https://declassified.library.utoronto.ca/files/original/badefcec578e81d0ea81c6739564c308.pdf c97a8b14764805e5d5909a7ecd1c9274 PDF Text Text Document disclosed under the Access to Information Act I'information I •pcument i QpCUdivulgue en vertu de la Loi sur I'acces a <y%> SA^ <fh* ^x>. '.^ •7, A % ' >.%. V * *^^ PERSONAL AND TOP SECRET December 6, 1957 Dear Ed, In the last few days (i.e.. four or five days after the first messages arrived here) I have been brought in to some extent on the new developments relating to exchange of information on atomic and weapons matters. The subject is, of course, in the hands of D.L. (1) at the divisional level, and I have not (at least so far) been involved in the drafting of our outgoing telegrams. One point did occur to me, however, which I thought it might be useful to put to you; Jim McCardle suggested that a personal note might be a more suitable channel than the official telegram net. "For legislative reasons" Canada has not been invited to join the sub-committees on nuclear warheads and nuclear materials. As the MacMahon Act requires "need-to-know" justification for transfer of information, this exclusion is fair enough as far as warheads go. In the case of nuclear materials, however, you will recall that there are contract arrangements for supply to the USAEC of our plutonium output in excess of our (very small) domestic requirements; although our output is not great, it will A. E. Ritchie, Esq. The Canadian Embassy Washington, D. C. ... 2 000356 �Document disclosed under the Access to Information Act Document divulgue en vertu de la Loi sur I'acces a I'information 2* nevertheless not be negligible when the NRU reactor is in full production. It is my understanding that these arrangements specify limits upon the isotopic composition of the plutonium delivered to ensure that it shall be of weapons grade. Neutron irradiation of uranium leads initially to the production of PU24O: further irradiation, however, gives rise to absorption of neutrons not only in the remaining uranium but in the PU24O w i t i l i t s consequent conversion to Pu24l a n d higher isotopes. Hence the isotopic composition of plutonium separated frora neutron-irradiated uranium depends upon the amount of irradiation, with the PUji*40 content diminishing relatively as the irradiation increases. The PU24O percentage must be above a certain figure for the plutonium to be satisfactory for production of weapons; hence our contract commitments in effect limit the exposure we can give our uranium. One of the important factors in economic operation of any reactor, and particularly of one designed to produce electric power, is to achieve as high a rate of burn-up as possible, i.e., to attain a high total irradiation of the uranium fuel. This means that our commitment to supply weapons-grade plutonium to the USAEC as a by-product of our reactors runs counter to the most efficient use of the reactors for our own primary (peaceful) purposes. Thus we would appear to have a real and direct Interest in information relating to nuclear materials for weapons use. I am not suggesting that we should seelc membership on the nuclear materials sub-committee, which may be set up to deal with quite different questions. It would not be my place to make such a suggestion, and Bennett and others here have available the information on what is going on in Washington. Nevertheless, I thought it might be useful to you to know, if you did not already, of this very direct connection between USAEC procurement of nuclear materials for weapons production and Canadian interests relating to the operation of our reactors at Chalk River. lours sincerely, v 000357 � Text A resource consisting primarily of words for reading. Examples include books, letters, dissertations, poems, newspapers, articles, archives of mailing lists. Note that facsimiles or images of texts are still of the genre Text. Dublin Core The Dublin Core metadata element set is common to all Omeka records, including items, files, and collections. For more information see, http://dublincore.org/documents/dces/. Identifier An unambiguous reference to the resource within a given context CDNW01250 Title A name given to the resource Personal and Top Secret Letter Date A point or period of time associated with an event in the lifecycle of the resource 12/6/1957 Source A related resource from which the described resource is derived "Canada/US Agreement for Cooperation concerning military aspects of atomic energy." RG25-A-3-b, vol. 5957, 50219-AK-40, part 1, Library and Archives Canada (LAC). Creator An entity primarily responsible for making the resource Department of External Affairs Rights Information about rights held in and over the resource Canadian Crown Subject The topic of the resource Atomic energy cooperation Description An account of the resource Kirkwood to Ritchie Publisher An entity responsible for making the resource available Canada Declassified Type The nature or genre of the resource Text Format The file format, physical medium, or dimensions of the resource PDF Language A language of the resource en