General Electric Test Reactor NTD Silicon Development Program
The General Electric Test Reactor (GETR) was designed and constructed to provide large irradiation volumes outside the reactor pressure vessel in a surrounding water pool. The thermal neutron flux available for silicon irradiation spans four decades, 1011 to > 10li+nv. The large irradiation volume permits the inclusion of flux flattening and spectral softening devices if desired.
General Electric’s development program is planned as three phases: Phase 1 - calibration of a prototypical facility and irradiation volume, Phase 2 - limited pilot scale irradiations of selected test specimens under precisely controlled conditions, and Phase 3 - optimize the process and scale up for commerical irradiation of production quantities.
Phase 1 was successfully completed early in 1977. The results provided a calibrated flux monitor for use in subsequent irradiations and detailed neutron spectra and spatial variation in the prototypical irradiation volume.
The temporary shutdown of the GETR has delayed the Phase 2 program which will utilize the calibrated flux monitor and spectral data from Phase 1, coupled with two additional degrees of control, rotation and time, to irradiate three inch diameter silicon samples. Relatively long irradiation time is favored to reduce the error in absolute nvt to « 5%. Phase 2 results will be used to optimize the engineering design of a production facility incorporating in- situ nvt monitors, dry irradiation space and demand charge/discharge operations for variable diameter silicon specimens throughout the desired resistivity range.
KeywordsNeutron Flux Thermal Neutron Flux Reactor Pressure Vessel Flux Spectrum Flux Detector
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