A CANDU-Based Fast Irradiation Reactor
- Idaho National Laboratory, P.O. Box 1625, Idaho Falls, ID 83415 (United States)
A new steady-state fast neutron reactor is needed to satisfy the testing needs of Generation IV reactors, the Space Propulsion Program, and the Advanced Fuel Cycle Initiative. This paper presents a new concept for a CANDU-based fast irradiation reactor that is horizontal in orientation, with individual pressure tubes running the entire length of the scattering-medium tank (Calandria) filled with Lead-Bismuth-Eutectic (LBE). This approach for a test reactor will provide more flexibility in refueling, sample removal, and ability to completely re-configure the core to meet different users' requirements. Full core neutronic analysis of several fuel/coolant/geometry combinations showed a small hexagonal, LBE-cooled, U-Pu-10Zr fuel, with a core power of 100 MW{sub th} produced a fast flux (>0.1 MeV) of 1.5 x 10{sup 15} n/cm{sup 2} sec averaged over the whole length of six irradiation channels with a total testing volume of more than 77 liters. In-core breeding allowed the Pu-239 enrichment to be 15.3% which should result in core continuous operation for 180 effective full power days. Other coolants investigated included high pressure water steam and helium. An innovative shutdown/control system which consisted of the six outermost fuel channels was proven to be effective in shutting the core down when flooded with boric acid as a neutron absorber. The new shutdown/control system has the advantage of causing the minimum perturbation of the axial flux shape when the control channels are partially flooded with boric acid. This is because the acid is injected homogeneously along the control channel in contrast to regular control rods that are injected partially causing an axial perturbation in the core flux which in turn reduces safety analysis margins. The new shutdown/control system is not required to penetrate the core in a direction vertical to the fuel channels which allowed the freedom of changing core pitch as deemed necessary. A preliminary thermal hydraulic analysis of all three coolants revealed that LBE was the most favorable coolant of choice. It produced much lower pumping power and clad temperature than those generated by both water steam and helium. Helium came as second and steam came as distant third from the thermal-hydraulic point of view. Since steam required a pumping power greater than 1 MW (which was considered as a design limit) and produced clad temperature close to the metallic fuel melting temperature, it was not evaluated further. LOCA neutronic calculations for the LBE core resulted in a negative reactivity insertion which shut the reactor down. However, LOCA calculations for the He core resulted in positive reactivity insertion which is not desirable. Hypothetical accidents of draining the Calandria and/or the external LBE reflector tank of both the LBE and He cores resulted in negative reactivity insertion which shut the reactor down. (author)
- Research Organization:
- American Nuclear Society, 555 North Kensington Avenue, La Grange Park, IL 60526 (United States)
- OSTI ID:
- 21016359
- Resource Relation:
- Conference: 2006 International congress on advances in nuclear power plants - ICAPP'06, Reno - Nevada (United States), 4-8 Jun 2006; Other Information: Country of input: France; 9 refs; Related Information: In: Proceedings of the 2006 international congress on advances in nuclear power plants - ICAPP'06, 2734 pages.
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
BORIC ACID
CONTROL ELEMENTS
CONTROL SYSTEMS
COOLANTS
EXPERIMENTAL CHANNELS
FAST NEUTRONS
FUEL CHANNELS
HELIUM
IRRADIATION REACTORS
LOSS OF COOLANT
MELTING POINTS
NUCLEAR FUELS
PLUTONIUM 239
REACTIVITY INSERTIONS
STEAM
TEST REACTORS
THERMAL HYDRAULICS
WATER