Isotope identification as a part of the decommissioning of San Diego State University`s Texas Nuclear neutron generator
The Department of Physics at San Diego State University has maintained a Neutron Generator facility in room P-32C since the mid 1960`s. This facility has provided students and faculty with a resource for the study of neutron interactions with matter, such as activation analysis, flux determinations, cross section determinations and shielding studies. The model 9500 was built by Texas Nuclear Research in the early 1960`s, and could be used for either photon or neutron generation, depending on the source ions introduced into the accelerator`s plasma bottle and the target material. In February of 1988, the Texas Nuclear Research neutron generator was replaced by a unit manufactured by Kaman Sciences Corporation. The Texas Nuclear unit was then removed and stored for later disassembly and disposal. In the summer of 1993, the neutron generator was disassembled into three large sections consisting of the titanium-tritide target, the oil diffusion pump and the corona shield/accelerator tube assembly. The target was packaged and stored in room P-33A and the other 2 assemblies were wrapped in plastic for storage. In June of 1995 the neutron generator was further disassembled to enable storage in 55 gallon drums and thoroughly surveyed for loose surface contamination. Openings on the disassembled hardware components were closed off using either duct tape or bolted stainless steel flanges to prevent the possible spread of contamination. Significant levels of removable surface contamination could be found on system internal and some external surfaces, up to five hundred thousand disintegrations per minute. Initial analysis of the removable contamination using aluminum absorbers and a Geiger-Meuller tube indicated beta particle or possibly photon emitters with an energy of approximately 180 keV. This apparent radiation energy conflicted with what one would be expected to find, given knowledge of the source material and the possible neutron activated products that would be present in this type of unit. All activation products of neutron generator components, as a result of the exposure to 14 MeV neutrons are short lived, and would have decayed to below detection levels in the period of time since the unit was last operated, a period of approximately six years. This project consists of identifying the nuclide responsible for the apparent radiation energy. Additionally, as a service to San Diego State`s Radiation Safety Office, an estimate of the amount of activity in the unit will be made, as required for future disposal purposes as well as packaging the unit for shipment according to current state and federal regulations.
- Research Organization:
- San Diego State Univ., Dept. of Physics, CA (United States)
- Sponsoring Organization:
- USDOE Assistant Secretary for Environment, Safety, and Health, Washington, DC (United States)
- DOE Contract Number:
- AC05-76OR00033
- OSTI ID:
- 671980
- Report Number(s):
- DOE/OR/00033-T735; ON: DE97053612; TRN: 99:000333
- Resource Relation:
- Other Information: PBD: Jul 1997
- Country of Publication:
- United States
- Language:
- English
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