The Atomic Heritage Foundation has an excerpt of the 1940 Frisch-Peierls Memorandum, which “explains the feasibility of creating an atomic weapon.”

In order to produce such a bomb it is necessary to treat a few hundred pounds of uranium by a process which will separate from the uranium its light isotope (uranium-235) of which it contains about 0.7%. Methods for this separation of isotopes have recently been developed. They are slow and they have not until now been applied to uranium, whose chemical properties give rise to technical difficulties. But these difficulties are by no means insuperable. We have not sufficient experience with large-scale chemical plant to give a reliable estimate of the cost, but it is certainly not prohibitive.

It is a property of these super-bombs that there exists a “critical size” of about one pound. A quantity of separated uranium isotope that exceeds the critical amount is explosive; yet a quantity less than the critical amount is absolutely safe. The bomb would therefore be manufactured in two (or more) parts, each being less than the critical size, and in transport all danger of a premature explosion would be avoided if these parts were kept at a distance of a few inches from each other.

The memorandum adds this observation about a possible German nuclear weapons program:

We have no information that the same idea has also occurred to other scientists but since all the theoretical data bearing on this problem are published, it is quite conceivable that Germany is, in fact, developing this weapon. Whether this is the case is difficult to find out, since the plant for the separation of isotopes need not be of such a size as to attract attention. Information that could be helpful in this respect would be data about the exploitation of the uranium mines under German control (mainly in Czechoslovakia) and about any recent German purchases of uranium abroad. It is likely that the plant would be controlled by Dr. K. Clusius (Professor of Physical Chemistry in Munich University), the inventor of the best method for separating isotopes, and therefore information as to his whereabouts and status might also give an important clue. At the same time it is quite possible that nobody in Germany has yet realized that the separation of the uranium isotopes would make the construction of a super-bomb possible. Hence it is of extreme importance to keep this report secret since any rumour about the connection between uranium separation and a super-bomb may set German scientists thinking along the right lines.

In a 2004 interview, Dr. Garwin spoke about Germany and the first U.S. plutonium-production reactors:

This work was all shared between the British and the Americans, ultimately. The British then bombed the Norwegian plants — heavy water plants — to keep the Germans from getting the heavy water. The Germans had initially tried graphite as a moderator, but it absorbed too many neutrons and they gave it up. But Szilard knew that the graphite manufacture — heating oil, wood, whatever to very high temperature — was usually done using boron carbide electrodes or other materials. The boron has a tremendous appetite for neutrons, so tiny traces of boron in the graphite were responsible for this parasitic loss of neutrons.

Szilard then worked with the suppliers, got somebody to provide very pure graphite without boron, and that’s how our first reactors were made: the Fermi Reactor that went critical December 2nd, 1942 in Chicago, and then the production reactors. Fermi’s Reactor was about two watts of thermal power maximum under the west stands, because it didn’t have any shielding and would have exposed people to too much radiation. The next step was the design of these 200-megawatt reactors for producing plutonium. You get about one gram of plutonium per day for a one-megawatt reactor. So, 200-megawatt reactor, two-tenths of a kilogram per day, and the first Nagasaki bomb used six kilograms of plutonium. So you could make — every 30 days you could make a new core for such a bomb.

This 2002 lecture by a former Swedish Air Force intelligence analyst, has a few entertaining anecdotes. Here’s one:

In Sweden we had a company with the name Pressklipp, literally translated “Press cutting.” It was a perfectly adequate name since that was exactly the service that the company offered its customers–cutting out and sending copies of newspaper articles on specified subjects or search-words. In the mid-1990s the company changed its name to Observer Media Intelligence. It still supplied most of its customers with the same press cuttings, with the exception that you could get them by email, along with video-recordings and links to pages on the Internet. This is certainly media information – but it is hardly media intelligence. The word ”intelligence” has simply, like in numerous other cases, been added to attract customers and to create an impression of qualified analysis.

The other day, the UN published a list of documents before the First Committee, complete with links.

The 1954 letter (about which I previously wrote) from an attendee of the Tenth Session of the NATO Senior Officers Course on Special Weapons (Atomic) has an observation about the role of intelligence in nuclear weapons-employment:

The Barents Observer tells us that Rosatom posted the video on its YouTube channel:

The most recent issue of the CTBTO Spectrum has a good deal of worthy material. But I am especially interested in this piece about the restoration of a Senegalese seismic monitoring station which is part of the organization’s International Monitoring System auxiliary seismic network. The mundane details of international policy implementation are always worth a read:

…the first site survey was performed to verify if the site chosen under the Treaty was suitable for acquiring high quality seismic data for the IMS….Unfortunately, seismic background noise from industrial and other activities in Mbour, which is quite a large city, was too high and one of Senegal’s busy main national roads borders the IRD Center. This made the Treaty site, despite all the advantages linked to its location, not suitable for AS097 instal- lation. Alternate sites had therefore to be found.