Gradual corrosion and mechanical wear of equipment over a period of years has affected the seals and gasketing of the electric pot calcining equipment in the 224-U Building Cell E to such an extent that the desirable vacuum cannot be maintained in the pots. Air contamination has been gradually increasing, and this, together with a lowering of the mask working limits, has made it necessary to require personnel to wear assault masks continuously. Indications are that, with the increased production now required, the level of air contamination will continue to rise unless measures are taken to prevent it. The Manufacturing Department has requested that a project be established to reduce the contamination level. Several items of improvement are listed for consideration including, in general, the electric pot agitation and sealing, semi-automatic pot unloaders, cell ventilation and air locks, and the nitric acid off-gas system and stacks. Because of the urgency of improving the conditions, the project, at first, is to provide for immediate improvements for the electrical pot agitation, the pot cover leakage, and the nitric acid off-gas system and stack. Additional study will be required to determine the extent of the ventilation and semi-automatic unloading improvements required.

This report describes the evaluation of physical properties of AGHT and 185-W graphites that are important to pile construction and operation. On the basis of these data, purified AGHT graphite was allocated to either filler block positions in the central regions of the K piles or to the upper or lower reflectors. This decision was based on the similarities of physical properties between AGHT graphite and the other moderator components. A similar allocation could be made for 185-W graphite for some future pile if it can be successfully purified or if purification is not required.

Because of the excessive vertical fragility and high replacement costs of mice-window G-M tubes used in vertical and horizontal lead-pig shelf counters, it was requested that a simple system of conversions to reliable scintillation detection be accomplished.

A large (size 2) Purex pulse generator was installed in the 321 Building Tan Farm to pulse solutions in the prototype Purex HA Column. Flow sheet considerations indicated a need for information on leakage rates with various size weep holes in the pulse generator piston. In addition to leakage tests, experiments were conducted to determine the air required under the piston to hold the column contents away from the pulse generator piston thereby preventing leakage during shut down and the determine the time required to bleed the air trapped in the pulse leg when the column is first filled. [...] Leakage past the piston was not appreciably affected by pulse frequency. [..] Bleeding the air out of the pulse leg under start-up conditions, even with the piston weep hole plugged, was rapid. The longest time required to bleed the pulse leg was 36 minutes, which included a column-filling time of 30 minutes.