High Temperature Fission Chamber for He- and FLiBe-cooled Reactors
- Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
We have evaluated candidate technologies for in-core fission chambers for high-temperature reactors to monitor power level via measurements of neutron flux from start-up through full power at up to 800°C. This research is important because there are no commercially available instruments capable of operating above 550 °C. Component materials and processes were investigated for fission chambers suitable for operation at 800 °C in reactors cooled by molten fluoride salt (FLiBe) or flowing He, with an emphasis placed on sensitivity (≥ 1 cps/nv), service lifetime (2 years at full power), and resistance to direct immersion in FLiBe. The latter gives the instrument the ability to survive accidents involving breach of a thimble. The device is envisioned to be a two-gap, three-electrode instrument constructed from concentric nickel-plated alumina cylinders and using a noble gas–nitrogen fill-gas. We report the results of measurements and calculations of the response of fill gasses, impurity migration in nickel alloy, brazing of the alumina insulator, and thermodynamic calculations.
- Research Organization:
- Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
- Sponsoring Organization:
- USDOE
- DOE Contract Number:
- AC05-00OR22725
- OSTI ID:
- 1193184
- Resource Relation:
- Conference: 9th International Topical Meeting on Nuclear Plant Instrumentation, Control, and Human Machine Interface Technologies (NPIC&HMIT 2015), Charlotte, NC (United States), 22-26 Feb 2015
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
IN CORE INSTRUMENTS
FLIBE
FISSION CHAMBERS
TEMPERATURE RANGE 0400-1000 K
TEMPERATURE RANGE 1000-4000 K
ALUMINIUM OXIDES
BRAZING
NICKEL ALLOYS
RARE GASES
NITROGEN
NEUTRON FLUX
POWER DENSITY
CYLINDERS
IMPURITIES
SENSITIVITY
HELIUM COOLED REACTORS
MOLTEN SALT COOLED REACTORS