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Progress on the development of an electrostatically suspended spinning-rotor vacuum gauge is described. The objective is to create a transfer standard capable of making consistent measurements down to 10 ?Pa (10-7 mbar), and lower if possible. The slowing down of the rotor due to gas pressures of this magnitude is very small, so its measurement in a reasonable time raises a signal-processing problem. The approach to this is outlined. The rotor can also change its speed for reasons other than impact with gas molecules. It is necessary to ensure that these effects are as small as possible and stable with time. One approach is to arrange for some of the effects to cancel one other out.

To facilitate the procurement and handling of the glass former for Am/Cm vitrification in the F-Canyon MPPF, 1/4 inch and 3/8 inch diameter glass beads were purchased from Corning for evaluation in the 5 inch Cylindrical Induction Melter (CIM5). Prior to evaluating the beads in the CIM5, tests were conducted in the Drain Tube Test Stand (DTTS) with 1/4 inch beads, 3/8 inch beads, and a 50/50 mixture to identify any process concerns. Results of the DTTS tests are summarized in Attachment 1. A somewhat larger volume expansion was experienced in all three DTTS runs as compared to a standard run using cullet. Further testing of the use of glass beads in the CIM5 was requested by the Design Authority as Task 1.02 of Technical Task Request 99-MNSS/SE-006. Since the Technical Task Plan was not yet approved, the completion of this task was conducted under an authorization request approved by the SRTC Laboratory Director, S. Wood. This request is included as Attachment 2.

The successful demonstration of sequentially drying, calcining and vitrifying an oxalate slurry in the Drain Tube Test Stand (DTTS) vessel provided the process basis for testing on a larger scale in a cylindrical induction heated melter. A single processing issue, that of batch volume expansion, was encountered during the initial stages of testing. The increase in batch volume centered on a sintered frit cap and high temperature bubble formation. The formation of a sintered frit cap expansion was eliminated with the use of cullet. Volume expansions due to high temperature bubble formation (oxygen liberation from cerium reduction) were mitigated in the DTTS melter vessel through a vessel temperature profile that effectively separated the softening point of the glass cullet and the evolving oxygen from cerium reduction. An increased processing temperature of 1470°C and a two hour hold time to fine any remaining bubbles successfully reduced bubbles in the poured glass to an acceptable level. The success of the preliminary process demonstrations provided a workable process basis that was directly applicable to the newly installed Cylindrical Induction Melter (CIM) system, making the batch flowsheet the preferred option for vitrification of the americium-curium surrogate feed stream.

One alternative for closing the nuclear fuel cycle is efficient, high decontamination separation of uranium and plutonium and fabrication of a Pu-U mixed-oxide fuel Detailed flowsheets were prepare...

The paper investigates the feasibility of externally powered lower-limb prostheses, in particular those in which walking motions would be automatically controlled. The lack of a suitable power supply is a major obstacle to the rapid development of a practical prosthesis, but a theoretical and practical study is being made of a ‘prototype walking device’, out of which, if successful, a prosthesis might evolve. The configuration of this device is outlined, with reasons for the choice, and possible actuators and sensors are discussed. A mathematical model is formulated and a control scheme is outlined which should enable the device to walk stably on small feet over uneven terrain. Results of analogue simulation of the device are summarized.

(1977). An ultrasonic mobility aid for blind persons in wheelchairs. Journal of Medical Engineering & Technology: Vol. 1, No. 5, pp. 290-291.