National Institute of Standards & Technology, Acquisition & Assistance Div., Bldg. 301, Rm B117, Gaithersburg, MD 20899

44 -- FABRICATION OF MECHANICAL COMPONENTS FOR THREE (3) NEUTRON MONOCHROMATOR DRUMS!! SOL 52SBNB7C1082!! DUE 031097 POC Joan M. Smith (301) 975-6458/C.O. Pauline Mallgrave (301) 975-6330!! WEB: NIST Contracts Homrpage, http://www.nist.gov/admin/od/contract/contract.htm. E-MAIL: NIST Contracts Office, Contract@mailserver3.nist.gov. The National Institute of Standards and Technology (NIST) has a requirement for the fabrication of both small and large components of high precision and quality for three (3) very large identical neutron monochromator drums for the Reactor Research Facility (NBSR) located in Gaithersburg, MD. These components shall be fabricated out of steel, cast ductile iron, and high density polyethylene. Some shall need extensive machining, others shall have to be welded. Some welding shall be water tight. Certified welders are required. The approximate overall dimensions of each drum are 8 feet in diameter and 6 feet tall. The assembled weight of each drum is approximately 88,000 pounds. Each drum is made up of four main sections. Three of these sections are filled with steel shot and paraffin. This filling is NIST's responsibility. The third section, which is sandwiched between the second and fourth sections, is composed of composite materials, i.e., a series of seventy two (72) wedges, weighing approximately 7,000 pounds, divided into two groups, upper and lower, and a collimator section fabricated out of concentric sections of steel and high density polyethylene. The wedges, except for four of them, are made of machined cast iron. The latter are filled with paraffin. This filling is the responsibility of NIST. The wedges are suspended by pairs of rails which are attached to the second and fourth sections. The collimator and wedges are driven externally from a gunmount, provided by NIST. The collimator assembly is cantilevered from the driving mechanism and drives the wedges. The first, second, and fourth sections do not move and are supported by a central hollow pillar, approximately 6 feet high and 3 feet in diameter, which is rigidly attached to a shielding support base assembly. Each drum shall be assembled by the manufacturer, unfilled, prior to delivery and shall be inspected at this time by NIST personnel. The drums will be subsequently disassembled for delivery. The final filling and assembly of the drums will be performed by NIST personnel at the NBSR. Complete specifications and drawings for the drums will be issued with the solicitation. -- 3 each -- Required delivery is 12 months -- All responsible sources may submit a proposal which shall be considered by the agency. -- Solicitation requests may be submitted in writing to telefax number (301) 963-7732. See Note 26.***** (0024)

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