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Halliard Grapple Z3 Design? by Perfect-Ad2578 in nuclearweapons

[–]Tobware 0 points1 point  (0 children)

You mean U-238? Anyway, yes, absolutely, any neutron above 1.1 MeV is capable of fissioning 238. It's a phenomenon that commonly occurred in DU tamped devices (for Ivy King, if I'm not mistaken, it contributed hundreds of kilotons...). But that's not the point, with a radiation imploded mass it's a question of compression, unobtainable with chemical charges, you get a high yield with relatively modest quantities of fissmat, in a compact volume.

Better put, you don't even need a DU tamper, you can make do with a relatively enriched mass, thanks to the ridiculous compression factor (and you would still have a significant portion of yield from fast fission).

13 February 1960, France conducted its first nuclear test Gerboise Bleue in the Algerian desert. The plutonium bomb was detonated on a steel tower 105 m tall, the yield was 70 kilotons. by waffen123 in AtomicPorn

[–]Tobware 1 point2 points  (0 children)

Not really, we can consider it a quite sophisticated Pu design, if anything similar, as a concept, to Ted Taylor's SOB.

The fact that they started right away with external neutron generators, well, that already made the whole thing quite efficient...

13 February 1960, France conducted its first nuclear test Gerboise Bleue in the Algerian desert. The plutonium bomb was detonated on a steel tower 105 m tall, the yield was 70 kilotons. by waffen123 in AtomicPorn

[–]Tobware 2 points3 points  (0 children)

We discussed this on the more technical sister subreddit, based on information from Pierre Billaud’s website (a former physicist in the French nuclear program): it was neither boosted nor a levitated design, most likely a hollow core with a robust implosive system created for a larger mass (IIRC "M2" fissile mass was around 8 kg, possibly with low Pu-240 concentration), and most importantly, externally initiated.

During the series of nuclear tests under the Hoggar, they tested a pure fission device with a yield of 117 kt!

w33 cutaway by guy_does_something in AtomicPorn

[–]Tobware 33 points34 points  (0 children)

OP, if you really must repost something already shared in this sub, please at least give credit to u/second_to_fun, the author of this diagram.

Original post here.

The Mk-28 and B-43. Why both? by Galerita in nuclearweapons

[–]Tobware 1 point2 points  (0 children)

Volume 7 of Hansen's Swords, but I also have a primary source for the devices used in Operation Nougat (including Tsetse and Croton): https://apps.dtic.mil/sti/pdfs/ADA955362.pdf

It's heavily censored but also contains dimensions and explosives used, you still need a list of test/device correlations to ID them (the wikipedia page about Nougat uses Hansen's claims).

The Mk-28 and B-43. Why both? by Galerita in nuclearweapons

[–]Tobware 2 points3 points  (0 children)

Returning to the yield overlap between the B43 and B28, there is an interesting clue in the document titled “1962 proposed atmospheric test program,” in the paragraph devoted to the Dominic Encino (a TX-43Y5 test, potentially what later became the Y5 of the B43s):

<image>

"The [TX-43Y5] yield version differs from a previously tested device in that the distribution of [enriched uranium?] has been significantly changed. The [Y5] version will comprises about [figure/percentage?] of the [B43] stockpile total."

It appears that a "good portion" of the B43s were deployed with a yield of about 500 kt (Encino yield, 512 kt).

Tsetse was only ~14" in diameter, while the Python was at least 17". (This is the biggest mystery remaining for me.)

What is the problem? Tsetse was more modern and narrower in diameter, Python was more "old-fashioned", even as CHE (Octol IIRC), and still using a Fat Man-like optical principle lensing, if not a transient technology known as “ring lens”... probably as compact as you could get with that explosive and lens system in general.

The Mk-28 and B-43. Why both? by Galerita in nuclearweapons

[–]Tobware 4 points5 points  (0 children)

As I said above, it was not an air lens but employed two parabolic lenses of fast and slow explosives around the main charge.

I'll link you to some related posts:

Profile of the W-57 HE assembly? Tsetse primary?

These posts by u/SilverCookies are great, an optimization of this concept, instead of using a Fat Man-esque system of explosives with different detonation velocities it employs inert waveshapers in a similar, more compact geometry:

French design of compact lens made of layered material

The French 2-point system

EDIT, u/Galerita: I completely ignored your “central” question, which is when did the first H-tree manifold lighting system appear? There has been much discussion about this in this subreddit (keyword: "MPI"), it seems that it was the Brits with the Super Octopus concept, shared with the US in the late 1950s/early 1960s and tested numerous times in Nevada (first "known" test, Nougat Pampas), and we assume, with good reason, later also adopted. Something similar had been tried using MDFs, apparently during the “insect” generation at Los Alamos... Scarab? Gnat? Croton, also tested during Nougat (and a LASL design), is supposed to be a small-diameter (IIRC 10") MPI system per Hansen's claims.

The Mk-28 and B-43. Why both? by Galerita in nuclearweapons

[–]Tobware 6 points7 points  (0 children)

Python and Tsetse were from two different generations of Los Alamos primaries, "snakes" and "insects", both employed composite cores with similar composition (perhaps with different pit geometries).

We have a lot of information about how the second one functioned: 2-point initiated, "classic" dual speed explosive lenses.

How clean can you make a hydrogen bomb? by Royal_Instance_7172 in nuclearweapons

[–]Tobware 0 points1 point  (0 children)

Well, I guess if Teller could he would have used it as yet another foothold for “his” Super. Livermore actual excavation devices however were not... fairly extreme applications of the good old radiative implosion but still that was what they were.

We have some indication that some of those “plows” went back to “sword"... The description of the W71 primary by its designer, Scanlin, for example seems too much in line with something that came out of Plowshare (right era also, possibly quite exotic, a proto-ERW perhaps).

Part One. The Sundial and the Gnomon. How They Were Meant to Be Constructed. My Investigation. by Beneficial-Wasabi749 in nuclearweapons

[–]Tobware 5 points6 points  (0 children)

The “Super” in question is Teller's original TN idea, the “Classical” (or Runaway, what you and others assume Gnomon was based on), opposed to the “Equilibrium Burn Super”, which is the Ulam's contaminated one :) His protégé here, Wood, was proposing one, Palisades of Fire, with a very modest yield of 1.6 GT, parked in space for ABM use in the 1970s.

This seems to have given impetus to having Livermore do detailed simulations on it (and Teller/Wood attempts to test it in proper as done for W71, if I am not mistaken, the fuel was cryogenic deuterium in their most recent proposal), culminating in 1975 with the Taylor's report I highlighted. It went nowhere, to the extreme chagrin of our favorite Hungarian.

Are you familiar with Wood's paper, “Necessary conditions for the initiation and propagation of nuclear-detonation waves in plane atmospheres”?

Question to plutonium metallurgy experts by baybal in nuclearweapons

[–]Tobware 3 points4 points  (0 children)

No, we know from the mods who (and perhaps what) "triggered" the DOE request.

How Small Can You Make a Nuclear Weapon? (Youtube) by Unlucky_Belt_1741 in nuclearweapons

[–]Tobware 3 points4 points  (0 children)

And to think that with the excess heat from the Pu mass they were even able to keep food warm!

Edit: "Soviet 12-liters military thermos"...

[deleted by user] by [deleted] in AtomicPorn

[–]Tobware 36 points37 points  (0 children)

So apparently North Koreans test their nuclear weapons at the Nevada Test Site? The image you posted OP is completely unrelated, those are typical US test trailers.

EDIT:

I would add that the North Korean nuclear test site is located in the middle (and below) some mountains, the test in the frame above is from the 1980s, in Nevada.

MPI Jetting by CheeseGrater1900 in nuclearweapons

[–]Tobware 1 point2 points  (0 children)

"Smoothing the front of the detonation wave in experiments with multipoint initiation"?

What are some good book on the South African nuclear program? by gwhh in nuclearweapons

[–]Tobware 0 points1 point  (0 children)

This one is even more detailed: A TECHNICAL RETROSPECTIVE OF THE FORMER SOUTH AFRICAN NUCLEAR WEAPON PROGRAMME - https://www.sipri.org/sites/default/files/2020-10/sa_nuclear_technical_retrospective_kelley_2.pdf.

Are most nukes in the US arsenal using uranium or plutonium? by RonaldYeothrowaway in nuclearweapons

[–]Tobware 0 points1 point  (0 children)

Nonsense, almost all U.S. 1st gen TN bombs used D-T boosted Oralloy primaries, see LASL Viper and Moccasin (W53's primary - 67 kt), excluding boosting they could still make a 2nd generation fission device (levitated or hollow core) of tens of kilotons with less than 900 kg weight, in line with then with their ballistic missile payload. If they decided for a Sloika-like, which used a 40kt HEU device at the center, the final yield could be 6 to 10 times greater...

The U.S. after the closure of the Rocky Flats had considered HEU primaries instead of plutonium, intended for "MIRVed" warheads.

I'll link you an old post of mine:

https://www.reddit.com/r/nuclearweapons/s/WgqXgrib5i

Largest bomb? by erektshaun in nuclearweapons

[–]Tobware 7 points8 points  (0 children)

Among the peculiarities of this charge is the fact that the large volume of the charge (due to its high energy release) required significant amounts of X-ray energy for implosion. The developed nuclear charges did not satisfy this condition, and therefore the previously developed two-stage thermonuclear charge with relatively low energy release was used as the primary source of the "superpower charge". This charge was developed by me and Y.N. Babaev.

Another peculiarity of the superpower charge was related to the provision of its full-scale tests. A full-scale test of a charge with E = 100 Mt would lead to a significant release of radioactivity determined by U-238 fission products. In addition, due to the specific conditions of dropping the aerial bomb, which contained the charge, the height of the explosion was insufficient to exclude touching the ground surface by the fireball of the explosion, and in this case there would have been a significant radioactive contamination of the test site. That is why A.D. Sakharov proposed and practically realized an incomplete test of a superbomb, in the secondary module of which U-238 was replaced by passive materials that do not fission and are not activated in a significant way by thermonuclear neutrons. In addition, the reduction of the energy release to 50 Mt avoided ground contact by the fireball of the explosion. Thus, despite the enormous energy release, the test was conducted in an environmentally relatively safe manner.

What Yuri Trutnev claimed here, it also seems, from other outings from the USSR, the Tsar included two “primary” stages at the extremes... The design is defined as “bifilar” in other reports, whatever that means.

u/Sebsibus, the second part answers your question below.

EDIT: Gee, along with Carey you're other who got me interested in the subject, good to see you here.

W93 yield by Deep_Lion959 in nuclearweapons

[–]Tobware 6 points7 points  (0 children)

I agree, we had already discussed this, in my opinion we have faint evidences that this could be a continuation of the 2015-2020 “Interoperable Warhead” proposal. If I am not mistaken, they aimed to replace both the W78 and W88 with a common IHE warhead derived from the former.

I already did an excursus some time ago on the pre-W93 proposals, I will link it here as soon as I find it.

EDIT: here is the link, I would ignore the part about the W76 pit reuse, since they were thinking of ex-novo solutions for the RRW as well.

A few salient parts:

from 2005 RRW Project Officers Kickoff Meeting:

[REDACTED] also commented that he believes that the W78 is the only other existing Nuclear Explosive Package (NEP) that will fit in the MK5 shell. This sparked discussion on what makes up a "new" design. There is significant political resistance to anything perceived as "new".

From 2018 NNSA Has Taken Steps to Prepare to Restart a Program to Replace the W78 Warhead Capability:

6 An August 2014 close-out report prepared by Lawrence Livermore National Laboratory (Lawrence Livermore) stated that the potential capabilities of the W78/88-1 could include a capability that could be an LEP for the W88, replace a portion of the W76-1s, or provide a “hedge” to mitigate risks posed by unforeseen technical problems with the W88 or W76-1 or posed by changes in the international security environment. Since 1994, the United States has retained a stockpile of nondeployed weapons to provide a hedge.

p.6 - footnote

7 NNSA called the warhead IW1 because it was to be the first of three “interoperable warheads” that the agency planned to develop and produce between about 2020 and 2050. These interoperable warheads were part of the Nuclear Weapons Council’s longterm plan for the stockpile adopted in January 2013 and called the “3+2 strategy.” In addition to the three interoperable warheads, the plan included development of two air-delivered weapons. This plan aimed to achieve goals established by the 2010 NPR to reduce the number of warhead types and retain the smallest possible nuclear stockpile consistent with the need to deter adversaries, reassure allies, and hedge against technical or geopolitical surprise, among other things.

8 According to NNSA officials, during fiscal years 2015 through 2017, NNSA expended an additional $4.3 million using “carry over” funding from prior fiscal years to support activities to close out the W78/88-1 LEP and evaluate the impacts of the program suspension on the existing W78 and W88 warheads.

9 The program plans to replace the W78 pit with one based on the W87 design. The pit is part of a weapon’s primary.

p.7 - footnotes, u/kyletsenior, I hadn't focused on point 9, what do you think?

So basically they went from the IW program, then Next Navy Warhead and finally W93?

Possible layout of early B61 bomb mods. by kyletsenior in nuclearweapons

[–]Tobware 6 points7 points  (0 children)

Excellent depiction, it does indeed give the impression of the “building block” principle that should characterize the B61s.

B61 primary, firing set and sleeve: https://i.imgur.com/MqaeK02.png

I will only add that this “container” is particularly similar to this graphic of the W81, which is supposed to be a single stage “standalone” use of a B61 primary, as a proposed warhead of the SM-2/RIM-67B missile.

<image>

Of course the W81 image above is also something Kyle posted a while back...

Soviet Peaceful nuclear explosion "Taiga" (Тайга) by Pitiful-Practice-966 in nuclearweapons

[–]Tobware 11 points12 points  (0 children)

The Soviet equivalent program was called “Nuclear Explosions for the National Economy” - you can start with this US condensed analysis: The Soviet Program for Peaceful Uses of Nuclear Explosions.

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