The TR-2 nuclear reactor, also known as the Westinghouse Test Reactor or Westinghouse Testing Reactor (WTR) was a small research and test reactor designed and manufactured by Westinghouse Electric Corporation at their Waltz Mill site near Madison, Pennsylvania, approximately 30 miles southeast of Pittsburgh. TR-2 was the first privately owned research and test reactor. The reactor suffered an accident which involved severe fuel damage in 1960.
Design TR-2 was a heterogeneous, low pressure, low temperature, light water cooled and moderated, pressurized water reactor. The primary function of the reactor was to test reactor materials and components. Rather than incorporating an electrically-heated pressurizer vessel as is common in commercial PWRs designed since the 1960s, TR-2 relied on the static water pressure delivered by a tank of water, known as the head tank, which was elevated high above the ground and connected to the reactor vessel by piping. Heat generated by the reactor was transferred to heat exchangers for ultimate heat rejection to the environment via a mechanical draft cooling tower. The reactor was initially permitted to operate at up to 20 Megawatts thermal, though it was designed and constructed to permit eventual operation at a power level of 60 thermal megawatts. Positions for experimental capsules, test loops, and fuel experiments were included in the reactor design; as was a neutron beam port. On January 8, 1960, the Atomic Energy Commission (AEC) issued Amendment 1 to the facility license to permit operation at up to 60 Megawatts thermal. The reactor was housed inside a structure known as the vapor container, referred to in some literature as a containment structure, which was designed to contain fission products that might be released from the reactor during an accident. The vapor containment was a metal right cylinder approximately 74 feet tall above the surrounding ground level and 70 feet in interior diameter. The top of the vapor container was slightly rounded. There were two airlocks to the vapor container. A mechanical ventilation system was provided to the process water surge tank and the process water head tank which was elevated almost 250 feet above the ground on a metal support frame approximately 500 feet east of the vapor container. Forced air swept over the surge tank, removing the gasses normally produced during reactor operation, and was then routed to the head tank where the gasses were released via a vent about 250 feet above the surrounding ground level. The stainless steel reactor vessel was 32 feet tall and 8 feet in diameter, with 1-inch-thick walls. The rector vessel was oriented vertically and surrounded by concrete for radiation shielding. Fuel elements were loaded and removed via a diagonal tube that extended from mid-height of the reactor vessel down to a water-filled transfer canal which connected the vapor shell to the surrounding facility buildings. Typical for a research and test reactor, it did not produce electricity. The test reactor was located in the northwest portion of the developed area of the larger Waltz Mill site. The reactor was located on the east side of Waltz Mill Road, approximately 2,300 feet north of the present intersection of Waltz Mill Road and Interstate 70.
Fuel The TR-2 core consisted of cylindrical fuel elements. The fuel elements were mechanical assemblies including multiple individual aluminum fuel tubes which contained the uranium fuel; some fuel elements included other reactor instrumentation or experiment components in addition to the fuel tubes. Each fuel assembly had 200 grams of highly enriched uranium fuel as an aluminum-uranium alloy in the walls of three long concentric cylinders around a central aluminum mandrel tube in which small canned specimens could be irradiated. The uranium-aluminum fuel alloy was aluminum clad: cladding thickness was 36 mils; the fuel alloy, 52 mils. The fuel tubes were 44 inches long and the outside diameter of the fuel assembly was 2.5 inches. Orifices at both ends distributed the coolant flow through the channels within the assembly and provided some of the static pressure required on the fuel assemblies to prevent boiling at the hot spots. The AEC allocated to Westinghouse for use in the operation of the facility 156 kilograms of uranium-235 contained in highly enriched uranium (HEU) enriched to approximately 93% in the isotope uranium-235.
History Westinghouse applied for a Construction Permit from the AEC on February 29, 1956. Construction Permit No. CPRR-8 (henceforth designated CPTR-l) was Issued by the AEC on July 3, 1957. The AEC issued Facility License Number TR-2 on June 19, 1959. TR-2 reached criticality for the first time in July 1959. The primary use of the reactor was to test metallic and non-metallic materials for suitability and performance in a high neutron nuclear environment, as well as to test the performance of new fuel designs, for many commercial, academic, and government customers. The reactor experienced an accident resulting in fuel damage in 1960. After a restart following the 1960 accident, the reactor was retired in 1962 due to low customer demand. On March 25, 1963, the facility license was amended to allow only possession of special nuclear material but not reactor operation. The minimally radioactive reactor vessel was shipped from the site on May 15, 2000 for dismantling and ultimate disposal. Westinghouse removed the TR-2 vapor shell in the spring of 2012.
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