6,315 Matching Results

Search Results

Materials Compatibility Studies for the Spallation Neutron Source

Description: The Spallation Neutron Source (SNS) is a high power facility for producing neutrons that utilizes flowing liquid mercury inside an austenitic stainless steel container as the target for a 1.0 GeV proton beam. The energy deposited in the target is transported by two separate mercury flow streams: one to transport heat in the interior target region and one to cool the stainless steel container. Three-dimensional computational fluid dynamics simulations have been performed to predict temperature, velocity, and pressure distributions in the target. Results have generally shown that the power deposited in the bulk mercury can be effectively transported with reasonable flow rates and the bulk mercury temperature should not exceed 160{deg}C. Assuming good thermal contact, the maximum stainless steel wall temperature should be 130 {deg}C. Type 316 SS has been selected as the container material for the mercury and consequences of exposure of 316 SS to radiation, thermal shock, thermal stress, cavitation and hot, flowing mercury are all being addressed by R&D programs. In addition, corrosion studies include evaluation of Inconel 718 because it has been successfully used in previous water cooled spallation neutron systems as a window material. With type 316 SS selected to contain the mercury target of the SNS, two types of compatibility issues have been examined: LME and temperature gradient mass transfer. Studies have shown that mercury does not easily wet type 316 SS below 275{deg}C. In the LME experiments, attempts were made to promote wetting of the steel by mercury either by adding gallium to the mercury or coating the specimen with a tin-silver solder that the mercury easily wets. The latter proved more reliable in establishing wetting, but there was no evidence of LME in any of the constant extension rate tensile tests either at 23 or 100 {deg}C. Inconel 718 also showed no ...
Date: September 1, 1998
Creator: DiStefano, J.R.; Manneschmidt, E.T. & Pawel, S.J.
Partner: UNT Libraries Government Documents Department

Preliminary definition of geophysical regions for the Middle East and North Africa

Description: The ability to calibrate seismic stations to improve the monitoring of the Comprehensive Test Ban Treaty is partially limited by the availability of seismic events with known locations and source properties. To confidently extrapolate from these events to aseismic regions, and to properly account for discontinuities in seismic properties requires accurate geophysical models. This paper lays out a preliminary, first-order, regionalization of the Middle East and North African (MENA) region. The model specifies boundaries and velocity structures based on the geology and tectonics of the region, previously published studies, and empirical data observations by the LLNL group. This model is a starting point and is expected to be improved and refined by comparisons with ongoing tomography efforts and the collection of new data. We anticipate that this model and its successors will prove useful as a background model in the process of forming station calibration maps based on intelligent interpolation techniques such as kriging. We also hope the model, as it improves and demonstrates some predictive power, will provide a reference model for broader CTBT research efforts in detection, location and discrimination as well as other aspects of earth science.
Date: December 1998
Creator: Sweeney, J. J. & Walter, B.
Partner: UNT Libraries Government Documents Department

Thermal-Hydraulic Bases for the Safety Limits and Limiting Safety System Settings for HFIR Operation at 100 MW and 468 psig Primary Pressure, Using Specially Selected Fuel Elements

Description: This report summarizes thermal hydraulic analyses performed to support HFIR operation at 100 MW and 468 psig pressure using specially selected fuel elements. The analyses were performed with the HFIR steady state heat transfer code, originally developed during HFIR design. This report addresses the increased core heat removal capability which can be achieved in fuel elements having coolant channel thicknesses that exceed the minimum requirements of the HFIR fuel fabrication specifications. Specific requirements for the minimum value of effective uniform as-built coolant channel thickness are established for fuel elements to be used at 100 MW. The burnout correlation currently used in the steady-state heat transfer code was also compared with more recent experimental results for stability of high-velocity flow in narrow heated channels, and the burnout correlation was found to be conservative with respect to flow stability at typical HFIR hot channel exit conditions at full power.
Date: September 1, 1998
Creator: Rothrock, R.B.
Partner: UNT Libraries Government Documents Department

Bedrock geologic Map of the Central Block Area, Yucca Mountain, Nye County, Nevada

Description: Bedrock geologic maps form the foundation for investigations that characterize and assess the viability of the potential high-level radioactive waste repository at Yucca Mountain, Nevada. As such, this map focuses on the central block at Yucca Mountain, which contains the potential repository site. The central block is a structural block of Tertiary volcanic rocks bound on the west by the Solitario Canyon Fault, on the east by the Bow Ridge Fault, to the north by the northwest-striking Drill Hole Wash Fault, and on the south by Abandoned Wash. Earlier reconnaissance mapping by Lipman and McKay (1965) provided an overview of the structural setting of Yucca Mountain and formed the foundation for selecting Yucca Mountain as a site for further investigation. They delineated the main block-bounding faults and some of the intrablock faults and outlined the zoned compositional nature of the tuff units that underlie Yucca Mountain. Scott and Bonk (1984) provided a detailed reconnaissance geologic map of favorable area at Yucca Mountain in which to conduct further site-characterization studies. Of their many contributions, they presented a detailed stratigraphy for the volcanic units, defined several other block-bounding faults, and outlined numerous intrablock faults. This study was funded by the U.S. Department of Energy Yucca Mountain Project to provide a detailed (1:6,000-scale) bedrock geologic map for the area within and adjacent to the potential repository area at Yucca Mountain, Nye County, Nevada. Prior to this study, the 1:12,000-scale map of Scott and Bonk (1984) was the primary source of bedrock geologic data for the Yucca Mountain Project. However, targeted detailed mapping within the central block at Yucca Mountain revealed structural complexities along some of the intrablock faults that were not evident at 1:12,000 (Scott and Bonk, 1984). As a result, this study was undertaken to define the character and extent of the ...
Date: September 29, 1998
Creator: Day, W.C.; Potter, C.; Sweetkind, D.; Dickerson, R.P. & Juan, C.A. San
Partner: UNT Libraries Government Documents Department

Corrective Action Investigation Plan for Corrective Action Unit 500: Test Cell A Septic System, Nevada Test Site, Nevada, Revision 0, DOE/NV--528 UPDATED WITH TECHNICAL CHANGE No.1

Description: This Corrective Action Investigation Plan (CAIP) addresses one of three leachfield systems associated with Test Cell A, which is located in Area 25 at the Nevada Test Site (NTS). The NTS is approximately 105 kilometers (km) (65 miles [mi]) northwest of Las Vegas, Nevada (see Leachfield Work Plan Figure 1-1). Corrective Action Unit 500 is comprised of the Test Cell A Septic System (CAS 25-04-05) and the associated leachfield system presented in Figure 1-1 (FFACO, 1996). The leachfield is located 60 meters (m) (200 feet [ft]) southeast of the Building 3124 gate, and approximately 45 m (150 ft) southwest of Building 3116 at Test Cell A. Test Cell A operated during the 1960s to support nuclear rocket reactor testing as part of the Nuclear Rocket Development Station (NRDS) (SNPO, 1970). Various operations within Buildings 3113B (Mechanical Equipment Room), 3115 (Helium Compressor Station), 3116 (Pump House), a water tank drain and overflow, a ''yard and equipment drain system'' outside of Building 3116, and a trailer have resulted in potentially hazardous effluent releases to the leachfield system (DOE, 1988a). The leachfield system components include discharge lines, manways, a septic tank, an outfall line, a diversion chamber, and a 15 by 30 m (50 by 100 ft) leachfield (see Leachfield Work Plan Figure 3-1 for explanation of terminology). In addition, engineering drawings show an outfall system that may or may not be connected to the CAU 500 leachfield. In general, effluent contributed to the leachfield was sanitary wastewater associated with floor drains, toilet and lavatory facilities in Building 3113B and floor drains in the remaining source buildings. The surface and subsurface soils in the vicinity of the collection system, outfall, and leachfield may have been impacted by effluent containing contaminants of potential concern (COPCs) generated by support activities associated with Test Cell A ...
Date: December 1, 1998
Creator: ITLV
Partner: UNT Libraries Government Documents Department

Corrective Action Investigation Plan for Corrective Action Unit 261: Test Cell A Leachfield System, Nevada Test Site, Nevada UPDATED WITH TECHNICAL CHANGE No.1

Description: This Corrective Action Investigation Plan (CAIP) has been developed in accordance with the Federal Facility Agreement and Consent Order (FFACO) that was agreed to by the US Department of Energy, Nevada Operations Office (DOE/NV); the State of Nevada Division of Environmental Protection (NDEP); and the US Department of Defense (FFACO, 1996). The CAIP is a document that provides or references all of the specific information for investigation activities associated with Corrective Action Units (CAUs) or Corrective Action Sites (CASs). According to the FFACO (FFACO, 1996), CASs are sites potentially requiring corrective action(s) and may include solid waste management units or individual disposal or release sites. Corrective Action Units consist of one or more CASs grouped together based on geography, technical similarity, or agency responsibility for the purpose of determining corrective actions. This CAIP contains the environmental sample collection objectives and the criteria for conducting site investigation activities at CAU 261, the Area 25 Test Cell A Leachfield System, which is located in Area 25 at the Nevada Test Site (NTS). The NTS is approximately 88 kilometers (km) (55 miles [mi]) northwest of Las Vegas, Nevada. As presented, CAU 261 is comprised of CASs 25-05-01 and 25-05-07, respectively known as the Leachfield and the Acid Waste Leach Pit (AWLP) (FFACO, 1996). The leachfield is an area with dimensions of approximately 23 by 17 meters (m) (75 by 55 feet [ft]) and is located south of Building 3124, which is southwest and adjacent to Test Cell A. Test Cell A was operational during the 1960s to test nuclear rocket reactors in support of the Nuclear Rocket Development Station (NRDS) (SNPO, 1970). Various operations within Building 3124, from 1962 through 1972, have resulted in liquid waste releases to the leachfield and the AWLP (DOE, 1988a). The surface and subsurface soils in the vicinity ...
Date: September 18, 1998
Creator: /NV, DOE
Partner: UNT Libraries Government Documents Department

Federal Radiological Monitoring and Assessment Center Overview of FRMAC Operations

Description: In the event of a major radiological emergency, 17 federal agencies with various statutory responsibilities have agreed to coordinate their efforts at the emergency scene under the umbrella of the Federal Radiological Emergency Response Plan. This cooperative effort will ensure that all federal radiological assistance fully supports their efforts to protect the public. the mandated federal cooperation ensures that each agency can obtain the data critical to its specific responsibilities. This Overview of Federal Radiological Monitoring and Assessment Center (FRMAC) describes the FRMAC response activities to a major radiological emergency. It also describes the federal assets and subsequent operational activities which provide federal radiological monitoring and assessment of the off-site areas.
Date: March 1, 1998
Partner: UNT Libraries Government Documents Department

Streamlined Approach for Environmental Restoration Work Plan for Corrective Action Unit 461: Joint Test Assembly Sites and Corrective Action Unit 495: Unconfirmed Joint Test Assembly Sites Tonopah Test Range, Nevada

Description: This Streamlined Approach for Environmental Restoration plan addresses the action necessary for the clean closure of Corrective Action Unit 461 (Test Area Joint Test Assembly Sites) and Corrective Action Unit 495 (Unconfirmed Joint Test Assembly Sites). The Corrective Action Units are located at the Tonopah Test Range in south central Nevada. Closure for these sites will be completed by excavating and evaluating the condition of each artillery round (if found); detonating the rounds (if necessary); excavating the impacted soil and debris; collecting verification samples; backfilling the excavations; disposing of the impacted soil and debris at an approved low-level waste repository at the Nevada Test Site
Date: August 1, 1998
Creator: Smith, Jeff
Partner: UNT Libraries Government Documents Department

The Effects of Site Characterization Activities on the Abundance of Ravens (Corvus corax) in the Yucca Mountain Area

Description: In response to the Nuclear Waste Policy Act of 1982 and the Nuclear Waste Policy Amendments Act of 1987, the U.S. Department of Energy (DOE) developed and is implementing the Yucca Mountain Site Characterization Project. Raven abundance was measured from August 1991 through August 1995 along treatment and control routes to evaluate whether site characterization activities resulted in increased raven abundance at Yucca Mountain. This study fulfills the requirement set forth in the incidental take provisions of the Biological Opinion that DOE monitor the abundance of ravens at Yucca Mountain. Ravens were more abundant at Yucca Mountain than in the control area, and raven abundance in both areas increased over time. However, the magnitude of differences between Yucca Mountain and control surveys did not change over time, indicating that the increase in raven abundance observed during this study was not related to site characterization activities. Increases over time on both Yucca Mountain and control routes are consistent with increases in raven abundance in the Mojave Desert reported by the annual Breeding Bird Survey of the US. Fish and Wildlife Service. Evidence from the Desert Tortoise Monitoring Program at Yucca Mountain suggests that ravens are not a significant predator of small tortoises in this locale. Carcasses of small tortoises (less than 110 mm in length) collected during the study showed little evidence of raven predation, and 59 radiomarked hatchlings that were monitored on a regular basis were not preyed upon by ravens. Overall, no direct evidence of raven predation on tortoises was observed during this study. Small tortoises are probably encountered so infrequently by ravens that they are rarely exploited as a food source. This is likely due to the relatively low abundance of both desert tortoises and ravens in the Yucca Mountain area.
Date: May 8, 1998
Creator: Lederle, P.E.
Partner: UNT Libraries Government Documents Department

Report on Intact and Degraded Criticality for Selected Plutonium Waste Forms in a Geologic Repository, Volume I: MOX SNF

Description: As part of the plutonium waste form development and down-select process, repository analyses have been conducted to evaluate the long-term performance of these forms for repository acceptance. Intact and degraded mode criticality analysis of the mixed oxide (MOX) spent fuel is presented in Volume I, while Volume II presents the evaluations of the waste form containing plutonium immobilized in a ceramic matrix. Although the ceramic immobilization development program is ongoing, and refinements are still being developed and evaluated, this analysis provides value through quick feed-back to this development process, and as preparation for the analysis that will be conducted starting in fiscal year (FY) 1999 in support of the License Application. While no MOX fuel has been generated in the United States using weapons-usable plutonium, Oak Ridge National Laboratory (ORNL) has conducted calculations on Westinghouse-type reactors to determine the expected characteristics of such a fuel. These spent nuclear fuel (SNF) characteristics have been used to determine the long-term potential for criticality in a repository environment. In all instances the methodology and scenarios used in these analyses are compatible with those developed and used for Commercial Spent Nuclear Fuel (CSNF) and Defense High Level Waste (DHLW), as tailored for the particular characteristics of the waste forms. This provides a common basis for comparison of the results. This analysis utilizes dissolution, solubility, and thermodynamic data that are currently available. Additional data on long-term behavior is being developed, and later analyses (FY 99) to support the License Application will use the very latest information that has been generated. Ranges of parameter values are considered to reflect sensitivity to uncertainty. Most of the analysis is focused on those parameter values that produce the worst case results, so that potential licensing issues can be identified.
Date: September 21, 1998
Creator: McClure, J.A.
Partner: UNT Libraries Government Documents Department

Concrete Chemical Evolution

Description: The objectives of this analysis are to discuss and evaluate testing results that were performed for the M&O by the Pennsylvania State University (PSU) to evaluate the potential long-term evolution of organic admixtures in cementitious materials at elevated temperatures. The testing was designed to help provide a basis for a determination by the Performance Assessment group (PA) of the long-term acceptability and longevity of cementitious materials for repository use. The main purpose of the testing was to assess the evolution of gases (especially CO{sub 2}) from hydrated cement paste at elevated temperatures and to determine the impact on alkalinity, i.e., the pH value of cement paste pore solution. This information in turn can be used as scoping information to determine if further tests of this nature are needed to support PA. As part of this discussion and evaluation of the PSU results, an assessment of alkalinity in a ''cementitious repository'' and an evaluation of organic materials are presented.
Date: July 31, 1998
Creator: Tang, D.H.
Partner: UNT Libraries Government Documents Department

Technology Assessment Report: Duty Cycling Controllers Revisited

Description: This report covers an assessment of two brands of energy management controllers that are currently being offered that utilize the principle of duty cycling to purportedly save energy for unitary air conditioners and heat pumps, gas furnaces, and gas fired boilers. The results of an extensive review of past research on this subject as well as a review of vendor sponsored field testing of these controllers compares these newer controllers to those of the past. Included also is a discussion of how the duty cycling principle is prone to misinterpretation as to its potential to save energy.
Date: May 1, 1998
Creator: Webster, Tom & Benenson, Peter
Partner: UNT Libraries Government Documents Department

Self-pinched beam transport experiments Relevant to Heavy Ion Driven inertial fusion energy

Description: An attractive feature of the inertial fusion energy (IFE) approach to commercial energy production is that the fusion driver is well separated from the fusion confinement chamber. This ''standoff'' feature means the driver is largely isolated from fusion reaction products. Further, inertial confinement fusion (ICF) target ignition (with modest gain) is now scheduled to be demonstrated at the National Ignition Facility (NIF) using a laser driver system. The NIF program will, to a considerable extent, validate indirectly-driven heavy-ion fusion (HIF) target designs for IFE. However, it remains that HIF standoff between the final focus system and the fusion target needs to be seriously addressed. In fact, there now exists a timely opportunity for the Office of Fusion Energy Science (OFES) to experimentally explore the feasibility of one of the attractive final transport options in the fusion chamber: the self-pinched transport mode. Presently, there are several mainline approaches for HIF beam transport and neutralization in the fusion chamber. These range from the (conservative) vacuum ballistic focus, for which there is much experience from high energy research accelerators, to highly neutralized ballistic focus, which matches well to lower voltage acceleration with resulting lower driver costs. Alternatively, Z-discharge channel transport and self-pinched transport in gas-filled chambers may relax requirements on beam quality and final focusing systems, leading to even lower driver cost. In any case, these alternative methods of transport, especially self-pinched transport, are unusually attractive from the standpoint of chamber design and neutronics. There is no requirement for low chamber pressure. Moreover, only a minuscule fraction of the fusion neutrons can escape from the chamber. Therefore, it is relatively easy to shield sensitive components, e-g., superconducting magnets from any significant neutron flux. Indeed, self-pinched transport and liquid wall protection endow DT fusion with many of the advantages of aneutronic fusion. The question ...
Date: February 6, 1998
Creator: Herrmannsfeldt, W.B.; Bangerter, R.O.; Fessenden, T.J.; Lee, E.P.; Yu, S.S.; Olson, C.L. et al.
Partner: UNT Libraries Government Documents Department

Project W420 Air Sampler Probe Placement Qualification Tests for Four 6-Inch Diameter Stacks: 296-A-25, 296-B-28, 296-S-22, and 296-T-18

Description: The W420 project covers the upgrading of effluent monitoring systems at six ventilation exhaust stacks in tank-farm facilities at the U.S. Department of Energy's Hanford Site. The discharge stacks of five of the six systems will be completely replaced. Four of these (296-A-25, 296-B-28, 296-S-22, and 296-T-18) will be of the same size, 6-inches in diameter and about 12-ft high. This report documents tests that were conducted to verify that these four stacks meet the applicable regulatory criteria regarding the placement of the air sampling probe. These criteria ensure that the contaminants in the stack are well mixed with the airflow at the location of the probe such that the extracted sample represents the whole. There are also criteria addressing the transport of the sample to the collection device. These are not covered in this report, but will need to be addressed later. These tests were conducted by Pacific Northwest National Laboratory on a full-scale model of the 6-inch stick. The sequence of tests addresses the acceptability of the flow angle relative to the probe and the uniformity of air velocity and gaseous and particle tracers in the cross section of the stack. All tests were successful, and all acceptance criteria were met.
Date: September 30, 1998
Creator: Maughan, A.D. & Glissmeyer, J.A.
Partner: UNT Libraries Government Documents Department