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Studies of Unprotected Loss-of-Flow Accidents for the Clinch River Breeder Reactor

Description: Studies of unprotected loss-of-flow accidents in the CRBR for various rates of flow coast-down and with various options in the SAS 3A code did not lead to conditions for a violent disassembly. Maximum fuel temperatures using the SLUMPY module for disassembly were in the range 4000-4500 deg C. An approximate treatment of the LOF-driven TOP accident, not properly modeled by SAS 3A, indicates the possibility of some increase in accident severity. The effect of fission gas in dispersing fuel was not taken into account in these calculations. Parameter variations included the presence or absence of axial fuel expansion and of clad motion and use of the moving coolant film model versus the static film model. Study of severe pipe rupture accidents with scram indicated that pin power density and fuel-clad conductance were important parameters in determining what coolant flow rate was needed to prevent boiling after the rupture. It appears that for the CRBR when engineering hot channel factors are considered, this fraction would have to exceed 25 percent.
Date: April 1976
Creator: Hummel, Harry H.; Pizzica, P. A. & Kalimullah
Partner: UNT Libraries Government Documents Department

Regulatory Safety Issues in the Structural Design Criteria of ASME Section III Subsection NH and for Very High Temperatures for VHTR & GEN IV

Description: The objective of this task is to identify issues relevant to ASME Section III, Subsection NH [1], and related Code Cases that must be resolved for licensing purposes for VHTGRs (Very High Temperature Gas Reactor concepts such as those of PBMR, Areva, and GA); and to identify the material models, design criteria, and analysis methods that need to be added to the ASME Code to cover the unresolved safety issues. Subsection NH was originally developed to provide structural design criteria and limits for elevated-temperature design of Liquid Metal Fast Breeder Reactor (LMFBR) systems and some gas-cooled systems. The U.S. Nuclear Regulatory Commission (NRC) and its Advisory Committee for Reactor Safeguards (ACRS) reviewed the design limits and procedures in the process of reviewing the Clinch River Breeder Reactor (CRBR) for a construction permit in the late 1970s and early 1980s, and identified issues that needed resolution. In the years since then, the NRC and various contractors have evaluated the applicability of the ASME Code and Code Cases to high-temperature reactor designs such as the VHTGRs, and identified issues that need to be resolved to provide a regulatory basis for licensing. This Report describes: (1) NRC and ACRS safety concerns raised during the licensing process of CRBR , (2) how some of these issues are addressed by the current Subsection NH of the ASME Code; and (3) the material models, design criteria, and analysis methods that need to be added to the ASME Code and Code Cases to cover unresolved regulatory issues for very high temperature service.
Date: May 7, 2007
Creator: O’Donnell, William J. & Griffin, Donald S.
Partner: UNT Libraries Government Documents Department

Sodium removal process development for LMFBR fuel subassemblies

Description: Two 37-pin scale models of Clinch River Breeder Reactor Plant fuel subassemblies were designed, fabricated and used at Westinghouse Advanced Reactors Division in the development and proof-testing of a rapid water-based sodium removal process for the ORNL Hot Experimental Facility, Liquid Metal Fast Breeder Reactor Fuel Reprocessing Cycle. Through a series of development tests on one of the models, including five (5) sodium wettings and three (3) high temperature sodium removal operations, optimum process parameters for a rapid water vapor-argon-water rinse process were identified and successfully proof-tested on a second model containing argon-pressurized, sodium-corroded model fuel pins simulating the gas plenum and cladding conditions expected for spent fuel pins in full scale subassemblies. Based on extrapolations of model proof test data, preliminary process parameters for a water vapor-nitrogen-water rinse process were calculated and recommended for use in processing full scale fuel subassemblies in the Sodium Removal Facility of the Fuel Receiving Cell, ORNL HEF.
Date: October 1, 1981
Creator: Simmons, C.R. & Taylor, G.R.
Partner: UNT Libraries Government Documents Department

Selection of lubricant material for the roller chains of the AHM grapple drive system for the CRBRP

Description: Properties of Anderol 732 lubricating grease are evaluated to meet the design requirements for the Clinch River Breeder Reactor Plant (CRBRP) auxiliary machine (AHM) chain lubrication. Based on the evaluation made in this report, the material is recommended as a lubricant for the specified application. The material is to be applied by the chain manufacturer prior to installation in the AHM.
Date: January 1, 1984
Creator: Kuster, C.A. & Sarraf, R.J.
Partner: UNT Libraries Government Documents Department