A Method for the Coupled Thermal-Structural Analysis of Radioactive Material Shipping Packages in Hypothetical Accident Conditions: Part 1—NCT Thermal Load and Some HAC Mechanical Loads

2010 ◽  
Author(s):  
Tsu-te Wu ◽  
Narendra K. Gupta ◽  
Allen C. Smith ◽  
Paul S. Blanton
Keyword(s):  
Thermal Stresses ◽  
Nuclear Regulatory Commission ◽  
Foot Drop ◽  
Radioactive Material ◽  
Mechanical Loads ◽  
Structural Responses ◽  
Hypothetical Accident ◽  
Accident Conditions ◽  
Regulatory Commission ◽  
Free Drop

The design of radioactive material (RAM) shipping packages are designed to withstand the mechanical and thermal loads specified in Title 10 Code of Federal Regulations Part 71 (10CFR71). The Hypothetical Accident Conditions (HAC) specified in 10CFR71 include a 30-foot free drop, a crush by an 1100-pound plate, a 40-inch free drop onto a round bar and a 30-minite fire. Furthermore, in accordance with the Nuclear Regulatory Commission Guide 7.8, these loads should be applied sequentially. The current common practice is to base the thermal modeling on the un-deformed (or un-damaged) packaging configuration and thermal stresses are neglected in structural analyses. This paper presents a methodology to simulate the coupled thermal and structural responses and to evaluate the accumulated damages caused by both sequentially applied thermal and mechanical loads of the Hypothetical Accident Conditions. Part 1 of the paper discusses the thermal analysis for the Normal Conditions of Transport (NCT) to establish the initial temperatures of the shipping package. It also discusses the subsequent analyses of closure-bolt tightening preload analysis and 30-foot drop analysis.

The Department of Energy Replacement for the 110-Gallon Specification 6M Shipping Container for Radioactive Contents

2008 ◽  
Author(s):  
Jeffrey G. Arbital ◽  
Paul T. Mann
Keyword(s):  
Nuclear Regulatory Commission ◽  
Department Of Energy ◽  
Department Of Transportation ◽  
Safety Requirements ◽  
Shipping Container ◽  
Regulatory Testing ◽  
Hypothetical Accident ◽  
Accident Conditions ◽  
Regulatory Commission ◽  
Energy Replacement

The Department of Energy (DOE) has been shipping university reactor fuels and other fissile materials in the 110-gallon Department of Transportation (DOT) Specification 6M container for over 20 years. The DOT 6M container has been the workhorse for many DOE programs. However, packages designed and used according to the Specification 6M (U. S. Code of Federal Regulations, 49 CFR 178.354; 2003) do not conform to the latest package safety requirements in 10 CFR 71, especially performance under hypothetical accident conditions. For that reason, the 6M specification containers are being terminated by the DOT. Packages designed to the 6M specification will no longer be allowed for in-commerce shipments after October 1, 2008. To meet on-going transportation needs, DOE evaluated several different concepts for replacing the 110-gallon 6M. After this evaluation, DOE selected the Y-12 National Security Complex for the project. The new Y-12 container, designated the ES-4100 shipping container, will have a capacity of four times the current 6M and will be certified by the Nuclear Regulatory Commission (NRC). The ES-4100 project began in September 2006 and prototypes of the new container are now being fabricated. Details on the design features and the upcoming regulatory testing of this new container are discussed in this paper.

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.

scholarly journals Dynamic Analysis of the Bulk Tritium Shipping Package Subjected to Closure Torques and Sequential Impacts

2007 ◽  
Author(s):  
Tsu-Te Wu ◽  
Paul S. Blanton ◽  
Kurt R. Eberl
Keyword(s):  
Finite Element ◽  
Numerical Solutions ◽  
National Laboratory ◽  
Cumulative Damage ◽  
Foot Drop ◽  
Radioactive Material ◽  
Structural Deformations ◽  
Structural Responses ◽  
Accident Conditions ◽  
Element Technique

This paper presents a finite-element technique to simulate the structural responses and to evaluate the cumulative damage of a radioactive material packaging requiring bolt closure-tightening torque and subjected to the scenarios of the Hypothetical Accident Conditions (HAC) defined in the Code of Federal Regulations Title 10 part 71 (10CFR71). Existing finite-element methods for modeling closure stresses from bolt pre-load are not readily adaptable to dynamic analyses. The HAC events are required to occur sequentially per 10CFR71 and thus the evaluation of the cumulative damage is desirable. Generally, each HAC event is analyzed separately and the cumulative damage is partially addressed by superposition. This results in relying on additional physical testing to comply with 10CFR71 requirements for assessment of cumulative damage. The proposed technique utilizes the combination of kinematic constraints, rigid-body motions and structural deformations to overcome some of the difficulties encountered in modeling the effect of cumulative damage. This methodology provides improved numerical solutions in compliance with the 10CFR71 requirements for sequential HAC tests. Analyses were performed for the Bulk Tritium Shipping Package (BTSP) designed by Savannah River National Laboratory to demonstrate the applications of the technique. The methodology proposed simulates the closure bolt torque preload followed by the sequential HAC events, the 30-foot drop and the 30-foot dynamic crush. The analytical results will be compared to the package test data.

An Experimental Study on Head Loss of Prototypical Fibrous Debris Beds During Loss-of-Coolant Accident Conditions

2016 ◽  
Vol 2 (3) ◽  
Author(s):  
Amir Ali ◽  
Edward D. Blandford
Keyword(s):  
Safety Issue ◽  
Nuclear Regulatory Commission ◽  
The United States ◽  
Head Loss ◽  
Pressurized Water Reactor ◽  
Pressurized Water ◽  
Debris Accumulation ◽  
Loss Of Coolant Accident ◽  
Accident Conditions ◽  
Regulatory Commission

The United States Nuclear Regulatory Commission (NRC) initiated a generic safety issue (GSI-191) assessing debris accumulation and resultant chemical effects on pressurized water reactor (PWR) sump performance. GSI-191 has been investigated using reduced-scale separate-effects testing and integral-effects testing facilities. These experiments focused on developing a procedure to generate prototypical debris beds that provide stable and reproducible conventional head loss (CHL). These beds also have the ability to filter out chemical precipitates resulting in chemical head loss. The newly developed procedure presented in this paper is used to generate debris beds with different particulate to fiber ratios (η). Results from this experimental investigation show that the prepared beds can provide reproducible CHL for different η in a single and multivertical loops facility within ±7% under the same flow conditions. The measured CHL values are consistent with the predicted values using the NUREG-6224 correlation. Also, the results showed that the prepared debris beds following the proposed procedure are capable of detecting standard aluminum and calcium precipitates, and the head loss increase (chemical head loss) was measured and reported in this paper.

Design and Analysis of Shipping Container for Big Rock Decommissioned Reactor Vessel

2014 ◽  
Author(s):  
Bruce (Bart) Slimp ◽  
Mick Papp ◽  
Phuong H. Hoang
Keyword(s):  
Structural Analysis ◽  
Base Material ◽  
Reactor Vessel ◽  
Radioactive Material ◽  
Type B ◽  
Shipping Container ◽  
Analysis Methodology ◽  
Maximum Wall Thickness ◽  
Hypothetical Accident ◽  
Accident Conditions

A major milestone in 2003 on the Big Rock Point (BRP) decommissioning project involved shipping the Reactor Vessel (RV) in a steel cask for burial. The Reactor Vessel Transport System (RVTS) cask was a sealed integral container, which provided necessary radiological shielding and containment of radioactive waste for shipping and disposal. The RVTS, using the provisions of the ASME BPVC Section III, Subsection NB, was designed as a Type B package in accordance with the requirements of 10 CFR Part 71. This included meeting Normal Condition of Transport (NCT) and the Hypothetical Accident Conditions (HAC) loading per 10 CFR 71, Regulatory Guide 7.6, “Design Criteria for the Structural Analysis of Shipping Cask Containment Vessels,” Regulatory Guide 7.8, “Load Combinations for the Structural Analysis of Shipping Casks for Radioactive Material” and Regulatory Guide 7.11, “Fracture Toughness Criteria of Base Material for Ferritic Steel Shipping Cask Containment Vessels with a Maximum Wall Thickness of 4 Inches.” The RVTS was designed to withstand accelerations and shocks postulated during highway and rail transit using guidelines from the Association of American Railroads (AAR) and ANSI N14.2. The design analysis methodology, fabrication process and transportation planning for the Big Rock RVTS Cask are presented in this paper.

A Successful Remediation Project

2009 ◽  
Author(s):  
L. Max Scott
Keyword(s):  
Public Relations ◽  
Manufacturing Industry ◽  
Nuclear Regulatory Commission ◽  
Management Plan ◽  
Lessons Learned ◽  
Radioactive Material ◽  
Aircraft Manufacturing ◽  
Molten Magnesium ◽  
Regulatory Commission ◽  
A Site

As part of a program to visit formerly licensed sites to determine if they meet current uncontrolled release conditions, a United States Nuclear Regulatory Commission (USNRC) inspection was conducted in the fall of 1993 at a site that had possessed a radioactive material license from about 1955 to 1970. While the license was in force, the plant processed magnesium scrap containing up to 4 percent thorium. The source of the scrap is believed to be the aircraft manufacturing industry. The scrap was placed in furnaces and heated to the melting point of magnesium, and the molten magnesium was drawn off, leaving the thorium with the residue (dross). Under the regulation in existence at that time, the thorium dross was buried on site in an approximate 14 acre field. In 1993 the inspector found readings up to 900uR/h. Early in 1994 an informal grid survey of most of the 14 acre site was conducted. Based on that survey, it was concluded that the thorium was widespread and extended beyond the property lines. The preliminary findings were reported to the USNRC, and in 1994 the site was designated as a Site Decommissioning Management Plan (SMPD) site. A remediation team was formed which included the following disciplines: remediation health physics, geology, hydrology, engineering, law, public relations, and project management. This remediation team planned, participated in selecting vendors, and provided project over site for all activities from site characterization through the final status survey. In 2006 the site was released for uncontrolled access. A chronology of activities with lessons learned will be presented.

Licensing of the ES-3100 Type B Shipping Container: Replacement of the DOT 6M Container

2005 ◽  
Author(s):  
Jeffrey G. Arbital ◽  
Dean R. Tousley ◽  
James C. Anderson
Keyword(s):  
State Of The Art ◽  
Nuclear Regulatory Commission ◽  
Department Of Energy ◽  
Radioactive Material ◽  
Shipping Container ◽  
Nuclear Security ◽  
Material Transportation ◽  
Enriched Uranium ◽  
Regulatory Commission ◽  
The U.S

The National Nuclear Security Administration (NNSA) is shipping bulk quantities of fissile materials for disposition purposes, primarily highly enriched uranium (HEU), over the next 15 to 20 years. The U.S. Department of Transportation (DOT) specification 6M container has been the workhorse for NNSA and many other shippers of radioactive material. However, the 6M does not conform to the safety requirements in the Code of Federal Regulations (10 CFR 71[1]) and, for that reason, is being phased out for use in the secure transportation system of the U.S. Department of Energy (DOE) in early 2006. BWXT Y-12 is currently developing the replacement for the DOT 6M container for NNSA and other users. The new package is based on state-of-the-art, proven, and patented technologies that have been successfully applied in the design of other packages. The new package will have a 50% greater capacity for HEU than the 6M, and it will be easier to use with a state-of-the-art closure system on the containment vessel. This new package is extremely important to the future of fissile, radioactive material transportation. An application for license was submitted to the U.S. Nuclear Regulatory Commission (NRC) in February 2005. This paper reviews the license submittal, the licensing process, and the proposed contents of this new state-of-the-art shipping container.

Justification for Elevated Hydrogen Limits in Risk-Based Radioactive Waste Packages

2005 ◽  
Author(s):  
Russell Wagner
Keyword(s):  
Nuclear Regulatory Commission ◽  
Department Of Energy ◽  
Radioactive Material ◽  
Transportation Safety ◽  
Elevated Concentration ◽  
Type B ◽  
Hanford Site ◽  
Regulatory Commission ◽  
Concentration Limits ◽  
The U.S

The U.S. Nuclear Regulatory Commission (NRC) has provided set guidance that hydrogen concentrations in radioactive material packages be limited to 5 vol% unless the package is designed to withstand a bounding hydrogen deflagration or detonation. The NRC guidance further specifies that the expected shipping time for a package be limited to one-half the time to reach 5 vol% hydrogen. This guidance has presented logistical problems for transport of retrieved legacy waste packages on the Department of Energy (DOE) Hanford Site that frequently contain greater than 5 vol% hydrogen due to their age and the lack of venting requirements at the time they were generated. Such packages do not meet the performance-based criteria for Type B packaging, and are considered risk-based packages. Duratek Technical Services (Duratek) has researched the true risk of hydrogen deflagration and detonation with closed packages, and has developed technical justification for elevated concentration limits of up to 15 vol% hydrogen in risk-based packages when transport is limited to the confines of the Hanford Site. Duratek has presented elevated hydrogen limit justification to the DOE Richland Operations Office and is awaiting approval for incorporation into the Hanford Site Transportation Safety Document. This paper details the technical justification methodology for the elevated hydrogen limits.

Field Experience With Code Case N-659: Ultrasonic Examination in Lieu of Radiography

2007 ◽  
Author(s):  
Douglas O. Henry
Keyword(s):  
Nuclear Power ◽  
Cost Benefit ◽  
Nuclear Regulatory Commission ◽  
Radioactive Material ◽  
Material Transport ◽  
Ultrasonic Examination ◽  
Key Factor ◽  
Asme Code ◽  
Regulatory Commission ◽  
Sample Set

Code Case N-659 Revision 0 was approved in 2002 to allow ultrasonic examination (UT) an alternative to radiography (RT) for nuclear power plant components and transport containers under Section III of the ASME Code. The Nuclear Regulatory Commission has not approved N-659 and its subsequent revisions (currently N-659-2) for general use, but they have been used on a case-by-case basis mainly where logistic problems or component configuration have prevented the use of radiography. Like the parallel Code Case 2235 for non-nuclear applications under Section I and Section VIII, Code Case N-659 requires automated, computerized ultrasonic systems and capability demonstration on a flawed sample as a prerequisite for using UT in lieu of RT. Automated ultrasonic examination can be significantly more expensive than radiography, so a cost-benefit evaluation is a key factor in the decision to use the Code Case. In addition, the flaw sample set has recently become an issue and a topic of negotiation with the NRC for application of the Case. A flaw sample set for a recent radioactive material transport cask fabrication project was successfully negotiated with the NRC. The Code Case N-659 approach has been used effectively to overcome barriers to Code required radiography. Examples are examination of welds in an assembled heat exchanger and in a radioactive material transport cask assembly where internal shielding prevented radiography of the weld. Future development of Code Case N-659 will address sample set considerations and application-specific Code Cases, such as for storage and transport containers, will be developed where NRC concerns have been fully addressed and regulatory approval can be obtained on a generic basis.

Severe Transportation Accidents: Impacts of Severe Fires on Radioactive Material Transportation

2009 ◽  
Author(s):  
Christopher S. Bajwa ◽  
Earl P. Easton ◽  
Darrell S. Dunn
Keyword(s):  
Spent Nuclear Fuel ◽  
Nuclear Regulatory Commission ◽  
Radioactive Material ◽  
Fire Investigation ◽  
Radioactive Materials ◽  
The Us ◽  
Material Transportation ◽  
Safe Transport ◽  
Regulatory Commission ◽  
Loss Of Strength

In 2007, a severe transportation accident occurred in Oakland, California in what is commonly known as the “MacArthur Maze” section of Interstate 580 (I-580). The accident involved a tractor trailer carrying gasoline that impacted an overpass support column and burst into flames. The subsequent fire burned for over 2 hours and led to the collapse of the overpass due to the loss of strength in the structural steel that supported the overpass. The US Nuclear Regulatory Commission (NRC) studied this accident to examine any potential regulatory implications related to the safe transport of radioactive materials, including spent nuclear fuel. This paper will discuss the details of the NRC’s MacArthur Maze fire investigation.

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