The "Biggest Nuclear Bomb" Ever Exploded by the US (My Title).

Nucle-Tech Info Services Co. Ltd | 2000 | Editorial Staff

[vannrox]

Atmospheric test explosions

The nuclear bombs detonated in the atmosphere over Novaya Zemlya were dropped by airplanes, or shot out as missiles either from land or from submarines. Bombs dropped from airplanes were equipped with a parachute in order to let the planes reach a safe distance before the detonation. The airplanes took off from airports on the Kola Peninsula. Nuclear missiles detonated over Novaya Zemlya were launched in Central Asia or the White Sea region. In the Barents Sea and by Novaya Zemlya, these missiles were shot down and detonated by ABM’ s (Anti Ballistic Missiles).

The atmospherical test explosions over Novaya Zemlya were performed during two periods. The first atmospherical test explosion over Novaya Zemlya was undertaken on the 24th of September 1957. By the 10th of October that year, three bombs had been detonated. During February and March 1958, six bombs were detonated. This is the only time nuclear bombs have been detonated on Novaya Zemlya during the first six months of the year. From the 20th of September to 25th of October 1958, 15 more bombs were detonated. Resistance to atmospheric test explosions increased among Russian arms engineers after 1958. Andrei Sakharov was one of the most noted opponents of atmospheric test explosions. He claimed there were no scientific reasons to perform repeated test explosions of bombs of megaton-sized explosive forces. No Soviet test explosions took place between the 3rd of November 1958 and the 1st of September 1961.

Test explosions were resumed in 1961. The decision to resume test explosions followed the tense political relations developed between the US and the Soviet Union during the course of 1961. After the summit meeting between Nikita Khrustshev and John F. Kennedy in Vienna, June 1961, the Berlin Wall was raised and the political climate of Europe cooled to a considerable degree. Khrustshev called for a meeting between the leaders of the Communist Party, the government and the foremost bomb constructors of the Soviet Union on the 10th of June 1961. Khrustshev opened the meeting with the following decision:

In connection with the changes in international relations and the fact that the combined amount of test explosions of the Soviet Union is considerably inferior to that of the US, we (the Soviet Union) will resume the test explosions during the autumn of 1961 and achieve a de facto increase of our nuclear power and demonstrate to the imperialists what we are capable of.

Between the 10th of September and the 4th of November 1961, 24 bombs of megaton-sized explosive force were detonated. During this period, bombs were being detonated almost every second day. The explosive force of these bombs ranged from 20 to 30 megatons.

The worlds most powerful hydrogen bomb was detonated on the 30th of October 1961. The bomb had an explosive force of 58 megatons, or almost 6,000 times more powerful than the Hiroshima bomb. The bomb was dropped by an aircraft, and detonated 365 metres (1,200 feet) above the surface. The shock wave produced by this bomb was so powerful, it went thrice around the earth. The mushroom cloud extended almost 60 kilometres into the atmosphere. Resulting downfall was measured over the entire northern hemisphere. A flash of light could be observed all the way to Hopen in the Norwegian Sea, Sør-Varanger in the Norwegian county of Finnmark and by the Inari Lake in Finnish Lappland.
MK-41 a 25 Mega-TON Nuclear Weapon.
(The largest tested is at 61MT above)
Highest yield U.S. weapon ever deployed;
only U.S. 3-stage TN weapon;
Y1 "dirty,"
Y2 "clean";
parachutes 1x4 ft,
1x16.5 ft;
retired in favor of Mk-53

The Mk/B-41 was the highest yield nuclear weapon ever deployed by the U.S. It was also the only three-stage thermonuclear wepaon ever developed by the U.S., and it achieved the highest yield-to-weight ratio of any U.S. weapon design.

Test explosions with several bombs of megaton-sized explosive force continued during the autumn of 1962. 32 bombs were detonated over Novaya Zemlya between the 5th of August and the 25th of December. 9 bombs were detonated during the Cuba crisis in October 1962. The Soviet Union, Great Britain and the USA signed the Moscow Treaty on the 5th of August 1963, banning test explosions in the atmosphere, outer space and under water. The treaty became operational on the 10th of October 1963. Negative effects of fallout following test explosions on both humans and the environment were causes for the creation of this treaty.

Model of the worlds biggest nuclear device (58 megatons) which were detonated over Novaya Zemlya 30 october 1961.
 

---------------------------------------------
No. Date                    Time   Explosive
                                   force
---------------------------------------------
1   24th of September 1957  09.00  Mt-size
2   6th of October 1957     08.58  Unknown
3   10th of October 1957    06.55  Small
4   23rd of February 1958   -      Mt-size
5   27th of February 1958   07.59  Mt-size
6   27th of February 1958   10.24  Large
7   14th of March 1958      -      >1 Mt
8   20th of March 1958      -      Small
9   22nd of March 1958      -      Medium
10  20th of September 1958  -      -
11  30th of September 1958  07.50  Medium
12  30th of September 1958  09.55  Medium
13  2nd of October 1958     08.00  Moderate
14  2nd of October 1958     09.01  Moderate
15  5th of October 1958     06.00  -
16  10th of October 1958    07.51  Large
17  12th of October 1958    07.53  Mt-size
18  15th of October 1958    07.51  Mt-size
19  18th of October 1958    09.51  Mt-size
20  19th of October 1958    07.27  Small
21  20th of October 1958    08.20  Mt-size
22  22nd of October 1958    08.21  Mt-size
23  24th of October 1958    08.03  Mt-size
24  25th of October 1958    08.20  Large
25  10th of September 1961  09.00  Several Mt
26  10th of September 1961  -      Some Kt
27  12th of September 1961  10.08  Several Mt
28  13th of September 1961  -      Small
29  14th of September 1961  09.56  Several Mt
30  16th of September 1961  09.08  Medium
31  18th of September 1961  07.59  Mt
32  20th of September 1961  08.12  Mt
33  22nd of September 1961  08.01  Mt
34  2nd of October 1961     10.31  Mt
35  4th of October 1961     07.30  Several Mt
36  6th of October 1961     07.00  Several Mt
37  8th of October 1961     -      Small
38  20th of October 1961    -      Several Mt
39  23rd of October 1961    08.31  25 Mt
40  25th of October 1961    08.33  1 Mt
41  27th of October 1961    08.30  Small
42  30th of October 1961    08.33  58 Mt
43  31st of October 1961    08.29  Several Mt
44  31st of October 1961    08.38  1 Mt
45  2nd of November 1961    08.41  Small
46  2nd of November 1961    -      Small
47  4th of November 1961    07.20  Several Mt
48  5th of August 1962      09.09  30 Mt
49  10th of August 1962     09.00  1 Mt
50  20th of August 1962     09.02  Several Mt
51  22nd of August 1962     09.00  Mt
52  25th of August 1962     09.00  Several Mt
53  27th of August 1962     09.00  Several Mt
54  1st of September 1962   12.40  -
55  2nd of September 1962   -      Mt
56  8th of September 1962   10.18  Mt-size
57  15th of September 1962  08.02  Several Mt
58  16th of September 1962  10.59  Several Mt
59  18th of September 1962  08.29  A few Mt
60  19th of September 1962  11.00  20 Mt
61  21st of September 1962  08.01  A few Mt
62  25th of September 1962  13.03  25 Mt
63  27th of September 1962  08.03  >30 Mt
64  7th of October 1962     16.32  Medium
65  22nd of October 1962    09.06  Several Mt
66  27th of October 1962    07.35  Medium
67  29th of October 1962    07.35  Medium
68  30th of October 1962    -      Medium
69  1st of November 1962    06.30  Medium
70  3rd of November 1962    08.31  Medium
71  3rd of November 1962    -      Medium
72  18th of December 1962   -      Medium
73  18th of December 1962   -      Medium
74  20th of December 1962   -      Medium
75  22nd of December 1962   -      Medium
76  23rd of December 1962   11.15  A few Mt
77  24th of December 1962   10.44  Unknown
78  24th of December 1962   11.11  20 Mt
79  25th of December 1962   13.35  A few Mt
---------------------------------------------
Mt=megaton(s)  Kt=kiloton(s)
Table: Atmospheric test explosions over Novaya Zemlya (1957- 1962). Source: Soviet Nuclear Weapons Databook, Volum IV.

Fallout from atmospheric test explosions

The test explosions performed by the Soviet Union, USA, Great Britain, France and China, make up the largest source of radioactive pollution observed today in the counties of Murmansk and Arkhangel’sk. The downfall can be traced over the entire earth. The combined radioactivity of downfall caused by test explosions is hard to estimate, but it is assumed that a couple of thousand kilos of plutonium have been released into the atmosphere between 1945 and 1984. France halted their atmospheric test explosions in the Pacific in 1980, while China continued until 1984 at Lop Nor.

The radioactive cloud of an atmospheric test explosion can be dispersed over an enormous area before the fallout reaches the ground. E.g. more fallout following test explosions on Novaya Zemlya was discovered on the western coast of Norway, than in the county of Finnmark, as the rainfall on the western coast is more considerable than in Finnmark. The atmospheric test explosions over Novaya Zemlya have given Norwegians an average radioactive dose corresponding to what they were exposed to following the Chernobyl incident of 1986. Certain sections of the population received considerably higher doses, notably the reindeer-keeping Lapps of Finnmark.

The downfall created by test explosions on Novaya Zemlya was a source of considerable unrest among the Norwegian authorities. During the autumn of 1961, all civil defence stations north of Saltfjellet measured levels of radioactivity three times a day. Aircrafts of the air defence undertook measurements above the Barents Sea on an almost daily basis. The Norwegian Health Directory worked out plans for extensive preparedness measures concerning the population of Finnmark in September 1961. The plans comprised early warnings to the population to take to air-raid shelters. The population was to be evacuated were the levels of radiation to exceed 100 milliSievert. These plans for preparedness measures were kept secret from the population of Finnmark until 1991.

 

.

Atmospheric test explosions

The nuclear bombs detonated in the atmosphere over Novaya Zemlya were dropped by airplanes, or shot out as missiles either from land or from submarines. Bombs dropped from airplanes were equipped with a parachute in order to let the planes reach a safe distance before the detonation. The airplanes took off from airports on the Kola Peninsula. Nuclear missiles detonated over Novaya Zemlya were launched in Central Asia or the White Sea region. In the Barents Sea and by Novaya Zemlya, these missiles were shot down and detonated by ABM’ s (Anti Ballistic Missiles).

The atmospherical test explosions over Novaya Zemlya were performed during two periods. The first atmospherical test explosion over Novaya Zemlya was undertaken on the 24th of September 1957. By the 10th of October that year, three bombs had been detonated. During February and March 1958, six bombs were detonated. This is the only time nuclear bombs have been detonated on Novaya Zemlya during the first six months of the year. From the 20th of September to 25th of October 1958, 15 more bombs were detonated. Resistance to atmospheric test explosions increased among Russian arms engineers after 1958. Andrei Sakharov was one of the most noted opponents of atmospheric test explosions. He claimed there were no scientific reasons to perform repeated test explosions of bombs of megaton-sized explosive forces. No Soviet test explosions took place between the 3rd of November 1958 and the 1st of September 1961.

Test explosions were resumed in 1961. The decision to resume test explosions followed the tense political relations developed between the US and the Soviet Union during the course of 1961. After the summit meeting between Nikita Khrustshev and John F. Kennedy in Vienna, June 1961, the Berlin Wall was raised and the political climate of Europe cooled to a considerable degree. Khrustshev called for a meeting between the leaders of the Communist Party, the government and the foremost bomb constructors of the Soviet Union on the 10th of June 1961. Khrustshev opened the meeting with the following decision:

In connection with the changes in international relations and the fact that the combined amount of test explosions of the Soviet Union is considerably inferior to that of the US, we (the Soviet Union) will resume the test explosions during the autumn of 1961 and achieve a de facto increase of our nuclear power and demonstrate to the imperialists what we are capable of.

Between the 10th of September and the 4th of November 1961, 24 bombs of megaton-sized explosive force were detonated. During this period, bombs were being detonated almost every second day. The explosive force of these bombs ranged from 20 to 30 megatons. The worlds most powerful hydrogen bomb was detonated on the 30th of October 1961. The bomb had an explosive force of 58 megatons, or almost 6,000 times more powerful than the Hiroshima bomb. The bomb was dropped by an aircraft, and detonated 365 metres (1,200 feet) above the surface. The shock wave produced by this bomb was so powerful, it went thrice around the earth. The mushroom cloud extended almost 60 kilometres into the atmosphere. Resulting downfall was measured over the entire northern hemisphere. A flash of light could be observed all the way to Hopen in the Norwegian Sea, Sør-Varanger in the Norwegian county of Finnmark and by the Inari Lake in Finnish Lappland.

Test explosions with several bombs of megaton-sized explosive force continued during the autumn of 1962. 32 bombs were detonated over Novaya Zemlya between the 5th of August and the 25th of December. 9 bombs were detonated during the Cuba crisis in October 1962. The Soviet Union, Great Britain and the USA signed the Moscow Treaty on the 5th of August 1963, banning test explosions in the atmosphere, outer space and under water. The treaty became operational on the 10th of October 1963. Negative effects of fallout following test explosions on both humans and the environment were causes for the creation of this treaty.

Model of the worlds biggest nuclear device (58 megatons) which were detonated over Novaya Zemlya 30 october 1961.
 

---------------------------------------------
No. Date                    Time   Explosive
                                   force
---------------------------------------------
1   24th of September 1957  09.00  Mt-size
2   6th of October 1957     08.58  Unknown
3   10th of October 1957    06.55  Small
4   23rd of February 1958   -      Mt-size
5   27th of February 1958   07.59  Mt-size
6   27th of February 1958   10.24  Large
7   14th of March 1958      -      >1 Mt
8   20th of March 1958      -      Small
9   22nd of March 1958      -      Medium
10  20th of September 1958  -      -
11  30th of September 1958  07.50  Medium
12  30th of September 1958  09.55  Medium
13  2nd of October 1958     08.00  Moderate
14  2nd of October 1958     09.01  Moderate
15  5th of October 1958     06.00  -
16  10th of October 1958    07.51  Large
17  12th of October 1958    07.53  Mt-size
18  15th of October 1958    07.51  Mt-size
19  18th of October 1958    09.51  Mt-size
20  19th of October 1958    07.27  Small
21  20th of October 1958    08.20  Mt-size
22  22nd of October 1958    08.21  Mt-size
23  24th of October 1958    08.03  Mt-size
24  25th of October 1958    08.20  Large
25  10th of September 1961  09.00  Several Mt
26  10th of September 1961  -      Some Kt
27  12th of September 1961  10.08  Several Mt
28  13th of September 1961  -      Small
29  14th of September 1961  09.56  Several Mt
30  16th of September 1961  09.08  Medium
31  18th of September 1961  07.59  Mt
32  20th of September 1961  08.12  Mt
33  22nd of September 1961  08.01  Mt
34  2nd of October 1961     10.31  Mt
35  4th of October 1961     07.30  Several Mt
36  6th of October 1961     07.00  Several Mt
37  8th of October 1961     -      Small
38  20th of October 1961    -      Several Mt
39  23rd of October 1961    08.31  25 Mt
40  25th of October 1961    08.33  1 Mt
41  27th of October 1961    08.30  Small
42  30th of October 1961    08.33  58 Mt
43  31st of October 1961    08.29  Several Mt
44  31st of October 1961    08.38  1 Mt
45  2nd of November 1961    08.41  Small
46  2nd of November 1961    -      Small
47  4th of November 1961    07.20  Several Mt
48  5th of August 1962      09.09  30 Mt
49  10th of August 1962     09.00  1 Mt
50  20th of August 1962     09.02  Several Mt
51  22nd of August 1962     09.00  Mt
52  25th of August 1962     09.00  Several Mt
53  27th of August 1962     09.00  Several Mt
54  1st of September 1962   12.40  -
55  2nd of September 1962   -      Mt
56  8th of September 1962   10.18  Mt-size
57  15th of September 1962  08.02  Several Mt
58  16th of September 1962  10.59  Several Mt
59  18th of September 1962  08.29  A few Mt
60  19th of September 1962  11.00  20 Mt
61  21st of September 1962  08.01  A few Mt
62  25th of September 1962  13.03  25 Mt
63  27th of September 1962  08.03  >30 Mt
64  7th of October 1962     16.32  Medium
65  22nd of October 1962    09.06  Several Mt
66  27th of October 1962    07.35  Medium
67  29th of October 1962    07.35  Medium
68  30th of October 1962    -      Medium
69  1st of November 1962    06.30  Medium
70  3rd of November 1962    08.31  Medium
71  3rd of November 1962    -      Medium
72  18th of December 1962   -      Medium
73  18th of December 1962   -      Medium
74  20th of December 1962   -      Medium
75  22nd of December 1962   -      Medium
76  23rd of December 1962   11.15  A few Mt
77  24th of December 1962   10.44  Unknown
78  24th of December 1962   11.11  20 Mt
79  25th of December 1962   13.35  A few Mt
---------------------------------------------
Mt=megaton(s)  Kt=kiloton(s)
Table: Atmospheric test explosions over Novaya Zemlya (1957- 1962). Source: Soviet Nuclear Weapons Databook, Volum IV.

Fallout from atmospheric test explosions

The test explosions performed by the Soviet Union, USA, Great Britain, France and China, make up the largest source of radioactive pollution observed today in the counties of Murmansk and Arkhangel’sk. The downfall can be traced over the entire earth. The combined radioactivity of downfall caused by test explosions is hard to estimate, but it is assumed that a couple of thousand kilos of plutonium have been released into the atmosphere between 1945 and 1984. France halted their atmospheric test explosions in the Pacific in 1980, while China continued until 1984 at Lop Nor.

The radioactive cloud of an atmospheric test explosion can be dispersed over an enormous area before the fallout reaches the ground. E.g. more fallout following test explosions on Novaya Zemlya was discovered on the western coast of Norway, than in the county of Finnmark, as the rainfall on the western coast is more considerable than in Finnmark. The atmospheric test explosions over Novaya Zemlya have given Norwegians an average radioactive dose corresponding to what they were exposed to following the Chernobyl incident of 1986. Certain sections of the population received considerably higher doses, notably the reindeer-keeping Lapps of Finnmark.

The downfall created by test explosions on Novaya Zemlya was a source of considerable unrest among the Norwegian authorities. During the autumn of 1961, all civil defence stations north of Saltfjellet measured levels of radioactivity three times a day. Aircrafts of the air defence undertook measurements above the Barents Sea on an almost daily basis. The Norwegian Health Directory worked out plans for extensive preparedness measures concerning the population of Finnmark in September 1961. The plans comprised early warnings to the population to take to air-raid shelters. The population was to be evacuated were the levels of radiation to exceed 100 milliSievert. These plans for preparedness measures were kept secret from the population of Finnmark until 1991.

 

.

[vannrox]

I hope that you may find this as interesting as I did.

Yield	25 Megatons
Weight	10,670 lb
Length	12 ft. 4 in (148 in)
Diameter (body)	52 in
Diameter (tail fin)	74 in
Number Manufactured	About 500
Manufactured	September 1960 to June 1962
Retired	November 1963 to July 1976

Design Features

Three stage radiation implosion weapon

Deuterium-tritium boosted primary.

Fusion stages presumalby use Lithium-6 (95% enrichment) deuteride fusion fuel.

The B-41 was deployed in a a "dirty" version (the Y1, with a U-238 encased tertiary stage) and a "clean" version (the Y2, with a lead encased tertiary stage). It may be that both used a secondary with a lead fusion tamper.

There are actually two reported yields for this bomb, "less than 10 Mt" and 25 Mt. It is possible that the 25 Mt yield applies only to the dirty Y1 version, with the clean Y2 version having the lower yield.

According to Dr. Theodore Taylor (physicist and former weapons designer), the practical limit for nuclear weapon yield to weight ratio is about 6 Kt/kg. Using the deployed weapon weight (10,670 lb), and a yield of 25 Mt, the Mk-41 achieved 5.2 Kt/kg. If we look at the test devices fired in Hardtack I however (see below), which lack such weighty and in principle unnecessary things as parachutes, we see weights 8,752 - 9,723 lb. Taylor's maximum achievable yield-to-weight ratio of 6 Kt/kg corresponds to a device weight of 9,190 lb; well within the weight range of these devices.

Delivery Method

Strategic bomber - most recently the B-52G (internal bomb bay)

Safeguards and Arming Features

Unknown

Fuzing and Delivery Mode

"Full Fuzing Options" (FUFO), options probably selected on ground prior to mission.
Five fuzing options:

• Free fall air burst
• Parachute retarded air burst
• Free fall surface burst
• Parachute retarded surface burst
• "Laydown" - parachute retarded delayed surface burst

Parachutes used: parachutes 4-5 ft diameter pilot chute, and a 16.5 ft diameter main ribbon chute for high-speed stabilization.

Development

The B-41 program originated in 1955 when the Air Force issued a requirement and a feasibility study for a Class "B" (10,000 lb), 62 inch diameter high yield thermonuclear weapon. UCRL proposed adapting an experimental three-stage thermonuclear system they were developing, which was subsequently scheduled for test-firing during Operation Redwing in 1956.

Two version of the proposed UCRL test device, named "Bassoon" and "Bassoon Prime", were test-fired in "clean" and "dirty" configurations during the Zuni and Tewa shots of Redwing.

The Bassoon device fired in Redwing Zuni (27 May 1956) was 39 inches in diameter, 135.5 inches long, and weighed 12,158 lbs. The predicted yield for Zuni was 2-3 Mt, it achieved 3.5 Mt. This device used a lead fusion tamper and was quite clean, with 85% of the energy coming from fusion, and only 15% from fission.

The Bassoon Prime device fired in Redwing Tewa (20 July 1956) was 39 inches in diameter, and 135.5 inches long, and weighed 15,735 lb. The predicted yield for Tewa was was 6-8 Mt, the actual yield was 5 Mt. In contrast to Zuni, Tewa used an uranium fusion tamper and was quite dirty, with only 13% of the energy coming from fusion, and 87% from fission. This device produced a fusion yield of only 650 Kt compared to the 3 Mt of Zuni.

Both were experimental "proof of concept" systems only, not test version of actual designs intended for deployment. Redesign to meet military requirements and additional testing was thus required, which was carried out in Operation Hardtack Phase I in 1958.

In November 1956 the feasibility study was completed and the designation TX/XW-41 for a bomb and a missile warhead version was assigned. On January 28, 1957, the DOD formally requested that the AEC develop a new Class "B" weapon using the UCRL design. The military characteristics for the bomb and warhead were approved in mid-February, and development engineering of the designs began. In June the proposed ordnance characteristics of the TX-41 bomb and XW-41 warhead were accepted by the Special Weapons Development Board; the ICBM warhead application was canceled at the end of July.

A test of the boosted TX/XW-41 warhead primary and secondary in a bomb mockup, was fired in Plumbbob Smoky at the NTS on 31 August 1957. The device yielded 44 Kt (predicted yield was 48 Kt, range 45-50 Kt); it measured 50" in diameter and 126.2" in length and weighed 9,408 lbs. The test included some thermonuclear yield.

Drop testing of the TX-41 ballistic shape was conducted between December 1957 and December 1959 at the AEC's Tonopah (Nevada) and Salton Sea (California) test ranges.

Prototypes of the TX-41 bomb, all of them clean variants, were fired during the Sycamore, Poplar and Pine shots of Operation Hardtack Phase I at the PPG between May 31 and July 27, 1958.

The Sycamore shot (31 May 1958) used a two-stage clean version of the TX-41. The predicted yield was five megatons, of which just 200 kilotons was to be fission yield. The device fizzled though, with a total actual yield of only 92 Kt although low level burning was detected in the second stage. The test device was 50 inches in diameter by 112.6 inches long and weighed 9,723 lbs.

The Poplar shot (12 July 1958) was a repeat test of the two-stage variant. This device had a diameter of 48.2 inches, a length of 112.1 inches, and a weight reduced of 9,316 lbs. The Poplar device was predicted to yield either 5-10 Mt, of which only 450 Kt was to be fission yield. This test was successful, with a yield of 9.3 Mt (the largest of Hardtack I, and the fifth largest U.S. test ever).

The Pine shot (26 July 1958) used a three-stage configuration. This device had a diameter of 50 inches, a length of 112.6 inches, and a weight reduced of 8,752 lbs. The predicted total yield was 4-6 Mt, only 200 Kt was to be from fission. Actual yield was only 2 Mt. The device is said to have had dual-primaries.

The ordnance characteristics of the TX-41 were revised and accepted by the SWDB in mid-October 1958. Production engineering of the TX-41 started soon afterwards.

B-41 Development Schedule

1955	Air Force issued a requirement and a feasibility study for a Class "B" weapon (high megaton range, 10,000 lb, 62 inch diameter or less)
1956
27 May	Bassoon device fired in Redwing Zuni (3.5 Mt), test firing of UCRL "clean" 3-stage concept for class "B" requirement
20 July	Bassoon Prime device fired in Redwing Tewa (5 Mt), test firing of UCRL "dirty" 3-stage concept for class "B" requirement
November	Feasibility study completed and designation TX/XW-41 assigned
1957
28 January	DOD formally requested that the AEC develop the TX-41 weapon using the UCRL design, development engineering begins
June	Proposed ordnance characteristics of the TX-41 bomb accepted
31 August	Plumbbob Smoky shot: test of the boosted TX-41 warhead primary and secondary in a bomb. Yield 44 Kt, test included some thermonuclear yield.
1958
May-July	Prototype tests of the Tx-41 weapon fired in Operation Hardtack Phase I at Enewetak: 31 May (GMT) Sycamore - two-stage clean version of the TX-41. Predicted yield 5 Mt total, 200 Kt fission. The device fizzled with total actual yield of 92 Kt although low level burning was detected in the second stage. 12 July (GMT) Poplar - repeat test of the two-stage variant. Predicted yield 5-10 Mt, 450 Kt fission. Successful, with a yield of 9.3 Mt. 26 July (GMT) Pine - used a three-stage configuration. Predicted total yield 4-6 Mt, 200 Kt fission. Actual yield was 2 Mt. The device said to have had dual-primaries.
October	Ordnance characteristics revised and accepted by SWDB; production engineering of the TX-41 begins
1960
September	Early production of the Mk-41 Mod 0 bomb begun
1962
June	Production terminated

Deployment

Early production of the Mk-41 Mod 0 bomb began in September 1960; by June 1962, approximately 500 units had been manufactured. These weapons were retired between November 1963 and July 1976 as the more-versatile Mk-53 replaced them in the stockpile.

[vannrox]

Some comparisons on size...

Bravo 15.0 Mega-Ton

Mike H-Bomb 10.4 Mega-Ton

RDS-37 Superbomb 1.6 Mega-Ton

Priscilla 0.37 Mega Ton (Mini-Nuke)

Grable 0.15 mega-Ton Mini-Nuke

Fizeau 0.11 Mega-Ton (Pocket Nuke)

[Tijeras_Slim]

I didn't see that the largest test by the USA (Castle Bravo 1954) mentioned anywhere. What is your point? Also, most of the documentation I have seen indicates that the HOB for the 57 megaton Soviet test was 12,000 feet.

[danielobvt]

Does the US still make or have any "Dirty nukes"? It doesn't seem in line with current american strategy. 58 Megatons!?! Yow!

[boris]

I would find it even more interesting if all the photos were visible.

--Boris

[Fulbright]

I'll have eight B-53's with 25 W70 warheads on the side.

[vannrox]

I'm still looking, slim. I haven't found any pictures of anything bigger than 25 Mega-Ton (2500 KTon) yet. But, I am still looking and will post when and if I find one. Whatever the picture looks like, It must be absolutely AWESOME!

The 25 Megaton explosion is truly frightful. Can you imagine a 61 Megaton? YIKES!!!!

[BansheeBill]

Of interest from a site that sells atomic prints:Link to that site HERE

Atomic Cannon

On May 25th,1953, a 280mm cannon with an atomic artillery shell made history. Code name, "Grable", this marked the first time and only time an atomic artillery shell was fired and detonated. The explosion had a yield of 15 Kilotons, the same force as the atomic explosion at Hiroshima.

The fascinating image of this historic event was taken by Lookout Mountain photographer, Jack Cannon. The Atomic Cannon is a beautifully restored Collectors Edition print from Defense Department Archives. This Collectors Edition print has been reproduced using the highest quality inks on the finest grade matte finish paper.

Silhoutted against a stark blue sky and the backdrop of the Nevada desert, a giant brightly lit mushroom cloud swells rapidly up and outward. Trails of silver smoke spiral skyward as a cloud of dust marks the path of destruction spreading over the landscape.

[ramdalesh]

Check the freerepublic archives for those photos. I remember a great article about nuclear testing was posted earlier this year. How about reposting that article along with it.

[vannrox]

Castle ROMEO test [160x120 Quicktime MOV, 2.1 MB] The Castle ROMEO test yielded 11 megatons. It was detonated from a barge in the BRAVO crater.

[vannrox]

	Ivy KING detonation [160x120 Quicktime MOV, 3.1 MB] Ivy KING was an air-drop of the "Super-Oralloy" all-fission bomb, with a yield of 500 kilotons.
	Castle BRAVO test [160x120 Quicktime MOV, 2.7 MB] The Castle BRAVO test on March 1, 1954, yielded 15 megatons, the largest nuclear weapon ever detonated by the United States. By accident the inhabited atolls of Rongelap, Rongerik and Utirik were contaminated with fallout, as was the Japanese fishing trawler Fukuryu Maru or Lucky Dragon.

[rwfromkansas]

How much would these suitcase nukes destroy?

[paul544]

So what kind of damage would this .11Mt do? What would be the size of the target area?

[vannrox]

BELOW - ONE OF AMERICA'S LARGEST EXPLOSIONS!

Below is the Castle Bravo Detonation.
This is a very very controversial test in several ways. The Castle Bravo was Detonated on Eniwetok Atoll in 1954. The result was a truly massive explosion, the biggest the DoE every managed, and it was all by accident!!!

The Bomb was only to have a predicted Yield of 6Mt, much smaller than Ivy Mike. The resulting chain reaction managed to cunjure up a whopping 15Mt Yield(15,000,000 tons of TNT equilivent)

(The largest is 61 MegaTon or 10 times larger than this one.)

This massive detonation blew half of the Atoll away. Although it made the biggest ever explosion in America's history(albeit by accident) it also produced the worlds first and very devastating Nuclear disaster. This was because the fact it was all done by accident. The Predicted 6MT explosion would of been 'within limits' but the whopping 15MT explosion that occurred caused extreme amounts of Nuclear fall-out and the whole area for hundreds of miles was completely contaminated. This mushroom cloud loomed over hundreds of miles and fell down on many Atolls and Islands with thousands of local inhabitants of Marshall Islander's and Japanese.

The result was many hundreds killed. Most of the Islanders got effected with 100-200R of fall-out and died of a horrible and painful death, some very slowly. Japanese fisherman were also caught in the fall-out well outside the exclusion zone like the islanders were. The japanese fisherman, although miles and miles outside the 'zone of danger' were contaminated with over 300R of fall-out and some of the crew died within a few days of exposure.

Many of the islander's children were born with serious deformalities that are reminiscent to todays Chernobyl nuclear disaster.

After this 'accidental' over-rated explosion, the DoE expanded its safe-zone to over 1% of the World's Surface around this Atoll incase other experiments went drastically wrong making it the largest military testing ground on earth.



The Resulting absolutely massive Fireball rising up into a dome shape with a hollow middle. burning its way through the atmosphere. The Radiant heat was so much that it would of melted steel in seconds on the Atoll.

This however was not the largest ever Nuclear Detonation

As a side note...The Russians also did a large explosion, but this time it was predicted to be as large as it was. Well over 15MT this Giant was detonated on a large island. The resulting effect was the island 'disappeared'

[wanderingstar]

as for the "bravo" test in the south pacific, National Geographic had a spectacular photo of the test from an old 1980`s issue - the photo was taken from a distance of 50 miles at the time of the blast. but for whatever reason, i seem to remember that they stated that the yield was around 50 megatons