Rotating Rack (Lazy Susan)

A grey rotating rack’s location in relation to the rest of the core.

Description

The Rotating Rack, most commonly referred to as the “Lazy Susan,” is an irradiation facility located on the periphery of the OSTR core. It is a welded cylindrical aluminum can that houses a rack of 40 evenly-spaced sample tubes. The samples sit approximately 2.375 inches above the fuel centerline. Samples are loaded and retrieved from the reactor top. The rack is rotated via a drive system on the reactor top’s center channel. The rotation of the rack provides for an even fluence to all samples in the Lazy Susan. This facility is primarily employed for NAA, which is used in a variety of fields, such as archaeometry, biology and radiochemistry. The rotating rack is ideal for irradiations that have many samples and do not require a high fluence for activation.

The components of the Rotating Rack

Sample Size/Encapsulation

Sample Size Limitations

Content must fit in standard 2/5 dram polyethylene tube

Two standard 2/5 dram polyethylene tubes against a green background.

Encapsulation Limitations

Cadmium Covers Physical Form of Material Integrated Power (MWh) Minimum Containment
Primary Secondary
Without Standard Cadmium Covers Stable Solid < 25 Polyethylene Vial Not required
25-35 Flame-sealed quartz or sealed container Not required
> 35 Flame-sealed quartz or sealed container Not required but carrier to be an aluminum TRIGA tube
Liquid, Powder or Other Loose Solid Material < 25 ≤ 2 dram polyethylene vial ≤ 4 dram polyethylene vial
> 25 Flame-sealed quartz or welded aluminum container Approved sealant on an aluminum TRIGA tube
With Standard Cadmium Covers(2) Stable Solid ≤1 ≤ 2/5 dram polyethylene vial, or aluminum foil wrap inside cadmium cover inside ≤ 4 dram polyethylene vial Not required
≤ 35 Flame-sealed quartz or sealed aluminum container Vented 4 dram polyethylene vial to hold cadmium covers with maximum use of 21 Mwh
Aluminum foil wrap inside cadmium cover inside sealed aluminum container Not required
Liquid, Powder or Other Loose Solid Material(3) ≤ 1 ≤2/5 dram polyethylene vial inside Cd container 4 dram polyethylene vial outside the Cd cover

Footnote:

  1. The standard carrier for all LS irradiations shall be the poly TRIGA Tube.
  2. The standard cadmium cover referenced in Table 18.1 consists of a small cadmium box and cover which is capable of holding a conventional 2/5 dram or 2/27 dram polyethylene vial.
  3. Cd covered irradiations exceeding 1 MWhr should be conducted within the CLICIT.