b'P ROVING THE P RINCIPLEReactorLast Day of Name Acronym S t a r t u p OperationSystems for Nuclear Auxiliary Power (SNAP) 10Aransient No. 1 (continued)Tpower-excursion conditions. SNAPTRAN-1, located at Test Area North, was subjected to non-destructive tests in conditions approaching but not resulting in damage to the zirconium-hydride-uranium fuel.47. Systems for Nuclear Auxiliary Power (SNAP) 10A Transient No. 3 S NA4-1-64 4-1-64P T R A N3-SNAPTRAN-3 was the first of two destructive tests on a version of the small space reactor (SNAP10A/2) designed to supply auxiliary power in space. The test, conducted at TANs Initial Engineering Test Facility on April 1, 1964, simulated the accidental fall of a reactor into water or wet earth such as could occur during assembly, transport, or a launch abort. The test demonstrated that the reactor would destroy itself immediately instead of building up a high inventory of radioactive fission products. 48. Systems for Nuclear Auxiliary Power (SNAP) 10A Transient No. 2 S N A P TRA N -21965 January 11,This test version of the small space reactor, SNAP 10A/2, was intentionally destroyed on January 11, 1966.1966It provided information on the dynamic response, fuel behavior, and inherent shutdown mechanisms of these reactors in an open air environment. In normal operation, the control drums of the SNAP10A/2 were rotated to obtain criticality after the reactor had been placed in orbit. In case of a launch abort, however, impact on the earth might cause the drums to rotate inward, go critical, conceivably destroy itself, and release fission products to the surrounding environment. The test data contributed to an understanding of reactor disassembly upon impact and methods for assessing or predicting the radiological consequences.49. Thermal Reactor Idaho Test Station THRITS 1964THRITS was a low-power reactor located at TAN. Its nuclear core was arranged in two halves of a vertical,Split-Table aluminum, honeycomb-like matrix. The reactor could not be operated until the two halves were broughtReactortogether to form the critical fuel mass. Operators mocked up reactor design concepts for thermal and fast-neutron reactor systems to obtain basic physics and design data for such concepts.50. Transient Reactor Test Facility TREAT 2-23-59 April 1994Part of the safety program for fast breeder reactors, TREAT was a uranium-oxide-fueled, graphite-moderated, air-cooled reactor designed to produce short, controlled bursts of nuclear energy. Located at Argonne-West, its purpose was to simulate accident conditions leading to fuel damage, including melting or even vaporization of test specimens, while leaving the reactors driver fuel undamaged. Early studies determined the effect of extreme energy pulses on prototype fuel pins designed for EBR-II. TREAT tests provided data on fuel-cladding damage, fuel motion, coolant-channel blockages, molten-fuel/coolant interactions, and potential explosive forces during an accident. The data helped refine computer simulations of reactor accidents, and, ultimately, design reactors with greater inherent safety.51. Zero Power Physics Reactor (Earlier name - Zero Power Plutonium Reactor) ZPPR 4-18-69 April 1992ZPPR, a low-power critical facility located at Argonne-West, provided reactor physics data for any type ofStandbyfast neutron spectrum reactor, from tiny space-power reactors to large commercial breeder reactors. The (full-size) reactor core configuration to be studied was mocked up in two halves, the fuel loaded into a honeycomb lattice in each of the separated halves.Extrapolation from the zero-power measurements to full-power conditions was readily achievable. Upon moving the two lattice together, ZPPR was brought to a low power, critical state by control rods. Heat removal was by air flow over the fuel elements.52. Zero Power Reactor No. 3 ZPR-III October 1955 N o v e m b e rThis was a low-power split-table reactor that achieved criticality by bringing two halves of a fuel configuration 1970t o g ethe r. Alow-power reactor, ZPR-III was used to determine the accuracy of predicted critical mass geometriesand critical measurements in connection with various loadings for makeup of fast-reactor core designs. The cores of EBR-II, Fermi, Rapsodie, and SEFOR reactors were originally mocked up in this facility.Experimental critical assembly results in this field were almost completely lacking before this reactor started up.The reactor was placed on standby in 1970 and later went on display in the EBR-I Visitor Center.268'