I have before me a copy of a letter of June 4 from Materials Handlers to Wrenn Wilson Construction Company regarding the Crane in the Nuclear Building.

We have now used this crane in a variety of ways for over a month. There are, as pointed out in my letter of early May, a number of ways in which this crane fails to achieve our anticipated performance. Through the experience gained in its use, however, we believe that a satisfactory compromise revision of these mechanism can be reached without great burden on the manufacturers by the four following adjustments: 1. The brake on the bridge should be changed to that specified, i.e. to a variable brake capable of adjustment or complete removal, or, if this is not possible, the brake should be removed entirely. 2. A positive step (not just a limit switch) should be provided on the beam to prevent the trolley mechanism from crashing against the concrete walls of the room. The trolley mechanism should be revised so that the hoist hook can approach to within 39 or 40 inches of the wall,--as apparently originally specified. This can be achieved with- out change of the carrier mechanism or other major revisions, excepting switching the drive unit to the other side of the hoist. 4. In lieu of other revisions to meet specifications, some of which would require major changes, and since the major remaining limitation on the crane's use is its failure to approach sufficiently closely to the wall of the room to permit its easy use in moving objects betweenthe first floor rear hallway and the floor of the reactor room, a 3-ton capacity steel "drawbridge" platform extension of the rear hallway floor, 40 inches into the reactor room, will be accepted. The general plan for this platform I have discussed with you on previous occasions.