A fuel dispersal model for C-141 transport accidents was developed for the Defense Nuclear Agency's Fuel Fire Technology Base Program to support Weapon System Safety Assessments. The spectrum of accidents resulting from aircraft impact on a runway was div...

Contents: The LWR fuel cycle; Generic models for demography, dispersion, dose; Source terms and likelihoods; Risk assessment.

Progress in modeling the response of fast reactor fuel to accident transients is reported in four areas: fission gas release from grains and intragranular fuel swelling, fission gas redistribution and internal pressurization in solid fuel, fuel cracking models, and fuel ...

The reactivity feedback from fuel relocation is a central issue in the analysis of loss-of-flow (LOF) accidents in LMFBRs. Fuel relocation has been studied in a number of LOF simulations in the TREAT reactor. In this paper the results of these tests are analyzed, using, as the principal figure of merit, the changes in equivalent ...

Hazardous radioactive materials can be released into the atmosphere by accidents at nuclear power plants, fuel processing facilities, and other facilities, and by transportation accidents involving nuclear materials. In addition, the post-cold-war prolife...

Assessment of the environmental consequences of an accident in a fuel cycle facility ultimately involves calculating the atmospheric dispersion of radioactive materials and estimating the radiation dose to the surrounding population. Some uncertainty lies in the estimate of the nuclear facility source term to be used for atmospheric ...

A series of seven in-pile experiments (the STAR experiments) were performed in which clad motion and fuel dispersal were observed in small pin bundles with high-speed cinematography. The experimental heating conditions reproduced a range of Loss of Flow (LLF) accident scenarios for the lead subassemblies in LMFBRs. The experiments show ...

Because of the possibility of rapid physical and chemical molten fuel-water interactions during a core melt accident in noncommercial or experimental reactors, it is important to understand the interactions that might occur if these materials were to cont...

A fuel assembly for a liquid metal fast breeder reactor having an upper axial blanket region disposed in a plurality of zones within the fuel assembly. The characterization of a zone is dependent on the height of the axial blanket region with respect to the active fuel region. The net effect of having a plurality of zones is to ...

A fuel dispersal model for C-141 transport accidents was developed for the Defense Nuclear Agency`s Fuel Fire Technology Base Program to support Weapon System Safety Assessments. The spectrum of accidents resulting from aircraft impact on a runway was divided into three ...

The reactivity effects of fuel and clad motion during Unprotected Loss of Flow accidents (ULOFs) strongly influence the accident progression in LMFBRs. To study these phenomena, a series of in-pile experiments (the STAR experiments) are being performed in which clad motion and fuel dispersal ...

Core flow blockage events have been identified as a leading contributor to core damage initiation risk in the Advanced Neutron Source (ANS) reactor. During such an accident, insufficient cooling of the fuel in a few adjacent blocked coolant channels out o...

Core flow blockage events are a leading contributor to core damage initiation risk in the Advanced Neutron Source (ANS) reactor. During such an accident, insufficient cooling of the fuel could result in core heatup and melting under full coolant flow cond...

In the hypothetical accident of LMFBR, it is assumed that nuclear aerosol, mainly sodium oxide aerosol containing fuel material, is dispersed in the reactor containment vessels. Decrease of the aerosol concentration in the containment may be governed by s...

The mechanical and thermal response of Topaz II space nuclear reactor as a result of pre-launch and launch accidents is analyzed. Various accident scenarios such as land and water impact, propellant fires, and propellant explosions are examined. Emphasis is placed on the possibilities of loss of geometry leading to inadvertent criticality and ...

The oxidation of irradiated Chernobyl nuclear fuel at 670 to 1,170 K for 3 to 21 h resulted in its destruction into fine particles, the dispersal composition of which is well described by lognormal distribution regularity. The median radius of the formed particles does not depend on the annealing temperature and decreases with the increase of the annealing ...

For a sound evaluation of the consequences of a hypothetical nuclear reactor accident, a knowledge of the extent of fission product release from the fuel at anticipated temperatures and atmosphere conditions is required. Measurements of fission product release have been performed with a variety of nuclear fuels under various conditions ...

Postirradiation heating tests were conducted on segments of UAl{sub 4}/Al dispersion fuel plates clad with Al to scope the foaming (rapid swelling) behavior of such fuels during beyond-design-basis accident scenarios. Four tests investigated maximum temperature, ramp rate, and duration with a liquid phase as ...

The C06R test was the sixth single-pin test in the collaborative US/UK PFR/TREAT transient testing program. It was designed to study the mechanism, time and location of cladding failure and first fuel escape in an intermediate channel transient undercooling - overpower accident (TUCOP). It complements the LO5/sup 2/ and LO7/sup 3/ tests which studied post ...

The technology of thermal hydraulic aspects of the transition phase accident sequence in liquid metal fast breeder reactors has been reviewed. Previous analyses of the transition phase accident sequence have been reviewed and the current understanding of major thermal hydraulic phenomenology has been assessed. As a result of the foregoing, together with a ...

For analysis of a loss-of-flow (LOF) accident in an LMFBR, knowledge of the mode of disruption of irradiated fuel is of critical importance. In addition, to determine whether the reactor can undergo a severe prompt critical power excursion it is important to know the time of onset and rate of fuel dispersal, if ...

A framework for examining whole-core accident phenomena during the time interval beginning with loss-of-intact geometry up to the time of post-accident heat removal is presented in terms of four distinct stages of disruption: (1) disruption initiation, (2) meltout stage, (3) integral pool stage, and (4) termination stage. Each of the ...

Safety challenges for sodium-cooled fast reactors include maintaining core temperatures within design limits and assuring the geometry and integrity of the reactor core. Due to the high power density in the reactor core, heat removal requirements encourage the use of high-heat-transfer coolants such as liquid sodium. The variation of power across the core requires ducted assemblies to control ...

A series of Fuel Disruption (FD) experiments simulating LOF accident transients for homogeneous- and heterogeneous-core LMFBRs is currently being performed in the Annular Core Research Reactor at SNL. The test fuel is observed with high-speed cinematography to determine the timing and the mode of the fuel ...

At the time of the accident in the reactor of the fourth power-generating unit of the Chernobyl nuclear power plant on April 26, 1986, the core contained 1659 fuel assemblies. Each assembly contained 114.7 kg of uranium, and therefore the reactor contained a total of 114.7 x 1659 = 190,287.3 kg of uranium. If the amount of fuel is ...

Studies of unprotected loss-of-flow accidents in the CRBR for various rates of flow coastdown 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/sup 0/C. An approximate treatment of the LOF-driven TOP ...

The term 'ultimate risk' is used here to describe the probabilities and radiological consequences that should be incorporated in siting, containment design and accident management of nuclear power plants for hypothetical accidents. It is closely related with the source terms specified in siting criteria which assures an adequate ...

RADMODL is a set of computer codes that model the transport of material through a network of interconnected compartments. This version of RADMODL is designed to model the transport of radioactive material from either a loss of coolant accident (LOCA) or a fuel handling accident into a set of interconnected compartments and determine ...

A summary is presented of the subjects that should be included in safety analyis documents to avoid accidents during reprocessing of nuclear fuel. As a specific example, a potential criticality accident is used to illustrate how this accident is avoided i...

This paper describes the major aspects of tritium dispersion phenomenology, summarizes deposition attributes of the computer models used in the DOE Complex for tritium dispersion, and recommends an approach to account for deposition in accident analysis.

The report describes the Chernobyl accident and its consequences for Denmark in particular. It was commissioned by the Secretary of State for the Environment. The event at the accident site, the release and dispersal of radioactive substances into the atm...

In the unlikely event of a core meltdown accident, an important safety issue is the potential for steam explosions and their effects on the accident progression. Steam explosion phenomena can be divided into three stages: (a) mixing of the molten fuel and water; (b) triggering and spatial propagation of rapid fuel ...

Subassembly scale motion during the early fuel dispersal and extended fuel motion phases of an LMFBR loss of flow accident are examined with the SIMMER-II code. Results are compared and contrasted with previous analyses and selected experiments. The early fuel motion with a SIMMER-II model is ...

Over thirty in-pile experiments were performed to investigate fuel disruption behavior for LMFBR loss of flow (LOF) accidents. These experiments reproduced the heating transients for a variety of accidents ranging from slow LOF accidents to rapid LOF-driven-TOP accidents. In all experiments the ...

This report examines the various sources of radiological land contamination; its extent; its impacts on man, agriculture, and the environment; countermeasures for mitigating exposures; radiological standards; alternatives for achieving land decontamination and cleanup; and possible alternatives for utilizing the land. The major potential sources of extensive long-term land contamination with ...

Accidental releases of radioactive material at the Oak Ridge National Laboratory resulted in the establishment of building and ventilation design criteria and the requirement for a hazards evaluation for those facilities which contain or handle radioactive materials of physiological hazard greater than that equivalent to one gram of Pu-239. A quantitative method for estimating the ...

Research addressing LMFBR whole core accidents has been terminated, and there is now emphasis on quantifying reactivity feedbacks, and in particular enhancing negative feedback, so that advanced LMR designs will provide inherently safe operation. The status of recent HCDA-related laboratory research performed at ANL, up to the time that such activities were no longer needed to ...

In the transient-undercooling-driven overpower (TUCOP) accident scenario for moderate-to-high-sodium-void-worth-LMFBR cores, some computer codes predict large reactivity increases caused by compactive in-pin fuel motion in low power subassemblies during a power burst resulting from sodium voiding in the lead fuel subassemblies. In this ...

... Descriptors : , (*REACTOR FUELS, OPTIMIZATION), (*CERAMIC MATERIALS, REACTOR FUELS), (*METALS, REACTOR FUELS), (*ALLOYS ...

Hydrazine (HZ) fuels are used as examples of the relatively rapid chemical processes that may occur when propellants are released into the atmosphere from normal handling or during accidents. The experimental procedures used to study these processes are reviewed along with postulated chemical reaction mechanisms and measured reaction rates and products. ...

Objectives of this project are to: (1) Develop a computer program for calculating two-dimensional, transient, natural convection phenomena such as those arising from various sodium spill accidents in Liquid Metal Fast Breeder Reactor (LMFBR) heat transfer equipment vaults, head compartments, containment buildings, and secondary heat transfer systems. (2) Develop experimental ...

Minimizing inhalation hazards is a major consideration in the design, development, transportation, handling, testing, storage, launch, use, and ultimate disposition of nuclear space power systems (NSPSs). An accidental dispersion of {sup 238}Pu is of concern for missions involving the radioisotope thermoelectric generators (RTGs) or lightweight radioisotope heater units. ...

The postulated loss-of-coolant accident (LOCA) of a pressurized water reactor has been the subject of intensive experimental and analytical studies in light water reactor safety analysis. Many efforts are devoted to the investigation of the thermodynamic behavior of the reactor core and the effectiveness of the emergency-core-cooling system during reflood phase of a LOCA. In ...

This report documents the reentry safety analyses conducted for the TOPAZ II Nuclear Electric Propulsion Space Test Program (NEPSTP). Scoping calculations were performed on the reentry aerothermal breakup and ground footprint of reactor core debris. The calculations were used to assess the risks associated with radiologically cold reentry accidents and to determine if ...

This report documents the reentry safety analyses conducted for the TOPAZ II Nuclear Electric Propulsion Space Test Program (NEPSTP). Scoping calculations were performed on the reentry aerothermal breakup and ground footprint of reactor core debris. The calculations were used to assess the risks associated with radiologically cold reentry accidents and to determine if ...

The Chernobyl accident resulted in the contamination of the environment with long-lived radionuclides, including transuranium elements. The results, more accurate than the data, for the production of the basic long-lived radio-nuclides in the reactor core where the accident occurred. It is of interest to examine the Americium-241 contamination in greater ...

The objectives of the research program are to develop a computer program for calculating two-dimensional, transient, natural-convection phenomena, such as those arising from various postulated sodium spill accidents in LMFBR heat transfer vaults, head compartments, containment buildings, and secondary heat transfer systems; to develop experimental programs and conduct tests ...

Some postulated accident scenarios lead to a picture with most of the fuel and some structural steel sealed inside the original core volume by frozen plugs at the original core entrance and exit. eventually the fuel will either melt out or blow out of such a sealed volume but in the interim between plug formation and eventual ...

One of the key issues in assessment of the meltout phase of a hypothetical core disruptive accident in the LMFBR system involves the timing and paths for dispersal of molten fuel from the disrupted core. A program of experiments is underway at Argonne National Laboratory to investigate molten fuel penetration ...

A model for estimating the radiological consequences from a hypothetical accident in HEU and LEU fueled research and test reactors is presented. Simple hand calculations based on fission product yield table inventories and non-site specific dispersion data may be adequate in many cases. However, more detailed inventories and site ...

From confercnce on fast rea ctor safety; Los Angeles, California, USA (2 Apr 1974). Recent studies suggest that fuel which is dispersed upward by a mild prompt critical burst may reenter the core region causing a secondary excuraion. Several modes of fuel reentry recriticality are examined, and phenomena which strongly affect ...

Credible accidents were developed and analyzed for TRIGA and TRIGA-fueled reactors. The only potential for offsite exposure appears to be from a fuel-handling accident that, based on highly conservative assumptions, would result in dose equivalents of

... Descriptors : *DISPERSING, *MACHINE CODING, *DETONATIONS, *FUEL AIR EXPLOSIVES, MATHEMATICAL MODELS, COMPUTERIZED ...

The dispersion of radioactive contaminants in an estuary is more complex than the dispersion in a flowing freshwater stream due to tidal cycling in the estuary. Many approximate, analytical solutions are available for the hydraulic dispersion, but a model study is more accurate. The model study, however, ignores radioactive ...

Studying the effects of annealing of scaled-down dispersion fuel plates is an important part of the data base for fuel performance. One of the most critical aspects of fuel performance is the stability of a fuel/matrix dispersion which is usually measured...

A high-density fuel based on U/sub 3/Si/sub 2/ dispersed in aluminum has been developed and tested for use in converting plate-type research and test reactors from the use of highly enriched uranium to the use of low-enriched uranium. Results of preirradiation testing and the irradiation and postirradiation examination of miniature ...

Excessive oxidation, hydriding, and extensive irradiation damage occur in high-burnup fuel cladding, and as result, mechanical properties of high-burnup fuels are degraded significantly. This may influence the current fuel cladding failure limits for loss-of- coolant-accident (LOCA) situations, which are based on ...

Power units with channel-type uranium-graphite reactors occupy an important place in nuclear power, both in their number and in length of operation. Among them, the longest operating are the current unit of the Obninsk nuclear power plant, the first in the world, many industrial reactors which have now be decommissioned, and two first-series excursion-test units at the Beloyarsk nuclear power ...

This historic report is on letter which details the research into atmospheric dispersion of fissioviable materials in the event of a reactor accident at Savannah River Plant. Graphs are included.

Reductions in risk of Pu dispersal from hydrocarbon fuel fires were estimated using pool and spill fire data. Improvements in FRP temperature capabilities, on a system-independent basis, lead to the following estimated reductions in risk, using three probabilistic temperature distributions normalized to a temperature capability of 640[degree]C (the melting ...

This investigation strived for the aim to estimate with sufficient approximation the risks which are run with respect to the dispersion of heavy gases, when accidents under certain meteorological conditions occur. With regards to the contents some differe...

Over thirty in-pile experiments have been performed to investigate fuel disruption behavior for LMFBR loss of flow (LOF) accidents. These experiments reproduced the heating transients for a wide range of accidents ranging from slow LOF accidents to rapid ...

This report contains technical information used to determine accident consequences for the Spent Nuclear Fuel Project safety documents. It does not determine accident consequences or describe specific accident scenarios, but instead provides generic information.

This patent describes reaction products in which polyethers are connected to polyamines using diisocyanates. They have been found to be effective ashless dispersants and detergents for fuel.

Design requirements and performance characteristics of fuel pins for LMFBR reactors under accident conditions are discussed.

... Descriptors : (*JET ENGINE FUELS, *FIRE SAFETY), AIRCRAFT FIRES, AVIATION ACCIDENTS, IGNITION, KEROSENE, TEMPERATURE, WIND ...

The calculation of downwind concentrations from non-traditional sources, such as explosions, provides unique challenges to dispersion models. The US Department of Energy has assigned the Atmospheric Release Advisory Capability (ARAC) at the Lawrence Livermore National Laboratory (LLNL) the task of estimating the impact of accidental radiological releases to the atmosphere ...

The Defense Programs (DP) Office of Engineering and Operations Support (DP-62) requested SAIC to organize and conduct a survey-level evaluation of 27 DP non-reactor nuclear facilities. The purpose of the evaluation was to provide a consistent scoping effort to estimate, with high confidence, bounding accident consequences for hazards associated with DP non-reactor nuclear ...

This document discusses the irradiation behavior of aluminum-based dispersion fuels and evaluates metallurgical processes that control the dispersion behavior. Phase transformations and microstructural changes resulting from fuel-matrix interactions and the effect of fissioning in fuel are ...

This document discusses the irradiation behavior of aluminum-based dispersion fuels and evaluates metallurgical processes that control the dispersion behavior. Phase transformations and microstructural changes resulting from fuel-matrix interactions and the effect of fissioning in fuel are ...

Pacific Northwest Laboratory (PNL), operated for the Department of Energy by the Battelle Memorial Institute, is conducting a study for the Nuclear Regulatory Commission on the feasibility of altering current plutonium shipping forms to reduce or eliminate the airborne dispersibility of PuO/sub 2/ which might occur during a shipping accident. Plutonium ...