A high-density concrete shield is proposed for the biological shield. Adequate shielding of personnel and equipment can be obtained for about two-fifths the cost of a laminated shield of steel and masonite. The proposed shield is expected to behave satisfactorily during the life of the Reactor Unit and, in addition, the shield will possess considerable resistance to earthquake and blast loads. Details of design specification are given.

Since 1945 the routine production of plutonium (``A`` buttons) at Atomic Energy plants has been accomplished by heating mixtures of plutonium tetrafluoride, calcium and iodine in crucible-bomb assemblies. Yields above 97% and metal of adequate purity are consistently obtained by this process. Plutonium (``X`` button) production has also been carried out routinely by including plutonium turnings with the powder mixture given above. A majority (several thousand) of buttons produced in the 234-5 Building have been ``X`` buttons made by recycling up to 1.1 units of turnings/unit of plutonium in the plutonium tetrafluoride. Operating hazards exist in either process, however, and these are reviewed below.

None