Talk:Operation Hurricane/Archive 1

Calder Hall vs Windscale
According to the Sellafield article Calder Hall wasn't 'connected to the grid' until 1956. If can be trusted it wasn't even 'ordered' until 1953 (i.e. the year after this test). To me that looks like the UK produced plutonium must have come from the Windscale piles. miterdale 20:38, 15 March 2006 (UTC)
 * The first UK plutonium came from the first two (IIRC, i've none of my sources to hand) piles. The creation of "proper" power plants, (Magnox), connected to the grid (several used also for plutonium generation) didn't occur untill the mid 50's (tieing up that date anyway). Pickle 17:07, 26 January 2007 (UTC)
 * The declassified official files in the National Archives, London, are ES 1/11. These refer only to Windscale as the source of UK produced plutonium. Some (5kg) came from Canada in April 1952. Calder Hall was physically located on the Windscale site, was part of it. So both descriptions are probably OK. George.Hutchinson (talk) 20:36, 13 January 2013 (UTC)

Levitated - criticality
Not in the sense used in this article where it was claimed that there was a gap between Pu core and the tamper. Not true. Declassified official files in the National Archives, London, ES 1/11 show unquestionably that the Pu core outer diameter was a close machined fit inside the U-238 tamper. They show and describe a hollow core, with a levitated Urchin initiator. Something very different to what was described here. The claim that a non-existent core-tamper gap was to safeguard against an accidental criticality are not true and cannot be adequately referenced, and unsurprisingly the claim in the article was not referenced to a source. George.Hutchinson (talk) 21:20, 13 January 2013 (UTC)

Pu-240 and "hurried" production

 * It is untrue that "hurried production" was linked to unwanted Pu-240 contamination as claimed in the article. Production was of course a high priority, but not at the cost of sub-standard material. The editor was confused about why fuel rods in a thermal reactor are used to produce military-grade plutonium and withdrawn partially consumed after only a short period of burn-up. A short irradiation produces plutonium with minimal amounts of the Pu-240 isotope, which is still unwelcome in even these small amounts. Leaving the fuel rods in the reactor produces much more of the Pu-240 isotope than could then be used in a fission weapon. It creates a real risk of pre-detonation before the implosion is complete, leading to "fizzle", an incomplete nuclear fission. It is to prevent this possibility that fuel rods are withdrawn from the reactor "early", before they are fully consumed, and when only small amounts of the Pu-240 contaminant has formed. In reactors where the primary objective is electricity production, the fuel rods will be left in the reactor until fully consumed. The larger amounts of Pu-240 isotopes then formed are of no consequence in this "civil" plutonium, since it is not destined for weapon production.
 * Pu-240 is unwanted for another reason. Its Alpha emissions over a long period are a hazard to sailors in close proximity to warheads in submarines, and also accelerate the decay of rubber, plastics and other materials used in warheads and missiles.
 * Military grade plutonium has less than 7% Pu-240. In the case of the Hurricane device where the British scientists had little reliable evidence of the acceptable level, the official records show that they used plutonium with only 2% of Pu-240, - a similar level was used in Trinity and Fat Man. With experience a level of 6-7% was chosen for military-grade plutonium. That decision to use a 2% level resulted in greater expense because the fuel rods could be irradiated for an even shorter time. However not "hurried", because the process had to be repeated many more times to produce the required quantity. George.Hutchinson (talk) 21:20, 13 January 2013 (UTC)

Excessive alpha radiation would not have been a problem to nuclear submariners, as the particles could hardly get through a missile casing made from anything more substantial than paper-mâché, but it would have made handling the bomb pits much more hazardous for the makers of the devices Moletrouser (talk) 05:34, 2 May 2013 (UTC)

Fat Man
The weapon was a close copy of the Fat Man (Nagasaki) weapon, although the design was modified to use a levitated pit.

I was wondering how it can be a copy of Fat Man if all nuclear technology exchanges between the US and Britain were unilaterally cut-off by the US implementing the McMahon Act in 1946. If true, presumably the British must have already known a considerable amount about the Fat Man warhead design to have been able to copy it in the first place. —Preceding unsigned comment added by 213.40.254.8 (talk) 15:41, 2 November 2009 (UTC)


 * It had a similarity to Fat Man, in the same way that all modern airliners have a design similarity. Because when a specification is drafted to meet a very precise set of engineering characteristics, engineers frequently arrive at similar conclusions.
 * There is another factor here though. Many British scientists had worked on the Manhattan Project and were familiar with the design processes that led to Fat Man. The scientist who first proposed the explosive lens as a means of focusing the explosive energy of the HE was British. Although those scientists could not return to the UK with the Fat Man designs, many secrets were in their heads. So when working on a similar project in the UK it would be unsurprising for them to produce a similar product. Suggestions that Hurricane was a "close copy" are false. The US Atomic Energy Act of 1946 often referred to as the McMahon Act forbade US administrations from sharing nuclear information with any foreign power; and was a source of great irritation to the British, Canadians and others who had without quibbles helped the US with the Manhattan Project, jet engines, radar, the magnetron, penicillin etc, etc. No nuclear design information was supplied to the British. All they had was what was retained in memory. And we all know how fickle that can be. George.Hutchinson (talk) 20:36, 13 January 2013 (UTC)

Further to what George Hutchinson has written - who knows of a different approach to building a plutonium bomb? The Manhattan Project scientists originally considered a gun-type design (Thin Man) for their plutonium devices but had to reject it because it was impractical with the plutonium they had from Hanford, which had too much Pu-240 in it. Some gun-type weapons have been produced since 1945 (eg: Upshot-Knothole Grable - got to love that name!) but all have used highly-enriched uranium (AFAIK) Moletrouser (talk) 05:16, 1 May 2013 (UTC)


 * In fact, the use of a levitated core was considered in 1943, but considering the difficulty of getting implosion to work properly and the pressure to get a weapon into the hands of the military, that idea was shelved until the Mark 4 in the US. SkoreKeep (talk) 23:54, 19 December 2013 (UTC)

Table Notes
The notes attached to the table columns are there for reasons of qualifying and explaining the content of the columns. If you have problems with the notes, or perhaps a better way of handling them than present, please do us the favor of talking about them before deleting them willy-nilly. I'm not adverse to discussing how to handle them in a better way than they are at present. Be aware, however, that they are used in tables on some 100 or so other pages. SkoreKeep (talk) 15:43, 11 May 2014 (UTC)


 * Found a better way.SkoreKeep (talk) 15:30, 31 August 2014 (UTC)

The table on this page is generated by database
The table on this page and the contents of any nuclear tests infobox are generated from a database of nuclear testing which I have maintained and researched for a number of years. The table is automatically generated from that database by a Visual Basic script, and then has, periodically, been inserted into the page manually. I began doing this in October of 2013.

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SkoreKeep (talk) 15:30, 31 August 2014 (UTC)

External links modified
Hello fellow Wikipedians,

I have just added archive links to 2 one external links on Operation Hurricane. Please take a moment to review my edit. If necessary, add after the link to keep me from modifying it. Alternatively, you can add to keep me off the page altogether. I made the following changes:
 * Added archive https://web.archive.org/20160117155758/http://www.aic.gov.au/publications/lcj/wayward/ch16.html to http://www.aic.gov.au/publications/lcj/wayward/ch16.html
 * Added archive https://web.archive.org/20140729154525/http://www.atomicforum.org/uk/hurricane.html to http://www.atomicforum.org/uk/hurricane.html

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