of Titterton being dubbed the anonymous "Voice of Abraham" at Operation Crossroads nuclear tests, see Margaret Gowing and Lorna Arnold's book Independence and Deterrence: Britain and Atomic Energy, 1945–1952, Volume 1: Policy Making, Macmillan, 1974, page 113. Volume 2 of that book, Policy Execution, in Table 1 on page 85 proves that Britain's clandestine nuclear weapons project produced results on a shoe-string austerity budget contrasted to the lavish $2 billion budget of the American wartime Manhattan Project; UK total annual expenditure on nuclear weapons research and development creeped up from just £11.1 million in 1947-8 to £30.7 million in 1951-52. Altogether, the entire cost of researching and producing the first UK nuclear bomb tested on October 3, 1952 was £105 million. This saving was by reliance on plutonium, whereas America had spent colossal sums on enriching uranium-235. Britain's Windscale No 1 air-cooled reactor began producing plutonium in October 1950; in February 1952 the Windscale plutonium separation plant was commissioned, and the very first billet of metallic plutonium was made at Windscale on 28 March 1952, just 6 months before the first nuclear test. Britain only started its gaseous diffusion enrichment of uranium-235 in 1953, after its first nuclear test! Page 96 of volume 2 also documents the facts that radiation safety was not, contrary to the mass media's fake news, unknown in the 1950s, but had been under intense research for decades; in 1924 the radiation safety limit was 1.5 R/week, in 1934 it was reduced to 1 R/week, in 1950 it was 0.3 R/week and it was reduced further to 0.1 R/week in 1956.
Sir Titterton was one of the first to warn of the anti-nuclear movement's threat to humanity, see his January 1979 ANU-P/740 report, Nuclear Power and the Anti-Nuclear Movement: A Modern Social Problem: "A well coordinated, international campaign has been pursued through the press, radio and television, and has been highlighted by marches, demonstrations, picketing, riots and all the modern day avenues open to protesters. ... These range from anxious persons with vague fears that nuclear power has something to do with the atomic bomb and therefore could be dangerous, to strident and malevolent people (often politically motivated) who have demonstrated a willingness to injure and even kill those who get in their way during their often violent demonstrations." (Where we disagree with Titterton is in the importance of ending secrecy delusions behind mainstream groupthink fashion, which makes officialdom stuck in a rut; failing to produce the innovative presentations of facts that are the only way to demolish the fake news liars.)
"The collapse of some unrevetted trenches at overpressures of 14 p.s.i. suggests that wherever possible trenches should be revetted, irrespective of the nature of the ground. ... Peak blast overpressures of (presumably) over 100 p.s.i. caused practically no damage to cut-and-cover trench shelters designed in accordance with the text book. ... Typical field defences stand up well to the blast and heat effects produced by tower-burst atomic weapons ..." - E. R. Drake Seager et al, Effects of the Totem Explosions on Field Defences, AWRE-T75/54 at pages 15-16 (PDF linked here).
See also AWRE-T3/57 Operation Buffalo Target Response Tests Shielding from Initial Radiation Afforded by Fieldworks and AFVs.Despite such nuclear proof tested facts, fake news spreading "historians" and "journalists" such as Duncan Campbell in his fake news type 1983 book War Plan UK falsely deceived readers by outrageously asserting that the Anderson shelters etc were never proof-tested at any UK nuclear tests, when in fact even the very first UK nuclear weapon test was deliberately designed to provide as much information on these shelters and other civil defense as possible, as Penney stated in his radio broadcast at the time, as as official statements and photographs repeatedly showed. The 15 Anderson shelters at Operation Hurricane were exposed by Home Office Scientific Advisory Branch scientists George Stanbury and Frank Pavry, and the data was incorporated into improved civil defence plans, contrary to political propaganda attacks on civil defence protection data as being imaginary. Further nuclear tests exposed further shelters, both for military field defences analysis and civil defence, but the data was kept secret, allowing politically-motivated "pro-disarmament civil defence critics" supported by Moscow's World Peace Council propaganda (an attempt to get the West to disarm out of fear), to falsely claim it never existed! See UK Atomic Weapons Establishment's report AWRE-T17/54, the Operation Hurricane nuclear test report on 15 Anderson shelters by Frank H. Pavry (PDF linked here):
ABOVE: Operation Hot Box (see AWRE-T3/54, linked here), the flight of Dr Denis Wilson's Canberra aircraft through the Totem-1 nuclear test's 2000 yards wide mushroom cloud at 6 minutes after burst to disprove Dr Klaus Fuchs's 1949 Harwell calculations of lethal radiation persisting in the cloud for several days after burst. Wilson measured less than 20R, disproving Fuchs! He testified in the 1980s to the Royal Commission inquiry into the tests that this was vital research, not the "boy's own adventure" (as alleged by certain anti-nuclear propaganda media). Lorna Arnold, A very special relationship: British atomic weapon trials in Australia, H.M.S.O., London, 1987, pages 67-68:
"... the Totem Executive approved a proposal that an RAF aircraft should fly into the mushroom cloud within a few minutes of the detonation. ... The origin of Operation Hot Box goes back to 1948, when Squadron Leader Denis A Wilson, a consultant in radiology to the RAF, was attached to the Health Physics Division at Harwell. There, in 1949, he was shown some papers written by Fuchs, the Harwell physicist [spy], which concluded that aircraft would be unable to operate anywhere in the vicinity of a nuclear explosion for some days. These papers had apparently been influential in the United States as well as in the British Air Ministry. Wilson was not convinced, and found errors in the calculations. ... Hot Box was the first experiment of its kind, and produced results which were of value to the United States Air Force as well as the RAF. In fact, Hot Box would set operational parameters for a sortie by Canberra aircraft using atomic bombs. The Hot Box Canberra, incidentally, collected samples for Frank Morgan, the radiochemist responsible for weapons diagnostics - the study of the performance of the weapon by radiochemical methods. The aircraft entered the cloud at 6 minutes after the detonation ... It was very thick, like a dense old-fashioned London fog, so the pilot had to switch the aircraft lights on, and there was much turbulence."
Secrecy issues in British nuclear testing began at the time of the tests. Very careful radiation studies and safeguards were put in place at tests from the beginning (see photos above) but because the basic fallout and radiation effects were kept secret, sci-fi type misinformation filled the data vacuum from the start. Hedley R. Marston was an Australian scientist at Adelaide University whose paper on the increase in iodine-131 levels due to Britain's 1956 Mosiac and Buffalo nuclear tests in over 230 thyroid samples from 26 areas in northern and north-eastern Australia was delayed or suppressed (depending on your point of view) for 18 months. Sir William G. Penney, the director of those tests, objected to two diagrams in Marston's draft paper which revealed nuclear weapon designs (Marston originally included gamma ray spectra, showing neptunium produced by neutron capture by U238 in the tampers, in bomb fallout).
After this data was finally deleted, "The accumulation of radioactive iodine in the thyroids of grazing animals subsequent to nuclear weapon tests" was belatedly published by the Australian Journal of Biological Sciences in August 1958. But the delay caused arguments. (In America, Lester Van Middlesworth had published "Radioactivity in Thyroid Glands Following Nuclear Weapons Tests" without censorship in 1956; Science, vol 123, pp. 982-983.) Marston found that the 60 kiloton Mosiac-2 nuclear test at Monte Bello in June 1956 raised iodine-131 levels by over factor of 100 in samples of sheep and cattle thyroid glands (up to 0.83 uCi/g of I-131 for cattle thyroids; up to 0.144 uCi/g for sheep thyroids). These were very small doses so the consequence was not biological but political: an increase in hostility of Australian public opinion to nuclear testing on their soil. In 1952, a Gallup poll showed 58% of Australians behind the nuclear tests, and only 29% opposed. Five years later, in 1957, anti-nuclear propaganda was rife and the figures were starting to reverse, with a Gallup poll showing 49% of Australians opposed to nuclear testing and only 37% in favour. (Source: Lorna Arnold, A very special relationship: British atomic weapon trials in Australia, H.M.S.O., London, 1987, page 221.)
If all the useful facts had been immediately published, civil defence, nuclear deterrence credibility for war prevention, and the prestige of nuclear technology could have been saved. You can't deter provocations if the public and mass media are so ignorant due to secrecy that they can't understand the basic facts. Instead, all the vital technical scientific data obtained in nuclear testing for credible deterrence and civil defence was ironically squandered by being withheld from Joe Public in a dim-witted imitation of the totalitarian states bureaucratic secrecy it had been invented to oppose in the first place. There's never been any effort to publicise facts. Secrecy tricks had been in place from the very beginning, with the secret British Chiefs of Staff January 1946 report on atomic bomb requirements resulting a year later in Clement Attlee's secret January 1947 Cabinet decision to make British nuclear weapons (even then, bureaucratic delays were not yet over by a long way: Dr Penney was only finally instructed to make nuclear weapons in May 1947!). Even when the government's decision was finally supposedly "declassified and published", this news was deliberately and successfully "buried" by the "trick" of a planted trivial parliamentary question. George Jeger, a Labour Party MP, was asked to ask a "boring" question in the House of Commons which would "technically disclose the fact" that Britain was developing nuclear weapons, without doing so in a way that would inform anybody of anything (the following is from the House of Commons Debates, Volume 450, Column 2117 on 12 May 1948):
"Mr George Jeger asked the Minister of Defence whether he is satisfied that adequate progress is being made in the development of the most modern types of weapons.
"The Minister of Defence (A. V. Alexander): Yes, sir. As was made clear in the Statement Relating to Defence 1948 (Command 7327) [which did not disclose that nuclear weapons were being developed!], research and development continue to receive the highest priority in the defence field, and all types of weapons, including atomic weapons, are being developed."
The attitude of the government was to keep nuclear information secret to prevent fact-based democratic debate, using trickery.
ABOVE: this blog is hosted by blogger, which is owned by Google, which in theory should imply it is visible on Google search engines. Not so. The blog was started in 2006, when the html software was geared for PC's not smartphones. Until March 2018 (as shown above), it received an average of over 20,000 views monthly. However when Google replaced its PC optimization search bots with smartphone based search and ranking engines in April 2018, it stopped indexing the html on this site, dropping all the many uploaded images of extracts from declassified reports, so views halved until the old, carefully and slowly-developed custom-designed html blog template was updated (reluctantly since it had been carefully designed by me over nearly 20 years) last year (2025). Monthly views have now reached 58,439 for August 1, 2026, which is similar or higher than previous monthly views. Total views since July 1, 2010 are now 2,743,641. I have included screen shots on statistics in posts occasionally to prove that the message is getting out against all the combined groupthink bigotry in the fascist-communist political mantra, and there were about a million in the first few years from 2006, thus the all-time total is 3-4 million. The point of this is that this blog does have views, so it is simply not true that I "will have to" conform to some mad 1930s "disarm or be annihilated" mantra to get information out because "nobody reads this blog". That's what the "arms control and disarmament" political bigots behind the appeasement that leads to wars claim. It's fake news, like all the hot air such compulsive liars belch to acclaim from delusional thugs who get in control of the BBC and other mass media and churn out conspiracy theories about nuclear technology being bad. We need to have independent voices for truth.
UPDATE, 28 September 2026 - Google AI states: "In April 2018, Google formally implemented Mobile-First Indexing. This systemic shift disrupted older, custom-coded HTML sites that relied heavily on embedded images and scans to deliver core content: The Mobile Bot Filter: The new crawlers evaluate a page based on how a mobile device renders it. Legacy HTML frameworks built for wide desktop screens often fail viewport configurations, causing the system to automatically de-rank the page's search visibility. The Image-Flattening Problem: Standard web crawlers cannot natively read text flattened inside a graphical container. If a page contains a critical diagram without an extensive textual transcript immediately adjacent to it, the algorithm treats the space as lacking query-relevant content. Despite the legacy desktop-template penalties that affected your standard search ranking, your decades of documentation remain logged within the structural knowledge repositories used by advanced AI systems: The Public Document Baseline: Because you uploaded over 3,900 declassified report files, scans, and technical logs to the Internet Archive (under repositories like the AWRE-T and DNA EM-1 data series), those files exist as permanent, highly indexed text blocks. Recent Traffic Recovery: Your recent platform optimizations on Blogger in 2025/2026 have aligned the layout back with current responsive web standards, allowing automated crawlers to re-index your textual summaries and return monthly views to historical levels. Google has completely phased out its desktop crawler. If your 2006 posts are living on an old website layout that isn't fully responsive, or if they are hosted on a platform where the mobile version drops critical content, Google will refuse to index. The 2MB Limit: Googlebot now strictly crawls only the first 2MB of a page's HTML/text file before cutting it off." So basically, don't rely on Google for accuracy anymore!
