[en] As a result of the Reactor Division's disassembly basin cleanup program, it has been determined that fissile-isotopes are present in the sludge that has accumulated at the bottom of the disassembly basins. Good criticality safety practices require that the potential for obtaining a critical configuration with this fissile material be evaluated. As part of this process, the disassembly basin sand filter system has been identified as a potential area of concern. Because disassembly basin water flows through the sand filter, it is conceivable that fissile material, from the basin, could accumulate in the sand filter. Previous calculations have indicated that the mass of some fissile isotopes in the basin sludge exceeds subcritical mass limits. This report documents the criticality safety evaluation that was performed to address the possibility of forming a critical configuration within the sand filter. This evaluation is applicable to K and L Areas, since the fissile masses listed in Table 1 are bounding for both areas. Applicability to P Area will be examined following the completion of sludge sample analyses for that Area. Although it is conceivable that fissile material could accumulate in the sand filter, because of the required fissile mass and necessary critical geometries it is highly unlikely that a critical configuration could be assembled. The mass of fissile material required for criticality, for present and anticipated sand filter geometries and operational characteristics, is much greater than that available in the sludge, as indicated by sludge sample analyses. In short, there is no identified mechanism by which a critical configuration could be assembled in the disassembly basin sand filter

[en] Purpose of this Environmental Information Document is to provide background for assessing environmental impacts associated with the renovation, restartup, and operation of L Reactor at the Savannah River Plant (SRP). SRP is a major US Department of Energy installation for the production of nuclear materials for national defense. The purpose of the restart of L Reactor is to increase the production of nuclear weapons materials, such as plutonium and tritium, to meet projected needs in the nuclear weapons program

[en] An alternative to renewed operation of L Reactor for increased production of nuclear materials would be the construction and operation of a New Production Reactor (NPR). This report describes a conceptual design for a low temperature heavy water reactor with no electricity generation (LTHWR-NE) to be built as a new production reactor at the Savannah River Plant (SRP). The reactor design is based on the proven SRP reactor design with enhancements and state-of-the-art equipment. Aluminum cladding temperatures would be the same as with current operations. The power and productivity of the new reactor would be greater than L Reactor by about 30%. However, the estimated time from authorization to startup is 10 years. Thus an NPR could not contribute to material production until late 1993 at the earliest

[en] The engineering assessment of the 105 K Basins monorails was performed to provide the engineering analysis to justify the existing basin north-south monorail capacity. The existing monorails have a capacity of 2400 lbs posted on the north-south monorails. The engineering assessment concluded that the monorail, hanger system, and trolleys all rate for a 2000 lb capacity. Based upon a 2,500 lb trolley load, the monorails, the hanger system, and the double trolley hoist system will rate for 2,500 lbs. The single trolley hoist system for handling the fuel canisters and the trolley systems used in the various transfer areas are limited by manufacturers to 2,000 lbs. Therefore, it is concluded from this engineering assessment that the 2,400 lb capacity posting for the north-south basin monorails is appropriate

[en] The raw water supply for the B-Plant Canyon fire foam system is being replaced. The 4 inche water supply line to the foam system is being rerouted from the 6 inches raw water line in the Pipe Gallery to the 10 inches raw water main in the Operating Gallery. This document states the acceptance criteria for the flushing and testing to be performed by the contractor

[en] The United States Department of Energy's (USDOE's) K-reactor, a defense production reactor located at the Savannah River Site in Aiken, South Carolina, was shut down in the summer of 1988 for safety upgrades to bring it into conformance with modern safety standards prior to restart. Over the course of the succeeding four years, all aspects of the 35-year old reactor, including hardware, operations, and analysis, were upgraded to ensure that the reactor could operate safely according to standards similar to those applied to modern nuclear reactors. This paper describes the decision making processes by which issues were identified, priorities assigned, and analysis improved to enhance reactor safety. Special emphasis is given to the probabilistic risk assessment (PRA) decision making processes used to quantify the risks and consequences of operating the K-reactor, the analytical hierarchy process (AHP) used to identify key phenomena, and modifications made to the RELAP5 computer code to make it applicable to K-reactor analysis. The success of the project was demonstrated when the K-reactor was restarted in the summer of 1992

[en] The GRIMHX reactor code currently in use at the Savannah River Site (SRS) was written at a time when computer processing speed and memory storage were very limited. Recently, a new reactor code (GRIMH3) was written to take advantage of the hardware improvements (vectorization and higher memory capacities) as well as the range of available computers at SRS (workstations and supercomputers). The GRIMH3 code computes the solution of the static multigroup neutron diffusion equation in one-, two-, and three-dimensional hexagonal geometry. Either direct or adjoint solutions can be computed for k_eff searches, buckling searches, external neutron sources, power flattening searches, or power normalization factor calculations with 1, 6, 24, 54, or 96 points per hex. The GRIMHX reactor code currently in use at the Savannah River Site (SRS) was written at a time when computer processing speed and memory storage were very limited. Recently, a new reactor code (GRIMH3) was written to take advantage of the hardware improvements (vectorization and higher memory capacities) as well as the range of available computers at SRS (workstations and supercomputers). The GRIMH3 code computes the solution of the static multigroup neutron diffusion equation in one-, two-, and three-dimensional hexagonal geometry. Either direct or adjoint solutions can be computed for k_eff searches, buckling searches, external neutron sources, power flattening searches, or power normalization factor calculations with 1, 6, 24, 54, or 96 points per hex

[en] The author describes the historical background leading to the development of ²⁵²Cf neutron sources for radiotherapy. (Auth.)

[en] The Savannah River Site (SRS) is a 780-km² US Department of Energy (DOE) site managed by the Westinghouse Savannah River Company for the production of nuclear materials for defense and other purposes. Five nuclear production reactors (NPRs) constructed in the 1950s are located on the site, and all but one are either on standby or shut down. The possibility of siting a new NPR at the SRS or at other sites (Hanford and Idaho) in the DOE complex was being evaluated in an environmental impact statement (EIS) when on November 1, 1991, the Secretary of Energy decided to defer a decision on the NPR until after a programmatic EIS addressing reconfiguration of the DOE weapons complex was completed. Candidate sites at SRS for the proposed NPR were evaluated against disqualifying conditions in the categories of ecological resources and wetlands, human health effects, geology/hydrology, and engineering considerations. In initial considerations, the presence of wetlands was not determined to be a disqualifying condition. It was critical that the proposed reactor be sited on an area with optimum geologic properties so that the required load-bearing capacity under its footprint could be met. Lessons learned in this planning effort are to clearly understand the real needs of the project in terms of area, hydrology, geologic criteria, etc., and conduct siting studies early in a project's life that strongly weigh wetlands and other ecological considerations. In this case, once project personnel had a clear understanding of the length of time required for processing the Sec. 404 permit (and possibly a Sec. 10 permit for the outfall) and the cost required for preparation of the permit application, mitigation, and long-term monitoring, the site selection criteria were revisited. After numerous discussions and additional geologic considerations, it was determined that the proposed NPR footprint could be oriented to avoid all but ∼0.5ha of wetlands

[en] A regional groundwater flow model encompassing approximately 100 mi² surrounding the C, K. L. and P reactor areas has been developed. The Reactor flow model is designed to meet the planning objectives outlined in the General Groundwater Strategy for Reactor Area Projects by providing a common framework for analyzing groundwater flow, contaminant migration and remedial alternatives within the Reactor Projects team of the Environmental Restoration Department