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Loss-of-coolant accident analyses of the Advanced Neutron Source Reactor

Description: Currently in the conceptual design stage, the Advanced Neutron Source Reactor (ANSR) will operate at a high heat flux, a high mass flux, an a high degree of coolant subcooling. Loss-of-coolant accident (LOCA) analyses using RELAP5 have been performed as part of an early evaluation of ANSR safety issues. This paper discusses the RELAP5 ANSR conceptual design system model and preliminary LOCA simulation results. Some previous studies were conducted for the preconceptual design. 12 refs., 7 figs.
Date: January 1, 1991
Creator: Chen, N.C.J.; Yoder, G.L. (Oak Ridge National Lab., TN (USA)) & Wendel, M.W. (Martin Marietta Energy Systems, Inc., Oak Ridge, TN (USA))
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Partner: UNT Libraries Government Documents Department
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Large break loss-of-coolant accident analyses for the high flux isotope reactor

Description: The US Department of Energy's High Flux Isotope Reactor (HFIR) was analyzed to evaluate it's response to a spectrum of loss-of-coolant accidents (LOCAs) with potential for leading to core damage. The MELCOR severe accident analysis code (version 1.7.1) was used to evaluate the overall dynamic response of HFIR. Before conducting LOCA analyses, the steady-state thermal-hydraulic parameters evaluated by MELCOR for various loop sections were verified against steady-state operating data. Thereafter,… more
Date: January 1, 1989
Creator: Taleyarkhan, R.P. (Oak Ridge National Lab., TN (USA))
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Analysis of depressurized loss-of-forced cooling transients by HERA

Description: The Modular High-Temperature Gas-Cooled Reactor (MHTGR) is one of the next generation reactors, which has passive safety features. Among these safety features is the ability to withstand a depressurized, loss-of-forced cooling of the reactor without release of fission products from the primary containment. In order to assess the capability of the MHTGR to withstand this type of accident condition, the thermal behavior of the reactor core must be well understood. To accomplish this, we have empl… more
Date: January 1, 1991
Creator: Rider, W. J. & Cappiello, M. W.
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Partner: UNT Libraries Government Documents Department
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Evaluation of BWR emergency procedure guidelines for BWR ATWS using RAMONA-3B code

Description: An MSIV Closure ATWS calculation for a typical BWR/4 (Browns Ferry, Unit 1) was performed using the RAMONA-3B code which is a BWR systems transient code combining three-dimensional neutronic core representation with multi-channel one-dimensional thermal hydraulics. The main objective of the study was to perform a best-estimate evaluation of the recently proposed Emergency Procedure Guidelines for Anticipated Transients Without Scram (ATWS). Emphasis was placed on evaluating the effects of lower… more
Date: January 1, 1985
Creator: Neymotin, L.; Slovik, G.; Cazzoli, E. & Saha, P.
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Partner: UNT Libraries Government Documents Department
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ORNL analyses of AVR performance and safety

Description: Because of the high interest in modular High Temperature Reactor performance and safety, a cooperative project has been established involving the Oak Ridge National Laboratory (ORNL), Arbeitsgemeinschaft Versuchs Reaktor GmbH (AVR), and Kernforschungsanlage Juelich GmbH (KFA) in reactor physics, performance and safety. This paper presents initial results of ORNL's examination of a hypothetical depressurized core heatup accident and consideration of how a depressurized core heatup test might be … more
Date: January 1, 1985
Creator: Cleveland, J.C.
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Partner: UNT Libraries Government Documents Department
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Experiment data report for Semiscale Mod-1 Test S-28-5 (steam generator tube rupture test). [PWR]

Description: Recorded test data are presented for Test S-28-5 of the Semiscale Mod-1 steam generator tube rupture test series. These tests are among several Semiscale Mod-1 experiments conducted to investigate the thermal and hydraulic phenomena accompanying a hypothesized loss-of-coolant accident in a pressurized water reactor (PWR) system. Test S-28-5 was conducted from initial conditions of 15,768 kPa and 556 K to investigate the response of the Semiscale Mod-1 system to a depressurization and reflood tr… more
Date: November 1, 1977
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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Experimental Validation of Stratified Flow Phenomena, Graphite Oxidation, and Mitigation Strategies of Air Ingress Accidents

Description: The US Department of Energy is performing research and development (R&D) that focuses on key phenomena that are important during challenging scenarios that may occur in the Next Generation Nuclear Plant (NGNP) Program / GEN-IV Very High Temperature Reactor (VHTR). Phenomena identification and ranking studies (PIRT) to date have identified the air ingress event, following on the heels of a VHTR depressurization, as very important (Schultz et al., 2006). Consequently, the development of advanced … more
Date: December 1, 2008
Creator: Oh, Chang Ho; Kim, Eung Soo; No, Hee Cheon & Cho, Nam Zin
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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Regional and National Estimates of the PotentialEnergy Use, Energy Cost, and CO{sub 2} Emissions Associated with Radon Mitigation by Sub-slab Depressurization

Description: Active sub-slab depressurization (SSD) systems are an effective means of reducing indoor radon concentrations in residential buildings. However, energy is required to operate the system fan and to heat or cool the resulting increased building ventilation. We present regional and national estimates of the energy requirements, operating expenses, and CO{sub 2} emissions associated with using SSD systems at saturation (i.e., in all U.S. homes with radon concentrations above the EPA remediation gui… more
Date: March 1, 1996
Creator: Riley, W. J.; Fisk, W. J. & Gadgil, A. J.
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Partner: UNT Libraries Government Documents Department
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Scoping Study on the Safety Impact of Valve Spacing in Natural Gas Pipelines

Description: The U.S. Department of Transportation's Pipeline and Hazardous Materials Safety Administration (PHMSA) is responsible for ensuring the safe, reliable, and environmentally sound operation of the nation's natural gas and hazardous liquid pipelines. Regulations adopted by PHMSA for gas pipelines are provided in 49 CFR 192, and spacing requirements for valves in gas transmission pipelines are presented in 49 CFR 192.179. The present report describes the findings of a scoping study conducted by Oak … more
Date: July 1, 2007
Creator: Sulfredge, Charles David
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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Physical property changes in hydrate-bearingsediment due to depressurization and subsequent repressurization

Description: Physical property measurements of sediment cores containing natural gas hydrate are typically performed on material exposed at least briefly to non-in situ conditions during recovery. To examine effects of a brief excursion from the gas-hydrate stability field, as can occur when pressure cores are transferred to pressurized storage vessels, we measured physical properties on laboratory-formed sand packs containing methane hydrate and methane pore gas. After depressurizing samples to atmospheric… more
Date: June 1, 2008
Creator: Kneafsey, Timothy; Waite, W.F.; Kneafsey, T.J.; Winters, W.J. & Mason, D.H.
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Partner: UNT Libraries Government Documents Department
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TOUGH+Hydrate v1.0 User's Manual: A Code for the Simulation of System Behavior in Hydrate-Bearing Geologic Media

Description: TOUGH+HYDRATE v1.0 is a new code for the simulation of the behavior of hydrate-bearing geologic systems. By solving the coupled equations of mass and heat balance, TOUGH+HYDRATE can model the non-isothermal gas release, phase behavior and flow of fluids and heat under conditions typical of common natural CH{sub 4}-hydrate deposits (i.e., in the permafrost and in deep ocean sediments) in complex geological media at any scale (from laboratory to reservoir) at which Darcy's law is valid. TOUGH+HYD… more
Date: March 1, 2008
Creator: Moridis, George; Moridis, George J.; Kowalsky, Michael B. & Pruess, Karsten
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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Application of Gamma code coupled with turbomachinery models for high temperature gas-cooled reactors

Description: The very high-temperature gas-cooled reactor (VHTR) is envisioned as a single- or dual-purpose reactor for electricity and hydrogen generation. The concept has average coolant temperatures above 9000C and operational fuel temperatures above 12500C. The concept provides the potential for increased energy conversion efficiency and for high-temperature process heat application in addition to power generation. While all the High Temperature Gas Cooled Reactor (HTGR) concepts have sufficiently high … more
Date: February 1, 2008
Creator: Oh, Chang
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Implications of Air Ingress Induced by Density-Difference Driven Stratified Flow

Description: One of the design basis accidents for the Next Generation Nuclear Plant (NGNP), a high temperature gas-cooled reactor, is air ingress subsequent to a pipe break. Following a postulated double-ended guillotine break in the hot duct, and the subsequent depressurization to nearly reactor cavity pressure levels, air present in the reactor cavity will enter the reactor vessel via density-gradient-driven-stratified flow. Because of the significantly higher molecular weight and lower initial temperatu… more
Date: June 1, 2008
Creator: Oh, Chang; Kim, Eung Soo; Schultz, Richard; Petti, David & Liou, C. P.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Application of NUREG-1150 methods and results to accident management

Description: The use of NUREG-1150 and similar Probabilistic Risk Assessments in NRC and industry risk management programs is discussed. Risk management'' is more comprehensive than the commonly used term accident management.'' Accident management includes strategies to prevent vessel breach, mitigate radionuclide releases from the reactor coolant system, and mitigate radionuclide releases to the environment. Risk management also addresses prevention of accident initiators, prevention of core damage, and im… more
Date: January 1, 1990
Creator: Dingman, S.; Sype, T.; Camp, A. & Maloney, K.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Microseismic activity observed during depressurization of an oil storage cavern in rock salt

Description: In November 1978, the Los Alamos National Laboratory installed a triaxial downhole geophone package at the Bryan Mound Strategic Petroleum Reserve, a salt dome near Freeport, Texas. Monitoring was for the purpose of detecting microseismic activity during the depressurization of one of the oil storage caverns. Seismic activity started soon after the start of depressurization, reached a peak 5 days later, and rapidly died off. Nineteen locatable microearthquakes with magnitudes between -1 and -2 … more
Date: January 1, 1981
Creator: Albright, J. & Pearson, C.
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Partner: UNT Libraries Government Documents Department
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Thermohydraulics in a high-temperature gas-cooled reactor primary loop during early phases of unrestricted core-heatup accidents

Description: In High Temperature Gas Cooled Reactor (HTGR) siting considerations, the Unrestricted Core Heatup Accidents (UCHA) are considered as accidents of highest consequence, corresponding to core meltdown accidents in light water reactors. Initiation of such accidents can be, for instance, due to station blackout, resulting in scram and loss of all main loop forced circulation, with none of the core auxiliary cooling system loops being started. The result is a slow but continuing core heatup, extendin… more
Date: January 1, 1983
Creator: Kroeger, P. G.; Colman, J. & Hsu, C. J.
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Partner: UNT Libraries Government Documents Department
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Fission product plateout and liftoff in the MHTGR primary system: A review

Description: A review is presented of the technical basis for predicting radioactivity release resulting from depressurization of an MHTGR primary system. Consideration is restricted to so called dry events with no involvement of the steam system. The various types of deposition mechanisms effective for iodine, cesium, strontium, and silver are discussed in terms of their chemical characteristics and the nature of the materials in the primary system. Emphasis is given to iodine behavior, including means for… more
Date: April 1, 1991
Creator: Wichner, R.P. (Oak Ridge National Lab., TN (USA))
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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An assessment of BWR (boiling water reactor) Mark III containment challenges, failure modes, and potential improvements in performance

Description: This report describes risk-significant challenges posed to Mark III containment systems by severe accidents as identified for Grand Gulf. Design similarities and differences between the Mark III plants that are important to containment performance are summarized. The accident sequences responsible for the challenges and the postulated containment failure modes associated with each challenge are identified and described. Improvements are discussed that have the potential either to prevent or del… more
Date: January 1, 1991
Creator: Schroeder, J. A.; Pafford, D. J.; Kelly, D. L.; Jones, K. R. & Dallman, F. J.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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A study of the influence of a gravel subslab layer on radon entry rate using two basement structures

Description: In buildings with elevated radon concentrations, the dominant transport mechanism of radon is advective flow of soil gas into the building substructure. However, the building-soil system is often complex, making detailed studies of the radon source term difficult. In order to examine radon entry into buildings, the authors have constructed two room-size, precisely-fabricated basement structures at a site with relatively homogeneous, moderately permeable soil. The basements are identical except … more
Date: January 1, 1993
Creator: Robinson, A.L.; Sextro, R.G.; Fisk, W.J.; Garbesi, K.; Wooley, J. & Wollenberg, H.A.
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Partner: UNT Libraries Government Documents Department
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One-dimensional model of vapor generation in steady flashing flow

Description: In order to predict the critical flow rates of a vapor-liquid two-phase mixture through pipes discharging into a low pressure environment, it is necessary to understand the characteristics of a flashing two-phase mixture. Of particular importance is the transition from single-phase (liquid) to two-phase flow as a result of rapid depressurization of the liquid in the flow causing the liquid to vaporize or flash. Results of a series of flashing experiments performed by Reocreux (1974) are availab… more
Date: January 1, 1979
Creator: Wu, B.J.C.; Saha, P.; Abuaf, N. & Jones, O.C. Jr.
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Partner: UNT Libraries Government Documents Department
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MORECA: A computer code for simulating modular high-temperature gas-cooled reactor core heatup accidents

Description: The design features of the modular high-temperature gas-cooled reactor (MHTGR) have the potential to make it essentially invulnerable to damage from postulated core heatup accidents. This report describes the ORNL MORECA code, which was developed for analyzing postulated long-term core heatup scenarios for which active cooling systems used to remove afterheat following the accidents can be assumed to the unavailable. Simulations of long-term loss-of-forced-convection accidents, both with and wi… more
Date: October 1, 1991
Creator: Ball, S.J. (Oak Ridge National Lab., TN (United States))
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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PWR depressurization analyses

Description: Early containment failure resulting from direct containment heating (DCH) has been identified as a potential contributor to the risk of operating a pressurized water reactor (PWR). One important factor needed to evaluate the contribution of DCH to risk is the conditional probability that, given a core melt, the primary system will be at high pressure when the reactor vessel lower head fails. Two mechanisms that could reduce the pressure during a station blackout core melt accident are discussed… more
Date: January 1, 1992
Creator: Brownson, D.A.; Dobbe, C.A. & Knudson, D.L.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Analysis of two small break loss-of-coolant experiments in the BETHSY facility using RELAP5/MOD3

Description: Small break loss-of-coolant accident (SBLOCA) data were recorded during tests 9.lb and 6.2 TC in the Boucle d'Etudes Thermohydrouliques Systeme (BETHSY) facility at the Centre d'Etudes Nucleares de Grenoble (CENG) complex in Grenoble, France. The data from test 9.lb form the basis for the International Standard Problem number 27 (ISP-27). For each test the primary system depressurization, break flow rate, core heat-up, and effect of operator actions were analyzed. Based on the test 9.lb/ISP-27 … more
Date: July 1, 1992
Creator: Roth, P. A.; Schultz, R. R. & Choi, C. J.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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Appraisal of possible combustion hazards associated with a high-temperature gas-cooled reactor

Description: The report presents a study of combustion hazards that may be associated with the High Temperature Gas Cooled Reactor (HTGR) in the event of a primary coolant circuit depressurization followed by water or air ingress into the prestressed concrete reactor vessel (PCRV). Reactions between graphite and steam or air produce the combustible gases H/sub 2/ and/or CO. When these gases are mixed with air in the containment vessel (CV), flammable mixtures may be formed. Various modes of combustion inclu… more
Date: March 1, 1978
Creator: Palmer, H. B.; Sibulkin, M.; Strehlow, R. A. & Yang, C. H.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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