Reutilization Potential of Accelerator Components: A Decommissioning Perspective

There are perhaps as many as 1,200 particle accelerators in the United States, ranging in size from the very small Cockroft-Walton and electron linear accelerators to the multi-GeV research synchrotrons. At least 50 accelerators produce significant induced activation, and several hundred more are capable of producing fluxes of neutrons that could result in activation of various components of the accelerator facility. At decommissioning, some accelerators leave a legacy of low-level induced radioactivity in massive components. Although guidelines for acceptable surface contamination levels for release of materials and equipment to the general public do exist, there are presently no standards for release of materials and equipment with radioactivity distributed throughout their volumes. The decommissionings of five AEC-funded accelerators were examined: synchrocyclotrons operated by the University of Rochester and by Carnegie-Mellon University, the Cambridge Electron Accelerator, the Yale Heavy-Ion Linear Accelerator, and the Brookhaven Cosmotron. One common feature of these decommissionings was that major components usually were assigned and shipped for use or storage at other accelerator laboratories. In addition to reviewing selected past decommissionings, the authors also examined various aspects of decommissioning accelerators presently operating. The average mass with residual induced activity ranges from 1.5 × 102 kg for electrostatic devices and small cyclotrons up to 9.5 × 107 kg for a large proton synchrotron such as the Zero Gradient Synchrotron at Argonne National Laboratory. The estimated cost ($ 1978) of decommissioning ranges from $8.8 × 104 for an electron linac to $7.0 × 106 for the ZGS.