Analysis of the Impact of a Tunnel Fire Environment on a Spent Nuclear Fuel Transportation Cask

2003 ◽  
Author(s):  
Christopher S. Bajwa
Keyword(s):  
Pacific Northwest ◽  
Nuclear Fuel ◽  
Spent Nuclear Fuel ◽  
Thermal Conditions ◽  
Nuclear Regulatory Commission ◽  
Radioactive Material ◽  
Spent Fuel ◽  
Tunnel Fire ◽  
Accident Conditions ◽  
The Impact

On July 18, 2001, a train carrying hazardous materials derailed and caught fire in the Howard Street railroad tunnel in Baltimore, Maryland. Due to this accident, questions were raised about the performance of spent nuclear fuel transportation casks under severe fire conditions, similar to those experienced in the Baltimore tunnel fire. The U.S. Nuclear Regulatory Commission (NRC) evaluates the performance of spent fuel transportation casks under accident conditions. Title 10 of the Code of Federal Regulations Part 71 section 73(c)(4), (10 CFR 71.73(c)(4)) requires that transportation packages used to ship radioactive material must be designed to resist an engulfing fire of a 30 minute duration and prevent release of radioactive material to the environment. The staff of the NRC, in cooperation with the National Transportation Safety Board, the National Institute of Standards and Technology, Pacific Northwest National Labs and the Center for Nuclear Waste Regulatory Analysis, have undertaken an analysis to determine the thermal conditions present in the Howard Street tunnel fire, as well as analyze the effects that such a fire would have on a spent fuel transportation cask. This paper describes the analytic models used in the assessment and presents a discussion of the results.

An Analysis of a Spent Fuel Transportation Cask Under Severe Fire Accident Conditions

2002 ◽  
Author(s):  
Christopher S. Bajwa
Keyword(s):  
Nuclear Fuel ◽  
Spent Nuclear Fuel ◽  
Nuclear Regulatory Commission ◽  
Radioactive Material ◽  
Spent Fuel ◽  
Severe Fire ◽  
Tunnel Fire ◽  
Accident Conditions ◽  
Regulatory Commission ◽  
Fire Accident

Title 10 of the Code of Federal Regulations Part 71 section 73(c)(4), (10 CFR 71.73(c)(4)) requires that transportation packages used to ship radioactive material must be designed to resist an engulfing fire of a 30 minute duration and prevent release of radioactive material to the environment. In July, 2001, a derailed train carrying hazardous materials caught fire in a railroad tunnel in Baltimore, Maryland, and burned for several days. Although the occurrence of a fire of such duration during the shipment of spent nuclear fuel is unlikely, questions were raised about the performance of spent nuclear fuel casks under conditions similar to those experienced in the Baltimore tunnel fire incident. The U.S. Nuclear Regulatory Commission evaluates the performance of spent fuel transportation casks under accident conditions. The National Transportation Safety Board is responsible for investigating railroad accidents and identifying the probable cause(s) and offers recommendations for safety improvements. They are currently investigating the Baltimore tunnel fire accident. This paper assesses the performance of a spent fuel transportation cask with a welded canister under severe fire conditions. The paper describes the analytic model used for the assessment and presents a discussion of the preliminary results.

Performance of Spent Fuel Transportation Casks in Severe Tunnel Fires

2006 ◽  
Author(s):  
Earl P. Easton ◽  
Christopher S. Bajwa ◽  
Robert Lewis
Keyword(s):  
Pacific Northwest ◽  
National Laboratory ◽  
Pacific Northwest National Laboratory ◽  
Radioactive Material ◽  
Severe Accident ◽  
Spent Fuel ◽  
Performance Study ◽  
Fire Scenario ◽  
Tunnel Fire ◽  
Accident Conditions

As part of the Nuclear Regulatory Commission's (NRC) overall review of the performance of transportation casks under severe accident conditions, the NRC has undertaken a number of initiatives, including the Package Performance Study (PPS), described in USNRC Package Performance Study Test Protocols, NUREG-1768, which will test full size transportation casks in a severe accident, as well as an examination of the Baltimore tunnel fire of 2001. The final PPS test plan is currently under development by the NRC's Office of Research. The NRC, working with the National Institute of Standards and Technology (NIST), Pacific Northwest National Laboratory (PNNL), and the National Transportation Safety Board (NTSB), performed analyses to predict the response of three different spent fuel transportation cask designs when exposed to a fire similar to that which occurred in the Howard Street railroad tunnel in downtown Baltimore, Maryland on July 18, 2001. NRC Staff evaluated the potential for a release of radioactive material from each of the three transportation casks analyzed for the Baltimore tunnel fire scenario. The results of these analyses are described in detail in Spent Fuel Transportation Package Response to the Baltimore Tunnel Fire Scenario, NUREG/CR-6886, published in draft for comment in November 2005.

Used Nuclear Fuel Transportation Package Seal Performance in Beyond Design Basis Thermal Conditions

2011 ◽  
Author(s):  
Felix Gonzalez ◽  
Christopher Bajwa ◽  
Robert Einziger ◽  
Earl Easton ◽  
Jiann Yang ◽  
...  
Keyword(s):  
Nuclear Fuel ◽  
Spent Nuclear Fuel ◽  
Experimental Testing ◽  
Thermal Conditions ◽  
Nuclear Regulatory Commission ◽  
Pressure Vessels ◽  
Radioactive Material ◽  
Small Scale ◽  
Thermal Testing ◽  
Design Basis

The U.S. Nuclear Regulatory Commission (NRC) is evaluating the performance of seals in used fuel transportation packages during beyond-design-basis fires, similar to the Baltimore tunnel fire that occurred in 2001. The performance of package seals is important for determining the potential for a release of radioactive material from a package during a beyond-design-basis accident. Seals generally have lower temperature limits than other package components and are often part of the containment barrier between the environment and the cask contents. The NRC’s Office of Nuclear Regulatory Research (RES) funded the National Institute of Standards and Technology (NIST) to conduct small-scale thermal testing to obtain experimental data of the performance of seals during beyond-design basis temperature exposures. The experimental testing consisted of several small-scale pressure vessels fabricated with a modified ASME flange design, using commercial grade metallic seals, similar to those that might be used on an actual spent nuclear fuel transportation package. The vessels were heated in an electrical furnace for exposures up to 9 hours (hrs) at temperatures as high as 800°C (1472°F), which far exceeded the rated temperature of the seals in question. This paper will provide a summary of the testing completed as well as the preliminary results and conclusions of the experiments performed by NIST.

Risk Perspectives on Rail Transport of Spent Nuclear Fuel

2008 ◽  
Author(s):  
Christopher S. Bajwa ◽  
Earl P. Easton
Keyword(s):  
Nuclear Fuel ◽  
Spent Nuclear Fuel ◽  
Hazardous Materials ◽  
Nuclear Regulatory Commission ◽  
The United States ◽  
Rail Transport ◽  
Radioactive Material ◽  
Spent Fuel ◽  
Material Transport ◽  
Long Duration

The US Nuclear Regulatory Commission (NRC) has completed a study of historical rail accidents (from 1975 to 2005) involving hazardous materials and long duration fires in the United States. The study was initiated to determine what types of accidents had actually occurred, and what type of impact those types of accidents could have on the rail transport of spent nuclear fuel. The NRC found that almost 21 billion miles of rail shipments has yielded only a small number of accidents involving hazardous materials, eight of which involved both hazardous materials and long duration fires. The NRC reviewed these eight accidents in detail to determine what types of effects these accidents might have on a spent fuel cask, should one have been involved. The staff determined that the fires witnessed in the accidents studied would not have provided a fully engulfing fire environment as described by the hypothetical accident condition fire in NRC regulations for radioactive material transport found in Title 10 of the Code of Federal Regulations, Part 71, Section 73. This paper will detail the NRC study of these accidents and conclusions regarding effects on transportation casks exposed to the fires that resulted from these accidents.

Improvement in Toughness of Transportation and Storage Cask Steel for Spent Nuclear Fuel

2007 ◽  
Author(s):  
Hee Kyung Kwon ◽  
Byoung Koo Kim ◽  
Kuk Cheol Kim ◽  
Keun Ho Song ◽  
Jeong Tae Kim
Keyword(s):  
Heat Treatment ◽  
Low Temperature ◽  
Nuclear Fuel ◽  
Spent Nuclear Fuel ◽  
Radioactive Material ◽  
Low Alloy Steels ◽  
Tempering Temperature ◽  
Impact Properties ◽  
Temperature Impact ◽  
The Impact

Nuclear power plants have been operated for fifty years. Currently the managements of spent fuel are on progress vigorously. Casks for transportation and/or storage of spent nuclear fuel are usually made of SA350 low alloy steels. The wall thickness of the casks are greater than 300mm. But because leakage of nuclear fuel or radioactive material from unexpected brittle fracture is not acceptable, Nil-ductility transition temperatures of colder than −150°F are needed. The effects of chemical composition and heat treatment on low temperature impact properties of SA350 are investigated in this study. The microstructure of SA350 steel is composed of ferrite and pearlite. The variations of microstructure, low temperature impact properties and strength at room temperature with carbon, vanadium and manganese content are analyzed. To improve the low temperature impact properties, heat treatment at an temperature between quenching and tempering temperature is introduced. With the optimum combination of alloying elements and heat treatment, the impact properties can be improved down to the level of nil-ductility transition temperature −150°F.

Spent Nuclear Fuel Transportation Package Seals in Beyond Design Basis Temperature Excursions

2012 ◽  
Author(s):  
Felix Gonzalez ◽  
Christopher Bajwa ◽  
Robert Einziger ◽  
Earl Easton ◽  
Jiann Yang ◽  
...  
Keyword(s):  
Nuclear Fuel ◽  
Spent Nuclear Fuel ◽  
Experimental Testing ◽  
Extreme Temperature ◽  
Nuclear Regulatory Commission ◽  
Pressure Vessels ◽  
Radioactive Material ◽  
Small Scale ◽  
Thermal Testing ◽  
Design Basis

The US Nuclear Regulatory Commission (NRC) is studying the performance of seals in spent nuclear fuel (SNF) transportation packages exposed to fires that could exceed the hypothetical accident condition fire described in Title 10 of the Code of Federal Regulations, Part 71, such as the Baltimore Tunnel Fire that occurred in 2001, or the MacArthur Maze fire that occurred in 2007. The performance of package seals is important for determining the potential for release of radioactive material from a package during a beyond-design-basis accident. Seals generally have lower temperature limits than other package components and are the containment barrier between the environment and the radioactive package contents. The NRC Office of Nuclear Regulatory Research contracted the National Institute of Standards and Technology to conduct small-scale thermal testing to obtain experimental data of the performance of seals during extreme temperature exposures. The experimental testing consisted of several small-scale pressure vessels fabricated with a modified ASME flange design and tested metallic and polymeric seals, similar to those that might be used on an actual SNF transportation package. The vessels were heated in an electrical oven to temperatures as high as 800°C (1472°F), exceeding the rated temperatures of the seals in question. This paper will provide a summary of the testing conducted and present test results and conclusions.

Severe Transportation Accidents: Do Used Nuclear Fuel Transportation Packages Survive Real World Accidents?

2011 ◽  
Author(s):  
Christopher S. Bajwa ◽  
Earl P. Easton ◽  
Harold Adkins ◽  
Judith Cuta ◽  
Nicholas Klymyshyn ◽  
...  
Keyword(s):  
Pacific Northwest ◽  
Nuclear Fuel ◽  
Spent Nuclear Fuel ◽  
National Laboratory ◽  
Pacific Northwest National Laboratory ◽  
Nuclear Regulatory Commission ◽  
Analysis Model ◽  
Element Analysis ◽  
Tanker Truck ◽  
The U.S

In 2007, a severe transportation accident occurred near Oakland, California, on a section of Interstate 880 known as the “MacArthur Maze,” involving a gasoline tanker truck which impacted an overpass support column and burst into flames. The fire caused the collapse of portions of the Interstate 580 overpass onto the remains of the tractor-trailer. The U.S. Nuclear Regulatory Commission, with assistance from Pacific Northwest National Laboratory, the Center for Nuclear Waste Regulatory Analyses, the Southwest Research Institute, and the National Institute of Standards and Technology, examined the accident conditions in order to characterize the fire and collapse that occurred, analyzed material samples from the collapsed I-580 overpass as well as the gasoline tanker truck, and developed a fire model of the accident. This was followed by development of a finite element analysis model to determine the impacts of this accident on the thermal and structural performance of a spent nuclear fuel (SNF) transportation package. The analysis results will be used to determine any potential regulatory implications related to the safe transport of SNF in the U.S. This paper provides a summary of this effort and presents some preliminary results and conclusions.

Potential Effects of Historic Rail Accidents on the Integrity of Spent Nuclear Fuel Transportation Packages

2009 ◽  
Author(s):  
Christopher S. Bajwa ◽  
Earl P. Easton
Keyword(s):  
Nuclear Fuel ◽  
Spent Nuclear Fuel ◽  
Hazardous Materials ◽  
Nuclear Regulatory Commission ◽  
The United States ◽  
Radioactive Material ◽  
Material Transport ◽  
Long Duration ◽  
The Us ◽  
Regulatory Commission

The US Nuclear Regulatory Commission (NRC) completed an analysis of historical rail accidents (from 1975 to 2005) involving hazardous materials and long duration fires in the United States. The analysis was initiated to determine what types of accidents had occurred and what impact those types of accidents could have on the rail transport of spent nuclear fuel. The NRC found that almost 21 billion miles of freight rail shipments over a 30 year period had resulted in a small number of accidents involving the release of hazardous materials, eight of which involved long duration fires. All eight of the accidents analyzed resulted in fires that were less severe than the “fully engulfing fire” described as a hypothetical accident condition in the NRC regulations for radioactive material transport found in Title 10 of the Code of Federal Regulations, Part 71, Section 73. None of the eight accidents involved a release of radioactive material. This paper describes the eight accidents in detail and examines the potential effects on spent nuclear fuel transportation packages exposed to the fires that resulted from these accidents.

Evaluation of CANDU Spent Nuclear Fuel Bundle Structural Integrity During Normal Transport Conditions

2003 ◽  
Author(s):  
Greg Morandin ◽  
Eric Araujo ◽  
David J. Ribbans
Keyword(s):  
Plastic Deformation ◽  
Nuclear Fuel ◽  
Dynamic Load ◽  
Spent Nuclear Fuel ◽  
Spent Fuel ◽  
Shell Elements ◽  
Fuel Bundle ◽  
End Caps ◽  
The Impact ◽  
Transport Tube

The International Atomic Energy Agency requires that the transport of spent nuclear fuel in containers be able to handle certain loads in the axial, lateral and vertical direction under normal off-site handling scenarios. During transport, CANDU nuclear fuel bundles may experience axial impact loads due to possible sliding within a transport tube resulting in impact with the container wall. This paper presents a series of postulated fuel bundle impact scenarios in order to determine the enveloping dynamic g load that a bundle can experience before possible plastic deformation to the bundle fuel sheath. The IAEA load factors for envelope design are used as a reference to ramp the impact velocities and are not equivalent to the dynamic loads used in the analysis. Based on the transportation induced g loads outlined in the IAEA regulations for safe transport of spent fuel under normal handling conditions (IAEA 1985), these g loads are used to calculate a terminal velocity for the bundle whose motion impacts a rigid plate. One type of CANDU nuclear fuel bundle consists of 28 Zircaloy-4 fuel pencils loaded with Uranium Dioxide fuel pellets. The ends of the pencils are fitted with end caps and each end cap is spot welded to a Zircaloy-4 end plate at either end. The finite element model of the fuel bundle consists of 4-noded shell elements representing the fuel sheaths and end plates and 8-noded continuum elements representing the Uranium Dioxide pellets. For the purpose of the analysis, the fuel bundle is housed inside a transport tube, which limits the bundle lateral and vertical motion during impact rebound. The impact target is conservatively modelled as an infinitely rigid plate. Contact surfaces are modelled between the fuel bundle and transport tube, between the fuel bundle and impact plate and between each individual fuel pencil. Two bundle scenarios are considered. The first is a single fuel bundle impacting the plate and the second is two fuel bundles in series in a single transport tube impacting the plate. The second scenario considers the interaction between the two bundles during initial impact and rebound. The analysis covers these scenarios under various magnitudes of applied dynamic loading including 2g, 5g, and 8g. The objective is to determine at what applied load the fuel bundle will experience plastic damage to the fuel pencil sheath. This will effectively provide a bounding g load for CANDU spent fuel transport. The results of the analysis show that for a single bundle in a transport tube, a dynamic load of 8g results in plastic deformation of and the target are modeled using 4-noded shell elements. The pencil end caps are attached to the endplates using an area of common nodes (Fig. 3). Although the actual endcap to endplate connection is through a round spot-welded cross section, for modeling ease the interface is several fuel pencil sheaths. For the two-bundle case, a dynamic load of 8g does not result in any plastic deformation in the fuel pencil sheaths. Thus, a limiting dynamic load between 5g and 8g is determined for the fuel handling scenarios. This paper presents the methodology and models used in the analysis as well as the results of the simulations.

The Impact of Alpha-Radiolysis on the Release of Radionuclides from Spent Fuel in a Geologic Repository

1983 ◽  
Vol 26 ◽  
Author(s):  
Ivars Neretnieks
Keyword(s):  
Nuclear Fuel ◽  
Uranium Oxide ◽  
Spent Nuclear Fuel ◽  
Crystalline Rock ◽  
Reducing Agents ◽  
Spent Fuel ◽  
Geologic Repository ◽  
Oxidizing Agents ◽  
Dissolved Iron ◽  
The Impact

ABSTRACTSpent nuclear fuel buried in deep geologic repositories may eventually be wetted by water. The alfa-radiation will radiolyse the water and produce hydrogen and oxidizing agents, mainly hydrogen peroxide and oxygen. The hydrogen will escape by diffusion and the oxidizing agents may attack the canister materials, oxidize the uranium oxide matrix or diffuse out and oxidize reducing agents in the surrounding rock.The rate of radiolysis has been computed recently within the Swedish nuclear fuel safety projects KBS. It is strongly influenced by the amount of available water and by the presence of dissolved iron. The movement of the oxidizing agents out from the canister and their reaction with the reducing agents (mainly ferrous iron) in the Swedish crystalline rock has been modelled as well as the movement of the radionuclides within and past the redox front. Some substances such as uranium, neptunium and technetium will precipitate at the redox front and will be withdrawn from the water to a considerable extent.

Sign in / Sign up

Export Citation Format

Share Document