United Kingdom Archive | Program History | Testing Database | Image Gallery | Hurricane Date: 00:59 UTC 03/10/1952 | Type: Seasurface @-3m | Yield: 25 Kt The first British nuclear test, Hurricane was detonated in a lagoon on Trimouille Island. The bomb was exploded inside the frigate HMS Plym which was anchored in 12m of water. The device was a plutonium implosion bomb similar to the Fat Man using plutonium produced at Windscale (now Sellafield).The test was devised to investigate the effects of a ship-smuggled bomb. The ship was mostly vaporized by the explosion, except for pieces set fires to nearby scrub. The explosion left a crater on the seabed 6m deep and 304m wide.The cloud rose only to 4,572m due to the very dry air which cooled the ascending cloud, and a strong inversion layer. View 2 | View 3 | News Reel | Hurricane assembly Totem T1 Date: 21:30 UTC 14/10/1953 | Type: Tower @31m | Yield: 9.1 Kt Totem T1 was the first shot of operation Totem and the second ever British test shot. The series was intended to develop greater knowledge after the initial test (Hurricane) which was rushed and poorly instrumented. Plutonium with a much higher Pu-240 content (less costly) was now being produced by the Calder Hall power reactors and needed to be evaluated. Pu-240 is less desirable that Pu239 as it is prone to spontaneous fission, which increases the risk of a criticality accident and descreased yield. The cloud reached an altitude of 4,600m. The explosion was more powerful than expected, with fallout badly contaminating the areas of Wallatinna and Welbourn Hill 175km downrange. Mosaic G2 Date: 02:14 UTC 19/06/1956 | Type: Tower @30m | Yield: 98 Kt Mosaic G2 was a test of fusion-boosted weapon system, probably similar to the Soviet Sloika and U.S. Alarm Clock designs. It incorporated lithium-6 deuteride, and a uranium tamper. It was the highest yield test conducted in Australia up to that time, and 50% larger than expected. The test yield broke assurances made personally to the Australian PM, that the yield would not exceed 2.5 time that of Hurricane, a fact kept secret until 1984. The cloud rose to 14,000 metres, considerably higher than predicted. Buffalo R1/One Tree Date: 07:30 UTC 27/09/1956 | Type: Tower @30m | Yield: 15 Kt The first and largest of 3 test shots conducted at the One Tree site in Maralinga during operation Buffalo. A test of the Red Beard warhead developed by Aldermaston, that was half the size and one-fifth the weight of the Blue Danube. A reduction achieved through boosting and using an elevated pit. Even though meteorological conditions were unfavorable, the shot was not postponed causing greater fallout than expected. The cloud reached a height of 11,400m. One noteworthy feature of the first two Buffalo shots was the presence of an 'Indoctrinee Force' designed to give British military personnel operational experience of a nuclear weapon. Video courtesy of the Imperial War Museum Archives. View 2 Buffalo R2/Marcoo Date: 07:00 UTC 04/10/1956 | Type: Surface @2m | Yield: 1.5 Kt The second Buffalo shot was fired at the Marcoo site. It was a test of a low-yield Mark I enriched uranium device for the Blue Danube bomb. The device was detonated on the surface to collect ground shock and cratering data. The bomb was placed in a shallow concrete pit so the center of the nuclear reaction would be exactly at the surface. The explosion produced a crater 49m wide and 12m deep. Unexpected rain showers occurred after the explosion and as a result accurate fallout data could not be obtained. View 2 Buffalo R3/Kite Date: 05:57 UTC 11/10/1956 | Type: Airdrop @150m | Yield: 3 Kt Round Three Kite was the UK's first air drop test of the Blue Danube bomb from an RAF Valiant B1 bomber WZ366 at the Maralinga Kite site. This test was originally scheduled to use a service issue 40 kt core. But plans were changed due to concerns about contamination if the airburst fuze failed resulting in a surface explosion, so a low yield bomb core ith less fissile material was substituted. Originally the test was supposed to be the last test of Operation Buffalo. But after the Marcoo shot, William Penney decided to swap the last two tests, making the air drop the third test. site. Fireball | View 2 Buffalo R4/Breakaway Date: 14:35 UTC 22/10/1956 | Type: Tower @30m | Yield: 10 Kt This was the last test of Operation Buffalo, detonated at the Breakaway site. It was a test of the Red Beard tactical bomb. Some fusion fuel was included in the device as a physics experiment to supplement data collected during Operation Mosaic. Once again there were delays due to unfavourable weather. The cloud reached 11,000 metres, but soon became widely dispersed between Darwin in the Northern Territory and Newcastle New South Wales. The fallout was measured using sticky paper, and sampling air and water. Short Granite |Grapple 1| Date: 19:37 UTC 15/05/1957 | Type: Air drop @2400 m | Yield: 300 Kt Dropped by Valiant bomber XD818 piloted by Wing Commander K. Hubbard, detonating after 52 seconds of free fall from 14,000m. This was Britain's first test of a radiation implosion thermonuclear bomb design. The device named Green Granite Small weighed 4,500kg, and used a modified Red Beard primary ('Tom'), and a lead-encased lithium deuteride secondary ('Dick'). Most of the yield was from the secondary, providing evidence of successful radiation implosion. The yield was far below the predicted value of one megaton. Despite the disappointing result, the Grapple 1 test was hailed as a successful test of a thermonuclear weapon in the megaton class. View 2 Orange Herald |Grapple 2| Date: 19:41 UTC 31/05/1957 | Type: Air drop @2300m | Yield: 720 Kt The Grapple tests demonstrated Britains ability to produce a thermonuclear weapon. As a contingency plan, a huge fission bomb would be used and passed off as hydrogen bomb. Orange Herald was this insurance policy, and after the disappointing Short Granite, it was 'heralded' as proof of Britain's ability to produce an H-bomb. This deception was concealed from the world and the drop crew alike. The 800Kt yield was the largest ever by a fission only device, as there were doubts that the lithium-6 deuteride fusion secondary had contributed to the yield. The crew were required to deliver the bomb with extreme accuracy while flying with instruments only, as the windows were shuttered to prevent the blinding of the crew. While executing their escape, the aircraft stalled and the acceleometer failed, and the aircraft was nearly incinerated. Early Fireball | Wide view and cloud development Purple Granite |Grapple 3| Date: 19:40 UTC 19/06/1957 | Type: Air drop @2300m | Yield: 200 Kt Purple Granite was the third and final test of the Grapple series also failed to produce anywhere near the required yield, even less than Short Granite. The scientists assured the government that if they were able to redesign the weapon, that another test series ahead of an impending test-ban, would enable them to produce the required results. The "stop-gap" Orange Herald device was rushed into service with the RAF in 1958. The device was dropped by Valiant XD823 piloted by Squadron Leader Arthur Steele. Antler R3/Taranaki Date: 06:45 UTC 09/10/1957 | Type: Balloon @2250m | Yield: 26.6 Kt Test of a primary for a megaton range thermonuclear device. It used plutonium surrounded by highly enriched uranium. Three 2,000 m3 balloons were required to lift the bomb to 300m. The cloud reached 7,000m, with a secondary cloud forming at 3,000m. Due to the balloon height, the fireball did not touch the ground, and fallout was limited in both volume and extent. Firing from balloons was problematic, but the advantages were worth it, and they would subsequently be used in the following Grapple tests. Grapple X/Round C Date: 17:47 UTC 08/11/1957 | Type: Air drop @2250m | Yield: 1.8 Mt Grapple X was Britain's first truly successful thermonuclear bomb test that successfully it's design yield. This was Britain's first megaton-class explosion, showing that the UK had achieved mastery of H-bomb design. The test was detonated over the uninhabited far end of Christmas Island to save money and time. Only one device was tested of the planned three after significant and last minute design changes to the physics package, designated Round C. It exceed the precicted yield of 1 Mt, but used a relatively large quantity of expensive highly enriched uranium. Dropped by a Valiant bomber (XD824) piloted by Squadron Leader Barney Millett. Grapple Y Date: 18:00 UTC 28/04/1958 | Type: Air drop @2350 m | Yield: 3 Mt Grapple Y was a heavily redesigned version of Grapple X. Using a mixture of uranium-235, uranium-238 and a greater amount of lithium deuteride that was less enriched in lithium-6 (and therefore had more lithium-7) while reducing the amount of uranium-235 in the centre of the core. It achieved a huge three megaton yield, and remains the largest British nuclear weapon ever tested. The design of Grapple Y was notably successful because much of its yield came from its thermonuclear reaction instead of fission of a heavy uranium-238 tamper. The weapon was dropped by a Valiant bomber XD825 piloted by Squadron Leader Bob Bates. View 2 Pennant 3 |Grapple Z| Date: 18:00 UTC 22/08/1958 | Type: Baloon @450m | Yield: 24 Kt Grapple Z explored the use of external neutron initiators, core boosting with tritium gas and external boosting with layers of lithium deuteride. This permitted smaller lighter primaries better suited to two stage thermonuclear weapons. There were concerns that a hostile nuclear detonation could disable nearby weapons, especially those that used plutonim as it was prone to predetonation. Building a primary immune to this effect would require techniques new techniques. Rather than being dropped by an aircraft, the bomb was suspended from a string of four vertically-stacked barrage balloons. Pendant had a 24 kiloton yield and used solid fusion boosting with lithium deuteride, and an external neutron initiator. Flagpole 1 |Grapple Z| Date: 17:24 UTC 02/09/1958 | Type: Air drop @2850m | Yield: 1 Mt Flagpole was dropped from Valient bomber XD822 piloted by Bill Bailey, exploding at an altitude of 2850m. The wahead wad a scaled down version of the Grapple Y device with a small, unboosted primary known as Indigo Herald. This was the first British use of blind radar bombing with a nuclear device. The maximum diameter of the fireball was measured as being 2600m. Three Canberra aircraft flew cloud sampling missions, one of these spending over 11 minutes in the radioactive cloud. Initial fireball and cloud development Halliard 1 |Grapple Z| Date:17:49 UTC 11/09/1958 | Type: Air drop @2650 m | Yield: 800 Kt The main objective of operation Grapple had been achieved and the US were once again exchanging nuclear weapon design data with the UK. This meant that the testing of Halliard 3 was no longer required, the device was converted into Halliard 1 and was the last airdropped atmospheric test by the United Kingdom. Dropped by a Valiant XD827 piloted by Flight Lieutenant Tiff O'Connor. Initial fireball Burgee 2 |Grapple Z| Date: 18:00 UTC 23/09/1958 | Type: Baloon @450 m | Yield: 25 Kt Burgee 2 was an fission weapon boosted with gaseous tritium. The device was hoisted to altitude by four baloons, and detonated over the south east corner of Christmas Island. It was the last ever UK atmospheric test, signifying the end of operation Grapple. Fireball & cloud | View 2