Publications

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Sandia National Laboratories (SNL) personnel operate a low power research reactor (the Annular Core Research Reactor, or ACRR), and a zero-power critical experiment assembly referred to as CX. In accordance with 10 CFR 830, Subpart B, Appendix A, the acceptable methodology for developing a Documented Safety Analysis (DSA) for DOE nuclear reactors is the Nuclear Regulatory Commission’s (NRC’s) Regulatory Guide 1.70 (RG 1.70). RG 1.70 does not address certain areas required by 10 CFR 830 and expected by DOE (e.g., full facility hazard analysis).Thus, the current DSAs for SNL’s reactor nuclear facilities are based on RG 1.70, but also of necessity supplemented by DOE-STD-3009-94 methods. SNL personnel, in consultation with the National Nuclear Security Administration (NNSA) Sandia Field Office (SFO), have concluded that an alternate methodology is preferred to RG 1.70. The details of the proposal, and the reasons motivating its development, are discussed in the order described below. The proposed alternate methodology will be applicable to the ACRR and the CX (i.e., it will be applicable to nuclear facilities in which a reactor and/or a critical assembly will be operated).

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RAZORBACK is a research reactor transient analysis computer code designed to simulate the operation of a research reactor (such as Sandia National Laboratories' Annular Core Research Reactor (ACRR)). The code provides a coupled numerical solution of the point reactor kinetics equations, the energy conservation equation for fuel element heat transfer, the equation of motion for fuel element thermal expansion, and the mass, momentum, and energy conservation equations for the water cooling of the fuel elements. This Software Design and Development Report describes how the code is designed to implement the functional requirements established in the Software Requirements Specification document for RAZORBACK. The description presents the physical model equations used in the design, and how these equations are set up to be solved numerically. This report also provides an evaluation of how the software design meets each of the functional requirements.

Razorback is a research reactor transient analysis computer code designed to simulate the operation of a research reactor (such as Sandia National Laboratories Annular Core Research Reactor (ACRR)). The code provides a coupled numerical solution of the point reactor kinetics equations, the energy conservation equation for fuel element heat transfer, the equation of motion for fuel element thermal expansion, and the mass, momentum, and energy conservation equations for the water cooling of the fuel elements. This input manual describes how an input file is composed, and facilitates an understanding of the various code input parameters. The makeup of the various code output files is also described. This manual also provides instructions for the installation and setup of the code, and how to report bugs and/or errors.

This report describes the work and results of the verification and validation (V&V) of the version 1.0 release of the Razorback code. Razorback is a computer code designed to simulate the operation of a research reactor (such as the Annular Core Research Reactor (ACRR)) by a coupled numerical solution of the point reactor kinetics equations, the energy conservation equation for fuel element heat transfer, the equation of motion for fuel element thermal expansion, and the mass, momentum, and energy conservation equations for the water cooling of the fuel elements. This V&V effort was intended to confirm that the code shows good agreement between simulation and actual ACRR operations.

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This report describes the work and results of the initial verification and validation (V&V) of the beta release of the Razorback code. Razorback is a computer code designed to simulate the operation of a research reactor (such as the Annular Core Research Reactor (ACRR)) by a coupled numerical solution of the point reactor kinetics equations, the energy conservation equation for fuel element heat transfer, and the mass, momentum, and energy conservation equations for the water cooling of the fuel elements. This initial V&V effort was intended to confirm that the code work to-date shows good agreement between simulation and actual ACRR operations, indicating that the subsequent V&V effort for the official release of the code will be successful.

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Since the 1960's, Sandia National Laboratories (SNL) has conducted radiation effects testing for the Department of Energy (DOE) and other contractors supporting the DOE. Over this time, SNL's Technical Area V (TA-V) has operated research reactor facilities whose primary mission is providing appropriate neutron radiation environments for radiation testing and qualification of electronic components and other devices. The current generation of reactors includes the Annular Core Research Reactor (ACRR), a water-moderated pool-type reactor, fueled by elements constructed from UO 2-BeO ceramic fuel pellets, and the Sandia Pulse Reactor (SPR), a bare metal fast burst reactor utilizing a uranium-molybdenum alloy fuel. The ACRR has a 9-inch inner diameter central cavity, providing a means to expose reasonably large experiments to an epithermal neutron radiation environment. The ACRR also has a 20-inch inner diameter excore cavity surrounded by U-ZrH fuel elements to accommodate larger experiments. The SPR has a 6.5-inch inner diameter cavity, providing a means to expose experiments to neutron radiation environment which approximates a fission spectrum. The SPR is operated in a large reactor room which allows for experiments to be located external to the reactor and irradiated by the neutrons which leak from the reactor. Both the ACRR and the SPR may be operated in a steady-state or pulsed mode. In pulse mode, the ACRR and SPR can attain high-power pulses on the order of 40 GW (10 ms pulse width) and ISO GW (80 μs pulse width), respectively. The ACRR can also be operated in a transient mode, allowing for tailored power profiles ranging from tens to a few hundred MW for durations of a few seconds. The reactors have also been utilized to perform reactor fuel materials testing, reactor accident phenomenology testing, investigation of reactorpumped lasers, and space reactor fuel component testing. Various tests have included effects such as melting and vaporization of materials due to fission heating and have been conducted in environments including molten sodium, hydrogen gas, mechanical shocks greater than 1000 g, and cryogenic temperatures. In addition, TA-V has performed a variety of critical assembly experiments for purposes of gathering reactor physics benchmark data for space reactor fuel, and characterization of fission product reactivity effects for transportation criticality studies. This presentation provides an overview of the various radiation effects testing and critical experiment facilities, their capabilities and radiation environments, and the wide variety of testing for which the facilities have been utilized.

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The radioisotope 99mTc, used in greater than 80% of nuclear medicine applications, has traditionally been produced and supplied to radiopharmaceutical companies in the form of its precursor 99Mo. Nuclear fission produced 99Mo had been supplied by Nordion International of Canada and Cintichem, Inc. of New York, USA. With the shutdown of Cintichem's reactor in 1989, a need was recognized for a US supply, and the US Department of Energy recently published a record of decision designating Sandia National Laboratories (SNL) to meet that need. A recent campaign was launched which utilized the SNL Annular Core Research Reactor to irradiate UO2 coated targets fabricated by Los Alamos National Laboratory to produce 99Mo. The irradiated targets were chemically processed in the SNL Hot Cell Facility to separate and purify the 99Mo. The campaign also included final product quality analysis, and process waste handling. The campaign was accomplished with high 99Mo recovery. Final product quality was assessed at SNL, and samples were sent to an outside laboratory for independent verification. The campaign provided data and experience useful in pursuing US Food and Drug Administration and radiopharmaceutical company approval. © 1998 Akadémiai Kiadó, All rights reserved.

Sandia National Laboratories (SNL) has recently completed the irradiation of five isotope production targets at its Annular Core Research Reactor (ACRR) using targets fabricated by Los Alamos National Laboratory. Four of the irradiated targets were chemically processed in the SNL Hot Cell Facility (HCF) using the Cintichem process. The Cintichem method for processing {sup 99}Mo isotope production targets involves dissolution of a UO{sub 2} coating, separation of the Mo from the other fission products, and purifying the final product. Several processing issues were addressed during the initial process verification work. This paper discusses the results of work involving dissolving the UO{sub 2} coating, recovering Mo losses in purification columns, and radiation exposure testing of process glassware and components.

As a result of an Environmental Impact Statement (EIS) recently issued by the Department of Energy, Sandia National Laboratories (SNL) has been selected as the {open_quotes}most appropriate facility{close_quotes} for the production of {sup 99}Mo. The daughter product of {sup 99}Mo is {sup 99m}Tc, a radioisotope used in 36,000 medical procedures per day in the U.S.{close_quote} At SNL, the {sup 99}Mo would be created by the fission process in UO{sub 2} coated {open_quotes}targets{close_quotes} and chemically separated in the SNL Hot Cell Facility (HCF). SNL has recently completed the irradiation of five production targets at its Annular Core Research Reactor (ACRR). Following irradiation, four of the targets were chemically processed in the HCF using the Cintichem process.