Best Practices

Calendar Year 2007 Fermilab ALARA Project Summary (Apr 2008): During CY2007, the primary activities at Fermilab that resulted in occupational radiation exposures were associated with maintenance activities of the accelerator. Nearly all dose to personnel was due to exposures to items activated by the accelerated beams. Many maintenance activities were necessary as the Fermilab accelerator complex was challenged to meet the scientific objectives of the Tevatron Run II Collider Program while simultaneously operating the proton beam needed for the Neutrinos at the Main Injector (NuMI) and Booster Neutrino (MiniBooNE and SciBooNE) experiments. Fermilab safely accomplished many essential accelerator upgrades during the summer of 2007 shutdown. These upgrades included but were not limited to replacement of the antiproton target, lithium lens transformer assembly rebuild and drive shaft replacement, replacement of Booster long corrector magnets and quadrupole magnets, and work on NuMI target chase ventilation system. Additionally, Main Injector large electron-positron magnet upgrades were completed, Main Injector collimators were installed, and sections of beam pipe were replaced. Extensive ALARA pre-job planning, implementation of specific ALARA activities during radiological work, and post-job analyses were integral to all work conducted during calendar year 2007.

Assessment of ORNL Radiation Generating Device Safety Features and Programmatic Compliance (Aug 2007): In September of 2006, a researcher in the Alloying Behavior and Design Group of the Materials Science and Technology Division was performing an experiment using an X-ray powder diffractometer when he noted that the mechanical shutter position indicator indicated that the shutter was open, even though the instrument had been commanded to close the shutter. An investigation was chartered that concluded that the shutter had stuck in the open position and that the instrument safety features were not fault-tolerant for a stuck shutter fault and as such, did not operate as expected. As a result of the investigation, an assessment was ordered of all active Radiation Generating Devices (RGDs) in use at the Oak Ridge National Laboratory. Forty-four RGDs were assessed for both procedural compliance and safety feature function. One finding, fourteen opportunities for improvement, and four proficiencies were identified.

Remote Radiation Measurements of Remote-handled Waste Storage Drums (Jul 2007): The Argonne Radiation Safety Organization developed a swinging arm detector system to reduce radiation exposure during measurements of waste storage drum radiation levels. Use of the simple device kept doses ALARA and greatly reduced the measurement effort required.

Magic Salt — An Environmentally Friendly De-icer (Mar 2007): PPPL's Maintenance and Operations division recently began using a new environmentally friendly de-icer called "Magic Salt" to assist in safely and efficiently melting the ice and snow during the winter months.

Use of the Radiation Budget Concept at Jefferson Lab (Oct 2006): The Thomas Jefferson National Accelerator Facility (commonly referred to as Jefferson Lab) is located on a small footprint within the Newport News, Virginia community. JLab has a requirement to maintain the radiation dose at the site boundary to less than 10 mrem per year to the maximally exposed individual due to accelerator operations. As this number is small in light of the currents and energies run in the Continuous Electron Beam Accelerator Facility (up to 200 microAmps and up to 6 GeV, with a technical capability to exceed this boundary dose limitation), considerable effort is put forth in the shielding and scheduling of specific experiments, such that the site boundary dose limit is not exceeded. One tool that Jefferson Lab has developed to streamline and manage this process is the concept of "radiation budgeting."

Calendar Year 2005 Fermilab ALARA Project Summary (Apr 2006): During the majority of calendar year 2005, Fermilab operated under normal beam-on conditions, which involves producing, accelerating and delivering protons to the Tevatron Collider program, the neutrino physics experiments, (MiniBooNE and NuMI/MINOS), and the 120 GeV Fixed Target experimental program in the Meson Area. Some radiological work was performed on radioactive accelerator components consisting of repairs and corrective maintenance necessary for maintaining accelerator performance. In addition, beamline components were removed from the Meson Detector Building during this year.

PPPL Hazard Awareness Training (Jan 2006): A formal Hazard Awareness training course was developed at PPPL during 2004 and is currently being implemented. This new training course focuses on identifying and mitigating job hazards using classroom training and field exercises.

ANL IPNS Target Link Disassembly Project (Sep 2005): The ANL Intense Pulsed Neutron Source has produced neutrons for a great variety of scattering and diffraction experiments for almost 25 years. The neutrons are produced by targeting 450 MeV protons on a depleted uranium target. In 2001 a program was initiated for recycling used targets. Most of the irradiated uranium disks can be recovered and combined with unirradiated disks to make new targets. After about two years, the short lived radionuclides have decayed sufficiently for a target to be processed. The linkage used to lower the target into position has to be disassembled and the cooling water lines cut. When the first target was disassembled, it was under a slight positive pressure which resulted in worker contamination upon opening. Contamination control was therefore an important consideration for the second target disassembly.

Radioactive Sealed Source Control at Jefferson Laboratory (Aug 2005): As a result of heightened security issues for radioactive sealed sources, Jefferson Lab has initiated the use of computerized key-control cabinets for source control, in a centralized location convenient for authorized users. These properly posted cabinets, typically used to provide locked storage for high security keys used by multiple individuals, utilize software that can read proximity cards (Jefferson Laboratory identification cards) to unlock a particular compartment for source access.

Fermilab CY2004 ALARA Projects Overview (Apr 2005): During CY2004, the principal activities at Fermilab that resulted in occupational radiation exposures were associated with maintenance activities of the accelerator. Nearly all of the collective dose to personnel was due to exposures to items activated by the accelerator beams. Many maintenance activities were necessary as the Fermilab accelerator complex was challenged to meet the scientific objectives of Tevatron Run II while simultaneously operating the proton beam needed for the MiniBooNE experiment. The vast majority of this work occurred during a major shutdown of the accelerator carried out during the late summer and autumn of 2004. Fermilab accomplished several vital accelerator upgrades during this shutdown. This work included extensive ALARA pre-job planning, implementation of specific ALARA activities during radiological work, and post-job analyses. Several upgrades and component replacements were conducted in the Linac and Booster. Additionally, a new pulsed beam focusing horn was installed for the MiniBooNE experiment.