Since H-bombs require either U-235 or plutonium, as well as deuterium and tritium, and since absolute or near-absolute control of U-235 or plutonium is not possible, it becomes obvious that H-bomb controls must relate to both deuterium and tritium as well as to fissionable material. Since the UN plan does not mention them by name, added safeguards are necessary to regulate deuterium and tritium. No safeguards, however, could be devised even in this respect to provide absolute or near-absolute protection. 6. IS IT TECHNICALLY POSSIBLE TO DETECT THE MANUFACTURE OF HEAVY WATER AND DEUTERIUM THROUGH INTERNATIONAL INSPECTION? WOULD AN INTERNATIONAL AGREEMENT FLATLY PROHIBITING PRODUCTION IN QUANTITY BE DESIRABLE? The manufacture of heavy water and the separation of deuterium are relatively simple processes. They may be carried out in small plants which can exist in a variety of locales. The _Second Report_ of the UN Commission comments as follows: The international agency shall have the authority to require periodic reports from nations regarding the production, shipment, location, and use of specialized equipment and supplies directly related to the production and use of atomic energy, such as mass spectrometers, diffusion barriers, gas centrifuges, electromagnetic isotope separation units, very pure graphite in large amounts, heavy water, and beryllium or beryllium compounds in large amounts. In addition, the agency shall have authority to require reports as specified of certain distinctive facilities and construction projects having features of size and design, or construction or operation, which, in combination with their location and/or production or consumption of heat or electricity, are peculiarly comparable to those of known atomic facilities of dangerous character (p. 54). Would inspectors possessing freedom of movement be able to locate deuterium and heavy water plants? Would aerial surveys and aerial photographs of industrial areas help detect processes which produce hydrogen as a byproduct and which might therefore be concerned with the manufacture of heavy water or deuterium? Should quantity production of deuterium be prohibited even though it is used in certain types of peacetime reactors such as the Canadian reactor at Chalk River, the French reactor at Chatillon, Swedish reactors under construction, and a research reactor at the Argonne National Laboratory? Is it possible on technical grounds to enforce such a prohibition? AUTHOR’S COMMENT