Eight large diameter irradiation positions are located in the removable beryllium (RB) near the control region. These facilities are designated as RB-1A and -1B, RB-3A and -3B, RB-5A and -5B, and RB-7A and -7B. These are generally referred to as the RB* positions. The vertical centerline of these facilities is located 10.75 in. (27.31 cm) from the vertical centerline of the reactor and they are lined with a permanent aluminum liner having an inside diameter of 1.811 in. (4.6 cm). These facilities are designed for either instrumented or non-instrumented experiments. The instrumented capsule design can also employ sweep or cooling gases as necessary. Instrument leads and access tubes are accommodated through penetrations in the upper shroud flange and through special penetrations in the pressure vessel hatch.