Shield Cask

Single boreholes in the floors of galleries are provided to hold high-level glass cylinders. The cylinders are carried in heavily shielded casks and are then lowered into the boreholes. Single boreholes can be arranged in a way that the heat is sufficiently dissipated to maintain maximum permissible peak temperatures in the salt,... 

Alternatively, irradiated targets can be brought into the Zone 2A canyon in a shielded cask through the airlock at the north end of the canyon. The target would be removed from the cask once it is positioned in the shielded area of the canyon. Appropriate cask and target handling equipment will be required to effect this alternative entry. 

Shield cask Worker safety Provide radiation protection such that worker exposures from radioactive material during cask transport are in accordance with 10 CFR 835 Shield design (Design Feature) Cask lid closure (Administrative Control)... 

Target Entrance System (TES) mechanical interlock Worker safety Prevent removal of shield cask from STB with improperly installed cask lid Interlock is operable... 

The sole purpose of the shield cask is to provide protection for workers from potentially lethal doses of radiation emitted by irradiated material during transfer operations. The shield cask also provides limited physical protection to the radioacrive material should a mishap occur in transport. 

The safety-related feature of the shield cask is passive radiation shielding. Thus, the only functional requirement applicable to the cask is ... 

The shield cask provides an inherent, passive safety function as long as the cask lid is bolted in place whenever it contains an irradiated target. Thus, a TSR administrative control for ensuring that the cask lid is bolted in place before movement will effectively implement the required safety function. 

The TES provides a worker safety function by preventing the removal from the STB of a shield cask containing an irradiated target without the shield cask lid properly installed. Inadvertent exposure of workers to an irradiated target could be lethal. 

The performance criterion needed to demonstrate that the above functional requirement is met is that the shield cask cannot be removed from the TES with the cask lid off. Removing the cask lid in the TES results in the mechanical insertion of a locking pin between the moveable and stationary parts of the TES so that the moveable part cannot be retracted into Zone 2. The mechanical interlock provides a positive feature that precludes unintentional removal of an inadequately shielded target from the TES. 

The shield cask provides a worker safety function by shielding personnel from irradiated targets during target transfer between the Annular Core Research Reactor high-bay and the HCF target entrance system. 

As indicated in Section 5.3, there are no SLs, LCSs, or LCOs associated with the shield cask. 5.5.9.2 Surveillance Requirements... 

The shield cask serves to provide radiation shielding for facility workers during the transfer of irradiated targets from the ACRR core to the HCF steel transfer box. The thickness of DU in the cask is sufficient to reduce the dose rate from a Mo-99 target irradiated for 7 days at 20 kW fission power followed by a 6-hour decay to approximately 5 mR/hr on contact... 

Target Entrance System Mechanical Interlock Protection of HCF personnel from potentially lethal radiation exposures. The TES mechanical interlock must prevent a STB operator from removing the TES shield cover when the lid has been removed from a shield cask inside the TES. Administrative controls are in place to ensure periodic testing of the TES mechanical interlock that prevents removal of the TES shield cover when the shield cask lid has been removed. 

Shield Cask Protection of HCF personnel from potentially lethal radiation exposures. Workers must ensure shield cask integrity prior to and during movement of the cask from the ACRR highbay to the HCF with an irradiated target. Administrative controls are in place to ensure that the cask lid is securely bolted in place prior to cask movement and to minimize the potential for accidents during cask transport. 

A shield cover in the Target Entrance System (TES) is designed to remove the shield cask lid so that the cask and target can be translated after the lid is removed. A mechanical interlock (a metal pin) is physically pushed by the shield cask lid when it is removed from the cask. This pin extends into the shielding wall to prevent the removal of the TES shield cover with the cask lid removed. This assures that workers cannot be exposed to an unshielded irradiated target when the cask is removed from the TES. 

Forklift energy sources (e.g., hot brake pads, battery failure, electrical system ilure, collision, etc.) Hydraulic oil, diesel fuel, gasoline, propane fuel Irradiated isotope production target shielding casks are not combustible but heat of a tire could pressurize the target Some forklifts in HCF are electric so no fiiels present... 

Identify major process-related equipment In above monorail crane, hole shielding plugs, and associated shielding casks in 21 above. ForklifiL crane, shielded containers, temporary... 

Exposure of during removal of massive procedures RAMS/ shielded cask -Workers B-C 4 ... 

A DOT Type A shielded cask is shown in Figure 17.1. The packaging requirements for solid Type A materials are listed below ... 

TAG 14-212 Type A shielded cask. (Courtesy of TAG Technical Solutions, LLC, http //www.thetaggroup.co/.)... 

---