Research and Development Program for transportation packagings at Sandia National Laboratories

This document contains information about the research and development programs dealing with waste transport at Sandia National Laboratories. This paper discusses topics such as: Why new packaging is needed; analytical methodologies and design codes;evaluation of packaging components; materials characterization; creative packaging concepts; packaging engineering and analysis; testing; and certification support

Estimates of fire environments in ship holds containing radioactive material packages

Fire environments that occur on cargo ships differ significantly from the fire environments found in land transport. Cargo ships typically carry a large amount of flammable fuel for propulsion and shipboard power, and may transport large quantities of flammable cargo. As a result, sea mode transport accident records contain instances of long lasting and intense fires. Since Irradiated Nuclear Fuel (INF) casks are not carried on tankers with large flammable cargoes, most of these dramatic, long burning fires are not relevant threats, and transport studies must concentrate on those fires that are most likely to occur. By regulation, INF casks must be separated from flammable cargoes by a fire-resistant, liquid-tight partition. This makes a fire in an adjacent ship hold the most likely fire threat. The large size of a cargo ship relative to any spent nuclear fuel casks on board, however, may permit a severe, long lasting fire to occur with little or no thermal impact on the casks. Although some flammable materials such as shipping boxes or container floors may exist in the same hold with the cask, the amount of fuel available may not provide a significant threat to the massive transport casks used for radioactive materials. This shipboard fire situation differs significantly from the regulatory conditions specified in 10 CFR 71 for a fully engulfing pool fire. To learn more about the differences, a series of simple thermal analyses has been completed to estimate cask behavior in likely marine and land thermal accident situations. While the calculations are based on several conservative assumptions, and are only preliminary, they illustrate that casks are likely to heat much more slowly in shipboard hold fires than in an open pool fire. The calculations also reinforce the basic regulatory concept that for radioactive materials, the shipping cask, not the ship, is the primary protection barrier to consider

Convective effects in a regulatory and proposed fire model

Radiation is the dominant mode of heat transfer in large fires. However, convection can be as much as 10 to 20 percent of the total heat transfer to an object in a large fire. The current radioactive material transportation packaging regulations include convection as a mode of heat transfer in the accident condition scenario. The current International Atomic Energy Agency Safety Series 6 packaging regulation states ``the convection coefficient shall be that value which the designer can justify if the package were exposed to the specified fire``. The current Title 10, Code of Federal Regulations, Part 71 (10CFR71) packaging regulation states ``when significant, convection heat input must be included on the basis of still, ambient air at 800{degrees}C (1475{degrees}F)``. Two questions that can arise in an analysts mind from an examination of the packaging regulations is whether convection is significant and whether convection should be included in the design analysis of a radioactive materials transportation container. The objective of this study is to examine the convective effects on an actual radioactive materials transportation package using a regulatory and a proposed thermal boundary condition

Determination of spring modulus for several types of elastomeric materials (O-rings) and establishment of an open database for seals

Seals that provide the containment system interface between the packaging body and closure must function in high and low temperature environments, under dynamic and static loading conditions, and with different types of contained media. It is one of the most critical elements in the container since the container fails to meet regulations if the seal does not function properly. A research and testing program for seal materials was initiated at Sandia in 1988 with the goal of characterizing the behavior of seal materials commonly used in packages conditions as specified in the regulations (NRC IOCFR Part 71) and American National Standards Institute (ANSI) 14.5. The performance of elastomeric seals in undeformed closures at both high and low temperatures has been investigated (Bronowski 1995). Work has begun with this program to determine the response of elastomeric seals to fast acting dynamic deformations`` in the closure. The response of elastomeric o-ring seals during closure movements due to long-term deformations has already been characterized. What has not been well characterized are short-term closure movements with durations of only a few milliseconds that result in the so called ``burp`` release. Methods for generating this type of response in a repeatable manner had not been developed and standard leak detection equipment does not have a fast enough response time to measure these transient events. One factor which affects the length of the burp is the ability of the o-ring to quickly close the gap to prevent a significant leak. The dynamic characteristics of the elastomeric o-ring material including the dynamic spring modulus and internal damping are directly related to its ability to quickly close the gap. A set of tests designed to determine the dynamic properties for various material types and durometers (hardness) of elastomers that were both lubricated and dry at ambient temperature were conducted

Impact limiter tests of four commonly used materials and establishment of an impact limiter data base

In designing a package for transporting hazardous or radioactive materials, there are a number of components whose design can lead to the success or failure to meet regulatory requirements for Type B packages. One of these components is the impact limiter. The primary purpose of the impact limiter is to protect the package and its contents from sudden deceleration. It can also act as a thermal barrier. The package is protected by the impact limiter`s ability to act as an energy absorber. The crush strength of most impact limiting materials is determined by a standard quasistatic (QS) method. However it has been observed that there are a number of factors that affect crush strength. The material being used as an impact limiter may appear incompressible because of one or more of these factors. Factors that determine compressive strength of impact limiter materials are; the material density; the thickness of the impact limiter material. There must be adequate material to absorb the impact and not go into lockup, lockup up occurs when the free volume of the material is eliminated and the crush strength sharply increases; the angle of impact; and the loading rate and operating temperature. All of these are interactive and therefore difficult to model. It is the intent of tests discussed in this paper to determine the dependency of crush strength to loading rate and angle of impact to the basic grain direction of two different densities of four impact limiting materials

Experimental ship fire measurements with simulated radioactive cargo

Results from a series of eight test fires ranging in size from 2.2 to 18.8 MW conducted aboard the Coast Guard fire test ship Mayo Lykes at Mobile, Alabama are presented and discussed. Tests aboard the break bulk type cargo ship consisted of heptane spray fires simulating engine room and galley fires, wood crib fires simulating cargo hold fires, and pool fires staged for comparison to land based regulatory fire results. Primary instrumentation for the tests consisted of two pipe calorimeters that simulated a typical package shape for radioactive materials packages