FINAL REPORT 

US. Department of Transportation 

Research and Special Programs Administration 

John A. Volpe National Transportation Systems Center 

IDENTIFICATION OF FACTORS FOR 

SELECTING MODES AND ROUTES 

FOR SHIPPING HIGH-LEVEL 

RADIOACTIVE WASTE AND SPENT 

NUCLEAR FUEL 

April 1998 

Prepared By 

Environmental Engineering Division 

John A. Volpe National Transportation Systems Center 

Research and Special Programs Administration 

U.S. Department of Transportation 

Cambridge, Massachusetts ,,* 

Prepared For 

OfJice of Hazardous Materials Safety 

Research and Special Programs Administration 

U.S. Department of Transportation 

Washington, DC 
PREFACE 

This report was prepared in response to the requirements of Section 15 of the Hazardous 

Materials Transportation Uniform Safety Act of 1990 (HMTUSA) (49 U. S . C. 85 lO5(d) 

(1994)). The report identifies and evaluates the primary factors that should be considered by 

shippers and carriers in selecting the modes and routes for the transport of high-level 

radioactive waste and spent nuclear fuel in order to enhance overall public safety. 

The report was prepared by the U.S. Department of Transportation (DOT), Research and 

Special Programs Administration (RSPA), Volpe National Transportation Systems Center 

(Volpe Center). The report drew upon work performed under contract by the Battelle 

Cambridge Office, Cambridge, MA; Abkowitz and Associates, Inc., Nashville, TN; and 

Technology and Management Systems, Inc., Burlington, MA. 

This report was prepared for the Office of Hazardous Materials Safety, RSPA, DOT. 

iii 
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EXECUTIVE SUMMARY 

Section 15 of the Hazardous Materials Transportation Uniform Safety Act of 1990 (see 49 

U.S.C. Section 5 lO5(d)(l994)) requires the U.S. Department of Transportation (DOT) to 

conduct a study: 

"To decide which safety factors, if any, shippers and carriers should consider when 

selecting routes and modes that would enhance overall public safety related to the 

transportation of high-level radioactive waste and spent nuclear fuel." 

The Act also requires that DOT evaluate the degree to which each factor affects overall public 

safety in the transport of these materials. This report documents the results of the study. 

APPROACH. To identify and evaluate the safety factors requiring consideration, the study 

examined the risks associated with: 1) incident-flee radiological exposure--the exposure to 

low levels of radiation that normally occur as a result of the transport of radioactive materials, 

2) accident-related radiological exposure--the radiation exposure attributable to accidents that 

result in releases of radioactive materials, and 3) non-radiological consequences of accidents-- 

the fatalities, property damage, and other non-radiological consequences that result from 

accidents involving the transport of nuclear materials. 

Two distinct methodologies were used to identify the mode and route factors: (1) hierarchical 

analysis and (2) mathematical modeling of risk. The hierarchical analysis, drawing upon 

expertise of a 14-member technical advisory group, identified primary mode and route factors 

by first developing and ranking a comprehensive set of 82 safety factors. These factors were 

then screened to yield a set of eight primary factors. The mathematical modeling of risk 

allowed the identification of primary factors by establishing the relationships that affect nuclear 

transportation risk. The primary factors dominating the risk models were a subset of the 

primary mode/route selection factors found by the hierarchical analysis. A case study analysis 

was used to evaluate the variability of the primary mode and route factors identified by these 

two methodologies. 

The final set of eight primary safety factors were general population exposed, occupational 

population exposed, sensitive environment exposed, trip length, shipment duration, accident 

rate, emergency response, and quantity of material shipped. These primary factors were 

evaluated for five transportation options: 1) truck transport, 2) regular freight trains, 3) 

dedicated trains, 4) water transport, and 5) water-rail intermodal movements. The study 

considered the risk to the general public near loading and unloading facilities and along 

transportation routes, and to transportation personnel who handle radioactive materials or 

operate the equipment used to transport the materials. 

KEY FINDINGS. Radiation Risk Is Low. In the case study analysis, risks were estimated 

for 65 modelroute combinations between 8 generic originldestination pairs. For each of the 65 

trips, the projected amount of radiation risk, both to workers and the general public, was very 

low. In terms of non-incident radiation, risk for a complete trip ranged from about 0.04 
millirems to 172 millirems for any one individual crew member, the population category 

generally at highest risk. These exposure levels are well below current regulatory limits for 

occupational exposure of 5,000 millirems for an individual in any twelve month period, as 

well as below the guideline currently recommended by the International Atomic Energy 

Agency (IAEA) of 2,000 millirems in any twelve month period. Non-incident radiation risks 

to the general public were similarly low, with amounts for the 65 case study trips ranging from 

2 to 218 millirems for total public exposure. On average, no single individual received more 

than a fraction of a millirem on any given trip, and those levels are well within the presently 

contemplated Federal guidance of 100 millirems per year for any one member of the general 

public. 

In terms of accident-related radiation, the total per-trip risks ranged from less than 0.1 % to 

35 % as large as non-incident radiation exposure levels, due to the extremely low probability of 

a release. Within this range, the average accident-related radiation level for the 65 trips was 

only 3 % as large as the non-incident radiation. 

Most Primary Safety Factor Values Vary Si@icantly. For most of the primary safety 

factors, including general and occupational population exposure, accident rates and shipment 

duration, the values varied considerably among the available mode and route options. For 

other primary factors, the values varied much less from option to option or could not be 

explicitly quantified. The sizeable variation in most primary safety factor values, however, 

indicates that shippers and carriers can affect shipment risks through selection of mode and 

route. 

Shipment Duration Is The Most Significant Safety Factor. Among all the safety factors, 

the most important in determining the risk for a given shipment option was shipment duration. 

The total time it takes to move a shipment from origin to destination affects non-incident 

radiation exposure levels, and the group most affected by this safety factor is transport 

personnel. 

Amount to Be Shipped May Affect Mode Choice, Number of Trips, and Total Risk. The 

much larger capacity of casks that can be carried by rail and barge and the potential for multicask shipments in a single railroad or barge movement mean that a shipment campaign by rail 

or barge will typically require fewer trips than the same campaign by truck. While multiple 

trips by motor vehicle may in some instances result in lower risk than a rail movement, fewer 

trips usually reduce total risk by reducing the risks associated with incident-free radiation, 

accident-related radiation, and non-radiation accident consequences. 
OVERVIEW 

As directed by Congress in Section 15 of the Hazardous Materials Transportation Uniform 

Safety Act of 1990 (HMTUSA) (now codified as 49 U.S.C. §5105(d)), the U.S. Department 

of Transportation (DOT) has conducted a study of mode and route selection factors for 

shipments of high-level radioactive waste and spent nuclear fuel. 

HMTUSA required DOT "To decide which safety factors, if any, shippers and carriers should 

consider when selecting routes and modes that would enhance overall public safety related to 

the transportation of high-level radioactive waste and spent fuel." Furthermore, the Act 

required that the study assess the degree to which each factor affects the overall public safety 

of this transportation. 

This report documents the results of that study. 

SCOPE, FOCUS, AND APPROACH 

Scope. The scope of the study was established by defining "public safety" to encompass the 

risk associated with 

Incident-free radiological exposure--Exposure of the general population and 

transportation workers that occurs as a normal result of the transportation of 

radioactive materials. 

Accident-induced radiological exposure--Exposure of the general population and 

transportation workers that occurs as a result of an accidental release of radioactive 

material. A vehicle, rail car, or vessel accident would be the presumed cause, but a 

handling incident is also possible. 

Non-radiological conseauences of accidents--Accident-related consequences (e.g., 

injuries, deaths, property damage, etc.) that are not attributable to exposure to 

radiation. 

These three categories of risk were considered in the study for the purpose of identifying and 

evaluating mode and route selection factors. All affected populations, including people near 

the route and transportation and related workers, were considered. [Section 1.31 

Focus. The focus of the Mode and Route study was on safety and on the selection factors that 

should be considered by shippers and carriers. Economic considerations were not explicitly 

considered in the analysis, nor were factors that were more appropriately the purview of state 

and local governments. [Section 1.11 

Approach. The mode and route selection factors that would enhance overall public safety of 

the transport of spent nuclear fuel were identified by (1) defining the problem (see Chapter I), 

(2) examining current mode/route selection practices relative to the transport of all 

vii 
commodities and of hazardous materials, including spent nuclear fuel (see Chapter 2), (3) 

developing a comprehensive list of candidate factors (see Chapter 3), (4) determining primary 

factors via hierarchical analysis of the candidate factors (see Chapter 4), (5) using risk 

modeling as an alternative method for identifying the primary factors (see Chapter 3, and (6) 

using case study analysis to extend the risk modeling effort in order to evaluate the 

relationships between primary factors and public safety (see Chapter 6). An overall 

assessment of the identified primary mode and route selection factors concludes the analysis 

(see Chapter 7). [Section 1.21 

= SUMMARY OF FINDINGS 

Assessment of the primary factors concluded that the most significant findings of the study 

were 

The values for most primary factors vary considerably across the mode and route 

options available to shippers and carriers. [Section 7.11 

Incident-free radiological risk is expected to be much more important than accident 

related risks. [Section 7.1) 

The amount of spent nuclear fuel to be shipped can affect the number of trips and 

thereby impact the total risk. [Section 7.1) 

Additional findings included 

Mode and route selection factors are not generally separable. With very few 

exceptions-- amount of material to be shipped being the most notable--they must be 

considered together. [Section 7.11 

Trip duration is the major factor affecting incident-free radiological risk. [Section 7.11 

The ability to measure and the ease of gathering the necessary data for most of the eight 

primary factors are very good. [Sections 7.2 and 7.3; also, see Section 4.3) 

= CURRENT PRACTICES 

To provide necessary information and perspective on the transport of spent nuclear fuel, the 

study examined (1) the current and expected future levels of spent nuclear fuel transported and 

(2) current industry practices for selecting modes and routes. [Chapters 1 and 21 

Spent Nuclear Fuel Transported. Currently, relatively few shipments of spent nuclear fuel 

are moved annually in the U.S. Some shipments are intra-utility transfers from one generating 

plant to another, while other movements are to away-from-reactor storage facilities. On 

average, approximately 100 shipments of various sizes were made per year between 1979 and 

1995, inclusive. Federal efforts to establish storage facilities for spent nuclear fuel should 

viii 
eventually increase the number of shipments several fold, with the annual number of spent fuel 

shipments increasing to over 400 per year. [Section 1.41 

Current Industry Practices. Because many overlaps exist, practices relating to general 

commodities and to hazardous materials (including spent nuclear fuel) were both considered. 

[Chapter 21 

For general commodities and most hazardous materials, mode choice decisions are usually 

made by the shipper. These decisions tend to focus on price and on service attributes, such as 

convenience and availability. Once mode choice has been made, the choice of routes is limited 

to those that are available to that mode, and the selection is generally made by the carrier to 

coincide with the routes it most heavily travels. Except where precluded by law or regulation, 

the carriers make their routing decisions on the basis of operational efficiency. [Sections 2.1, 

2.2, and 2.31 

For the transport of spent nuclear fuel, safety is an extremely important consideration. 

Accordingly, the transportation casks used for the movement of commercial spent nuclear fuel 

are, by law, designed to the most stringent packaging standards in transport use today. The 

cask design helps reduce much of the risk associated with the transport of the material. To 

further reduce risks and ensure safety, mode and route choice is made as a group decision 

involving, shippers, carriers, and government officials. 

= IDENTIFICATION OF MODE AND ROUTE SELECTION FACTORS 

A comprehensive list of mode and route selection factors was compiled through literature 

research, review of existing laws and regulations, and from the judgements of a Technical 

Advisory Group (TAG). This TAG was composed of representatives from carriers, shippers, 

government organizations, and public interest groups. [Section 3.11 

The literature consulted in compiling the comprehensive list of factors included routing 

guideline documents developed previously by DOT for use by state and local governments, the 

Canadian route screening guidelines for dangerous goods by truck [Section 3.21, as well as a 

wide variety of modal studies, routing studies/evaluations, risk assessments, environmental 

assessments, and general hazardous materials transportation studies. [Section 3.4 and 

Appendix C] The laws consulted in the search for mode and route selection factors included 

Sections 4 and 15 of HMTUSA. [Section 3.31 

A comprehensive list of 82 candidate mode and route selection factors was compiled. These 

factors, which were considered to be directly or indirectly related to transportation safety, fell 

into eight general categories: (1) Population and Environment, (2) Transportation 

Infrastructure and Utilization, (3) Operating Procedures, (4) Emergency Response, (5) Quality 

Control, (6) WeatherIClimate TerrainIConditions, (7) Shipment Characteristics, and (8) 

Regulation and Other Restrictions. [Section 3.5 and Exhibit 61 
= QUALITATIVE EVALUATION OF FACTORS 

The 82 candidate mode and route selection factors were screened and evaluated to identify 

those factors that are the primary determinants of transport risks. [Chapter 41 

Initial screenings of the candidate factors were performed by the project team and by the TAG 

convened for this study. These screenings included consideration of (1) the candidates' 

relationship to the project's definition of public safety, (2) their impact on mode or route 

choice, (3) their interdependencies, and (4) their ability to be measured and applied. During 

the screenings, it was noted that three candidate factors were exclusively related to mode: (1) 

mode accessibility, (2) cask availability, and (3) amount of material to be shipped. All of the 

rest were related to mode and route in combination. There were no factors that were 

exclusively related to route. [Section 4.11 

After the initial screenings were completed, a hierarchical analysis was performed in which the 

candidate factors were characterized and ranked, and those factors subsumed by others were 

identified. 

In performing the hierarchical analysis, primary factors were identified separately for (1) 

incident-free radiological exposure, (2) accident-induced radiological exposure, and (3) nonradiological impact. These were then combined to create the full set of primary factors 

[Section 4.21, which, along with illustrative units of measure, is presented in the following 

table. 

Primary Mode and/or Route Selection Factors 

Prirnarv Factor Illustrative Unit of Measure 

General population exposed 

Occupational population exposed 

Sensitive environment exposed 

Shipment duration 

Accident rate 

Trip length 

Emergency response 

Amount of material to be shipped 

Nearby persons per unit area 

Number of crew, others 

Number of sensitive areas, etc. 

Overall time including stops 

Accidentslunit distance 

Distance 

Tie or distance to qualified responders 

Cask shipments required 

Further review of these primary factors found that the ability to measure most of them is good. 

Widely accepted analytical measures for sensitive environment exposed and emergency 

response do not currently exist, making these factors somewhat more difficult to use in a 

quantitative risk assessment than the other factors. [Section 4.31 
= MODELING THE RISK 

In addition to hierarchical analysis, a risk modeling approach was developed to independently 

identify primary mode and route factors. Three mode-specific risk models were derived: (1) 

an incident-free radiological risk model, (2) an accident-induced radiological risk model, and 

(3) a non-radiological risk model. Because of the way these models were specified, the set of 

possible independent variables that could be used in the models did not include some of the 

primary factors found by the hierarchical analysis. [Sections 5.1, 5.2, and 5.31 

The results of the risk modeling exercise corresponded quite well with the results of the 

hierarchical analysis. The risk models identified (1) general population, (2) occupational 

population, (3) accident rate, (4) trip length (distance travelled), and (5) shipment duration as 

primary risk factors, all of which were identified by the hierarchical analysis. [Section 5.31 

= CASE STUDY ANALYSIS 

A case study exercise was conducted to examine the risks of transporting radioactive material 

between representative originldestination (OID) pairs by various modes over realistic routes. 

This exercise explored the variability of the identified primary selection factors and of the 

risks across modes and routes. If factor values and risks vary substantially, then that is an 

indication that risks can indeed be moderated through the choice of mode andlor route. 

[Chapter 61 

The case study considered transport between eight generic OID pairs. The modes of 

transportation considered were highway, rail (using both regular and dedicated trains), water, 

and intermodal (waterlrail). In all, risks were estimated for 65 modelroute combinations 

between the OID pairs, using primary factors to characterize the safety of these transport 

alternatives. The modelroute combinations included short, medium, and long distance 

shipments. The shorter distance shipments were included to represent intra- and inter-utility 

shipments, while the longer distance shipments were included to represent movements to 

interim or long-term storage facilities. HazTransl, a routing and risk management computer 

program, was used to derive the primary factor values and non-radiological risks for the case 

study exercise. The Radtran 4 model2, a computer program that evaluates the radiological 

consequences of incident-free transportation and the radiological risks caused by vehicular 

accidents occurring during transportation, was used to calculate the radiological risks based on 

HazTrans inputs. [Section 6.11 

Case study estimates for all three elements of risk (incident-free radiological risk, accidentinduced radiological risk, and non-radiological risk) were found to vary substantially across 

modes, routes, and OIDs, indicating that the selection of mode and route can moderate risk. 

[Section 6.21 

'HazTrans is a registered trademark of Abkowitz & Associates, Inc., Nashville, Tennessee. 

'Radtran 4 was developed by Sandia National Laboratory for the U.S. Department of Energy. 
The case study inputs and outputs were used to estimate values for the coefficients for the risk 

models developed for this study. [Section 6.31 A sensitivity analysis was conducted to 

determine the influence of each of the primary factors on radiological risks for each mode. 

Trip duration--the total time that a shipment took from start to finish--was found to have the 

largest effect on incident-free radiological risk. Accident rate, trip length, and general 

population exposure (number of people exposed) were the dominant factors when considering 

accident-induced radiological risk for highway and rail. [Section 6.41 

The case study estimates of risks per shipment were adjusted for modal cask capacity in order 

to examine the influence that the amount of material to be shipped can have on transport 

choices for a shippin? campaign, that is, for multiple shipments from one site. It was found 

that the total amount of material to be shipped in a campaign was a primary determinant of the 

mode with the lowest risk. This is because with a shipping campaign, using larger raillbarge 

casks, if practicable, rather than truck casks, can reduce the number of shipments that must be 

made, and, consequently, lower the overall risk of the transport. [Section 6.61 

xii 
TABLE OF CONTENTS 

Section 

Preface ................................................. . 

Executive Summary ......................................... 

I 

Overview ................................................ 

, List of Exhibits ............................................ 

Acronyms ............................................... 

I 1 . Introduction ........................................... 

1.1 Purpose and Role of This Study ......................... 1.2 Study Approach .................................... 1.3 Definition of Overall Public Safety ....................... 1.4 Spent Nuclear Fuel Transport ........................... 

I 

I 2 . Overview of Mode and Route Selection Practices ................... 

~ 2.1 General Mode and Route Selection Practices for All Commodities ... 

2.1.1 General Mode Selection Practices ................. 2; 1.2 General Route Selection Practices ................. 

1 2.2 Overview of Mode and Route Selection for Hazardous Materials .... 

vii 

xvii 

xix 

2.2.1 Mode Selection for Hazardous Materials ............. 2-5 

2.2.2 Route Selection for Hazardous Materials ............. 2-5 

2.3 Overview of Regulations Affecting Mode and Route Selection ...... 2-7 

2.3.1 Regulation of Mode and Route Selection for 

Non-Hazardous Materials ....................... 2-7 

2.3.2 Regulation of Mode and Route Selection for 

Hazardous Materials .......................... 2-8 

3 . Identification of Candidate Mode and Route Factors ................. 3-1 

3.1 Enumeration of Factors ............................... 3-1 

3.2 Guidelines for Routing Hazardous Materials ................. 3-1 

xiii 
TABLE OF CONTENTS (CONTINUED) 

Section 

3.2.1 DOT Hazardous Materials Routing Guidelines ......... 3.2.2 DOT Routing Guidelines for Highway Route Controlled 

Quantity Shipments of Radioactive Materials .......... 3.2.3 Canadian Route Screening Guidelines for 

Dangerous Goods by Truck ..................... 

3.3 Candidate Mode and Route Factors Identified in HMTUSA ........ 3.4 Candidate Mode and Route Factors Identified in the Literature ...... 3.5 Comprehensive List of Candidate Factors ................... 

4 . Qualitative Evaluation of Candidate Factors and Selection of Primary 

Mode and Route Factors .................................. 

4.1 Screening of Comprehensive List of Factors ................. 

4.1.1 Technical Advisory Group ...................... 4.1.2 TAG Meeting and Review of Factors ............... 4.1.3 Distinction Between Mode and Route Factors .......... 

4.2 Development of Factor Hierarchy ........................ 

4.2.1 Hierarchical Approach to Mode and Route Factors ...... 4.2.2 Hierarchy for Incident-Free Radiological Exposure ...... 4.2.3 Hierarchy for Accident-Induced Radiological Exposure ... 4.2.4 Hierarchy for Non-Radiological Impact .............. 

4.3 Identification of Primary Factors ......................... 4.4 Representative Units of Measure for the Primary Factors ......... 

5 . Identification of Primary Mode and Route Factors by Modeling 

Risk of Transporting Radioactive Materials ...................... 

5.1 Elements of Risk ................................... 5.2 Model Development ................................. 

5.2.1 Incident-Free Radiological Risk Model .............. 5.2.2 Accident-Induced Radiological Risk Model ........... 5.2.3 Non-Radiological Risk Model .................... 

5.3 Relationship of Risk Modeling to ModeIRoute Factors ........... 

Page 

3-2 

3-3 

3-5 

3-6 

3-7 

3-9 

4-1 

4-1 

4-1 

4-2 

4-4 

4-5 

4-5 

4-6 

4-8 

4-10 

4-11 

4-13 

5-1 

5-1 

5-1 

5-2 

5-5 

5-6 

5-6 

xiv 
TABLE OF CONTENTS (CONTINUED) 

Section 

6 . Case Study and Analysis of Factors ........................... 

6.1 Development of Analysis Framework ...................... 

6.1.1 Selection of Sample Routes ..................... 6.1.2 Data Collection ............................. 6.1.3 Development of Primary Factor Values .............. 6.1.4 Development of Risk Values Using Radtran 4 ......... 

6.2 Case Study Results .................................. 

6.2.1 Estimates of Non-Radiological Risk ................ 6.2.2 Estimates of Radiological Risk ................... 

6.3 Variability of Primary ModeIRoute Factors 

and Risk Values .................................... 

6.3.1 Variation in Primary Factor Values ................ 6.3.2 Variation in Risk Values ....................... 

6.4 Radiological Risk Model Estimation ....................... 6.5 Sensitivity Analysis ................................. 6.6 Emergency Response ................................ 6.7 Shipping Campaigns ................................. 6.8 Case Study Analysis Summary .......................... 

6.8.1 Ease of Developing Primary Factor and Risk Values ..... 6.8.2 Variations in Primary Factor Values and Risk Estimates ... 6.8.3 Interaction of Primary Factors and Risks ............. 

7 . Overall Assessment of Primary ModeIRoute Selection Factors .......... 

7.1 Summary of Identification and Selection of 

Primary ModeIRoute Factors ........................... 7.2 Evaluation of Primary ModeIRoute Factors .................. 

7.2.1 General Population Exposed ..................... 7.2.2 Occupational Population Exposed ................. 7.2.3 Shipment Duration ........................... 7.2.4 Accident Rate .............................. 7.2.5 Trip Length ............................... 
Section 

TABLE OF CONTENTS (CONTINUED) 

Page 

7.2.6 Environment ............................... 7-9 

7.2.7 Emergency Response ......................... 7-10 

7.2.8 Amount of Material .......................... 7-12 

7.3 Summary Assessment of Primary ModeIRoute Factors ........... 7-12 

8 . References ........................................... 8-1 

Appendix A . Definitions ..................................... A- 1 

Appendix B . Invitees to and Attendees at ModeIRoute 

Technical Advisory Group Meeting ..................... B- 1 

Appendix C . Bibliography .................................... C- 1 

Appendix D . HazTrans Model Description .......................... D-1 

Appendix E . Radtran 4 Model Description .......................... E- 1 

Appendix F . Derivation of Transport Radiation Risk Models .............. F- 1 

Appendix G . Development of Case Study Input and Output ............... G- 1 

Appendix H . Model Estimation Using Case Study Analysis Results .......... H- 1 

Appendix I . DOT Response to Comments on the December 1993 Draft Report . . I- 1 

xvi 
LIST OF EXHIBITS 

Exhibit 

Overall Approach to Mode and Route Study ..................... Factors in Routing Guidelines Developed for Use by State 

and Local Governments .................................. Potential Mode and Route Selection Factors Identified in HMTUSA ..... 

List of Factors Identified During Literature Review That Have Been 

Evaluated or Proposed as Key Issues for Mode and/or Route Selection .... Comprehensive List of Candidate Factors ...................... Factor Hierarchy for Incident-Free Radiological Exposure ............ Factor Hierarchy for Radiological Accident Exposure .............. 

Factor Hierarchy for Non-Radiological Impact ................... Recommended Primary Mode and Route Factors .................. Representative Units of Measure for Primary Mode and Route Factors .... 

Relationship of Risk Modeling to Primary ModeIRoute Factors ........ Summary of Routes Used for Case Study ....................... Estimated Number of Fatalities (Per Single Cask Shipment) ........... Range of Estimated Component and Overall Radiological Risks 

(Per Single Cask Shipment) ............................... Variation of Primary Factor Values by O/D ..................... Variation of Incident-Free Risk Values (Person-Rems) by OID ......... Variation of Accident-Induced Radiological Risk Values (Person-Rems) by OID 

Variation of Non-Radiological Accident Risk Values (Fatalities) by O/D . . Sensitivity Analysis .................................... Relative Modal Risk for a Single Cask Movement vs . a Shipping Campaign 

Overall Assessment of Primary Factors ........................ 

xvii 
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xviii 
ACRONYMS 

AAR 

AASHTO 

AEC 

ALARA 

CFR 

CHP 

DOD 

DOE 

DOT 

EPA 

ER 

ERDA 

FHWA 

FR 

FRA 

GIs 

Hazmat 

HLW 

HMTA 

HMTUSA 

HRCQ 

IAEA 

ICC 

INEL 

LLW 

MRS 

NRC 

O/D 

PIH 

PWR 

RAM 

ROW 

RSPA 

SNF 

SNL 

TAG 

TMI 

TRIS 

UP 

USCG 

VNTSC 

Association of American Railroads 

American Association of State Highway and Transportation Officials 

Atomic Energy Commission 

As low as reasonably achievable 

Code of Federal Regulations 

California Highway Patrol 

U. S . Department of Defense 

U.S. Department of Energy 

U .S . Department of Transportation 

U. S . Environmental Protection Agency 

Emergency response 

Energy Research and Development Administration 

Federal Highway Administration 

Federal Register 

Federal Railroad Administration 

Geographic information system 

Hazardous materials 

High-level waste 

Hazardous Materials Transportation Act 

Hazardous Materials Transportation Uniform Safety Act 

Highway route controlled quantity 

International Atomic Energy Agency 

Interstate Commerce Commission 

Idaho National Engineering Laboratory 

Low-level waste 

Monitored Retrievable Storage 

Nuclear Regulatory Commission 

Origiddestination 

Poisonous by inhalation 

Pressurized Water Reactor 

Radioactive material 

Right-of-way 

Research and Special Programs Administration, 

U.S. Department of Transportation 

Spent nuclear fuel 

Sandia National Lab 

Technical Advisory Group 

Three Mile Island 

Transportation Research Information Service 

Union Pacific Railroad 

U.S. Coast Guard 

Volpe National Transportation Systems Center (Volpe Center) 

xix 
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1. INTRODUCTION 

Section 15 of the Hazardous Materials Transportation Uniform Safety Act of 1990 (HMTUSA) 

(49 U.S.C. 85 lO5(b) (1994)) directs the U.S. Department of Transportation (DOT) to conduct 

a study to identify and evaluate factors that should be considered in selecting the modes and 

routes for transporting high-level radioactive waste and spent nuclear fuel. This report 

describes the approach and findings of study activities performed in response to this 

requirement. 

1.1 PURPOSE AND ROLE OF THIS STUDY 

This study is intended to meet the requirements of Section 15 of HMTUSA as it relates to 

shipments of high-level radioactive waste and spent nuclear fuel. The two principal requirements of this section are (1) to determine which factors, if any, should be taken into consideration by shippers and carriers in selecting routes and modes that, in combination, would 

enhance overall public safety and (2) to assess the degree to which the various factors affect 

the overall public safety of such shipments. 

Several points concerning the direction given by Section 15 of HMTUSA are worth noting: 

The emphasis is on identifiing factors related to public safety. This study, therefore, does 

not provide a mode or route selection methodology, nor is it a set of selection guidelines. 

The study focuses on identifying mode and route factors and evaluating their relationship 

to overall public safety. As such, it may serve as a precursor to developing selection 

strategies. 

Economic considerations are excluded from the process of identifying and evaluating factors. The benchmark to be used is "overall public safety. " 

Selection factors to be identified in this study are those that should be considered by 

shippers and carriers. There may be other factors, principally those that affect public 

perceptions of safety and related concerns, that are more appropriately the purview of 

state and local governments and interest groups. 

This study has an important, albeit limited, role in the overall process of choosing modes and 

routes for shipping high-level radioactive materials. It provides guidance to shippers and 

carriers regarding what they should consider when sorting through the options available to 

them. It does not require that certain factors be considered; however, a duly promulgated 

regulation would be necessary to establish such requirements. This study does not address the 

need for such regulation nor make any recommendation in that regard. Also, the selection 

factors that shippers and carriers should consider are only a part of the overall decisionmaking process. It is presumed that these parties would make an initial assessment to identify 

the better mode and route options among the array available, typically using data that is, of 
necessity, more generic than detailed in nature. Then, shippers and carriers would consult 

with state and local governments and interest groups to ensure that the ultimate choice reflects 

also the detailed knowledge and particular concerns of the affected parties. 

1.2 STUDY APPROACH 

The sequence of activities undertaken to complete this study (i.e., the approach) is illustrated 

in Exhibit 1; the organization of this report follows those same steps. 

Define Public Safety (Chapter 1). The first step was to define "overall public safety" for the 

purposes of this study. This step was considered crucial because the definition would serve as 

the basis for the remainder of the study and subsequently guide the evaluation process. 

Review Mode and Route Selection Practices (Chapter 2). The second step was to provide 

background for the general topic of mode and route selection in transportation. Industry 

practice with regard to mode and route selection for general commodities, as well as for 

hazardous and nuclear materials, was reviewed. 

Identify Candidate Mode and Route Factors (Chapter 3). The next step was to develop a 

comprehensive list of candidate mode and route selection factors. A list was created using the 

four major sources that were reviewed: existing regulations and routing guidelines, legislation 

(primarily HMTUSA), relevant transportation and nuclear literature, and suggestions from an 

expert group assembled for this study. The only criterion used to create the list was that an 

intuitive relationship should exist between each factor and public safety. 

Conduct Qualitative Evaluation of Candidate Factors and Select Primary Factors (Chapter 4). Each factor from the comprehensive list was systematically evaluated on the basis of 

its impact on public safety. A hierarchical framework was used to develop interrelationships 

among the many candidate factors and to identify a set of primary factors that arguably affects 

the modelroute choice in the most direct way. 

Identify Mode and Route Factors by Modeling the Risk of Transporting Radioactive 

Materials (Chapter 5). Models representing the three components of transportation risk were 

developed from the fundamental relationships between the key factors that affect the 

component risks. These factors were then compared to the factors selected from the 

qualitative analysis. 

Develop Case Study and Perform Analysis of Primary Factors (Chapter 6). For the 

primary factors that were readily quantifiable and for which data were readily available, a case 

study was developed and implemented using existing routing and risk assessment models. 

Values for these primary factors were derived for representative origin and destination (OID) 

pairs and the variability of the selected factors was measured as modes and routes changed. In 

addition, the relative impact of these factors on public safety was evaluated. 
Exhibit 1. Overall Approach to Mode and Route Study 

Section 15 HMTUSA: 

I ldentify factors for mode and route selection to enhance overall public safety 

Assess degree to which factors affect overall public safety 

I 

Define "overall public safety" 

I Review industry mode and route selection practices I 

ldentify all candidate mode and route factors 

Criteria: 

Affects overall public safety 

Affects mode or route decision 

Sources: 

Regulations/guidelines 

LegislationlHMTUSA factors 

Prior studies and analyses 

Expert group 

- 

Screen and select primary mode and route factors 

Screen candidate 

Develop factor hierarchy 

Select primary factors 

I Develop risk models for transporting radioactive materials 

Develop models for incident-free risk, radiological I 

accident risk, and non-radiological accident risk 

Analyze relationship of each primary factor with each risk 

component 

Develop case study and perform statistical analysis of 

primary mode and route factors 

Case Study: 

Select representative originsldestinations 

ldentify candidate modes and routes 

Quantify risk for each option and compare 

Analysis: 

Measure variability among factors 

Evaluate impact of each factor on risk by estimating 

coefficient of risk models using case study results 

V 

Perform overall qualitative assessment of primary mode and 

route factors 

Criteria: 

Degree of impact on overall public safety 

Variability from mode to mode and route to route 

Ability to measure 

Feasibility of implementation 
Conduct Overall Assessment of Primary Mode and Route Factors (Chapter 7). An overall 

assessment of each primary factor was conducted using the results of the qualitative evaluation 

as well as the results of the risk modeling and case study analysis. The criteria were (1) 

degree of impact on public safety, (2) variability from mode to mode and route to route, (3) 

ability to measure, and (4) feasibility of implementation. 

1.3 DEFINITION OF OVERALL PUBLIC SAFETY 

The definition of overall public safety was the benchmark used for this study. Overall public 

safety is a difficult concept to define because of the many different aspects of safety that can be 

considered in this context. In absolute terms, overall public safety can be viewed as freedom 

from danger, injury, or damage. Complete freedom from harm is impossible to achieve and, 

because the mandate of this study is to identify factors that enhance overall public safety, an 

appropriate working definition had to be placed in a comparative context. With this in mind, 

the enhancement of overall public safety was defined as: 

Minimizing exposure of the public and the environment to spent nuclear fuel and high-level 

radioactive waste during transportation. This includes minimizing incident-free 

radiological exposure of both the public and transportation workers and minimizing the 

potential exposure caused by a radiological release into the environment as a result of an 

incident during transportation. 

Minimizing the impact of accidents during transportation when no radiological release 

occurs (non-radiological efects) . 

Based on this definition, three categories of impact on public safety were considered for the 

purpose of identifying and evaluating mode and route factors: 

1. Incident-free radiological exposure (exposure of both the general public and transportation 

workers that results from normal transportation of radioactive materials); 

2. Potential accident-induced radiological exposure (exposure of people and the environment 

that results from factors affecting both the likelihood and consequence of an accident); the 

effect of emergency response in minimizing the impact of such potential exposure is explicitly included as a factor that affects the consequences of an accident; 

3. Potential non-radiological impacts on public safety (effects of accidents that include traffic 

fatalities and injuries unrelated to the nature of the cargo). 

Incident-free radiological exposure occurs every time radioactive materials are transported. 

This exposure is generally very small because of regulations that limit the maximum amount of 

radiation that can be measured outside the shipping container. The related risk is associated 

with long-term health effects, usually expressed in terms of latent cancer fatalities. 
Accident-induced radiological exposure is a probabilistic event and is considered a rare 

occurrence. Such exposure results from an incident during transportation that causes a release 

of radioactive material. If such a release occurred, the resulting consequences could be greater 

than those for incident-free exposure, but would still result in health and environmental effects 

that might require some time to fully manifest themselves. 

Non-radiological impacts are expected to occur much more frequently than radiological 

exposure. The most acute health effects of non-radiological impacts occur at or very near the 

time of an accident. The health effects of non-radiological impacts include injuries or 

fatalities. 

1.4 SPENT NUCLEAR FUEL TRANSPORT 

Spent nuclear fuel has been transported in the U.S. for over 40 years. Currently, the number 

of spent nuclear fuel shipments averages around 100 per year from all sources, including 

utilities; academic institutions; industrial facilities; foreign imports, exports, and material in 

transit; and military sources. Some of these shipments are intra-utility transfers; other 

shipments are to away-from-reactor facilities. 

To move spent nuclear fuel, either highway or rail transport is used. Currently, the majority 

of spent nuclear fuel shipments move by highway. Between 1979 and 1995, 89 percent of the 

shipments under the regulatory purview of the U.S. Nuclear Regulatory Commission (NRC) 

moved by highway, while only 11 percent moved by rail. The majority of the tonnage of 

spent nuclear fuel that is transported, however, moves by rail. Between 1979 and 1995, over 

73 percent of the tonnage of spent fuel shipped under the purview of the NRC moved by rail, 

while less than 27 percent moved by truck. For the shipments under the purview of the NRC, 

the average size of a highway shipment between 1979 and 1995 was about 300 kilograms of 

spent fuel. The average size of a rail shipment was about 7100 kilograms of spent fuel. ' 

Once away-from-reactor facilities for the interim or permanent storage of spent nuclear fuel 

become available, the number of spent nuclear fuel shipments is expected to increase. It is 

estimated by DOT that there could be over 400 spent nuclear fuel shipments per year, on 

average, from all sources. The quantity of spent nuclear fuel moved will probably exceed 

3000 metric tons per year. 

'See U.S. Nuclear Regulatory Commission, Public Information Circular for Shipments of Irradiated Reactor Fuel, 

NUREG-0725, Rev. 11, Washington, DC, July 1996. 
Page intentionally left blank. 
2. OVERVIEW OF MODE AND ROUTE SELECTION PRACTICES 

Shippers and carriers have been selecting modes and routes for general commodities for many 

years. Their choices are made for a variety of reasons, some of which have changed 

significantly over the last decade in response to deregulation of transportation modes and 

general economic conditions. 

Shippers also have been making mode and route choices for spent nuclear fuel and other highlevel radioactive waste for several decades. Influences on these choices include regulatory 

requirements and traditional industry practices. The factors that have been considered or proposed in making mode and route choices for both general commodities and hazardous materials (of which radioactive material, or RAM, is a subset) are identified in this chapter. 

2.1 GENERAL MODE AND ROUTE SELECTION PRACTICES FOR ALL 

COMMODITIES 

Modal choice and route selection are often directly related. A change of mode will require a 

change in route (because modes generally do not share rights-of-way), and conversely, a 

change in route may require a change in mode. At the same time, some origins or destinations 

are not served by certain modes. This obviously limits modal choice and routing options. 

With regard to transportation in general, modal choices have historically been made by 

shippers (the companies sending the products), and routing choices have been made by carriers 

(the companies moving the products), but this distinction has begun to blur. In the past, regulation kept carriers from providing services in more than one mode. In recent years, 

deregulation of the transportation industry has allowed carriers to expand into other modes or 

to develop cooperative arrangements with carriers in other modes. Presumably, carriers are 

more able to influence-although still not decide-which mode will be used. At the same 

time, shippers' concerns about service attributes and liability have caused them to seek participation in certain carrier internal activities, such as routing decisions. Additionally, shippers 

who have a vested interest in a particular mode-perhaps because they own a short railroad, a 

fleet of trucks, or a fleet of barges-will often choose to use that mode without regard for 

optimizing modal choice over the short run. Finally, since railroads operate over route 

structures that they own and control, and some shippers have a choice of several railroads, a 

shipper's choice of carrier in some cases will essentially determine the route that will be used. 

2.1.1 General Mode Selection Practices 

Discussions with carriers, shippers, and other persons knowledgeable about these 

transportation issues and who have worked with hazardous and non-hazardous shipments by 

highway, rail, and water, revealed that modal choices are made for a variety of reasons. 
First and foremost, shippers can make modal choices only from among those modes that are 

physically available to them and their customers. Although almost all businesses are now 

accessible by highway, fewer have rail service available, and fewer still have waterways available. Furthermore, to complete a shipment, the chosen mode should be available at both the 

origin and destination. In the case of rail and waterways, this often limits the modal choices 

available to shippers. This constraint has been somewhat mitigated in recent years by the 

development of intermodal operations. In intermodal shipments, the product is interchanged 

one or more times between modes while moving from the shipper to the customer. This 

allows access to modes that would otherwise be unavailable, although it frequently limits the 

size and type of equipment that can be used and requires the commodity and its container to be 

handled (i.e., unloadedlloaded) away from the origin or destination. 

Second, shippers choose modes based on various service attributes. Shippers want to maxi- ' 

mize the value of their products by getting them to their customers quickly, without damage, 

at the lowest possible cost, and in lot sizes convenient to the shipper or the customer. Each of 

the modes has a different ability to provide speed of transport, frequency of service, and 

avoidance of damage and to offer low prices, while making a profit for the carrier. Shippers, 

who have different levels of interest in each of these characteristics based on the nature of their 

businesses, choose the mode that provides the best combination of service attributes. 

Third, shippers sometimes choose modes to ensure continued availability of a mode or to provide competition among carriers. For example, a shipper may choose to use highways because 

of service attributes, but also occasionally makes a rail shipment just to keep a rail line active 

for possible future use. 

Safety is not usually given as the reason for choosing a particular mode. Some observers in 

the shipping ~ommunity have noted that all modes are considered safe and that no mode holds 

a clear advantage, especially for non-hazardous shipments. 

These reasons for modal choice are generally supported by the results of a survey of Canadian 

shippers in the mid-1980s [Wilson, Bisson, and Kobia 19861. That study found that shippers 

choose a particular mode primarily to minimize transit time and generally favor highways for 

shorter hauls and rail for longer hauls. The study also found that shippers make modal choices 

based on availability of pickup and delivery services (favoring highway), cooperation between 

carrier and shipper personnel (favoring highway), and shipment tracing capability (favoring 

rail). The study further found that in-transit damage (which can be indicative of poor safety 

performance) is not significant in influencing the choice of any mode. 

An earlier survey asked U.S. shippers why they chose a particular mode and carrier within 

that mode [Stock and LaLonde 19771. The study found that, in general, shippers choose 

modes based on pickup and delivery services and overall cost. Other selection criteria, in 

decreasing order of importance, were (1) line haul (ability to serve origin and destination 

without changing mode or carrier), (2) tracing and expediting, (3) loss and damage, (4) special 

service and equipment, and (5) sales staff support. This survey was conducted before the 

transportation modes were deregulated, when carriers' abilities to tailor their services to their 
customers were restricted. In assessing this survey in the mid-1980s, one of the original 

authors stated that consistency of service had become "the most important single criterion for 

evaluating alternatives" [Stock and Larnbert 19871. 

2.1.2 General Route Selection Practices 

Analysis, including discussions with carriers, shippers, and other knowledgeable persons, 

revealed that routing choices are made for a variety of reasons. 

Like shippers, carriers can only choose routes physically available to them. Truck companies 

and barge operators use highways and waterways that are publicly owned, or, in the case of 

tollroads and tollbridges, are at least available to the public. Since any company's trucks can 

use any highway, and since almost all shippers and customers have access to highways, all 

truck companies are physically able to serve almost all shippers. Similarly, although few 

shippers and customers have access to waterways, those that have the appropriate facilities can 

be physically served by all barge companies. There are, of course, regulatory restrictions on 

locations that some truck companies and barge operators can serve, and some truck companies 

and barge operators may choose not to serve certain areas. 

In contrast, railroad lines are privately owned (with the exception of certain Amtrak routes and 

state or locally owned rail lines); service over those lines is controlled by the owning railroad 

company. Trackage rights agreements are a means of extending a railroad's service area 

whereby it pays the owning railroad for the right to operate its trains over the other's tracks. 

When the originating railroad cannot provide service all the way to the shipment destination, 

the cars are interchanged-handed off to another railroad at a common junction for further 

transportation to (or toward) the destination. Revenue is divided among the railroads that 

handle the shipment. 

Trackage rights agreements take place in a competitive environment in which each railroad 

attempts to optimize its own interests. Sometimes those interests result in the owning railroad 

refusing access to the other railroad. When that occurs, routing options are affected. Occasionally, railroads may be ordered by federal regulators or the courts to allow access to other 

railroads to preserve local competition or as a condition of merger or abandonment 

proceedings. The rate structures established by railroads can also impact routing options, 

since those structures can give preference to one route over another, and can determine (and 

thereby limit) interchange points. 

Routing is more complex for rail shipments, and the options are more constrained. Few 

shippers have direct access to more than one railroad, which significantly limits routing 

options. Also, the originating railroad (via its rate structure), and not the shipper, usually 

determines how a shipment is to be routed. If the originating railroad serves the destination, 

routing will be a function of the routes and schedules of the trains it runs and the location of 

its yards. If other railroads are needed to reach the destination, competitive forces will also 

affect routing. Railroads generally divide revenues for a shipment based roughly on the 

proportion of the distance that each railroad hauls the shipment. Each railroad has some 
incentive, then, to haul the shipment as far as possible before interchanging it with another 

railroad, even if a shorter haul would result in overall lower costs or shorter time in transit. 

The railroad that originates the shipment traditionally controls where it is interchanged and 

gets as long a haul as practical. In contrast to the practice for general commodities, some 

shipments of hazardous materials appear to receive expedited handling when a railroad 

believes that revenues fail to cover the greater risks and costs involved. In any event, 

deregulation and increased competition from other modes have caused railroads to begin to 

focus more in recent years on customer service. Shippers can and sometimes do specify the 

preferred routing for a shipment, including the junction point(s) at which the shipment is to be 

interchanged from one railroad to another. Routing of RAM shipments is usually specified by 

the shipper in conjunction with the carrier(s) involved. 

Finally, one additional option of routing is available only to railroads-the temporary ability to 

embargo their own routes. In essence, a railroad embargoes a route by placing it out of service to all trains, to those over a certain length or weight, or to those carrying a particular 

commodity. Embargoes are generally based on temporary conditions (such as the flood 

damage that occurred in the Midwest in the early 1990s), but can become permanent under 

special circumstances. A recent example is the March 19, 1993, embargo of all hazardous 

materials shipments on the Long Island Railroad. This embargo was unusual in that it was 

applied by the Association of American Railroads (an industry group) to an entire railroad, 

rather than applied by a railroad to a single route. Attempts by railroads to embargo the 

transportation of RAM or hazardous materials were consistently disallowed by the Interstate 

Commerce Commission (see, for instance, Class@cation Ratings of Chemicals, Conrail, April 

30, 1986, I&S Docket No. 9265, 3 I.C.C. 2d 33 1, December 19, 1986). The Surface 

Transportation Board would generally be expected to resist allowing long-term or permanent 

embargoes by railroads in order to prevent such embargoes from becoming de facto 

abandonments . 

Truck, railroad, and barge companies tend to make routing decisions, including those 

embodied in their rate structures, for the same reason: operational efficiency. Carriers in 

each mode seek to make best use of their equipment and fixed facilities. For truck companies, 

this means avoiding long routes, toll roads, states with high fuel taxes, and congested or 

unreliable routes (perhaps due to weather). For railroads, this means avoiding long routes and 

congested classification facilities. Railroads also manage their train movements to concentrate 

traffic on main lines, to accommodate single-track routes, and to utilize efficient schedules and 

train consists (i.e., the specific engines and cars that make up a train). Barge operators, as 

mentioned earlier, have very few routing options but, when they do, they try to avoid long 

routes, congested locks, and, to a smaller degree, routes affected by seasonal weather. 

'The ICC was terminated (per the ICC Termination Act) on December 29, 1995. Remaining authority with 

respect to rail went to the newly created Surface Transportation Board, an independent board within the U.S. 

Department of Transportation. 
2.2 OVERVIEW OF MODE AND ROUTE SELECTION FOR HAZARDOUS 

MATERIALS 

2.2.1 Mode Selection for Hazardous Materials 

There appears to be little difference between the modal choices made by shippers of most 

hazardous materials and the modal choices made by those shipping non-hazardous materials. 

In fact, most shippers of hazardous materials also transport a large volume of non-hazardous 

materials and follow the same practices in doing so. Generally speaking, from the shippers' 

perspective, all modes are considered safe, and modal choices are made for reasons other than 

safety, such as cost and convenience. Exceptions include the Department of Defense (DOD) 

and certain chemical companies that review carrier safety records before making carrier 

choices. Recently, the concept of exercising "responsible care" in handling and transporting 

hazardous materials has caused chemical companies to take an increased interest in selecting 

modes and carriers based on safety records. 

Shipments of spent nuclear fuel (SNF) are an exception to general practice; they are jointly 

planned by shippers, carriers, and government officials. Modal choice is based primarily on 

two factors-physical availability of a mode and the amount of material to be shipped. For 

shipments of a single fuel element, highway will almost always be the mode of choice, even if 

rail or. barge access is available. Given the much larger capacity of raillbarge casks, however, 

one of these will be the mode of choice for multi-element SNF shipments if the origin and 

destination points are accessible and can handle the heavier casks. 

2.2.2 Route Selection for Hazardous Materials 

Carriers' routing choices in all modes are affected to varying degrees by federal, state, Indian 

tribe, and local regulations. On their own, most carriers make routing adjustments only for a 

limited number of hazardous materials. In general, hazardous materials are not differentiated 

from non-hazardous materials when making routing decisions. 

For railroads, however, there has been a modest movement toward changing routing or operating practices in recognition of certain hazardous materials. Industry inquiries during this 

study found these examples: 

The Association of American Railroads (AAR) suggests that its member railroads follow 

its Circular No. OT-55-B [AAR 19931, which contains operating practices that apply to 

many hazardous materials. One of its recommendations is industry-wide use of key trains 

and designation of key routes. 

Key trains are trains with 5 or more loaded tank cars containing poisons with an inhalation 

hazard, or 20 or more carloads or intermodal portable tankloads of a combination of 

poisons with inhalation hazards, flammable gases, certain explosives, and environmentally 

sensitive chemicals. Key trains are restricted to a maximum speed of 50 mph, hold the 

mainline when passing other trains (unless the siding meets Federal Railroad 
Administration [FRA] Class 2 standards), and may not contain any cars with friction 

bearings. When a key train is stopped by emergency brake application or unknown cause, 

the train must be inspected for derailed or defective cars. If a defective axle journal is 

reported by a trackside detector but has no visible defect, the train must be limited to 30 

mph until it has successfully passed the next detector. Failure to pass the second detector 

requires that the car be set out from the train. 

Key routes are tracks with yearly traffic that includes 10,000 or more carloads or 

intermodal portable tankloads of hazardous materials or a combined total of 4,000 or more 

carloads of hazardous materials that are poisonous by inhalation, flammable gases, certain 

explosives, or environmentally sensitive chemicals. Key routes.must have defective wheel 

bearing detectors no more than 40 miles apart and must be inspected by track geometry 

inspection cars (or equivalent) at least twice each year. Sidings on key routes must be 

similarly inspected at least once each year. All track where key trains are met or passed 

must be FRA Class 2 or better. 

The key route concept does not stipulate how hazardous materials should be routed, but 

highlights high-volume routes while ensuring a minimum level of safety detection and 

inspection equipment [AAR 19931. 

The AAR recommends that trains moving spent fuel (and certain other forms of 

radioactive materials) be moved only in special trains. AAR's policy states that 

"[slhipments of casks containing irradiated spent fuel cores or empty casks previously 

loaded with such material should be moved in special trains containing no other freight, at 

speeds not faster than 35 mph. When a train handling these shipments meets, passes, or is 

passed by another train, one train should stand while the other moves past not faster than 

35 mph" [AAR 19751. 

The Union Pacific railroad system follows the AAR recommendation that key trains be 

identified and key routes be designated. The Union Pacific has designated routes that 

carry high volumes of hazardous materials as key routes. Two to five permanently 

designated key trains have operated daily over these routes in recent years. 

Hazardous materials shipments are usually routed no differently than non-hazardous ones. 

One exception, which predates the key route concept, is that the Union Pacific routes 

hazardous materials shipments around St. Louis because an equivalent quality parallel 

mainline is available 100 miles to the east.3 In a survey several years ago, the railroad 

said that it prefers not to route hazardous materials around population centers because 

doing so often requires using lower quality track [Midwest Research Institute 19901. 

The Union Pacific's current practice is to move RAM shipments via dedicated trains. The 

railroad's position is that "dedicated trains are essential for the movement of these 

3Leo Tierney, Union Pacific Railroad, telephone conversation with Gary Watros, Volpe Center, December 3, 

1993. 
radioactive materials in order to satisfy all the operational and safety considerations 

surrounding these shipments. Dedicated train service is also necessary to accommodate 

the 35 mph operating restriction that is imposed by DOEIDOD for the transportation of 

these radioactive materials, including the movements of empty casks. "4 Shipments of 

debris from Three Mile Island were handled in dedicated trains restricted to 50 mph 

(based on negotiations with the DOE and other interested parties).' 

The Norfolk Southern follows the AAR's key train recommendations for certain 

hazardous materials and the AAR's special train recommendations for spent fuel cask6 

Conrail follows AAR key train recommendations for hazardous materials and AAR special 

train recommendations for spent fuel casks. Conrail also prefers to route trains carrying 

spent fuel on main lines whenever possible.' 

2.3 OVERVIEW OF REGULATIONS AFFECTING MODE AND ROUTE 

SELECTION 

Various federal, state, Indian tribe, and local governmental agencies have limited authority to 

regulate transportation. Sometimes state, Indian tribe, and local agency regulations are 

overridden by federal regulations. Sometimes federal, state, Indian tribes, and local agencies 

choose not to exercise the authority that they have been given. 

2.3.1 Regulation of Mode and Route Selection for Non-Hazardous Materials 

Mode Selection. A detailed review of federal, state, Indian tribe, and local regulations found 

none that require the use of a particular mode for non-hazardous materials. 

Route Selection. Routing restrictions vary widely by jurisdiction. 

Federal. The study found no federal regulations that address the routing of non-hazardous 

materials. The U.S. Coast Guard does have authority to suspend navigation on a 

particular waterway due to seasonal conditions or emergencies. This could cause a rerouting or change of mode; but, because of the limited route options available to barge 

4 Comments to the docket on "Draft Report, Identification of Factors for Selecting Modes and Routes for Shipping 

High-Level Radioactive Waste and Spent Nuclear Fuel," from Union Pacific Railroad Company, undated. 

%ee note 2 above. 

6Paul Henson, Director of Safety and Hazardous Materials, Norfolk Southern Railroad, telephone conversation 

with Gary Watros, Volpe Center, December 3, 1993. 

'Allan C. Fisher, Director of Operating Rules, Conrail, telephone conversation with Gary Watros, Volpe Center, 

December 3, 1993. 
companies, these closings are more likely to cause a delay or change of mode than a 

change in route. 

States, Indian tribes, and local jurisdictions. There are a variety of approaches to 

regulating, or at least influencing, routing of highway shipments. Some jurisdictions 

routinely restrict trucks from operating on certain highways by imposing weight and 

clearance limits. These limits reflect the design or condition of the infrastructure and are 

intended to prevent damage or excess wear to the surfaces and structures. Truck routes 

are also designated through many cities to keep trucks on highways considered more 

suitable to that type of vehicle or to avoid residential neighborhoods and other selected 

locations. The criteria for designating these truck routes vary from jurisdiction to jurisdiction and, in some cases, are extended to exclude trucks from parkways and other autoonly roadways. 

Some jurisdictions impose curfews on hours of truck operation on certain roads or in 

certain areas of a city. Those curfews are either for noise abatement or to alleviate 

congestion. Waivers and exceptions to all these restrictions are granted with varying 

degrees of regularity. 

2.3.2 Reelation of Mode and Route Selection for Hazardous Materials 

Mode Selection. A detailed review of federal, state, Indian tribe, and local regulations found 

none that require the use of a particular mode for hazardous materials. Some regulations, 

however, prohibit or restrict carrying specific materials by certain modes. One example is air 

transport of certain shipments of radioactive material (10 CFR 71.88 and 73.24). 

Route Selection. Generally speaking, the commodity being shipped does not affect the 

routing choice made by the carriers in any of the modes. Exceptions include explosives; 

combustibles; certain other hazardous materials that are prohibited from some tunnels, 

bridges, and highways by state or local regulation; and highway route controlled quantities 

(HRCQ) of radioactive materials. The governmental routing regulations frequently apply only 

to hazardous materials passing through a locality; pickups and deliveries are routinely 

exempted from the restrictions. 

Various federal, state, Indian tribe, and local agencies have jurisdiction over aspects of hazardous materials routing on highways. Authority over hazardous materials routing is complicated 

by overlapping jurisdictions and issues of interstate commerce. 

The Hazardous Materials Transportation Act (HMTA) provides DOT with the authority to 

regulate the routing of hazardous materials shipments. For many years, the Federal Highway 

Administration (FHWA) had the only regulation that prescribed routing restrictions for 

hazardous materials. The Federal Motor Carrier Safety Regulations (49 CFR 397.67) state 

that unless there is no practicable alternative, a motor vehicle which contains hazardous 

materials must be operated over routes which do not go through or near heavily populated 
areas, places where crowds assemble, tunnels, narrow streets or alleys, but give no specific 

definitions for when these restricted conditions exist. 

In 1980, the DOT published a set of routing guidelines for general hazardous materials (not 

RAM) to be used by state and local agencies. These guidelines were most recently updated in 

1989 as "Guidelines for Applying Criteria to Designate Routes for Transporting Hazardous 

Materials " (DOTIRSPAIOHMT-89-02, July 1989). The guidelines are not mandatory but 

have been used by many agencies. The FHWA was delegated the authority and responsibility 

for highway routing of hazardous materials (56 FR 31343, July 10, 1991) and promulgated 

new hazardous materials routing regulations pursuant to HMTUSA (see 57 FR 44129, Sept. 

24, 1992; and 59 FR 51824, Oct. 12 1994). 

DOT also issued regulations in 1982 (see 46 FR 5298, Jan. 19, 1981) that prescribe highway 

routing requirements for certain quantities of radioactive materials (49 CFR 173.22 and 

177.825). These regulations require that carriers follow "preferred routes," which are 

Interstate highways, andlor any other route designated by a state routing agency. Carriers are 

instructed to choose a preferred route to reduce travel time and to use urban bypasses where 

available. DOT also has published a set of guidelines to assist state agencies and Indian tribes 

in designating routes that satisfy DOT Regulations (57 FR 44129, Sept. 24, 1992). 

There are no comparable DOT regulations or guidelines for rail or water shipments. The 

reasons that routing regulation has been limited to highway were expressed in the Notice of 

Proposed Rulemaking for HM-164 (45 FR 7140, January 3 1, 1980), as follows: "Rail 

operations.. .differ significantly from highway operations.. . . Also, the routing choices 

available in rail operations with regard to populated or congested areas are considerably more 

limited than in highway transportation. " 

The Nuclear Regulatory Commission (NRC) also has authority to regulate highway routing of 

certain types of radioactive materials to ensure adequate security. A Memorandum of Understanding between DOT and the NRC stipulates that each agency will coordinate any 

radioactive materials transportation regulations developed by the other. 

States and Indian tribes. A survey by the American Association of State Highway and 

Transportation Officials (AASHTO) found that 22 of 46 responding states have some form 

of routing authority over hazardous materials shipments [Midwest Research Institute 

19901. The presence of routing authority does not necessarily mean that the states are 

exercising that authority. Several states are considering expanding or implementing 

routing authority over hazardous materials shipments. In general, states regulate hazardous materials routing by prohibiting the use of certain routes rather than designating 

acceptable routes [Midwest Research Institute 19901. Indian tribes can invoke authority 

over routing of shipments through their jurisdictions in the same manner as states. 

California is one of the few states that regulates explosives routing. The state has 

designated a network of approved routes with enforcement by the California Highway 
Patrol (CHP). California has also established a network of routes for hazardous materials 

that are poisonous by inhalation. 

Because the federal government has promulgated highway routing requirements for 

radioactive materials, states and Indian tribes have often focused instead on ancillary 

transportation regulations, such as notification requirements, inspection, and escorts. 

Some of the truck and cask combinations used to transport spent nuclear fuel and highlevel nuclear waste exceed state and Indian tribe highway weight limits. As such, they 

usually require special permits and are restricted to using certain highways. These 

restrictions are due to the total weight of the loaded truck, rather than the nature of the 

commodity being transported. 

Several states have taken advantage of the provisions within HM-164 and have designated 

alternative routes for spent nuclear fuel shipments. The routes are in place of, or in 

addition to, the base HM-164 network of Interstate highways and urban bypasses. 

Local jurisdictions. The AASHTO survey found that local agencies exercise hazardous 

materials routing authority in 19 of 46 states. In 7 of the 19 states, the local agencies 

exercise routing authority over all roadways, including state highways. The authority in 

each state, and the degree to which that authority is exercised, varies widely. In 

Washington, for example, local agencies have complete authority to prohibit hazardous 

materials on all roadways under their jurisdiction. In California, local agencies can 

regulate hazardous materials routing, subject to review by the CHP [Midwest Research 

Institute 19901. In that state, a routing restriction must 

1. Apply only to highways appreciably less safe than alternatives 

2. Not be preempted by federal regulation 

3. Not eliminate access to pickup and delivery points or necessary service 

4. Preserve at least one legal alternative route. 

Columbus, Ohio, has implemented a type of routing restriction that is gaining popularity 

in the Midwest. The city requires that all through shipments of hazardous materials must 

use an outer-belt Interstate highway around the city, even if total mileage and time is 

increased. "Hazardous Cargo" routes are posted and exceptions require permits from the 

Fire Chief [Columbus City Code, Chapter 25511. The restriction was prompted by the 

overturn of a truck carrying hydrogen peroxide at the downtown interchange of the two 

main Interstate highways in the late 1980s. 

Local agencies are generally not involved in routing radioactive materials, although they 

have, on several occasions, attempted to impose routing regulations that were later overturned or pre-empted. The most notable case was New York City's attempt to prevent 

SNF shipments from moving off Long Island through the city. New York City's attempts 
to block these shipments raised the question of how to involve state and local jurisdictions 

in radioactive material shipments and resulted in the promulgation of HM-164 [Mullen, 

Welch and Welles 19861. Another example is the proclamation by certain municipalities 

that they are "Nuclear Free Zones" in which no radioactive materials can be handled, processed, stored, or transported. More than 100 cities have declared themselves Nuclear 

Free Zones, including Takoma Park, Maryland; Chicago, Illinois; and Oakland, 

California. Court cases have decided that these declarations do not have the force of law. 

The designations, however, indicate a community's opposition to nuclear transportation 

and could, in certain cases, influence routing decisions. 

There are no known local routing requirements for radioactive materials shipments by rail 

or waterway. 

'New York Times, 9/20/87 and 4/28/90; UP1 Wire, 2/17/86, 3/12/86, and 8/12/86; Philadelphia Inquirer, 

4/28/90. 
Page intentionally left blank. 
3. IDENTIFICATION OF CANDIDATE MODE AND ROUTE FACTORS 

As seen in Chapter 2, mode and route decisions have traditionally been based on 

considerations other than safety, though shippers of hazardous materials have begun using 

safety as a criterion in choosing carriers in recent years. The purpose of this chapter is to 

focus on selection criteria related to "overall public safety," as defined in Chapter 1. 

The first step in the effort to identify the most important safety factors for mode and route 

selection was to develop a comprehensive list of candidate factors. These factors were then 

carefully screened and evaluated and ultimately narrowed down to a set of primary mode and 

route selection factors for more detailed assessment. Chapter 3 describes the process for 

identifying mode and route factors. Chapter 4 then describes the manner in which the 

candidate factors were evaluated and prioritized. 

3.1 ENUMERATION OF FACTORS 

A comprehensive list of candidate mode and route factors was compiled using the project definition of overall public safety as a guide. Few constraints were imposed in developing the list, 

other than a factor's intuitive relationship to public safety. In the initial compilation, no effort 

was made to organize the factors or to group them in any way. 

The factors were collected from several sources including (1) current regulations and routing 

guidelines, (2) HMTUSA, (3) a literature review, (4) a ModeIRoute Technical Advisory 

Group (TAG) convened for this study, and (5) project team expertise. All identifiable factors 

contained in current regulations and published documents were added to the list without reference to the route selection procedure or risk assessment technique. This was considered 

important because shippers and carriers are generally familiar with current routing guidelines 

and operate with these factors and procedures in mind. 

The TAG was convened specifically to act as an expert panel for this study. The group represented broad interests including carriers; shippers; local, state, and federal governments; 

public interest groups; and regional energy groups (see Appendix B). The members were 

provided with a list of factors prior to the meeting and at the meeting were asked to provide 

input on additions or changes to the initial comprehensive list, as well as guidance on representative units of measure and ability to measure the factors. 

3.2 GUIDELINES FOR ROUTING HAZARDOUS MATERIALS 

Federal regulations governing the routing of hazardous and radioactive material were mentioned in Section 2.3. It was noted that the U.S. DOT has prepared guidelines for states and 

other jurisdictions to use when designating routes for both general hazardous materials and for 

highway route controlled quantities of radioactive materials. Similarly, Transport Canada has 
developed a set of hazardous materials routing guidelines for shipments in Canada [Transport 

Canada 19871. Routing guidelines are an important source of candidate mode and route factors, though it is recognized that these guidelines were prepared for use by goveinmental 

routing officials and not for use by shippers and carriers, who are the focus of this report. 

Because of the importance of routing guidelines, it is worthwhile to provide some background 

on the methodology and criteria they employed. 

3.2.1 DOT Hazardous Materials Routinp Guidelines 

DOT'S hazardous materials (hazmat) routing guidelines are based on the concept of relative 

risk. That is, only those factors that are potentially different between alternate routes are 

considered in the risk assessment that forms the basis for the route decision. Risk is measured 

using two primary factors: 

1. The expected, per-mile population exposure to a release (population risk). 

2. The expected, per-mile property value exposure (property risk). (The estimation of property risk is considered optional in the route selection process.) 

These two primary factors are computed for each route but are not combined in any way. 

Population risk is estimated using accident rate and population density information. Property 

risk is also estimated using accident rate information but considers property values instead of 

population density. 

The DOT guidelines suggest that accident rate information be obtained from the best possible 

information source. The DOT suggests that, when available, the analyst should use accident 

rates that are based on the most severe accidents (such as fatal accidents). This is in 

recognition of the fact that many accidents are not severe enough to cause a release of 

hazardous materials from containers. A simple regression model, based on the average daily 

traffic volume of each Interstate route segment, is also provided for estimating accident 

probabilities. 

Population density information along each route is necessary to estimate the number of people 

who would be at risk during an accidental release. The approach recommended in the guidelines is to use census tract data to estimate the fraction of the population along a route within 

the release impact zone. The choice of width for the impact zone along each route is based on 

the suggested evacuation distance of the nine classes of hazardous materials. 

Property value is estimated by measuring lineal frontage and its value along each route. The 

release impact zones that are important in the population risk assessment process are not used 

in the property risk assessment process. 

Route selection is based on the primary risk factors (population and property risk) and on subjective factors. If the primary risk factors for multiple routes are so close that a definitive 
decision cannot be made, the secondary subjective factors are employed. Decision makers use 

the secondary subjective factors to differentiate close calls. 

Four types of secondary subjective factors are considered in the guidelines: 

1. Special populations located in facilities that are difficult to evacuate (nursing homes, 

schools, hospitals, and prisons) 

2. Special properties (utilities, transportation bottlenecks, and difficult-to-reach facilities) 

3. Emergency response capability 

4. Other subjective factors of special interest to a community. 

The evaluation process requires listing the types and quantities of these secondary factors for 

each route. There is no attempt to analytically combine these factors. 

The primary and subjective factors from the DOT hazardous materials guidelines are shown in 

Exhibit 2. Each of these factors is broken down into more specific factors in the second 

column of the exhibit and into measurable components in the third column. 

3.2.2 DOT Routing Guidelines for Hi~hwav Route Controlled Quantitv Shiuments of 

Radioactive Materials 

These DOT routing guidelines provide a methodology for states and other jurisdictions to use 

when determining the lowest risk route for the transport of highway route controlled quantity 

(HRCQ) radioactive materials. "Highway route controlled quantity" is a term specifically 

defined in the Federal Hazardous Materials Regulations (see 49 CFR 173.403). 

The methodology used in the guidelines is to develop a "figure of merit" for each route considered. This figure represents the comparative risk between routes; it is not a measure of absolute risk. Each figure of merit is developed based upon three primary risk factors: normal 

radiation exposure, public health risk from accidents, and economic risk from accidents (see 

Exhibit 2). 

Normal radiation exposure refers to the amount of radiation emitted during normal, or 

incident-free, transportation operations. An equation is used to calculate the normal radiation 

exposure factor. This equation includes the following components: average population 

density, length of route, vehicle speed, and average traffic count. 

Public health risk from accidents refers to the potential number of people exposed if a transportation accident were severe enough to lead to a release of the radioactive materials from the 

transport container. Risk from accidental release of radioactive materials depends on two 

factors: 
Exhibit 2. Factors in Routing Guidelines Developed for Use by 

State and Local Governments 

Generic Factors Specific Factors Measurable Components 

U.S. DOT Hazmat Guidelines 

Primary Factors: 

Relative Population Accident probability Accident rate 

Risk 

Population potentially at risk Population within "impact" zone (depends 

on hazard class) 

Relative Property Risk Accident probability Accident rate 

Property potentially at risk Property value of lineal frontage 

Subjective Factors: 

Special Populations Type of special populations Number along route 

(schools, hospitals, etc.) 

Special Properties Type of special properties Number along route 

(utilities, structures, etc.) 

Emergency Response Emergency response facilities Proximity to route segments 

Other As identified by the community doing 

the analysis 

U.S. DOT HRCQ Guidelines 

Primary Factors: 

Normal Radiation Population potentially exposed Population with 0-5 mile band; Transport - 

Exposure workers (drivers, handlers, etc.); 

Passengers in other vehicles; People 

at stops 

Travel time Shipment distance; Vehicle speed 

Public Health Risk Accident release consequence Population within 0-5 mile band; 

from Accidents Population within 5-10 mile band 

Accident release frequency 

Economic Risks from Accident release consequence 

Accidents 

Accident rate 

Types of property within 0-5 mile band; 

Types of property within 5-10 mile band 

Accident release frequency Accident rate 

Secondary Factors: 

Emergency Response Response time; equipment availability; None-Subjective scaling 

training; manpower availability; type 

of land use 

Evacuation Population density; egress availability; None-Subjective scaling 

manpower/equipment; evacuation time; 

evacuation impacts; land use type 

Special Facilities Dose response; accident evacuation; None-Subjective scaling 

economics; type of facility 

Traffic Fatalities and Fatalities and injuries Accident rate 

Injuries 

Canadian Route Screening for Dangerous Goods by Highway 

Population Risk Population potentially exposed Population within impact area 

Accident probability Accident rate 

Property Risk Property potentially exposed Property within impact area 

Accident probability Accident rate 

Environmental Risk Sensitive environments potentially Sensitive environments within impact area 

exposed 

Accident probability Accident rate 

Emergency Response Emergency response capability Number of units within 10 minutes 
1. The frequency of accidents that could result in release 

2. The consequence from such accidents, in terms of the number of people that could be 

exposed to radioactive materials if a release occurs. 

Accident release frequencies are calculated by multiplying the accident rate by the route or 

route segment length. Packages containing HRCQ radioactive materials are required by DOT 

and NRC regulations to retain their contents even in very severe accidents. Consequently, the 

guidelines suggest the use of accident rates that represent the most severe accidents involving 

the types of vehicles expected to carry HRCQ. The most appropriate would be the fatality rate 

for drivers of vehicles containing hazardous materials. Since this level of specificity in 

accident rates is usually not available, DOT provides a rank preference list for the types of 

accident rates that could best represent accident release frequencies. 

Accident release consequences depend on a number of factors, many of which (such as atmospheric conditions and type of material transported) would be similar for two alternate routes. 

This greatly simplifies the calculation of consequences to a consideration of the differing levels 

of population along the route or route segment. 

Economic risk from accidents refers to the potential contamination of property near the roadway that could result if a transportation accident were to occur. The cost of removing 

contaminated property would vary widely based on the type of property adjacent to the 

roadway. To determine the risk, the type of property along the route segment is classified as 

rural, residential, commercial/industrial, park, or public area. 

If an analysis of the primary factors does not indicate a clear choice for the lowest risk route, 

secondary factors may be considered. These include emergency response, evacuation 

potential, special facilities, and traffic fatalities and injuries. 

A summary of the primary and secondary factors for the HRCQ guidelines is presented in the 

middle portion of Exhibit 2. Again, these factors are further broken down into more specific 

elements and measurable components for each of these elements. 

3.2.3 Canadian Route Screening Guidelines for Danperous Goods bv Truck 

The Canadian route screening guidelines provide the Canadian national approach for routing 

hazardous materials (dangerous goods). This methodology is similar to the current U.S. DOT 

hazardous materials routing guidelines, but it puts greater emphasis on emergency response 

and environmental impacts to make the final routing decision. Overall, four major factors are 

identified to help select routes: population risk, property risk, environmental risk, and 

emergency response. This is shown in the lower portion of Exhibit 2. 

The routing method relies on three major inputs: (1) accident probability, (2) accident consequences, and (3) emergency response capabilities. Accident consequences are further subdivided into population, property, and environmental exposure. 
Accident probabilities are composed of accident rate data and length of route segments. Consequences are estimated assuming a hazard exposure corridor two kilometers in width (other 

corridor widths can be used). Reference data are provided to help quantify population, 

property, and environmental exposure. Emergency response capability is defined as the 

number of qualified response units that could respond to the accident within 10 minutes 

divided by the length of the relevant route segment. 

Routes are screened using the lowest level of analytical detail to eliminate those routes that are 

clearly not suitable. This screening includes consideration of physical and legal constraints to 

hazardous material transport. Once the number of potential routes has been reduced to a 

manageable size, a more detailed analysis is performed. The final selection of a route is made 

in either of two ways. In one method, each route receives a single risk number that translates 

various risk assessment elements into one number (the route with the highest number is 

preferred). The other method is to stop short of this final translation, present the major 

assessment attributes in a tabular form, and allow the decision makers to apply subjective judgment. 

3.3 CANDIDATE MODE AND ROUTE FACTORS IDENTIFIED IN HMTUSA 

HMTUSA contains several provisions that relate directly to modehoute selection criteria. 

First, as discussed in Chapter 1, Section 15 of HMTUSA requires conducting a mode and 

route study. Section 15 also identifies a number of specific factors that are to be considered in I that study (see Exhibit 3). Second, Section 4 of HMTUSA directs DOT to establish federal 

I Exhibit 3. Potential Mode and Route Selection Factors Identified in HMTUSA 

~ 

I Section 4-Hiehwav Routi~auiremen& 

Population density 

Type of highways 

Type and quantities of hazardous materials 

Emergency response capabilities 

Results of consultations with affected parties 

Exposure and other risk factors 

Terrain considerations 

Continuity of routes 

Alternative routes 

Effects on commerce 

Delays in transportation 

I Section 15--Mode and Route Studv ReauiremenQ 

Population density 

Types and conditions of modal infrastructures (such as highways, 

railbeds, and waterways) 

Quantities of high-level waste and spent nuclear fuel 

Emergency response capabilities 

Exposure and other risk factors 

Terrain considerations 

Continuity of routes 

Available alternative routes 

Environmental impact factors 
standards for the states and Indian tribes to use to designate routes. (The FHWA has 

promulgated this rule, as previously mentioned.) Congress also includes a list of factors that 

DOT is to consider for this rulemaking. These factors are also shown in Exhibit 3 and were 

included in the comprehensive list of factors developed for consideration in this study. 

3.4 CANDIDATE MODE AND ROUTE FACTORS IDENTIFIED IN THE 

LITERATURE 

An extensive literature review was conducted to identify factors that carriers, shippers, and 

other interested parties have identified as being particularly important in selecting a mode and 

route to improve safety. Over 200 documents were reviewed. Documents were chosen by 

consulting with DOT staff, other federal and state agencies, the TAG established for this 

study, and carriers and shippers, as well as by searching the Transportation Research 

Information Service (TRIS). A bibliography of pertinent documents reviewed by the project 

team is given in Appendix C. 

The documents reviewed for this project can be categorized as follows: 

Modal studies 

Routing studieslevaluations 

Risk assessments 

Environmental assessments 

General hazardous material transportation studies. 

Obviously, there is considerable overlap of some documents across these categories. 

Exhibit 4 presents a comprehensive list of every potential factor identified from the review of 

past studies and documents as important for route andlor mode selection. Only minor editing 

has been done to the initial raw list of factors drawn from the literature review. Some of the 

factors appeared in many documents, while others appeared in only one or a few documents. 

No attempt was made to weight their importance by the number or type of documents in which 

the factor was considered. No importance is implied by the order of presentation in Exhibit 4. 

The project team was careful not to prejudge the validity of the factors during the literature 

review. The factors were included in the comprehensive list regardless of their source. Many 

of the source documents were technical studies in which few mode or route factors were 

evaluated in great detail. Other documents treated factors in a more summary fashion. A 

number of documents reviewed were actually reports on the results of public meetings or were 

reports that incorporated public input. As such, the list represents a broad cross section of 

viewpoints. 
Exhibit 4. List of Factors Identified During Literature Review That Have Been Evaluated 

or Proposed as Key Issues for Mode and/or Route Selection - 

- Population at risk 

Length of shipment 

Community "safety index" 

Classification of highway, railway, or waterway 

Grade of highway or railway 

Separation of traffic 

Accident likelihood 

Tradeoff between risk and travel time 

Population density 

Number of crossings or intersections 

High accident locations ("hot spots") 

Local viewpoints 

Worker population at risk 

Cask design and fabrication 

Emergency response 

Tradeoff between population centers and circuitous routes 

Train stops per trip 

Stop times 

Train speed between terminals 

Posted speed limits by routelmode 

System elasticitylrecoverability 

Train crew exposure 

Track profile 

Exposures during train stops to crew and surrounding population 

Track or road curvature 

Run-through (dedicated) vs. classification trains 

Shipment duration 

Amount of other hazmat traffic along modelroute 

Wayside detectors along rail routes 

Exposure to escorts and responders 

- Movement control, signalization, etc. by mode 

Carrier communicationltracking capability 

Hiring practices and training by camerlmode 

Substance abuse programs (vary by modelcamer) 

Sabotage and vandalism (vary by mode) 

Quantity of material to be shipped and cask capacity (causes 

number of shipments by mode to vary) 

- Population brought into contact 

Non-occupation exposure to persons beside the right-of-way (offlink dose) 

Exposures during highway stops (truck stops, etc.) 

Low probabilityhigh consequence accident potential 

Time of day for shipment 

Distance of crew from packagings 

Distance of population from shipments 

Configuration of shipment (dedicated vs. regular train, single vs. 

truck convoy, etc.) 

Escort requirements by mode 

Percent of travel in population zones (urban, suburban, rural) 

Non-radiological impacts such as regular accidents 

Radiological impacts from accidents 

* Number of waste shipments 

Vehicle speed 

Quality control by camer 

Human error potential 

Equipment exchanges en route 

Number of inspections (may vary by mode and route) 

Exposure to others sharing same route (on-link exposure) 

Stop timeldelays at origin and destination rail terminals 

Originldestination 

Need to pick up or drop off cars en route 

Work ruleslunion procedures (vary by camerlmode) 

Proximity of emergency responders 

Communication capability of responders 

Equipment availabilitylreplacement for emergency response 

Ability to restore to normal after response to accident 

Total number of stops en route 

Number of handling railroads 

Incidence of classification 

Level of enforcement (varies by route or mode) 

State licensing requirements 

* Camer shipment monitoring capability 

Weatherlwind conditions (differ by route location) 

Visibility conditions en route 

Cask size limitations (weight, height) 

Degree of cooperation with jurisdiction along route 

Person exposure 
3.5 COMPREHENSIVE LIST OF CANDIDATE FACTORS 

The factors identified from routing guidelines, legislation, and the literature review were consolidated into a comprehensive list of potential mode and route factors. Before this could be 

done, the raw lists had to be edited to eliminate redundancies and anomalies. First, there was 

some duplication of the factors in the lists (see Exhibits 2, 3, and 4). For example, 

"population density" is listed as a factor in Exhibits 3 and 4. Second, a number of factors 

could be combined into one representative factor. For example, "population at risk," 

"exposure," "population density," and "population brought into contact" all relate to 

population subject to exposure. "Population" was used as the representative factor for all of 

these in the comprehensive list and was then broken up into its various components (residential, occupational, etc.). 

Finally, several "factors" in Exhibit 4 were either so general in nature or combined several 

discrete factors in such a way that they had to be broken up into constituent factors that could 

be measured and compared with other factors. Examples include: 

Tradeoffs between population centers and circuitous routes 

Low-probabilitylhigh-consequence accident potential 

Run-through vs . classification trains 

Configuration of shipments 

Stop timeldelays at origin and destination terminals. 

The net result of the editing process was a single comprehensive list of 82 potential mode and 

route factors. The factors were organized into eight general categories to facilitate the initial 

evaluation by the TAG (see Chapter 4 for more on this group). These factors and categories 

are shown in Exhibit 5 along with an example to further illustrate each factor. 
Exhibit 5. Comprehensive List of Candidate Factors 

Safety Factor Example 

Ponulation and Environment 

Occupational: on-board 

Occupational: support 

Public: residential 

Public: non-residential 

Public: shared-facility users 

Public: special populations 

Sensitive environments 

Transnortation Infrastructure and Utilization 

Functional classification 

Opposing traffic separation 

Grade 

Curvature 

Crossings 

"Hot Spots" 

Accident likelihood 

Posted speed 

Route length 

Clearancelweight limitations 

Traffic density 

Maintenance 

Accident rate and severity 

System elasticity 

Travel timesldelays 

Structural impediments 

Hazmat traffic density 

Wayside detectors 

- Available detours 

Qneratinv Procedures 

Time of day 

Operating speed 

Crew on vehicle 

Handling, security, interchange 

People at home 

People at work, tourists 

Other traftic on route, at stops 

Hospitals, schools, arenas, prisons 

Wetlands, refuges, reservoirs, tribal sacred grounds 

Arterial, collector, local or class 1, class 2 

Median or two tracks 

Uphill or downhill 

Curve in alignment 

Intersections, rail crossings, river confluences 

Known problem areas 

Number of accidents per mile along route or by mode 

Speed limit 

Distance for mode 

Bridge clearances, channel depth 

Vehicles per length per lane 

Upkeep of roads or rails or channels 

National or local accident statistics 

Ability to resume normal conditions after an incident 

Congestion 

Light poles or guardrails 

Density of other hazmat vehicles 

Hotbox, dragging equipment 

systemrm-r- - -- 

Rush hour conditions 

Controlled speed 

Number of stops Rests or sidings for other traffic to pass, refueling, locks and dams 
Exhibit 5. Comprehensive List of Candidate Factors (Continued) 

Safety Factor Example 

Ooeratin~ Procedures (Continued) 

Stop times 

Crew distance from cask(s) 

Configuration 

Escorts 

Interchanges 

Classifications 

Handlings 

Equipment changes en route 

Inspections 

Originldestination 

Pick upldrop off en route 

Work rules 

Available alternatives 

Emer~encv Resoonse (ER) 

Proximity/accessibility 

Capability 

Evacuation potential 

Communication 

Equipment replacement 

Restoration to normal operations 

Medical care 

Response times 

Training 

Available manpower 

Oualitv Control 

Movement control 

Communication 

Training 

Hiring practices 

Enforcement 

Dispatching 

Average time of stops 

Locating crew on vehicle 

Dedicated vs. regular trains, convoys, other hazmat involved 

Chase vehicles, ER, armed guards, medical 

Changing rail carriers 

Rail yard classification 

Casks are loaded/unloaded on vehicle 

Changing locomotives 

Checking equipment at stops 

Beginning and ending of route 

Adding vehicles from sidings 

Hours for driver operation 

Other routes or modes available to serve O/D 

Location of ER with respect to route 

Ability to respond to nuclear waste accident 

Can surrounding population be evacuated 

Remote computer, fax links 

Availability of equipment (rail cars, tractor trailers) 

Time for normal activity to resume 

Type of care for radiation exposure 

Time to provide effective response 

Quality and amount of training for ER 

Number of available responses 

Signalization 

Procedure for contacting vehicle 

Driving, emergency, handling 

Driver experience, previous driving record 

Company procedures 

Hours of operation 

Vehicle maintenancelinspection Company procedures 
Exhibit 5. Comprehensive List of Candidate Factors (Continued) 

Safety Factor Example 

(Continued) 

Licensing 

System monitoring 

Substance abuse enforcement 

Sabotage and vandalism 

WeatherIClimate TerrainICondition~ 

Seasonal road conditions 

Terrain 

Wind speed, direction, stability 

Visibility 

Shinment Characteristie 

Waste type and level of radioactivity 

Number of waste shipments 

Quantity per shipment 

Cask capacity 

Release rates 

Cask availability 

Cask size limitations 

Re~ulation and Other Restrictions 

Cask design and fabrications 

Legal restrictions 

Time of day restrictions 

Jurisdictional cooperation 

Continuity of routes 

Effects on commerce 

Consultations with affected parties 

Communitv Safetv Index 

State procedures 

Ability to track vehicle 

Monitoring for substance abuse 

Obstructions on right of way (ROW), destruction of signs and signals 

Snow or sleet, hot or cold 

Mountainous, hilly, flat 

Wind conditions for dispersal 

Fog, dust, fires 

Age and type of nuclear waste 

Number of shipments per time 

Size of shipment 

Size of cask 

Non-accident material release 

Type and size of cask 

Physical constraints (weight, length, etc.) 

Type of cask 

Existing legal restrictions due to overweight, oversize, or hazmat 

City blackouts (no-travel times) 

State-Federal cooperation 

Continuous route for carrier 

Increased transit times 

Discussions with surrounding communities 

Subjective rating of local conditions 
4. QUALITATIVE EVALUATION OF CANDIDATE FACTORS AND 

SELECTION OF PRIMARY MODE AND ROUTE FACTORS 

Screening and evaluating the comprehensive list of candidate mode and route factors led to the 

identification of a set of primary factors. This chapter reviews the screening process and the 

results of the evaluation of candidate factors. 

4.1 SCREENING OF COMPREHENSIVE LIST OF FACTORS 

The purpose of the screening process was to begin to narrow down the number of candidate . 

mode and route factors so that, ultimately, the most important factors could be identified. 

Key considerations in the screening process included (1) a factor's relationship to the project 

definition of public safety, (2) the extent to which a factor could affect mode or route choice, 

(3) interdependencies among factors, and (4) the extent to which candidate factors can be measured and applied. A factor may be closely related to safety, yet its importance is diminished 

if it cannot be effectively measured or if it would be difficult or impractical to use it in the 

decision-making process. These criteria were applied to each factor within every functional 

group on the comprehensive list. 

4.1.1 Technical Advisorv Group 

A ModeIRoute Technical Advisory Group (TAG) was convened for this study to assist in 

reviewing and screening the comprehensive list of factors. The group consisted of representatives from most sectors that have an interest in the selection of mode and route factors for 

transporting high-level radioactive waste and spent nuclear fuel. Representatives were invited 

from the following sectors: 

Highway carriers 

Rail carriers 

Water carriers 

Nuclear shippers 

State and local governments 

Tribal governments 

Regional state groups 

Regional energy groups 

Public interest groups 

Federal agencies 

Federal agencies that were invited to participate included the DOT (including the Research and 

Special Programs Administration, FHWA, FRA, and the U.S. Coast Guard), the Nuclear 

Regulatory Commission, the Nuclear Waste Technical Review Board, and the U.S. Depart- 
ment of Energy (DOE). The individuals and organizations participating in the TAG are 

identified in Appendix B. 

The purpose of convening the TAG was to gather viewpoints from as broad a spectrum as possible. A consensus on selection of mode and route factors was not envisioned, given the wide 

difference of backgrounds and positions of the members. The goal was for the TAG to assist 

in the screening process by reviewing the comprehensive list of candidate factors and making 

recommendations on each factor. 

4.1.2 TAG Meeting and Review of Factors 

The TAG met for one day in Chicago, Illinois, on May 18, 1993. Prior to the meeting, the 

group was provided with the initial comprehensive list of factors for review. The group was 

divided into three workshops, each facilitated by a study team member. The factors on the 

comprehensive list were reviewed and discussed in the workshops. TAG members were asked 

their opinions on the validity of the initial list, the relative importance of each factor, the 

manner in which the factors should be organized, the possibility of measuring the factors, and 

the feasibility of implementing the factors. 

The individual workshops proved to be very useful for generating detailed discussions of some 

of the potential modelroute factors on the comprehensive list. There was a common 

recognition that substantial interrelationships existed among many of the factors and that the 

list could be better organized to reflect the relationships. Several categories of factors 

generated the most interest. These included emergency response and environmental factors. 

Most of the TAG members were familiar and comfortable with factors relating to population, 

accident rates, and shipment duration as mode and route selection factors. Environmental and 

emergency response factors were recognized as important safety considerations by all TAG 

members, but there was disagreement on whether these were modelroute discriminators. 

Some TAG members were strongly in support of both factors, while others completely 

disagreed that they had any relationship to modelroute selection. 

During the course of the workshops, a number of important issues surfaced that were related 

to this study. Some of the issues could be addressed, and the study approach was adjusted 

accordingly. Other issues could not be addressed because their resolution would go beyond 

the scope and resources of the project. 

One issue was the context and timeframe for which this study was to apply. The specific concern raised was that the context for this study should be the commercial radioactive waste program and, therefore, the timeframe should be for the next 10 to 20 years. The argument was 

that almost all of the future shipments of high-level radioactive waste and spent nuclear fuel 

would be the movement of commercial reactor waste from utilities to a repository. Thus, the 

consideration of modelroute factors should be designed primarily to address the specific issues 

and the long planning horizon related to the commercial repository program. Others disagreed 

that this study should be tailored to that program, however important it will be in the future. 

A significant number of shipments could commence earlier (1998-2000) if DOE is successful 
in siting and building a Monitored Retrievable Storage (MRS) facility, if Congress authorizes 

commercial SNF storage at DOE facilities, or if private entities fund the development of an 

independent storage facility. Subsequently, DOT decided to keep this study generic s6 that its 

findings would be useful for planning both ongoing and relatively near-term shipments as well 

as NWPA shipments further in the future. For the latter, guidance provided by this study may 

facilitate both the establishment of modelroute selection policies for DOE and agreement 

among DOE, carriers, and representatives of the public interest regarding specific routes to the 

MRS and repository. 

Another issue of concern was whether the project definition of public safety should include 

perceived risk. Almost everyone agreed on the importance of risk perception in public 

acceptance of radioactive material transportation. It was also agreed that perceived risk 

directly impacts some decisions about transporting these materials. The question was how to 

reconcile perception and reality in a study such as this. It was noted that addressing perceived 

risk is not something that can actually enhance safety in the same manner as addressing actual 

risk, such as incident-fiee exposure and accident risks. It was pointed out that perceived risks 

can actually be addressed, at least in part, by doing a better job of addressing the actual risk 

factors. 

The TAG'S discussion of perceived risk was reviewed in light of the objectives of this study 

and other considerations to determine what role, if any, it should play in this study. The study 

team acknowledged that perceived risks may have a legitimate role in modelroute selection. 

Such concerns, however, are usually local in nature, difficult to treat quantitatively, and vary a 

great deal from case to case. It would, therefore, be unrealistic to expect shippers and carriers 

to anticipate what those concerns may be for a given shipping campaign, much less to be 

effective advocates for such issues. Rather, it is appropriate for state and local governments 

and other entities representing public interests to identify and advance such concerns. In a 

joint decision-making process (among shippers, carriers, and representatives of public 

interests), perceived risks would be considered when arriving at a final choice among a set of 

viable options identified by shippers and carriers using the selection factors recommended by 

this report. Consequently, it was decided not to include perceived risk within the project 

definition of public safety. 

Another issue addressed by the TAG was intermodal shipments. To scope the range of modal 

and intermodal options to be addressed by this study, the project team proposed to the TAG 

members that not all intermodal combinations need to be addressed in detail by this study 

because of the significant exposure resulting from intermodal transfer of the casks. Previous 

studies have shown that this exposure greatly increases the total exposure and overall risk of 

shipments. There was general acknowledgment that the intermodal transfer exposure is a very 

significant factor that tends to favor single-mode transport. Some members, however, felt 

very strongly that intermodal combinations should be considered for at least two options. 

First, for the present transportation infrastructure, a highway link between rail and the potential commercial repository site in Nevada would be required. Second, because barge transport 

is being considered, a barge-rail route would be the most feasible option since cask size 
limitation for trucks would make barge-highway of limited practicality. These 

recommendations were adopted in the study approach. 

The issue of weighting radiological and non-radiological risk was also brought up by some 

TAG members. This has always been a major area of concern in conducting risk assessments 

for transporting radioactive materials. The issue is whether these components of risk should 

be given equal weight. Some argued strongly that non-radiological risk should not be included 

as a primary routing criterion with the same level of importance or weight as radiological risk 

because it does not address the risk from the nature of the cargo. If non-radiological risk is 

included on the same level as radiological, then the overall risk of transport is dominated by 

the non-radiological accident impacts, since non-radiological accidents occur far more 

frequently than accidents involving a radiological release. Thus, the risk analysis would 

always find that the mode/route combinations with the lowest general accident rate would be 

the safest route. Others argued that non-radiological impacts are, in fact, legitimate impacts 

from shipping radioactive materials and that it would be inappropriate to exclude them. This 

issue involves significant policy considerations and was not resolved as a part of this study. It 

was decided by the project team that non-radiological impacts should be included as a 

component of the project definition of public safety, since it is traditionally included in risk 

assessment studies. Also, since it is not an objective of this study to assign weights to model 

route factors, this issue did not have to be resolved to complete the study. 

4.1.3 Distinction Between Mode and Route Factors 

As the evaluation process developed, only a few factors could be identified that affect mode 

selection exclusively. For most factors, it was difficult to separate mode from route 

considerations. Three factors were found to be mode-only selection factors: (1) mode 

accessibility, (2) cask availability, and (3) amount of material to be shipped. The first two 

factors are obvious practical constraints in mode selection. Circumstances will dictate the 

mode to be used if either (1) the waterway or rail system is not accessible from a given 

location, (2) the facility lacks the capability to handle the heavy raillbarge casks, or (3) a cask 

needed for a mode is unavailable. These constraints, however, are not necessarily 

insurmountable; in most cases, they can be overcome if there is sufficient incentive to use a 

given mode and enough time or funding. 

The amount of material to be shipped is the single most important factor that could affect the 

choice of mode exclusively, because of the substantial difference in payload between truck and 

rail casks. A rail cask (which is also used for barge transport) has from four to seven times 

the payload of a truck cask. This ratio may actually increase in future generations of casks 

(unless an overweight truck cask is developed). This differential has an obvious impact on the 

number of shipments required for a given amount of material. The number of shipments, in 

turn, has a direct impact on the overall safety of a shipping campaign. 

The rest of the factors on the comprehensive list did not affect either mode or route exclusively. The factors had to be considered within the context of the mode and route combination 

(including intermodal). For example, when comparing the safety of highway and rail between 
common origin and destination points, more than one route will usually be possible by either 

mode (especially for longer shipments). In addition, intermodal combinations with different 

routing and interchange points are possible. The risk for one rail route may be lower than the 

risk of a highway route, yet the corresponding risk for another rail route may be higher. 

Thus, it cannot be concluded that one mode is safer than another without considering the 

specific route. 

Except for amount of material, mode accessibility, and cask availability, all other factors are 

considered a homogenous group of mode/route selection factors, not mode or route factors 

separately. The distinction between the mode-only factors (primarily the amount of material) 

and all of the other modelroute factors will be addressed later in this report. 

4.2 DEVELOPMENT OF FACTOR HIERARCHY 

Based on the findings of the initial screening of factors and the results of the TAG review process, a hierarchical matrix was developed with the goal of organizing the enumerated list of 

factors into different levels for each of the three public safety categories defined in Section 

1.3. The rationale for this approach is presented below. 

4.2.1 Hierarchical A~~roach to Mode and Route Factors 

During the screening process, any initially identified factor that did not affect public safety 

was deleted. It became very difficult to eliminate many factors, no matter how inconsequential 

the factors seemed to be, however, because the applicability of each potential factor depends 

on the level of analysis to be conducted. For example, excessive curvature along a route 

cannot be categorically excluded as unrelated to safety. It depends on how detailed the 

shipper, carrier, or public official intends the routing analysis to be (e.g., local, regional, or 

national in scope). 

To evaluate a route at the local level (e.g., comparing two modelroute alternatives over a distance of 40 miles), decision makers may want to consider such microscopic factors as highaccident locations ("hot spots"), grades, or structures along the route of travel. On the other 

hand, if the shipment is cross-country for 1,500 miles, the level of analysis needs to be more 

general. The analyst would not, and probably could not, be able to account for the myriad of 

microscopic factors. Taken together, however, all three of the microscopic factors mentioned 

above are components of the infrastructure along the route, which, in turn, is a prime determinant of the accident rate. Accident rate, therefore, represents a higher level factor that can 

be used for regional and national analyses to help select modes/routes. This higher level 

factor implicitly accounts for the factors below it in the hierarchy, if the accident rate for a 

given route is derived from data for that route or otherwise reflects the characteristics of that 

route (i.e., if a national average or other generic rate is not used). 

The hierarchical approach to selecting modelroute factors allows adjustment of the level of 

analysis to the shipment situation. Many of the microscopic factors that have been identified 
in the past are valid for very short distances. The details, however, become unmanageable for 

regional and national shipments. The hierarchy shows that the analysis can be simplified by 

using factors at the upper end of the hierarchy, since they are fewer and more feasible to measure, and data are more readily available for them. Furthermore, these higher level factors are 

legitimately representative of the lower level factors, as shown by the hierarchical 

relationships. 

The three categories of impact from the definition of overall public safety (incident-free 

radiological exposure, potential accident-induced radiological exposure, and potential nonradiological impact) were considered separately in establishing the hierarchical factor matrix. 

Each factor from the comprehensive list was evaluated to identify which category or categories 

it affected and how it was related to other factors within that category. These relationships 

could be divided into two types: (1) factors that were subsets of other factors and (2) factors 

that could have a direct effect on another factor. An example of the first type would be people 

in hospitals as a subset of special populations, which is a subset of total population. An 

example of the second type would be road conditions that could affect the speed of the vehicle, 

which, in turn, would affect the overall shipment duration, which then affects the amount of 

incident-free radiological exposure. 

4.2.2 Hierarchv for Incident-Free Radiolo~ical Exmsure (Exhibit 6) 

The comprehensive list of factors was carefully reviewed to determine which factors affect 

incident-free radiological exposure during transportation. These factors were then evaluated 

for interrelationships. The major factors influencing normal dose from radioactive material 

transportation were the number of people potentially exposed and the amount of exposure 

time. The rest of the factors are lower-level, but nonetheless important, elements that 

contribute to and are subsets of these two primary factors. 

For people exposed, the major dichotomy is the exposure of the general population versus the 

occupational population. These are treated as two separate modelroute factors because of their 

fundamentally different impacts (involuntary, short-term, and distant exposure versus 

voluntary, longer-term, and close proximity exposure). 

Four primary factors were identified that affect modelroute choices because of their influence 

on incident-free exposure. These are (1) general population exposure, (2) occupational exposure, (3) shipment duration, and (4) amount of material. Each of these comprises a number of 

components or subfactors, which are arranged in a hierarchy and presented in Exhibit 6. 

General population exposure can be segmented into several major subfactors: residential, 

non-residential, and "special." Residential population represents census population. Non-residential population can be broken down into employment population (which recognizes that 

time-of-day population varies considerably as people go from home to work and back), tour- 
Exhibit 6. Factor Hierarchy for Incident-Free Radiological Exposure 

General Ponulation Shinment Duration 

Residential 

Non-Residential 

People at work 

Tourists 

Pedestrians 

Shared-facility users in other vehicles at stops 

Shared-facility users on route 

Special Populations 

Hospitals 

Schools 

Prisons 

Events 

Occunational Ponulatioq 

On-boardlnearby 

Crew 

Escorts 

Support 

Handlers 

Security 

Inspectors 

Emergency 

Responders to non-radiological incident 

Amount of Material 

Number of shipments 

Packages per shipment 

Size of cask 

Cask availability 

Waste typeAevel of radioactivity 

Cask size limitation 

Length of route 

Originldestination distance 

Vehicle speed 

Normal operation 

functional classification 

posted speed 

operating speed 

traffic density 

traffic mix 

maintenance 

time of day 

work rules 

movement control 

enforcement 

time of day restrictions 

Delays 

communication 

seasonal road conditions 

hot spots 

incidentlaccident rate 

available detours 

right-of-way maintenance 

weatherlclimate 

visibilityllighting conditions 

Stops 

Number of stops 

interchanges 

classifications 

handlings 

inspections 

equipment changes 

pick-upldrop-off route 

union vs. non-union rules 

delays idout of originldestination 

priority passing 

locks and dams 

sabotage 

stop timesists, people in other vehicles along the right-of-way, and people at stops (see Exhibit 6). An 

important related issue for this factor is the distance from the right-of-way to affected 

populations. Special populations are those people believed to be more sensitive to the effects 

of radiation (e.g., children) and/or those located in large facilities that would be difficult to 

evacuate, such as hospitals, schools, prisons and stadiums. 

Occ~p~onalpopulation exposure consists primarily of two subgroups: (1) on-board crew 

and nearby escorts and (2) support workers (such as handlers) at the shipment origin, 

destination, and transfer points, as well as inspectors and security staff. This would also 

include emergency response and service personnel at the scene of a non-radiological traffic 

accident or other incident involving a vehicle carrying radioactive material. 

Shipment duration, or time of exposure, is the other primary factor for incident-free 

exposure. Many factors in the comprehensive list could affect shipment duration. These can 

be categorized into three major subfactors: (1) route length, (2) vehicle speed, and (3) stops 
en route. Route length is simply the distance between the origin and destination. Vehicle 

speed can be influenced by many factors, including both normal operations and delay conditions. Some of these include the speed limits, type of transport link, traffic deniity, and time 

of day. Stops en route include the number of stops and stop times. These can be affected by 

the number of interchanges, inspections, classifications, breakbulk operations, equipment 

changes, union rules, fuel stops, and other factors. 

It should be noted that several members of the TAG argued that there is an incident-free 

radiological exposure risk for the environment. This potential impact, however, has never 

been measured and others in the TAG believed that such an impact, if it exists, is 

inconsequential. It is not included as a factor in this study. 

Amount of material is not a selection factor that affects incident-free radiological exposure on 

a per shipment basis. Regulatory requirements limit the permissible amount of surface 

radiation, which does not vary with the size of the package or the mode. The amount of 

material, however, can become a factor for mode selection, if multiple shipments are 

necessary. If the amount of material to be shipped exceeds the capacity of a single truck cask, 

then the shipper may choose to use the larger raillbarge cask which would reduce the number 

of shipments needed. That, in turn, affects the total incident-free exposure from an entire 

shipping campaign. 

4.2.3 Hierarchv for Accident-Induced Radioloskal Exposure (Exhibit 7) 

Seven primary factors affect modelroute choices because of their influence on accident-induced 

radiological exposure. Two affect the statistical likelihood of accidents: (1) accident rate and 

(2) trip length. Four affect accident consequences: (1) general population exposure, (2) 

occupational exposure, (3) sensitive environments, and (4) emergency response. Amount of 

material is included because it could affect cask payload and the number of shipments 

required. Exhibit 7 lists the primary factors for accident-induced radiological exposure in 

which associated subfactors are arranged in a hierarchy. 

Using the same procedure as for incident-free radiological exposure, the comprehensive list 

was scanned to identify factors that could conceivably affect accident-induced radiological 

exposure. This category of public safety is more complex than the incident-free category, 

however. First, two major subcategories of factors influence potential accidents that are 

severe enough to cause a release of material: (1) accident likelihood (probability) and (2) 

accident consequences. Each of these is composed of a number of other factors. Second, two 

major types of impact could result from a release: (1) impact on people and (2) impact on the 

environment. Impact on property is a third type of impact from a release. Finally, emergency 

response capability must be considered, since it can have a significant effect on the magnitude 

of consequences following an accidental release. 

Accident Likelihood. All factors that could affect the likelihood of an accident during 

transportation, particularly one that could cause the release of RAM, were identified. A 

number of these fall under the category of infrastructure. These include the classification of 
Exhibit 7. Factor Hierarchy for Radiological Accident Exposure 

Accident Rate 

Infrastructure 

Functional classification 

Opposing traffic separation 

Grade 

Curvature 

Crossings 

Hot spots 

Posted speed 

Clearance 

Maintenance 

Structural impediments 

Wayside detectors 

Operating procedures 

Time of day 

Work rules 

Quality control 

Training 

Movement control 

Hiring practices 

Enforcement 

Vehicle maintenance/inspection 

Licensing 

Substance abuse enforcement 

Sabotage and vandalism 

Human error 

Weather/climate 

Seasonal road conditions 

Visibilityllighting conditions 

bgth of Trip 

Distance 

Weather conditions 

Route restrictions 

General Pooulation 

Residential 

Non-residential 

People at work 

Tourists 

Pedestrians 

Shared-facility users in other vehicles 

at stops 

Shared-facility users in other vehicles 

on route 

Special populations 

Hospitals 

Schools 

Prisons 

Events 

Bcuoational Pooulation 

On-boardhearby 

Crew 

Escorts 

Support 

Handlers 

Security 

Inspectors 

Responders 

Sensitive Environment 

Water supply 

Reservoirs 

Sensitive areas 

Wetlands 

Refuges 

Sacred tribal grounds 

Emereencv Resoonse 

Preparedness 

Training 

Equipment 

Response 

Proximity 

Accessibility 

Capability 

Communication 

Time to medical care 

Evacuation 

emount of Material 

Number of shipments 

Size of cask 

Cask availability 

Waste typellevel of radioactivity 

Cask size limitations 

Fire, police, etc. 

the right-of-way, grade and elevation, geometry and curvature, structures and clearances along 

the right-of-way, bottlenecks, and even maintenance practices of the authority responsible for 

the quality of the right-of-way. Two other subfactors that could contribute to accident 

likelihood are the operating practices of carriers and quality control. Although these would 

not normally be considered routing-related factors, they could have an influence on accident 

potential because they address the issue of quality of carrier. Carrier operating practices, 

although subject to minimum regulatory rules (such as driver service hours), can be 

substantially different from one mode to another and from one carrier to another. Quality 

control can affect accident likelihood and includes internal company procedures and degree of 

oversight to ensure quality performance. Quality control factors include training, maintenance 

policy, hiring policy, and drug and alcohol enforcement. 

Each of these three factors-(1) infrastructure, (2) operating practices, and (3) quality control-is a major contributor to the accident 1ikeliRood along a given modelroute combination. 

Thus, accident rate is considered a primary factor. Length of trip is also considered a primary 

factor, since it is traditionally used in conjunction with the number of accidents to calculate the 

accident rate (see Exhibit 7). 

The amount of material to be shipped affects mode choice and so indirectly affects accident 

likelihood in two ways. First, accident rate varies with mode. Second, cask capacity affects 
the overall number of shipments and, therefore, the likelihood of an accident during the 

campaign. 

Accident Consequences. As intimated above, three major factors relate to this category: 

(1) general population, (2) occupational population, and (3) environment. Obviously, the 

population within the proximity of an accidental release of radioactive materials is the major 

component of accident consequences. The subfactors of general population exposure and 

occupational exposure were discussed in the previous section. A third major factor under accident consequences is sensitive environments, because of the growing concern about long-term 

public health effects of contamination of sensitive environmental areas as a result of 

transportation spills. The lack of a universally accepted definition for "sensitive 

environments" and the difficulties inherent in determining what can reasonably be avoided 

during long-distance shipments, however, make this factor difficult to measure. The two 

principal environmental subfactors initially identified are water supply areas (such as reservoirs) and sensitive areas (such as wetlands, refuges, and sacred tribal grounds). 

A fourth component of accident consequences, emergency response, was identified separately 

as a primary factor. The emergency response along potential modes and routes of travel can 

be significant in limiting the consequences of an accident. Several key subfactors determine 

the level of efficiency of emergency response. Emergency preparedness (training, plans, and 

equipment) and actual emergency response operations (capability including number of 

personnel, proximity, and accessibility) are the key factors. 

Finally, amount of material to be shipped is also a major determinant of accident 

consequences, albeit indirectly. As discussed in the last section, the amount of material could 

affect the size of the cask used and, in turn, the potential amount of material that could be 

released in an accident. 

4.2.4 Hierarchv for Non-Radiolo~ical Im~act (Exhibit 8) 

Three primary factors were identified that affect the modelroute choice because of their 

influence on non-radiological impacts: (1) accident rate, (2) length of trip, and (3) amount of 

material. Exhibit 8 lists these primary factors for non-radiological impact, arranging 

associated subfactors in a hierarchy. 

The non-radiological impact was handled differently than the first two categories, because its 

impacts are related to injuries or deaths resulting from vehicular accidents and are unrelated to 

the radioactive nature of the cargo. It is included as a public safety impact because shipping 

spent nuclear fuel may necessitate additional trips on the transportation infrastructure, 

introducing an additional non-radiological traffic impact that otherwise would not exist. This 

would certainly be true for highway, dedicated train, and probably barge shipments, although 

probably not for regular train shipments. 

The two major factors in this category are (1) accident rate and (2) trip length. Accident rate 

is represented by a number of other lower-level factors, as discussed earlier. The major sub- 
Exhibit 8. Factor Hierarchy for Non-Radiological Impact 

Accident Rate 

Infrastructure 

Functional classification 

Opposing traffic separation 

Grade 

Curvature 

Crossings 

Hot spots 

Posted speed 

Route length 

Clearance 

Traflic density 

Maintenance 

Structural impediments 

Wayside detectors 

Operating procedures 

Time of day 

Work rules 

Amount of Material 

Quality control Number of shipments 

Training 

Movement control 

Hiring practices 

Enforcement 

Vehicle rnaintenance/inspection 

Licensing 

Substance abuse enforcement 

Sabotage and vandalism 

Human error 

Weatherlclimate 

Seasonal road conditions 

Visibilitynighting conditions 

LenHh of Trio 

Distance 

Weather conditions 

Route resbictions 

factors include infrastructure, carrier operating procedures, and quality control. Amount of 

material is also included as a primary factor because it affects both accident rate through mode 

choice and the number of shipments required. 

4.3 IDENTIFICATION OF PRIMARY FACTORS 

Exhibit 9 presents the list of primary modelroute factors identified for the three categories of 

impacts on overall public safety (incident-free radiological, accident-induced radiological, and 

non-radiological). These factors are primary because they are at the top of the factor 

hierarchy previously discussed and are representative of a number of subfactors positioned 

lower in the hierarchy. 

The eight primary factors are listed in the first column of Exhibit 9. The applicability of these 

factors to each of the three components of public safety are given in the next three columns. 

For example, "general population exposed" includes all of the population along the route of 

travel for incident-free radiological exposure and the population within an affected area for 

accident-induced radiological exposure. Population exposed is not considered a primary factor 

related to non-radiological impact. The other primary factors are treated in a similar manner. 

It is apparent from Exhibit 9 that, although eight primary factors are identified, they do not 

affect all components of public safety. Some of these factors affect two components of public 

safety, while others affect only one component. To be identified as a primary factor, at least 

one component of public safety must be significantly affected. 
Exhibit 9. Primary Mode and Route Factors 

Incident-Free Accident-Induced Non-Radiological 

Primary Factor Radiological Exposure Radiological Exposure Impact 

General population exposed People along route People in area affected by Not a primary factor 

accident 

Occupational population People moving and handling People moving material and Not a primary factor 

exposed material responders 

Environment exposed Not a factor Environment in area affected Not a factor 

by accident 

Shipment duration Length of time material is Not a factor 

transported 

Not a primary factor 

Accident rate Not a factor Likelihood of accident Likelihood of traffic 

releasing material accident with injury1 

fatality 

Trip length Not a primary factor Distance material moves Distance material moves 

Emergency response Not a factor Length of time for trained Not a primary factor 

responders 

Amount of material* Number of shipments required Number of shipments required Number of shipments 

* Amount of material is the only primary factor identified that could dictate &by itself. This is because of its impact on 

the number of shipments required, given the cask payloads of highway vs. rail transport modes. 

Furthermore, each of the primary factors may be measured differently from one component of 

public safety to another. An example is measuring accident rate. For accident-induced 

radiological exposure, the likelihood of a release-causing accident would be an appropriate 

measure, while for non-radiological impacts, the likelihood of an injury or fatality-related 

traffic accident (without considering release) would be a more relevant measure. 

Finally, the amount of material is listed as a primary factor because of its effect on the number 

of shipments required, which is perhaps the key factor for mode selection. The number of 

shipments required is determined by the quantity of material to be shipped and the cask 

payload. A rail cask payload can be four to seven times that of a legal weight truck cask. 

Thus, roughly four to seven times as many truck shipments are required to move the same 

amount of material as moved by rail or barge. This difference must be taken into account 

when comparing the relative impact on public safety among the three modes. 

It should be noted that it also is possible to include more than one cask per shipment for rail 

and barge shipments. If there is enough material to be moved at one time, it is theoretically 

possible to move ten, twenty, or more casks (if they were available) in a single rail or barge 

shipment. Shipments by rail or barge from different locations could be consolidated to obtain 

multiple casks per shipment. 

To facilitate the comparison of mode and route factors on a shipment-by-shipment basis without the complications of considering the effects of multiple casks per shipment, this study 

addresses mode and route factors only on a single cask per shipment basis. When the specific 

circumstances of a particular shipping campaign are known, the effect of multiple casks per 
shipment by rail or barge should be the subject of systems analyses and trade-off studies. 

Based on the results of such studies, the shipper should then consider the effect of multiple 

casks per shipment in the selection of the mode and route. 

4.4 REPRESENTATIVE UNITS OF MEASURE FOR THE PRIMARY FACTORS - 

The primary factors listed in Exhibit 9 are presented on a "generic" level. As stated earlier, 

even the best modehoute factor is really of little use in selecting mode/routes if it cannot be 

measured. To conduct an actual modelroute comparative analysis, it is necessary to identify 

the precise item that is to be compared. The project team has identified the most 

representative unit of measure for each primary factor. These are presented in Exhibit 10. 

These units of measure will serve as the basis of the case study analysis presented later in this. 

report. 

Exhibit 10. Representative Units of Measure for Primary 

Mode and Route Factors 

Primary Factor Representative Units of Measure 

General Population Exposed Census population within designated bandwidth along route in milesikilorneters 

Occupational Population Exposed Number of drivers and other transport workers involved during shipment 

Environment Exposed Number of environmentally sensitive areas within designated bandwidth along route 

Shipment Duration Transit time in hours (including stops) 

Accident Rate Number of fatalities based upon fatal accident rate and route length (fatal accident rate) 

Trip Length Trip distance in miles 

Emergency Response Average time to respond for qualified units in minuteshours 

Amount of Material Number of shipments required based upon cask payload 
Page intentionally left blank. 
5. IDENTIFICATION OF PRIMARY MODE AND ROUTE FACTORS 

BY MODELING RISK OF TRANSPORTING RADIOACTIVE 

MATERIALS 

Chapters 3 and 4 describe the development of a comprehensive list of modelroute factors that 

represent diverse interests identified through an exhaustive review of work and literature in 

the field. A qualitative evaluation of these factors resulted in the development of a factor 

hierarchy for each component of public safety, from which a set of primary modelroute 

factors was identified. This chapter presents a modeling approach to identify primary mode 

and route factors. Modeling the relationship between various factors that contribute to 

nuclear transportation risk serves two purposes: (1) it allows a comparison of factors 

developed in this way with the factors developed using the hierarchical approach described in 

Chapters 3 and 4, and (2) it helps establish the nature and type of relationship between each 

primary factor and the three components of risk that make up the project definition of public 

safety. 

5.1 ELEMENTS OF RISK 

As noted previously, risk is composed of incident-free radiological exposure, accident-induced 

radiological exposure, and non-radiological impact. These three components of risk can 

impact different population groups, which can be categorized as follows: 

Off-link population - people residing, working, or otherwise congregating in areas 

within the zone of radiation impact along the route of a spent nuclear fuel shipment 

On-link population - people in other vehicles along the route 

Crew - transport crew, on-board security and emergency response personnel, and 

inspectors (within the immediate vicinity of the cask) 

Population at stops - other transportation workers, including emergency responders 

during an accident and people near the stops (away from the immediate vicinity of the 

cask) 

Handling personnel - workers at an intermodal transfer facility. 

5.2 MODEL DEVELOPMENT 

The models described below are derived with the following simplifying assumptions: 

The applicable models are mode-specific; separate coefficient values are generated for 

each mode, resulting in a unique model for each respective mode. 
The width of incident-free radiation effect zones is a constant for each mode. 

An individual shipment contains a single cask; multiple cask shipments are 

considered. 

Only risks to handlers at intermodal transfer facilities are considered. 

Detailed derivations of the model equations and nomenclature presented in this section appear 

in Appendix F. 

5.2.1 Incident-Free Radiolo~ical Risk Model 

The total incident-free radiological risk from a single shipment on a specified mode between 

origin and destination consists of the sum of the component risks to each population group: 

R,:=R, +R,+R,+R,+R, 

where: 

RIFE = total risk (in p.erson-rems) due to incident-free exposure 

R, = risk to off-link population 

R, = risk to on-link population 

R3 = risk to crew 

& = risk to population at stops 

R, = risk to handlers 

Model formulations for each of the component risks are as follows. 

Off-Link Population. Off-link population risk is a function of the duration of exposure of 

each person along the route and is expressed by 

R, = a, x 

number of persons average duration of 

over the route exposure of each individual 1 (2) 

That is: 

where: 

= the coefficient for off-link population risk 

= mean population density over the route within the exposure range of significant 

radiation 

= overall shipment duration from origin to destination, excluding stop times 
On-Link Population. The on-link population risk value, R,, is also a function of the duration 

of exposure of each individual and is represented by 

of people average duration of %=a2x exposed on route exposure of each individual 1 (4) 

with: 

number of number of on-link average number 

people = vehicles passing a x of people aboard 

exposed point per hour on -link vehicle 

average distance on the passing or same 

average duration - lane with simcant radiation effects 

of exposure mean relative velocity between 

cask vehicle and other vehicles 

The above equations reduce to 

% = 82 T t:/~ 

where: 

a, = coefficient for on-link population risk 

T = on-link traffic density (vehiclesthr) 

L = route length 

t, = overall shipment duration from origin to destination, excluding stop times 

Crew Risk. Crew risk is a function of the duration over which each crew member is exposed 

to radiation from the cask and is represented by 

number of crew %=%.[ and inspectors x exposure of each individual 1 average duration of (8) 

Crew risk is then given by 

% = a3 *am" t, 

where: 

a, = coefficient for crew risk 

N,,, = average number of persons on-board the vehicle 

t, = overall shipment duration from origin to destination, excluding stop times 

The value of a, will vary with mode because the distance between the crew and the cask will 

be different. 
Risk to Populadion ad Stops. The total risk at various stops can be represented by 

number of avg. number of avg. duration 

stops over x persons exposed x 

route length of exposure per stop 

It is assumed that the number of stops is directly proportional to the distance tra~eled,~ and 

that at each stop only a certain number of persons is exposed (based on an average population 

at stops and a constant radiation affected area by mode). Hence 

where: 

a, = coefficient for stop risk 

L = route length 

Handling Risk. Handling risk is assumed to arise only in the case of intermodal transfers 

when casks have to be handled by transportation personnel. Both the number of handlers andthe average duration of handling are assumed to be constant. Hence, the risk itself is 

considered to be a constant, irrespective of the distance of transportation. This is represented 

by 

where: 

a, = coefficient for handling risk 

H, = Boolean variable (1 for intermodal shipments; 

0 otherwise) 

Overall Incident-Free Radiological Risk. By summing the component risks, overall incidentfree radiological risk can be specified as 

The terms are measured in different units and are, therefore, not dimensionally consistent. 

The product of each coefficient and the parameters in that term have units of radiation dosage 

expressed in person-rems, however. 

aThe assumption of number of stops being proportional to distance may not apply for very short distances. 
The simplified equation for overall incident-free radiological risk (equation 13) contains the 

same factors previously identified in Exhibit 9 as primary factors affecting incident-free 

exposure. These factors include general population (p and T), occupational population (N,,, 

and H,), and shipment duration (t,). Route length (L) is not listed in Exhibit 9 as a primary 

factor, but it is obviously an important component of shipment duration. Furthermore, the 

equation mathematically shows the type of relationship that each variable (factor) has with 

overall incident-free radiological risk. 

5.2.2 Accident-Induced Radiolo~ical Risk Model 

The risk associated with radiation exposure from releases of radioactive material in transportation accidents can be represented as follows: 

RM = probability of an consequence of release 

accident release (in person -rerns) (14) 

Using the above equation and assuming that the principal radiation exposure pathway to the 

population is by dispersing radioactive material (radionuclides), risk can be expressed as 

where: 

b = coefficient for accident-induced radiological risk 

p = mean density of population potentially exposed to the effects of the dispersing 

radioactive cloud (including occupational population) 

S, = mean traffic accident rate over the entire route (probability of an accident per 

unit distance in a given shipment) 

L = route length 

In deriving equation 15, the probability of release of radioactive material given that an accident occurs is assumed to be a constant within each mode. 

Equation 15 contains three of the factors that were presented in Exhibit 9 as primary factors 

affecting accident-induced radiological risk. These are the accident rate (S,), the route length 

(L), and the population at risk (p). Again, the type of relationship between these factors and 

the manner in which each contributes to overall risk is illustrated by the model. 
5.2.3 Non-Radiological Risk Model 

The risk to the population from vehicle accidents that do not involve the nature of the cargo 

is represented as 

RNR = probabfir of a x length of route serious accident 

Using the above equation and assuming that the measure of non-radiological exposure is 

fatalities, the risk can be expressed as 

where: 

S,, = mean traffic fatal accident rate over the entire route (probability of an accident 

resulting in at least one fatality per unit distance for a given shipment) 

L = route length 

The resulting risk is expressed as expected number of fatal accidents. 

Equation 16 above relates directly to Exhibit 9, which identified fatal accident rate and trip 

length as primary factors contributing to non-radiological risk. 

5.3 RELATIONSHIP OF RISK MODELING TO MODEIROUTE FACTORS 

The relationships described in this chapter present a method for evaluating the risk of shipping spent nuclear fuel for different modes through association with key mode and route 

factors. Their development was based on the physical relationships between key factors that 

affect component risks. The values of the model coefficients in the preceding equations can 

be estimated using appropriate statistical estimation techniques. 

Exhibit 11 provides a matrix that summarizes the relationship between key modelroute factors 

identified through development of the risk models presented in this chapter and the three 

types of risk. As noted, incident-free radiological risk is derived from consideration of 

general population, occupational population, trip (route) length, and shipment duration 

(excluding stop times). This comes from the need to consider these factors in various 

relationships that describe component risks related to off-link, on-link, crew, stop, and handling exposures. Accident-induced radiological risk is directly related to general population, 

accident rate, and trip (route) length as primary factors. Non-radiological risk is derived 

from consideration of accident rate and trip length. 
Exhibit 11. Relationship of Risk Modeling to Primary ModeIRoute Factors 

- pp ppp 

General Occu~ational Accident Trip Shipment 

Population Population Rate ~en&h Duration 

Incident-Free Radiological Risk x x x x 

stop (4 

Handling (x) 

Accident-Induced 

Radiological Risk 

Non-Radiological Risk x x 

Collectively, the fundamental relationships, as established, share five of the eight primary factors identified in Chapter 4: general population exposed, occupational population exposed, 

shipment duration, accident rate, and trip length. Amount of material, emergency response, 

and environment exposed are the remaining factors potentially linked to public safety that are 

not explicitly represented in the model formulations. These effects can be incorporated into 

the process, however, using the following approaches. 

Amount of material is implicitly represented in the prescribed approach as a single shipment 

of a single cask. Assuming linearity and using a post-processing activity once the relationship 

between primary factors and safety is established on a per shipment basis, this factor can be 

included in the risk models. The relative payload capacity becomes the determinant of the 

number of shipments required for comparative analysis. 

Proximity to effective emergency response potentially lowers accident-induced radiological 

risk by reducing the number of people exposed and duration of exposure. This is not 

considered in the models, as presented. Knowledge of the location of qualified responders 

with respect to the route being evaluated, however, can provide a measure of this effect. 

Environmentally sensitive areas, like population groups, can be exposed to radiation. Model 

development could be extended to environmental areas by measuring the size and character of 

the affected area and predicting the associated consequences. This development is dependent 

on obtaining information about these areas and subsequently establishing the fundamental 

relationships that would apply. 

Each of these three factors, amount of material, emergency response, and environment 

exposed, will be addressed again later in the report. 
Page intentionally left blank. 
6. CASE STUDY AND ANALYSIS OF FACTORS 

The case study was designed to accomplish three objectives: (1) demonstrate the feasibility of 

measuring and estimating the previously identified modelroute factors in a complex analysis 

environment, (2) evaluate the variability of modelroute factors across various modes and 

routes, and (3) evaluate in more detail the specific relationship of the modelroute factors with 

public safety. To address these objectives, transportation risk management models were used 

to measure primary factor values and then to calculate the risks of transporting a single 

shipment (truck or raillbarge cask) between selected origins and destinations by various 

modes. Case study results were also used to estimate values for the coefficients of the 

radiological risk equations presented in Chapter 5. These equations were then used to conduct 

a sensitivity analysis in which the relative effect of each of the primary factors on the risk 

estimates was examined. 

6.1 DEVELOPMENT OF ANALYSIS FRAMEWORK 

The analytical environment for achieving the case study objectives required selecting sample 

modes and routes thought to be representative of spent nuclear fuel shipments and subsequently deriving and analyzing factor and risk values for each case. An integrated approach, 

combining two previously developed transportation risk assessment tools, was used to develop 

factor inputs and calculate risk measures across several mode and route combinations for each 

OID pair. Model coefficients were then estimated using the data for each case. 

6.1.1 Selection of Sample Routes 

To develop the case study, a series of possible shipment OIDs was selected that represents 

historical or anticipated campaigns. The selection criteria included actual spent fuel shipment 

origins and likely destinations with access to all three modes and intermodal shipments; 

differing route lengths, infrastructures, and populations; and travel in different parts of the 

country. An effort was made to include routes that passed through large urban areas, as well 

as routes that were predominantly rural. The shorter-distance routes were felt to be 

representative of those that would be used for intrdinter-utility shipments, while the longerdistance routes could be considered typical of those to be used for transport to either 

monitored retrievable storage or long-term storage facilities. 

The following modes were considered in the case study: (1) highway, (2) regular (scheduled) 

trains, (3) dedicated trains, (4) waterway, and (5) intermodal. Regular and dedicated trains 

were considered separate modes because characteristics of both train configurations and 

operations are significantly different. All intermodal shipments were grouped together because 

they involved waterwaylrail combinations where the waterway movement and intermodal 

handling activities were common characteristics. 
For each O/D pair, analyses were separated by mode; within each mode, analyses were performed for several routes. The criteria used to select prospective routes included identifying 

both economical routes (those that minimize travel time) and routes that offer a significant 

reduction in exposure by avoiding heavily populated areas. By using this approach, a wide 

range of candidate routes were represented, and the characteristics of direct and more 

circuitous routings could be examined. Routes were also selected on the basis of combined 

consideration of travel time and population exposure, as well as population exposure and accident likelihood. Additionally, minimizing the number of interchanges was considered in rail 

route selection. 

The ~az~rans" routing and risk management model was used in the selection of candidate 

routes on the basis of multiple criteria. Appendix D contains additional information on 

HazTrans. An optimization routine within HazTrans permits selection of preferred routes on 

the basis of minimizing trip distance, travel time, population exposure, accident likelihood, or 

weighted combinations involving two or more of these criteria. By applying this process, up 

to three basic routes were identified for each mode and O/D and up to two alternative variants 

were identified for each basic route. In cases where different criteria resulted in the selection 

of the same route, fewer routes were analyzed. Each identified route was carefully reviewed 

for transport feasibility prior to its inclusion in the analysis. Exhibit 12 summarizes the 65 

unique mode and route combinations generated from this process. l1 

Each sample route required collecting primary factor values and calculating associated risks. 

This necessitated the development of a hybrid analysis environment using two assessment 

models. HazTrans was used to derive the primary factor values and non-radiological risks, 

while Radtran 4 was used to calculate the radiological risks based on inputs from HazTrans. 

Appendix E contains additional information on Radtran 4. 

6.1.3 Develo-t of Prim Factor Values 

The primary factors for which quantifiable data were readily available included amount of 

material, emergency response, general population, occupational population, accident rate, trip 

length, and shipment duration. The development of quantitative measures for environmentally 

sensitive areas was not practicable, given the time and resource constraints on this project. 

Appendix G contains a detailed description of the measures and assumptions used to develop 

primary factor values. 

10HazTrans is a registered trademark of Abkowitz & Associates, Inc., Nashville, Tennessee. 

11 The 65 mode and route combinations developed for the case study are not a random sample. Consequently, the 

results derived from them are indicative, rather than demonstrative. 
Exhibit 12. Summary of Routes Used for Case Study 

Origin1 Total Number of 

Length Mode ~estination Pairs Routes 

Short Water 2 2 

Short Rail 2 4 

Short Highway 2 6 

Moderate Water 2 2 

Moderate Watermail 2 4 

Moderate Rail 4 14 

Moderate Highway 4 

Long Watermail 2 

Long Rail 2 

Long Highway 2 

TOTAL 65 
The HazTrans system was used to measure several primary factor values. HazTrans contains 

an intelligent mapping system'with truck, rail, barge, and intermodal analysis capability. 

These transportation networks are defined using geographic information system (GIs) 

coordinates, permitting direct association of the transportation system with the surrounding 

population and location of emergency response capability. Furthermore, characteristics of 

each individual route segment are stored within HazTrans and can be extracted to derive trip 

lengths, travel times, and accident rates. Since the version of HazTrans available to this 

project maintains only the principal highway, rail, and waterway networks, new links were 

defined to connect the transportation network to shipment origination or receiving points, as 

necessary. 

6.1.4 Development of Risk Values Usin? Radtran 4 

Radtran 4 is a risk assessment tool developed by DOE to calculate comprehensive radiological 

consequences from route-specific input. It was used in the case study to evaluate the 

radiological consequences of incident-free transportation, as well as the radiological risks from 

vehicular accidents during transportation. Radtran 4 contains mathematical models of radiation exposure in different transportation environments for several different radioactive 

materials. In this case study, default parametric values for spent nuclear fuel were used, as 

were standard cask sizes for each mode. 

The five components of incident-free radiological risk are (1) crew risk, (2) handler risk (for 

intermodal only), (3) off-link (or surrounding) population risk, (4) on-link (or shared-facility 

user risk), and (5) stop risk (people exposed during stops). The four included components of 

accident-induced radiological risk are (1) groundshine (from external exposure to deposited 

particles), (2) inhalation (from breathing in particles), (3) resuspension (from inhalation of 

particles deposited and then resuspended), and (4) cloudshine (from external exposure to a 

passing cloud of radioactive particles). All risks are calculated in terms of person-rems. 

Radtran 4 requires input data beyond mode- and route-specific parameters for the model to 

perform its function. These inputs were defined to maximize consistency in treating various 

modes and routes within the Radtran 4 analytical framework and were subsequently verified in 

discussions with selected shippers and carriers. Appendix G contains a detailed description of 

the input and assumptions used to perform these analyses using Radtran 4. 

It might be noted that Radtran 4 has a built-in upper bound on radiological exposure. In 

Radtran 4, it is assumed that transportation workers and members of the public will receive no 

more than the maximum radiological dose rate permissible by regulation. 

To perform the analyses, the Radtran 4 route-specific option was used, which allows the analyst to include segment-specific information about length of segment, vehicle speed, population 

density, traffic density, accident rate, and land use for every segment along the specified 

route. A special interface protocol between HazTrans and Radtran 4 was developed for this 

study to accommodate the transfer of route-specific data from HazTrans into Radtran 4 input 

formats. 
In this study, shipments were assumed to move by exclusive-use vehicles (e.g., trailer, railcar, 

barge) requiring no storage during transit. Also, because ingestion risk calculations have been 

disabled within the version of Radtran 4 used for the analysis, the associated risk could not be 

obtained. 

Since Radtran 4 does not model non-radiological transport risks, these were derived outside of 

the Radtran 4 methodology using HazTrans and national accident statistics. Non-radiological 

risk was measured as expected fatalities resulting from the force of a vehicular accident. 

National statistics have been compiled for each mode from which fatal accident rates can be 

derived that are relevant for this study. The derivations are explained in Appendix G. 

6.2 CASE STUDY RESULTS 

For the case study, estimates of both non-radiological and radiological risk were derived. An 

overview of these results is presented in this section. Additional detail on the results can be 

found in Appendix G. 

The case study results are subject to a couple of limitations. First, the dataset used was not a 

randomly chosen sample. Consequently, the results are directly applicable only to the 65 

generic modelroute combinations for which they were calculated. Second, the results are only 

as good as the data and models used in their derivation. While every effort was made to 

ensure that the data and models used were appropriate and were appropriately applied, a 

complete and thorough validation of the results was not possible. As a consequence of these 

limitations, care should be exercised in the interpretation of the case study results. 

6.2.1 Estimates of Non-Radiological Risk 

The number of fatalities per shipment was the non-radiological risk measure that was estimated 

for the case study. 

The estimated number of fatalities per shipment was calculated using HazTrans and fatal 

accident rates by mode that were taken from the literature. For the highway estimates, heavy 

truck fatal accident rates were used. For regular trains, fatal accidents for rail were used. 

These were adjusted, because only a portion of the fatal accidents per train would be 

attributable to the spent nuclear fuel shipment that the train was hauling. The adjustment 

assumed that a typical regular rail consist had 70 cars and that, when hauling a spent nuclear 

fuel shipment, 4 of those cars would be associated with that shipment. For dedicated trains, 

fatal accidents for rail were used. For waterway movements, fatal accident rates for barges 

were used. These rates were converted from ton-mile to barge-mile assuming that there are 15 

barges in an average consist and that each barge carries 1,500 tons. 

Exhibit 13 presents the estimates of the number of fatalities per shipment for each OID pair by 

mode. All of the estimates in Exhibit 13 are for single cask shipments. Truck casks are 

assumed to hold 2 PWR (pressurized water reactor assemblies), while raillbarge casks are 
Exhibit 13. Estimated Number of Fatalities 

(Per Single Cask Shipment) 

OrigidDestination Mode 

Pair 

Highway* Dedicated Train* Regular Train* Waterway Intermodal 

O/D Pair 1 5.32E-06 2.35E-04 1.29E-05 2.64E-05 --- 5.93E-06 

7.05E-06 

OID Pair 2 9.24E-06 3.63E-04 2.00E-05 2.61E-05 --- 1.21E-05 

1.11E-05 

O/D Pair 3 1.74E-05 8.12E-04 4.46E-05 1 SME-04 -- 

1.90E-05 

O/D Pair 4 2.92E-05 1.51E-03 8.30E-05 1.10E-04 -- 3.43E-05 1.97E-03 1.09E-04 

3.27E-05 

OID Pair 5 2.45E-05 1.24E-03 6.80E-05 --- 1.73E-04 

2.54E-05 1.25E-03 6.89E-05 1.73E-04 

2.68E-05 

OID Pair 6 4.59E-05 2.76E-03 1 S2E-04 -- 3.42E-04 

5.98E-05 3.14E-03 1.72E-04 3 A2E-04 

4.92E-05 

OID Pair 7 6.07E-05 2.94E-03 1.62E-04 -- 3.49E-04 

7.42E-05 2.90E-03 1.60E-04 3.49E-04 

6.28E-05 2.76E-03 1 S2E-04 

O/D Pair 8 1.16E-04 5.07E-03 2.79E-04 -- 7.58E-04 

1.42E-04 5.23E-03 2.88E-04 7.58E-04 

*Multiple fatality values are shown for those OID pairs where multiple routes were identified. 
assumed to hold 14 PWR. Where there was more than one route identified for a modal 

movement between a particular OID pair, Exhibit 13 presents separate estimates of the number 

of fatalities for each route. Where a particular OID pair has multiple routes for several 

different modes, the routes for each mode may be different. 

As can bee seen in Exhibit 13, the lowest estimated number of fatalities was for movements of 

spent nuclear fuel by highway. The next lowest was the estimated number of fatalities 

resulting from movements by regular trains, followed by those resulting from movements by 

waterwaylintermodal. The highest estimated number of fatalities was for movements of spent 

nuclear fuel by dedicated train. Thus, for single cask movements, highway would appear to be 

the safest way to transport spent nuclear fuel, followed in descending order of safety by regular 

trains, waterway lintermodal movements, and dedicated trains. 

6.2.2 Estimates of Radiological Risk 

Component and overall radiological risks per shipment were estimated for incident-free 

exposure and accident-induced exposure. These estimates were derived using Radtran 4. 

Exhibit 14 presents the ranges for the radiological risk estimates derived for the case study. 

All of the estimates in Exhibit 14 are for single cask shipments. As before, truck casks are 

assumed to hold 2 PWR, while raillbarge casks are assumed to hold 14 PWR. 

As indicated by the figures in Exhibit 14, the radiological risks due to incident-free exposure 

tend to be significantly greater than those due to accident-induced exposure. The overall risk 

for incident-free exposure is estimated to range from 562 to 2 millirems, depending on mode 

and route, while the overall risk for accident-induced exposure is estimated to range from 11 

millirems to well below 1 millirem. 

The dominant component of incident-free risk appears to be crew exposure, which is estimated 

to range from 344'rnillirems to less than 1 millirem. The primary components of accidentinduced radiological risk are groundshine and resuspension exposure. 

The crew is the population category generally at highest risk during the movement of spent 

nuclear fuel. The projected amount of non-incident radiation exposure of an individual crew 

member for a complete trip can be estimated by dividing the total crew exposure estimates for 

each of the 65 modelroute combinations by the estimated number of crew required for each 

modelroute combination (for estimates of the total incident-free risk for the crew, see Exhibit 

G-5; for estimates of the total number of crew, see Exhibit G-4). The exposure estimates per 

crew member calculated in this fashion range from 0.04 millirem to 172 millirems. It might be 

noted that these levels are well below the current Federal guidance for occupational exposure, 

which is 5,000 millirems per individual per twelve month period.12 Furthermore, 

- -- 

12 EPA, "Radiation Protection Guidance to Federal Agencies for Occupational Exposure, " January 1987. 

6-7 
Exhibit 14. Range of Estimated Component and Overall Radiological Risks 

(Per Single Cask Shipment) 

Type of Risk 

Range of Risk Values 

(person-*ems*) 

Incident-Free Risks. 

Component Risks 

Crew 344 

Handlings? 49 

Off-Link 44 

On-Li 

stop 

Overall Risk 

Component Risks 

Groundshine 

Inhalation 

Accident-Induced Risks 

Resuspension 3 * 

Cloudshine * rt 

Overall Risk 11 * 

*All values have been rounded to the nearest millirem. 

thcident-free risk for handlings was calculated only for intermodal movements of spent nuclear fuel. No handlings were assumed 

to be required for highway, regular train, or dedicated train movements. 

*Less than 0.5 millirems. 
these levels are also well below the 2,000 millirems per individual per twelve month period 

guideline currently recommended by the International Atomic Energy Agency (IAEA). l3 

As might be expected, the general population will experience a significantly lower risk than the 

crew during the movement of spent nuclear fuel. In total, the exposure for the general 

population, taken as a whole,-will be between 2 and 210 millirems per trip. While the 

impacted population will vary depending on the route, no single individual is expected to 

receive more than a fraction of a millirem for any given trip. This level of exposure is 

consistent with the 100 millirems per year for any single member of the public that is currently 

proposed by the EPA as new guidance for federal agencies.14 

6.3 VARIABILITY OF PRIMARY MODEIROUTE FACTORS AND RISK 

VALUES 

The process of selecting modes and routes to enhance public safety only makes sense if, in 

fact, transportation risks vary significantly among the choices available. Similarly, the use of 

the identified primary factors to pick preferred routes only makes sense if their values vary 

significantly from mode to mode, route to route for a given OID pair. This section describes 

the results of an assessment of the variability of both risk and primary factors across the 

modelroute alternatives examined in the case study. 

6.3.1 Varlatlon Factor Vaw .. . 

This segment of the case study analysis focused on the extent to which values of primary 

factors vary by mode and route for a given origin and destination. If the variation is not 

significant, then the primary factor cannot be a discerning factor in determining preferred 

shipment alternatives. Exhibit 15 presents statistics associated with the values of each primary 

factor for each OID pair. The mean value and percentage variation about the mean are given 

for all modelroute options between a given origin and destination. Averages for all eight OID 

pairs are also presented. 

In reviewing Exhibit 15 (and subsequent tables), it should be noted that "number of crew" is 

synonymous with occupational population. In addition, shipment duration has been reported as 

"average speed" for ease of presentation. 

As indicated by the percentage variation about the mean, the values of primary factors 

fluctuate considerably across the case study sample for a given origin and destination. To 

illustrate from Exhibit 15, the mean of population density for OID pair #1 was 73.27 persons 

per square kilometer. The lowest population density for potential modelroute combinations 

131A~A, "Regulations for the Safe Transport of Radioactive Material, 1996 Edition." 

14~nvironmental Protection Agency, "Radiation Protection Guidance to Federal Agencies for Exposure of the 

General Public," Memorandum for the President, Draft, April 23, 1996. 
Exhibit 15. Variation of Primary Factor Values by O/D 

Origin/Destination 

All 

Factor Pair 1 Pair 2 Pair 3 Pair 4 Pair 5 Pair 6 Pair 7 Pair 8 Pairs* 

Length (km) 

mean 194.34 305.75 645.43 11 17.30 955.82 

min (% of mean) 88 62 87 72 83 

max (% of mean) 1 17 128 118 142 132 

Population Density (per/krn2) 

mean 73.27 149.05 218.31 81.28 49.53 

min (% of mean) 33 0 24 34 14 

max (% of mean) 162 263 164 199 204 

No. of Crew 

mean 3.83 3.83 4.20 3.75 4.37 

min (% of mean) 52 52 48 53 46 max (% of mean) 261 261 238 267 223 

Avg Speed (kmlhr) (includes stop times) 

mean 21.85 21.79 19.78 21.08 18.92 

min (YO of mean) 11 14 18 28 29 max (% of mean) 179 179 201 188 213 

Accident Rate (acclveh-km for highway and waterway; acclcar-km for rail) 

mean 3.16E-06 7.68E-07 2.03E-06 1.69E-06 1.93E-06 

min (% of mean) 21 40 18 22 19 

max (% of mean) 303 149 324 448 462 

Average Emergency Response Distance (km) 

mean 882.46 330.87 331.89 557.58 387.64 

min (% of mean) 96 97 88 80 96 

max (% of mean) 102 109 106 109 101 

No. of Cases: 6 6 5 8 9 

* The statistics in this column were derived by treating each pair as a single observation. The mean, min., and max. values 

represent averages of the statistics presented in the first eight columns of this table. Where regular and dedicated route values 

are identical, only one was used in the caluclation of the mean. 
between this OID pair was only 33.29 percent of the mean, or 24.39 persons per square 

kilometer. The highest population density was 162.42 percent of the mean, or 119.01 persons 

per square kilometer. This shows the substantial variation in population density between OID 

pair #1, depending upon the modelroute combination. It is evident from these results that 

primary factor values can change considerably by mode and route for the range of expected 

shipment distances, shipment purposes, and locations in the United States. 

6.3.2 Variation in Risk Values 

Exhibits 16 through 18 present the mean and percentage variations in case study values for 

components of incident-free and accident-induced radiological risks and non-radiological risks. 

The results presented in these exhibits indicate that the risk values can be expected to vary 

considerably by mode and route for a given shipment origin and destination. Incident-free 

radiological risk was found to vary an average of 23 % below and 176 % above the mean, for 

the eight pairs studied. Accident-induced radiological risk and non-radiological risk varied 

even more. Therefore, choice of mode and route does appear to have a powerful effect on the 

overall risks. 

The tables also lend themselves to some meaningful conclusions concerning the relative 

magnitudes of risk associated with various shipment characteristics. For example, incidentfree radiological risk tends to dominate the overall radiological risk associated with spent 

nuclear fuel shipments based on this case study. Also, although comparisons between 

radiological and non-radiological impacts are generally not advisable due to differences 

between acute and long-term health effects, it is apparent that non-radiological safety 

considerations are a significant aspect of overall operational safety involving the shipment of 

spent nuclear fuel. 

6.4 RADIOLOGICAL RISK MODEL ESTIMATION 

The previous discussion has demonstrated that there is reason to believe that both primary 

factor values and associated risks will fluctuate considerably by mode and route for each OID. 

To further investigate the relationship between primary factors and radiological risks, the case 

study data was used to estimate coefficients for the fundamental risk equations, presented in 

Chapter 5, for each mode. This process had two basic objectives: (1) to test the statistical 

confidence with which each previously identified factor contributes to incident-free and 

radiological risk, respectively, and (2) to allow for subsequent conduct of sensitivity analyses 

to ascertain the relative importance of primary factors in determining these risks. 

Details of both the derivation of the equation coefficients from case study data and the tests 

that determined the statistical significance of these numeric constants are given in Appendix H. 

Results of the statistical tests show a good overall fit between the model equations and the 

observed (case study) data, and the estimated coefficients are statistically significant, with rare 
Exhibit 16. Variation of Incident-Free Risk Values (Person-Rems) by O/D 

Origin/Destination 

Ail 

Factor Pair 1 Pair 2 Pair 3 Pair 4 Pair 5 Pair 6 Pair 7 Pair 8 Pairs* 

Crew 

mean 

min (% of mean) 

rnax (% of mean) 

Handlings 

mean 

rnin (% of mean) 

rnax (% of mean) 

Off-Link 

mean 

min (% of mean) 

rnax (% of mean) 

On-Link 

mean 

min (% of mean) 

rnax (% of mean) 

Stop 

mean 

rnin (% of mean) 

rnax (% of mean) 

Total 

mean 

rnin (% of mean) 

rnax (% of mean) 

No. of Cases: 

0.00E+00 0.00E+OO O.OOE+OO 

nla da nla 

nla da nla 

* The statistics in this column were derived by treating each pair as a single observation. The mean, 

rnin., and max. values represent averages of the statistics presented in the first eight columns of this 

table. 
Exhibit 17. Variation of Accident-Induced Radiological Risk Values 

(Person-Rems) by O/D 

Origin/Destination 

All . . Factor Pair 1 Pair 2 Pair 3 Pair 4 Pair 5 Pair 6 Pair 7 Pair 8 Pairs* ' 

Ground 

mean 

min (% of mean) 

max (% of mean) 

Inhalation 

mean 

min (% of mean) 

max (% of mean) 

Resuspension 

mean 

min (% of mean) 

max (% of mean) 

Cloudshine 

mean 

min (% of mean) 

max (% of mean) 

Total 

mean 

min (% of mean) 

max (% of mean) 

No. of Cases: 

* The statistics in this column were derived by treating each pair as a single observation. The mean, 

min., and max. values represent averages of the statistics presented in the first eight columns of this 

table. Where regular and dedicated route values are identical, only one was used in the calculation of 

the mean. 
Exhibit 18. Variation of Non-Radiological Risk Values (Fatalities) by O/D 

Factor 

All 

Pair 1 Pair 2 Pair 3 Pair 4 Pair 5 Pair 6 Pair 7 Pair 8 Pairs* 

Total 

mean 4.88E-05 7.36E-05 1.99E-04 4.85E-04 3.39E-04 7.84E-04 9.08E-04 1.67E-03 5.63E-04 

min (% of mean) 11 13 9 6 7 6 7 7 8 

max (% of mean) 482 493 407 407 370 400 324 317 400 

No. of Cases: 6 6 5 8 9 9 11 11 8 

* The statistics in this column were derived by treating each pair as a single observation. The mean, min., and max. values represent 

averages of the statistics presented in the first eight columns of this table. 

exceptions. Therefore, the equations developed in Chapter 5 do a relatively good job of 

representing the relationship between primary factors and risk estimates, at least for the case 

study data. 

6.5 SENSITIVITY ANALYSIS 

A sensitivity analysis was conducted to determine the relative influence of each of the primary 

factors on radiological risks for each of the modes. The model equations with the estimated 

coefficients were used to calculate both incident-free and accident-induced radiological risks 

for two values of each primary factor.15 The base value was that used in a given case study run 

(i.e., it was the unique combination of mode, route, and O/D pair for the case) and the second 

value was the base value increased by 10 percent. The factors were adjusted one at a time to 

determine their singular effects. Exhibit 19 presents the results of the sensitivity analysis. The 

last two columns show the percentage of increase in the risk caused by the 10 percent increase 

in the factor values. 

Trip duration was shown to have the largest effect on the incident-free radiological risk of all 

the factors. This is probably a result of the fact that so many of the incident-free risk 

component terms include trip duration, such that it has multiple effects on overall incident-free 

risk. Average number of crew is another major factor for highway and regular trains. 

15 The preferred analytic technique would be to vary the value of each primary factor, one at a time, and rerun the 

Radtran 4 assessment for each modelroute combination in the case study. Resource constraints, however, 

precluded this approach. 
Exhibit 19. Sensitivity Analysis 

Mode Variable 

Changed 

% of Increase % of Increase % of Increase in 

in Variable in Incident- Accident-Induced 

Free Risk Radiological Risk 

Highway 

Regular Trains 

Dedicated Trains 

Waterway 

Intermodal 

N,,, - Average number of crew 

t, - Average hip duration 

T - Average traffic density 

L - Average route length 

p - Average population density 

S, - Average mean accident rate 

N,,, - Average number of crew 

t, - Average hip duration 

T - Average traffic density 

L - Average route length 

p - Average population density 

S, - Average mean accident rate 

N - Average number of crew 

t, - Average trip duration 

T - Average traffic density 

L - Average route length 

p - Average population density 

S, - Average mean accident rate 

N - Average number of crew 

t, - Average trip duration 

T - Average traffic density 

L - Average route length 

p - Average population density 

S, - Average mean accident rate 

N,,, - Average number of crew 

t, - Average trip duration 

T - Average traffic density 

L - Average route length 

p - Average population density 

S, - Average mean accident rate 
For the highway and rail modes, accident-induced radiological risks change at a 

disproportionately higher rate in comparison with changes in primary factor values. This 

suggests that emphasis should be placed on reducing accident rate, trip length, and general 

population exposure when shipping via highway and rail modes, a not altogether unexpected 

conclusion. 

The results of the waterway and intermodal sensitivity analyses for both incident-free and 

accident-induced radiological risk are inconclusive. This may be due to the small sample sizes 

for these two transport categories. 

6.6 EMERGENCY RESPONSE 

A preliminary evaluation of emergency response coverage suggests that a slight inverse 

relationship may exist between qualified emergency response and accident-induced radiological 

risk. 

6.7 SHIPPING CAMPAIGNS 

The total amount of material to be shipped in a campaign was found to be a principal 

determinant of the mode with the lowest risk. The risk estimates in both the case studies and 

the risk model equations were for a single cask movement from origin to destination. Often, 

however, the amount of radioactive material to be moved from one place to another is great 

enough to require many shipments (i.e., a shipping campaign). In such circumstances, the 

number of shipments needed is a primary determinant of overall risk. The much larger 

capacity of raillbarge casks means that a rail or barge shipping campaign will require far fewer 

shipments than highway transport of the same material. To examine the effects of cask size on 

overall risks of a shipping campaign, risk estimates from the case study were adjusted to 

reflect the respective capacities of raillbarge and truck casks (to be conservative, a ratio of 5: 1 

was used as representative). Results show that use of the raillbarge cask is warranted (if 

practicable), when the amount of material to be shipped in a campaign exceeds the capacity of 

one or two truck casks. For all three types of risk, use of regular trains for a campaign is 

safer than trucking, essentially the reverse of the case study findings for a single shipment (see 

Exhibit 20). Also, the risks for dedicated trains (and barges) compared to trucks are more 

favorable on a campaign basis than on a shipment basis. 

6.8 CASE STUDY ANALYSIS SUMMARY 

This case study was designed to (1) explore the ease with which primary factor values and 

risk estimates can be derived for modelroute combinations, (2) assess the variation in primary 

factor values and risk estimates for each modelroute, and (3) evaluate the interaction among 

primary factors and their statistical significance in determining the risks to different segments 

of the population. 
Exhibit 20. Relative Modal Risk for a Single Cask Movement vs. a Shipping Campaign 

Incident-Free Radiological Risk 

Per Cask Movement dedicated < regular - highway 

Per Campaign dedicated < regular < highway 

Accident-Induced Radiological Risk 

Per Cask Movement highway < < regular = dedicated 

Per Campaign dedicated = regular < highway 

Non-Radiological Risk 

Per Cask Movement highway < regular < < dedicated 

Per Campaign regular < highway < < dedicated 

Note: "Per Campaign" risk reflects an adjusment in which the risk calculated per cask movement (i.e., shipment) in the case studies for 

highway was multiplied by a number representative of the ratio of millbarge to truck cask capacities. A value of 5 was used (range = 4-7). 

Accordingly, the relative rankings for a campaign reflect the need for five times more truck cask movements to transport a given amount of 

material, compared to rail or barge transport. 

A < B means that A is less than B A - B means that A is approximately equal to B 

A < < B means that A is much less than B A = B means that A is equal to B 

Findings related to these objectives are summarized below. These conclusions should be 

reviewed in the context of the analytical environment used in the case study. The extent to 

which factors inherent in HazTrans, Radtran 4, and the overall methodology affect generalization of these findings should be taken into consideration. 

6.8.1 Ease of Develo~in~ Primary Factor and Risk Values 

The case study clearly demonstrates that information describing primary factors can be 

assembled and that quantifiable measures of these values can be developed. In some instances, 

the methods used to develop factor values must rely on surrogate measures that have 

established validity based on prior studies. 

6.8.2 Variations in Primarv Factor Values and Risk Estimates 

Variations in primary factor values and corresponding risk estimates are expected if primary 

factors are discerning factors in determining preferred routes. The case study results indicate 

that primary factor values fluctuate considerably across mode, route, and OID. Similar 

variations were experienced in corresponding radiological and non-radiological risk values. It 

is evident from these results that primary factor values can be expected to change considerably 

by mode and route for different shipment lengths, shipment types, and locations in the United 

States. This underscores the need to evaluate those mode and route factors that significantly 

impact public safety. 

6.8.3 Interaction of Primarv Factors and Risks 

Incident-free radiological risk tends to dominate the overall radiological risk associated with 

spent fuel shipments; in most instances, incident-free radiological risk is much larger than 
accident-induced radiological risk. The significance of various factors in contributing to 

incident-free risk varies by OID. Groundshine and resuspension exposures, however, are 

consistently the primary components of accident-induced radiological risk. It is also apparent 

that non-radiological safety considerations are a significant aspect of spent fuel shipment 

safety. 

Results of the sensitivity analysis indicate that accident-induced radiological risk is strongly 

influenced by population, exposure, trip length, and accident rate for highway and rail 

operations. Trip duration has the most profound effect on incident-free radiological risk, 

although the other primary factors are also significant contributors. 

With respect to shipping campaigns, the amount of material to be shipped was found to be a 

principal determinant of the lowest risk mode. The use of regular trains for a shipping 

campaign is safer than trucking for all three risk categories. This is the reverse of the case 

study findings for a single shipment. Finally, compared to trucks, the risks for dedicated 

trains and barges are more favorable for a campaign than for a single shipment. 
7. OVERALL ASSESSMENT OF PRIMARY MODEIROUTE SELECTION 

FACTORS 

An overall assessment of the primary modelroute factors identified in this study is presented 

below. Following a brief overview of the background and approach used to select these 

primary factors, each primary factor is discussed in detail. 

7.1 SUMMARY OF IDENTIFICATION AND SELECTION 

OF PRIMARY MODEIROUTE FACTORS 

Generally, the selection of both mode and route by shippers and carriers has been based 

largely on operating efficiency, customer service needs, and economics. Increasingly, 

however, shippers of all hazardous materials, including high-level radioactive waste and spent 

nuclear fuel, have become more attuned to the need to carefully assess the relative safety of 

each mode before making a selection. Hazardous material carriers, especially for radioactive 

materials, have been subject to various federal and state requirements on routing for the last 

decade. Both shippers and carriers would benefit from the identification of a common set of - 

mode and route selection factors. 

The first approach employed in this study was a hierarchical approach that was based on 

identifying the most important modelroute factors through a review of all factors that had 

previously been considered or proposed as important for selecting modes or routes. To ensure 

that all viewpoints would be considered, a comprehensive candidate list of factors was 

developed. Each factor was qualitatively evaluated in terms of criteria such as impact on 

safety, interrelationships among the factors, measurability, and feasibility of implementation. 

This qualitative evaluation resulted in several important findings: 

Mode and route factors are difficult to evaluate separately. They must be considered 

together for a particular modelroute combination and then compared with mode and route 

factors for other modelroute combinations. 

The only separable mode choice factors found were cask availability, mode accessibility, 

and amount of material to be shipped. Cask availability and mode accessibility could be 

eliminated as constraints on modal choice in most cases, given sufficient time and 

resources. Amount of material is perhaps the single most important factor in mode 

selection because it directly impacts the number of shipments required. If there is enough 

material to warrant use of the larger raillbarge cask, then the number of cask shipments 

can be significantly reduced which, in turn, cuts the overall risks. Moreover, if the 

amount of material makes multiple-cask shipments possible, risk can be reduced still 

further when rail or barge modes are used. 

There are many legitimate modelroute factors. The validity and importance of each factor 

is ultimately dependent upon the level of analysis to be conducted. 
A hierarchy of modelroute factors can serve as a decision-making tool to help shippers 

and carriers. The hierarchy allows the analyst to see the relationships and 

interdependencies among the many potential factors. 

A hierarchy allows the analyst to adjust for the level of analysis to be conducted. The factors at the highest end of the hierarchy are at a level of detail suitable for a national level 

of mode and route analysis. The lower end of the hierarchy is more suitable for a state or 

local level of analysis. 

The hierarchical approach used by the project team led to the identification of eight primary 

modelroute selection factors. These factors are (1) general population exposure, (2) occupational population exposure, (3) environmental exposure, (4) accident rate, (5) shipment duration, (6) trip length, (7) emergency response, and (8) amount of material. These eight factors 

are believed to be the most suitable as national-level modelroute selection factors. 

The second approach used in this study was to develop models showing the relationships of 

various factors to the risks of transporting radioactive materials. These risk models were 

based on fundamental physical relationships. The factors developed in the risk modeling effort 

were shown to be quite consistent with the primary factors identified using the hierarchical 

approach. 

A case study was developed with multiple origins and destinations and representative routes. 

The case study helped to examine the following important elements of modelroute selection: 

the variability of factors and corresponding risks from mode to mode and route to route, the 

feasibility of measuring and evaluating the primary factors, and the nature and type of 

relationship between each primary factor and the three risk components of the project 

definition of public safety. 

7.2 EVALUATION OF PRIMARY MODEIROUTE FACTORS 

The framework for conducting the overall evaluation of factors included the following criteria: 

(1) the nature and degree of impact on public safety, (2) the degree of variability from mode to 

mode and route to route, (3) the ability to measure, and (4) the feasibility of implementation. 

Ability to measure involves the degree of confidence in the representativeness of the factor, its 

degree of accuracy, and the difficulty of measuring it. Feasibility of implementation involves 

the relative difficulty of obtaining the required information and the related institutional and 

political considerations. The purpose of the overall evaluation of factors is to bring together 

the results of all the analyses conducted in this project relative to each primary factor. 

7.2.1 General Population Exposed 

This primary factor includes people along the route of travel who are at risk from the 

transportation of high-level radioactive waste and spent nuclear fuel. Population along the 

route has a direct effect on two components of the project definition of public safety: (1) 
incident-free radiological exposure from normal transportation and (2) exposure to the release 

of radioactive material resulting from a severe accident. The relationship between population 

and these two measures of public safety is direct. The greater the population along the route 

of travel, the greater the potential for incident-free radiological exposure and the greater the 

potential for a radiological release to have human health consequences. All other things being 

equal, the mode or route that involves the lowest population would be the safest route. Of 

course, all other things are not usually equal, and population has to be considered in context 

with other factors. 

Incident-free exposure of the general population depends on the total number of people potentially affected, the proximity of the people to the route of travel, and the time of exposure. 

Results from the case study indicate that the (on-link and off-link) incident-free radiological 

risk for the general population is much lower than occupational risk for all modes. In previous 

quantitative risk studies, incident-free exposure to the general public has also been estimated to 

be low. As the distance from the radioactive material increases, the potential health effects fall 

off dramatically. In most cases, people in the "general population" category are hundreds to 

thousands of feet from the right-of-way. Nevertheless, when selecting a mode or route of 

travel, it is important to take into consideration the population within a reasonable distance 

from the right-of-way. 

The number of people near the right-of-way is also important in measuring accident-induced 

radiological risk. If there is an accident severe enough to cause a release of material, the 

population exposed would depend on the size of the release and the speed and direction of the 

wind. The location and specific population affected by such an accident would be very 

difficult to predict beforehand. From a mode and route comparison standpoint, the only 

variable that could be measured would be the population within a certain bandwidth of the 

right-of-way that could be subject to exposure from such an accident. If a release-causing 

accident did occur, the general population along the route would be likely to have a much 

greater potential exposure than occupational workers because of the greater number of people 

in this category potentially at risk. 

There is little question that population should be included as a modelroute factor. The real 

question is how best to account for it. Ideally, the process would be to count all individuals 

within a certain bandwidth along a right-of-way for each route and then compare the results 

for all of the routes under consideration. The population count would include everyone in all 

three categories of general population identified in the incident-free hierarchy in Exhibit 5: 

residential, non-residential, and special. That is, the count would include all people who are 

at their residences within the bandwidth, as well as all the people at work, all of the 

pedestrians, all of those in other vehicles (shared-facility users), tourists, all those in facilities 

such as hospitals, schools, and prisons, and people at special events, such as concerts and 

sports events. All of these segments of the population should be included in the population 

count. 

Obviously, such a count cannot actually be done for every potential route under consideration 

by a shipper or carrier. The next best approach would be to make general estimates for each 
of the most important components of population, using surrogates where appropriate. In this 

case, shippers and carriers might make estimates of residential population, employed 

population, and traffic density (as a surrogate for people in other vehicles), and might count 

the number and ascertain the capacities of special facilities (as a surrogate for the actual 

number of people in these facilities). Most of this information is available or can be derived 

from other data available at the local level. This may be feasible for detailed route 

assessments for short distances. For longer distance shipments and for considering a variety 

of modes and routes, however, the only feasible measure is the census population count. 

With the availability of the Census Bureau population data, the ability to measure residential 

population along any route is very good. This information is available in spatial (geocoded) 

form, and can be used to estimate the exposed population within a specified distance of the 

routes under consideration. Although Census Bureau population data are limited to residential 

population, the number of potentially exposed people obtained from this information can be 

considered representative of the entire population along the route in most cases, particularly at 

the primary factor level. Limitations to this approach include the under-representation of 

employment and tourist populations in urban and other areas and over-representation of 

residential populations in suburban areas during different times of the day, week, and year. 

Because these variations are dynamic and time-dependent, it is impractical to determine a more 

accurate estimate of potentially exposed population for a screening of candidate options, 

especially for longer O/D distances with a number of alternatives. Obtaining such information 

would be extremely time consuming and resource-intensive. Local and state entities, however, 

might provide information of this nature pertinent to the limited number of options that survive 

an initial screening by shippers and carriers. This would allow the final choice to reflect 

special circumstances, such as the presence of several large national or state parks along a 

route with a very low census (residential) population. 

In the past, the ability to collect population information has been limited. Counting people 

along different routes, particularly the longer routes, has been cost prohibitive. The 

availability to shippers and carriers of off-the-shelf geographic information systems (GIS) that 

use census population data, either directly or indirectly, has increased, however. These 

systems can now be used to obtain population counts and exposures along all defmable 

modes/routes. 

In addition to having a significant impact on public safety, population can be highly variable 

from mode to mode and route to route and, therefore, can be a clear mode or route 

discriminator. The case study results presented in Exhibit 15 illustrate the variability of most 

primary factors, including general population. The range of values of the population density 

(surrogate measure for the general population) is very broad for each O/D pair evaluated. 

Although every potential modelroute alternative must be evaluated in detail, there are a few 

general observations that can be made across modes. The first observation is that there are 

always tradeoffs involved in selecting either mode or route to minimize population. Highway 

offers the most flexibility to avoid large population centers because of the large number of 

route alternatives, although the best highways are the Interstate system highways, which 
usually connect urban centers. Selecting highway routes to avoid major cities could have other 

undesirable effects, such as increasing shipment duration and trip length (effects that will be 

discussed below). It is usually more difficult to follow a population avoidance strategy with 

rail because rail lines traditionally connect major cities and there are fewer alternative routes 

available than for highway. Barge shipments follow waterways, of course, and generally offer 

a low-population alternative, if they can be used. 

In summary, the use of general population as a modelroute selection factor is highly desirable 

because of its direct and significant impact on public safety, variability between modelroute 

alternatives, and reasonable measurability using readily accessible census data. 

7.2.2 Occupational Population Exposed 

This factor includes workers who may be in proximity to a cask containing spent fuel or highlevel radioactive waste at any time during the entire shipment cycle. This obviously includes 

transport workers, such as the crew and the cask handlers. It also includes other groups who 

could be subject to exposure by nature of their occupation, such as escort vehicle personnel, 

security guards, inspectors and other enforcement officials, and even emergency responders. 

The potential exposure to the occupational population is a major consideration for safety 

because of the close proximity of this group to the container. It has a major effect on both 

incident-free radiological risk and accident-induced radiologicd risk. 

Most of the support groups (handlers, security, etc.) within the occupational population 

receive a one-time exposure for each shipment. Handling risk is especially important for the 

intermodal shipments, as demonstrated in the case study. The analysis showed that handling 

exposure can be a significant percentage of total intermodal incident-free risk and that the 

intermodal incident-free risk is higher than that for any other mode. 

The vehicle crew receives exposure throughout the shipment cycle. Previous risk studies have 

found that incident-free radiological exposure to the crew is the single largest component of 

the overall risk of transporting high-level radioactive waste and spent nuclear fuel. The case 

study results from this report support this for highway, dedicated trains, and regular trains. 

Off-link population is the largest factor for waterway shipments and container handling for 

intermodal shipments, as noted earlier. 

There are important differences in the components of occupational risk from mode to mode. 

The truck crew is much closer to the package than either the rail or barge crew for a typical 

shipment and, therefore, will receive a higher dose on a per-mile basis. The rail or barge 

movement, however, may require longer distances, which increases the exposure of those 

crews, relative to truck. Also, there are generally more and longer stops by rail and barge. 

Shipment by rail usually requires at least one interchange between rail carriers. Shipments by 

barge usually require a modal interchange to get the cask to and from the barge loading 

facility. Stop times can have a significant effect on incident-free radiological exposure. 
The variability in occupational exposure is illustrated in Exhibit 15. The surrogate measure 

for occupational exposure was simply the number of crew. This does not usually vary within 

a mode. The fact that occupational exposure can vary by route can be illustrated by 

considering number of crew along with shipment duration (a combination of trip length and 

average speed from Exhibit 15). When the values for these two are taken together, the 

substantial variability in occupational population exposure from one modelroute alternative to 

another can be seen. 

The ability to measure occupational population is excellent. The number and proximity of 

crew and the number and proximity of package handlers are known for each mode. The 

number and proximity of people at stops and the duration of stops are less certain, but can be 

reasonably estimated based on carrier experience. Because of the predominance of the vehicle 

crew exposure, the best single measure that is representative of incident-free dose to the 

occupational population is probably the number of crew involved in the shipment. 

The practicality of implementing occupational exposure as a modelroute selection factor is 

considered excellent. Data collection would be simple and the cost of data collection would be 

nominal, since carriers and shippers are already familiar with crew and handler operations. 

One major philosophical issue in using occupational exposure as a rnodelroute selection factor 

is risk acceptance. It can be said that transport workers voluntarily accept the risk of 

exposure. On the other hand, the general public does not voluntarily accept the risk of 

exposure from the transport of radioactive materials. It is argued that the objective of 

modelroute selection should be to minimize the involuntary risk to the general population as 

opposed to the voluntary risk to the occupational workers. The manner in which this issue is 

treated could have a significant impact on modelroute selection. Past studies have shown the 

incident-free dose to the vehicle crew to be much larger than the cumulative dose to the 

surrounding population for a typical shipment. The vehicle crew dose is dependent primarily 

on shipment duration. If both occupational and public exposure were included together, the 

best modelroute alternative would usually be the shortest and most direct one in order to 

minimize the time of exposure to the vehicle crew. This could result in a modelroute 

alternative that has a much higher surrounding population than if public exposure were 

considered separately. Because of the significant difference in the types of exposure between 

public and occupational groups, it was decided to treat each one separately in this study. 

In summary, occupational population is highly desirable as a modelroute factor because it is a 

major contributor to the overall level of incident-free radiological exposure, it can be easily 

and accurately measured, and it can vary considerably by mode and route. 

7.2.3 Shi~ment Duration 

Shipment duration strongly affects the safety of radioactive material transportation because it 

has a direct relationship with incident-free radiological exposure. The longer the material is in 

transit, the longer the exposure of the crew and the general public. This is illustrated by the 
incident-free risk model presented in Chapter 5 and by the results of the sensitivity analysis 

presented in Chapter 6. 

This factor is determined by the combination of many other factors, as shown in the Exhibit 6 

hierarchy. The major considerations include the route length, vehicle speed, and the number 

and length of both delays and stops en route. Shipment duration is measured in units of time. 

In past studies, the surrogate used for shipment duration has usually been just the trip length. 

In some instances, this length has been combined with average vehicle speed to obtain exposure time. In others, the length has been used exclusively to compare miles of exposure or 

some equivalent measure. This approach has neglected the effect of stops and variations in 

vehicle speeds, which can vary substantially between different modes and their corresponding 

routes. 

The ability to measure shipment duration is very good. Shippers and carriers know the estimated time required to ship material from one location to another for their own scheduling and 

billing purposes. This would include reasonable estimates for planned and unplanned stops. 

Unforeseen delays en route, such as those that might result from adverse or bad weather or 

road conditions, create some uncertainty in the ability to estimate shipment duration. 

Shipment duration can vary significantly from mode to mode and from route to route and, 

thus, can be a good modelroute selection discriminator. As a general rule, highway offers the 

fastest movement among the three modes and waterway is the slowest. Rail movements 

usually involve more stops en route than highway, unless it is hy dedicated rail. The case 

study results in Exhibit 15 illustrate the variability of shipment duration when the results for 

trip length and average vehicle speed are combined. 

7.2.4 Accident Rate 

The greater the likelihood of an accident, the greater the potential for an injury to the crew and 

for the release of radioactive materials and corresponding exposure to the public. Thus, 

accident likelihood has an important impact on the safety of transporting radioactive materials. 

A measure of accident likelihood is a necessary component of estimating both accident-induced 

radiological risk and non-radiological risk. This is clearly illustrated by the risk models 

estimating both accident-induced radiological and non-radiological risks in Chapter 5. 

The accident rate, as a primary modelroute factor, represents many other factors that could 

have an influence on the likelihood of an accident. The quality, condition, and design of the 

highway, railway, or waterway infrastructure all have an impact on the potential for an 

accident. The operating procedures and quality control of the carrier also have an impact on 

the potential for an accident, and these can vary fiom mode to mode. Weather and seasonal 

conditions have an impact. All of these subfactors are listed in the hierarchy in Exhibit 6. 

Over time, the interplay of all these various components is reflected in the accident experience 

for each right-of-way. The accident rate is considered the best available broad measure of all 

these factors. 
The variability of accident rates can be significant for different modetroute combinations. 

This is illustrated by the high variation and minirnum/maximurn range for accident rates for 

the case study results shown in Exhibit 15. Much of the difference in accident rates by 

highway is reflected in the classification of the highway. The Interstate highways usually have 

lower accident rates than other highways because they are built to the highest design standards 

in terms of geometry, grade, roadway structures, guideway separation, access control, etc. 

The accident rates of various Interstate highway segments, however, can be significantly 

different, and some non-Interstate highways can have lower accident rates than the Interstates. 

The ability to measure this factor is excellent at a gross level of analysis, but becomes more 

difficult for a more detailed level of analysis. Accident rates are available at different levels of 

specificity and quality. National averages are available for different highway classifications. 

Average waterway accident rates are available for specific water systems, such as the 

Mississippi River system. These national averages may be sufficient at the primary factor 

level. The use of national, or even regional, accident rates, however, may not be sufficient to 

differentiate between route or mode alternatives. The more specific the accident rate is to the 

road, rail, or water segment of interest, the better. Some segment-specific accident rates for 

highway and rail are available in some routing models today. The quality and uniformity of 

accident data can also vary from state to state. The analyst should be careful to use the best 

available and most consistent data. 

Accident rates for specific rail links (accidentsltrain-mile or car-mile) are generally unavailable 

'outside the owning railroad, because traffic volume over a given link is considered proprietary 

information. Usable accident rate information can be developed by using data on shipment 

origins, destinations, and interchange points (such as can be obtained from the Rail Waybill 

Sample) to generate traffic flow patterns for the rail network. From this, traffic density by rail 

link can be obtained and then combined with FRA accident data by nearest rail station to 

estimate link accident rates. Large databases have been developed by consulting organizations 

using this approach. 

The type of accident rate employed is also important. Generally, the accident rate that reflects 

the most severe types of accidents is preferred, since only the most severe accidents could 

result in a release from the casks used to transport high-level radioactive waste and spent 

nuclear fuel. In most cases, this will be the fatal or injury-producing accident rates, as 

opposed to the overall vehicular accident rate. Also, the accident rate that most closely 

represents the type of operation of interest is preferred. For highway, this would be the 

high-level radioactive waste or spent nuclear fuel motor vehicle accident rate. Unfortunately, 

this level of specificity is not found in accident statistics. The best accident rate that is most 

often available is the general truck driver fatal accident rate. 

The practicality of using accident rate as a modelroute selection factor depends on the level of 

analysis. If the analysis is national or regional, where national average accident rates can be 

used, then carriers and shippers will have little difficulty in implementing the criterion. As the 

level of analysis becomes more local in nature, the limited availability of existing data and the 
relatively high cost of obtaining new data make implementing the criterion much more 

difficult. 

In summary, the accident rate is a necessary modelroute selection factor. It is needed to provide an estimate of the likelihood of an accident for both accident-induced radiological and 

non-radiological risk. It is broadly representative of other numerous factors that influence 

accident likelihood. It is also relatively easy to measure, since the accident histories of the 

mode or route under consideration are usually available, although one must exercise care in 

the type and quality of data to be used. 

Trip length affects all three components of public safety: incident-free radiological risk, 

accident-induced radiological risk, and non-radiological risk. It affects incident-free risk 

because it is a major component of shipment duration. All other things equal, the shorter the 

trip the lower the incident-free radiological exposure and risk. Trip length affects both 

accident-induced radiological and non-radiological risk because it is a component of the 

accident rate. 

The major tradeoff for trip length is, of course, population and sensitive environments. The 

most direct route often is the one through the highest population areas or the greatest number 

of environmentally sensitive areas. 

The ability to measure trip length is simple and straightforward. Most of the highway, rail, 

and waterway distance references are now readily available. Trip length can vary substantially 

by mode and by route between almost all origins and destinations. This is shown in Exhibit 

15 for the set of rautes selected for the case study. 

7.2.6 Environment 

This factor is related to public safety in that a radiological release resulting from an accident 

could have significant adverse impacts on sensitive environmental areas located close to the 

right-of-way. Contamination of sensitive environments, such as major drinking water 

reservoirs, could have direct public health consequences. 

This is a factor that has not traditionally been considered in most previous routing and environmental studies relating to radioactive material transportation. A comprehensive treatment 

of all potential public safety impacts from mode and route selection, however, requires that 

sensitive environmental areas be included. The question to be addressed is what constitutes a 

"sensitive environmental area". Some would argue that every water source, including all 

streams, rivers, ponds, and lakes should be considered sensitive to radioactive material 

releases. Some argue that all agricultural lands should be considered sensitive since 

contamination would potentially enter the human food chain. 
Although there are good arguments that contamination of such broad measures as bodies of 

water and agricultural land do relate to public safety, they would be of little use as mode or 

route discriminators, since virtually every mode and route crosses some body of water or 

travels through some agricultural area. 

There was a wide difference of opinion among the TAG participants on the inclusion of 

environment as a modelroute factor. There did seem to be some agreement that if it were to 

be included as a factor, that it be limited to something that could reasonably be measured and 

that could actually vary among routes. The initial definition that was arrived at was a 

designated area that had been set aside by an official agency for some special reason, such as 

drinking water reservoirs, wetlands, or refuges. Sacred Indian tribal grounds were added as 

another possibility. It was agreed that the definition of "sensitive environments" for the 

purposes of differentiating modelroute alternatives needs to be assessed in greater detail. 

Once the sensitive environment has been defined, another question is how to measure it. 

Should evaluation of the modelroute alternative be based on (1) the total number of areas 

crossed, (2) the average distance from sensitive areas, (3) the total square footage of the 

sensitive areas within a certain bandwidth, or (4) something else entirely? The answer to this 

question is currently uncertain. As with the definition of sensitive environments, the 

appropriate measures to be used for sensitive environments will need more study. 

In summary, environment is believed to be an important modelroute selection factor because 

environmental contamination can impact public safety. Its usefulness as a modelroute discriminator, however, is somewhat questionable, because almost all routes go through or by areas 

that could be regarded in some sense as environmentally sensitive. A generally acceptable 

definition for this factor needs to be developed, and the appropriate measures for this factor, 

its variability, and its interrelationship with other modelroute factors all need to be more 

intensively studied. 

7.2.7 Emer~encv Response 

The relationship of emergency response to public safety is in the potential mitigation of the 

consequences of an accidental release of radioactive material in transit. The extent of 

mitigation is difficult, if not impossible, to predict or measure. Nevertheless, emergency 

preparedness and response is considered an integral component of the overall system for safe 

transport of radioactive materials, and it is desirable to be able to account for it in modelroute 

selection. Response to a radioactive material release is much more sophisticated than that for 

most other emergencies and requires specialized training. Consequently, the greater the 

proximity or availability of trained responders to a modelroute alternative, the more desirable 

it is. 

Emergency response is another factor that has not been evaluated in much detail in terms of 

route or mode selection in the past. It is included as a secondary factor for the U.S. DOT 

routing guidelines for general hazardous materials. There are many facets to emergency 

response, and there was considerable discussion of this factor by the TAG. Two major facets 
of emergency response relative to modelroute choice came out of the discussion: proximity 

and capability. The first important element is the location of responders relative to the route of 

travel. How long would it take for responders to arrive at the scene of a transportation 

accident involving a release of radioactive material? The second major consideration is the 

level of capability (e.g., training and equipment). The consensus of the TAG seemed to be 

that the measure for emergency response should be based on the response time required by 

specially trained emergency responders, not just first responders. "Specially trained" 

responders were equated with DOE radiological response teams and other qualified units. This 

is acceptable for generic analysis, but for specific campaigns other trained teams need to be 

considered. 

Currently, the required response time for qualified responders can be determined using existing 

software packages that incorporate routing algorithms. The number of qualified responders are 

limited, and their capabilities and locations can be geocoded into these packages. First 

responders consist primarily of local fire departments and law enforcement agencies. The 

feasibility and cost of obtaining the necessary information to include first responders in the 

evaluation would be prohibitive. Therefore, the measure for this factor is recommended to be 

the maximum amount of time for a specially qualified responder to arrive at any point along 

the potential route of travel. 

The ability to effectively measure emergency response is possible using the required response 

time for qualified responders as the metric. As mentioned, computerized routing routines can 

determine the maximum time from the location of a qualified responder to any point on a 

network. The locations of these responders are available from the appropriate federal and state 

agencies and from most potential shippers. 

The variability of emergency response from one modelroute alternative to another is difficult 

to assess. This factor could also be relatively difficult to implement, since the cost of 

necessary data or software could be high. An attempt was made in the case study to evaluate 

the variability in this factor using average response distance from DOE response facilities as 

the measure (see Exhibit 15). l6 Differences using that measure for the emergency response 

factor among alternative routes were small compared to the other primary factors. 

A special analysis was also conducted of the correlation between average response distance and 

route length and population density. Some degradation in emergency response capability (i.e., 

greater response distances) was noted for lower risk routes.17 Such routes tend to be longer, 

pass through more rural areas, and be farther from DOE response centers. This finding 

implies that the ability to provide adequate emergency response may be compromised when a 

supposedly "lower risk" route is chosen. This aspect should be addressed by shippers 

16 Alternative measures could be distances to qualified (1) state and local units, but locational information is not as 

readily acquired, and (2) units maintained by the shipper and receiver. The data collection approach used is 

described in Appendix G. 

17 Remember that the risk estimates in the case study did not consider the quality of emergency response. 
or carriers, either by reassessing the routing decision or by identifying locations where 

improvements in response coverage are needed for an otherwise preferred route and 

undertaking to see that those improvements are made. 

In summary, emergency response is believed to be an important consideration for modelroute 

selection, because it could reduce radiological accident consequences. Its value, however, 

would depend on agreement on a suitable unit of measure that is reasonably accessible and cost 

effective. 

If feasible, rail or barge transport for a given shipping campaign could entail significantly 

lower risks than highway transport, assuming there was enough material to warrant use of the 

larger raillbarge casks. Since the payload of a raillbarge cask is four to seven times that of a 

highway cask, it would generally take that times as many shipments to move the same amount 

of material by highway. Consequently, truck transport of a given amount of RAM usually 

entails more radiological and non-radiological risk overall than the other modes. Furthermore, 

if there is sufficient RAM to be transported at one time, multiple-cask shipments by train or 

barge would reduce the risk even more.'' Nevertheless, the analyst should still conduct a 

careful evaluation of modal and routing alternatives to be sure of the relative safety of a 

particular mode, even considering the cask payload differential. 

The variability of this factor is substantial-from amounts too little to warrant use of a single 

raillbarge cask to enough for a multiple-cask train or barge shipment, such as from an interim 

storage/consolidation facility to the repository. The ability to measure is obviously excellent, 

since the quantity to be shipped has to be known by the shipper; the difficulty of data collection 

is low. 

7.3 SUMMARY ASSESSMENT OF PRIMARY MODEIROUTE FACTORS 

Exhibit 21 identifies each of the primary modelroute factors and summarizes the results of the 

overall assessment of each factor. These factors are identified as the most important for 

consideration by shippers and carriers in selecting modes and routes for shipping high-level 

radioactive waste and spent nuclear fuel. 

No attempt has been made to weight these factors or combine them into an easy-to-use formula. As stated in Chapter 1, the primary purpose of this study, as directed by Section 15 of 

18 Non-radiological and incident-free radiological risks are both reduced. Non-radiological risk is reduced 

because the risk of operating the vehicle (railcar or barge) is distributed among more casks, reducing the risk per 

cask proportionately. Incident-free radiological risk is reduced because each cask shields a portion of other 

cask's radiation. 
Exhibit 21. Overall Assessment of Primary Factors 

Degree of Impact on 

Factor Types of Risk Affected Overall Public Safety Variability Ability to Measure Feasibility to Implement 

General Population 

Exposed 

Occupational Population 

Exposed 

Shipment Duration 

Accident Rate 

Y 

c. 

W 

Trip Length 

Environment 

Emergency Response 

Amount of Material 

Incident-free radiological 

Accident-induced radiological 

Incident-free radiological 

Accident-induced radiological 

Incident-free radiological 

Accident-induced radiological 

Non-radiological 

All three types of risk 

Accident-induced radiological 

Accident-induced radiological 

All three types of risk 

Major factor for accident-induced 

radiological risk. Contributes to 

incident-free radiological risk, 

but much lower than occupational 

exposure. People at stops represent 

biggest risk from incident-free 

radiological exposure within general 

population. 

Largest component of total incidentfree radiological risk for all modes 

due to crew exposure. 

Major impact on incident-free 

radiological risk; influences times of 

exposure for both general and occupational populations. 

Major component of estimating 

probability of radiological and nonradiological accidents. 

Major impact on shipment duration, 

which affects incident-free 

radiological risk. Major component 

of accident rate, which affects 

radiological and non-radiological 

accident risk 

Long-term health effects from water 

and land contaminated by an 

accidental release. 

Can reduce consequences of 

accidental releases 

Major determinant of modal risk. 

Cask capacity affects number of 

Can vary substantially by 

mode and route 

Varies substantially by 

mode (no. of crew) and by 

route because of shipment 

duration 

Can vary substantially by 

mode and route 

Can vary by mode and 

route 

Can vary substantially 

by mode and route 

Uncertain, not evaluated in 

case study 

Difficult to estimate; 

average DOE response 

distance varies little 

Number of shipments 

for a campaign varies 

Excellent for residential; 

poor to good for others 

Excellent 

Excellent 

Fair to excellent, varies with 

geographic detail 

and route specificity 

Excellent 

Difficult, but depends 

on unit of measure 

Depends on unit 

of measure 

Excellent 

Data collection moderately 

difficult 

Data collection easy; "risk 

acceptance" issue 

Data collection easy; compliance 

easy 

Data collection moderately 

difficult; quality of data can be a 

problem 

Data collection easy 

Data collection dificult; compliance difficult; depends on 

definition of units 

Data collection difficult; compliance difficult 

Data collection easy; cask 

handling capability, modal access 

shipments needed. substanti&~by mode may dictate-mode 
HMTUSA, was to identify important factors and to assess their degree of impact on public 

safety. Weights, which reflect the relative importance of each primary selection factor, could 

simplify the selection of modes and routes by focussing attention on the more important 

factors. They could also provide the basis for a "formula" that could produce a figure of merit 

for each modelroute combination. There are several very serious difficulties, however, that 

prevented an attempt to weight the primary factors. Weighting depends first and foremost on 

the importance (weight) assigned to the three main categories of risk (incident-free radiological 

risk, accident-induced radiological risk, and non-radiological risk), and that is really a policy 

matter, which is outside the scope of this study. An additional complication is that the 

influence each primary factor has on the types of risk varies from mode to mode, as was 

demonstrated in the sensitivity analysis conducted as part of this study. 

Assigning weights is obviously a complicated process that requires extensive analysis, as well 

as public input and deliberation. That effort could not be undertaken, given the limited 

resources for this study. This report does, however, provide information on the manner in 

which these factors contribute to the risk of transporting radioactive materials. This can serve 

as a basis for the way that these factors are combined to make modelroute decisions.19 

19 The December 1993 version of this report was provided to the general public for review and comment. The 

preceding document has incorporated the comments that were received, where appropriate. The DOT response 

to the comments on the December 1993 version of the report can be found in Appendix I. 
8. REFERENCES 

Association of American Railroads. 1975. "General Committee, Operating Transportation 

Division, Policy Statement. " July 25, 1975. 

Association of American Railroads. 1993. "Recommended Railroad Operating Practices for 

Transportation of Hazardous Materials. " Circular No. OT-55-B, October 19, 1993. 

Columbus City Code. Hazardous Materials Transportation. Chapter 255 1. 

Federal Highway Administration. 1980. "Implementation Package: Guidelines for Applying 

Criteria to Designate Routes for Transporting Hazardous Materials," U.S. Department of 

Transportation, FHWA-IP-80- 15, November 1980. 

Federal Highway Administration. 1992. "Transportation of Hazardous Materials: Highway 

Routing. " Notice of Proposed Rulemaking, Docket No. MC-92-6, 57 Federal Register 

169, August 31, 1992. 

Hazardous Materials Transportation Uniform Safety Act of 1990. Public Law 10 1-6 15, 104 

Stat. 3244 (16 November 1990). 

ICF, Inc. 1989. "Nuclear Waste: Is There a Need for Federal Interim Storage?" 

Monitored Retrievable Storage Review Committee. November 1989. 

Midwest Research Institute. 1990. "Present Practices of Highway Transportation of 

Hazardous Materials. " Washington, DC: Federal Highway Administration. 

Mullen, Saah, Miriam J. Welch, Bradford, W. Welles. 1986. "HM- 164: Radioactive 

Materials; Routing and Driver Training Requirements. " U.S. Department of Energy, 

SAND-85-7 160, January 1986. 

Prowler, S. 1993. "Mixed Bag of Trouble Dashes Hope for Quick End to Northeast's 

Supply Pinch." Butane-Propane News (May 1993): 27-30. 

Research and Special Programs Administration. 1981. "Highway Routing of Radioactive 

Materials." Final Rule, U.S. DOT, Docket No. HM-164, February 1, 1981. 

Research and Special Programs Administration. 1989. "Guidelines for Applying Criteria to 

Designate Routes for Transporting Hazardous Materials. " U.S. Department of 

Transportation, DOTIRSPAIOHMT-89-02, July 1989. I 

Research and Special Programs Administration. 1992. "Guidelines for Selecting Preferred 

Highway Routes for Highway Route Controlled Quantity Shipments of Radioactive 

Materials. " U. S. Department of Transportation, DOTlRSPAlHMSl92-02, August 1992. 
Stock, J. R. and B. J. LaLonde. 1977. "The Transportation Mode Decision Revisited." 

Transportation Journal 17, No. 2: 51, 59, Winter 77. 

Stock, 9. R. and D. M. Lambert. 1987. Strategic Logistics Management. Homewood, IL: 

Richard D. Irwin, Inc. 

Transport Canada. 1987. "Dangerous Goods Truck Route Screening Method for Canadian 

Municipalities. " 

U.S. Nuclear Regulatory Commission, Public Information Circular for Shipments of 

Irradiated Reactor Fuel, NUREG-0725, Rev. 1 1, Washington, DC, July 1996. 

Wilson, F. R., B. G. Bisson, and K. B. Kobia. 1986. "Factors That Determine Modal 

Choice in the Transportation of General Freight. " Transportation Research Record 1061: 

26-3 1. Washington, DC: Transportation Research Board. 
Appendix A. 

DEFINITIONS 

DEDICATED TRAINS - 

Dedicated trains are usually considered to be a subset of regular train service that is 

characterized by homogeneity of the cargo. This term includes both unit trains and scheduled 

high-speed trains, such as those hauling trailers and/or containers on flatcars (TOFCICOFC). 

As used in this study, the term "dedicated train" refers to a relatively short unit train operated 

exclusively for the transportation of high-level radioactive materials. 

HAZARD 

Hazard refers to a condition or circumstance that has the potential to cause an injurious 

accident or otherwise affect human health. "Hazard" is not the same as "risk" because the 

latter also incorporates the consequences of an accident should it occur. 

HIGH-LEVEL RADIOACTIVE MATERIALS 

High-Level Radioactive Materials include spent nuclear fuel (SNF, q.v.) from power plants 

plus high-level radioactive wastes (HLW) that result from the reprocessing of spent nuclear 

fuel, a step in the production of nuclear weapons, the program to recycle commercial spent 

fuel (now inactive), or the reprocessing of naval reactor fuel. 

INCIDENT-FREE RISK 

Incident-free risk refers to the radiological risk to people resulting from the radiation that is 

normally emitted from a cask during transportation. Even heavily shielded, radioactive 

materials emit small amounts of radiation. The levels of this radiation are regulated by 

cognizant federal agencies. 

NON-RADIOLOGICAL RISK 

Non-radiological risk refers to those risks associated with hazards of transportation that have 

nothing to do with exposure to radiation. Only accident-related risks of transport operations 

are addressed in this study; secondary effects, such as impacts on health from pollution 

generated by transport vehicles, are not addressed. Non-radiological risk is expressed in this 

study in terms of expected fatalities that might occur to vehicle crews, occupants of other 
vehicles, pedestrians, security personnel, protesters, and casualties of evacuations and other 

emergency response operations. 

OPERATIONAL RESTRICTIONS (RAIL) 

For the purposes of this study, it is assumed that both dedicated and regular trains may be 

operated under restrictions derived from both the DODIDOE shipping instructions for naval 

reactor spent fuel shipments and current Association of American Railroad (AAR) guidelines. 

These restrictions are 

Maximum speed is limited to 35 mph 

One train is stopped (stands) during passes while the other moves past at no more than 

35 mph (AAR only) 

Cask car must be placed at the rear of the train (DOD only). 

RADIOLOGICAL RISK 

Radiological risk refers to the risk to people voluntarily (transport workers and emergency 

responders) and involuntarily (the public) exposed to radiation from sources contained within 

casks, as well as material released from them. Non-accident (incident-free) risk is that associated with the radiation that always emanates from the loaded cask, sometimes called normal 

radiation. Accident risk is that associated with radioactive material released from a damaged 

cask, as well as exposure to radiation from a cask, perhaps heightened by damage, during 

response operations. Radiological risk is typically quantified in terms of person-rems, which 

is a combination of the number of people exposed and the health effects of individual exposure 

(i.e., type, intensity, and duration of radiation, and manner in which the individual is 

affected). In this report, risk is usually referred to on a per cask-mile basis, which is the risk 

associated with the transport of one cask one mile. A conversion factor of 2500 person-rems 

per expected fatality is used. Affected populations include crews and other personnel, onboard escorts and others accompanying a shipment, inspectors, the populace along the route of 

travel, and emergency responders. Radiological effects on plants and animals were not 

considered in this study. 

REGULAR TRAIN 

As used in this study, "regular train" refers to any of the types of trains, other than dedicated 

trains, that could be expected to handle a portion of the movement of a cask car from origin 

to destination. A regular train would typically be a lower priority, advertised freight service, 

or "manifest" train in general service containing a mixture of commodities that may include 

grain, automobiles, building materials, explosives, flammables, and other hazardous 
materials. Operation would be in accordance with "operational restrictions" as defined 

above. 

RISK 

Risk typically refers to a combination of the likelihood that an injurious event or accident will 

occur and the consequences should it occur. Risk analysts define risk as the product of the 

probability and consequences of an accident, weighted equally. Implicit in this definition is 

the presumption that probability is as important as the consequences. In contrast, those 

responsible for public safety often discount the likelihood (probability) and focus on the 

potential consequences. 

SAFETY 

This study recognizes that safety is not absolute. Therefore, safety is regarded as the relative 

freedom from risk afforded by the available transport modes. Safety concerns acknowledged 

and addressed by this study include: 

Radiological effects of normal incident-free transport 

Radiological effects of accidents during transport 

Non-radiological casualties of accidents during transport. 

SPENT NUCLEAR FUEL 

Spent nuclear fuel (SNF) is irradiated fuel discharged from a nuclear reactor. 
Page intentionally left blank. 
Appendix B. 

INVITEES TO AND ATTENDEES AT MODEIROUTE TECHNICAL 

ADVISORY GROUP MEETING 

StateILocal 

Governments 

Representative Group 

Carriers 

-Highway 

-Rail 

-Water 

Shippers 

Regional Organizations 

Tribal Governments 

Invitee Attendee 

Jeffrey Cooney Yes 

Leo Tierney Yes 

Craig Philip No 

John Vincent Yes 

Julie Jordan No 

Michael Kirkland Yes 

Public Interest Groups 

Affiliation 

Tri-State Motor Transit Co. 

Union Pacific Railroad 

Ingram Barge Co. 

GPU Nuclear 

Edison Electric Institute 

General Electric 

Alan Turner Yes 

Rose Harnrnitt Yes 

Rick Bamsey Yes 

Robert Halstead Yes 

James Reed No 

James Miemyk Yes 

Colorado State Highway Patrol 

Illinois Department of Nuclear Safety 

Iowa Emergency Management Division 

Nevada Nuclear Waste Project Office 1 National Conference of State Legislatures 

I 1 western Interstate Energy Board 

Mervin Tano No 

Robert Tipple Yes 

Ted Glickman No 

Council of Energy Resource Tribes 

National Safety Council 

Resources for the Future 

Nuclear Waste 

Technical Review Board 

Nuclear Regulatory 

Commission 

U.S. Department of 

Energy 

U. S . Department of 

lkinsportation 

- - 

Sherwood Chu Yes 

John Cook No 

Michael Conroy Yes 

Susan Smith No 

Joseph Nalevanko Yes 

Claire Orth Yes 

E.P. Pfersich No 

Henry Sandhusen Yes 

Robert Walter Yes 

Paul Zebe Yes 

Gary Watros Yes 

-- 

Nuclear Waste Technical Review Board 

Nuclear Regulatory Commission . 

Transportation Management Division 

Office of Civilian Radioactive Waste 

Management 

Research and Special Programs 

Administration 

Federal Railroad Administration 

U.S. Coast Guard 

Federal Highway Administration 

Volpe National Transportation Systems 

Center 

Volpe National Transportation Systems 

Center 

Volpe National Transportation Systems 

Center 
Representative Group 

Contractor Support 

Invitee Attendee 

John Allen Yes 

David Kerr Yes 

Mark Abkowitz Yes 

Kitty Hancock Yes 

Emily Goodenough Yes 

Phani Raj Yes 

Affiliation 

Battelle 

Battelle 

Abkowitz and Associates, Inc. (AAI) 

Abkowitz and Associates, Inc. (AAI) 

Abkowitz and Associates, Inc. (AAI) 

Technology and Management Systems, Inc. 
Appendix C. 

BIBLIOGRAPHY 

MODAL STUDIES 

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Association of American Railroads. 1989. Train handling study on the relative safety 

of spent nuclear fuel carrying cars: Dedicated train vs. a conventional freight train. 

Research and Test Department. 

Basinger, K. L., P. L. Hoffman, and L. A. Smith. 1990. Comparative analysis of 

regular and dedicated train service for the transport of spent nuclear fuel: Costs and 

risks. U.S. Department of Energy. 

Brentlinger, L. A., P. L. Hofrnan, and R. W. Peterson. 1988. Comparative analyses 

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Brentlinger, L. A., P. L. Hofinan, and R. W. Peterson. 1989. Comparative analyses 

of spent nuclear fuel transport modal options: Transport options under existing site 

constraints. U. S . Department of Energy. 

Daling, P. M., G. W. McNair, and W. B. Andrews. 1985. Considerations in the 

selection of transport modes for spent nuclear fuel shipments. U.S. Department of 

Energy. 

Fischer, L. E., C. K. Chou, M. A. Gerhard, C. Y. Kimura, R. W. Martin, R. W. 

Mensing, M. E. Mount, and M. C. Witte. 1987. Shipping container response to 

severe highway and railway accident conditions. U . S . Nuclear Regulatory 

Commission. 

Goodman, L. S., and R. M. Jefferson. 199 1. Review of the draft report circulated by 

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materials in dedicated trains. 

Interstate Commerce Commission. 1977. Transportation of radioactive materials by 

rail. 

Kassen, D. 1982. Transportation of radioactive material by rail: Special train issue. 

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Starry, C., K. E. McCaleb, and W. A. Stock. 1992. "Truck transportation of 

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ROUTING STUDIES 

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Abkowitz, M., and P. Cheng. 1988. "Developing a risk-cost framework for routing 

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51. 

Abkowitz, M., M. Lepofsky, and P. Cheng. 1992. "Selecting criteria for designating 

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Coakley, L. G. 1987. "Highway routing of commercial spent fuel shipments: Local 

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Glickman, T. S. 1983. "Rerouting railroad shipments of hazardous materials to avoid 

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Kessler, D. 1985. Establishing hazardous materials truck routes for shipments through 

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McClure, T. A., L. A. Brentlinger, V. J. Drago, and D. C. Kerr. 1988. 

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U.S. Department of Transportation. 1989. Review of the selection of the rail route for 

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Wentz, C. J. Lessons learned: State of New Mexico's experience in the WIPP highway 

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Record 1264. Washington, DC: Transportation Research Board. 
FUSK ANALYSIS STUDIES 

Allen, J. C., and T. S. Glickman. 1988. Regulation and risk analysis of hazardous 

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routes in the vicinity of existing and planned disposal facilities." In Proceedings of 

HAZMACON '86. 

Elder, H . K., et a1 . 198 1. An analysis of the risk of transporting spent nuclear fuel by 

train. U. S . Department of Energy. 

Fenstermacher, T. E., et al. 1987. A Manual for peqorming transportation risk 

assessment. Washington, DC: Chemical Manufacturers Association. 

Fullwood, R. R., E. A. Straker, D. Moffat, W. Aron, and P. Lobner. 1976. 

Preliminary risk analysis of the transportation of nuclear waste. U.S. Department of 

Energy. 

Glickman, T. S. 1979. Network-related risk attributes in the rail transportation of hazardous materials. Volpe National Transportation Systems Center, U. S. Department of 

Transportation. 

Glickman, T. S. 1986. "A methodology for estimating time-of-day variations in the 

size of a population exposed to risk. " Risk Analysis 6, 317-324. 

Glickman, T. S. 1988. "Benchmark estimates of release accident rates in hazardous 

materials transportation by rail and truck. " TransportQtion Research Record 1 193. 

Glickrnan, T. S., and D. B. Rosenfield. 1984. "Risks of catastrophic derailments 

involving the release of hazardous materials. " Management Science 30, 503-5 1 1. 

Glickman, T. S., and E. D. Silverman. 1990. Gauging the degree of conjidence in 

choices between risky alternatives. Washington, DC: Resources for the Future. 

Golding, D., and A. White. 1990. Guidelines on the scope, content, and use of 

comprehensive risk assessment in the management of high-level nuclear waste 

transportation. Nuclear Waste Project Office, Carson City, NV. 

Hubert, P., J. Lombard, and P. Pages. 1986. Multicriteria analysis of protection 

actions in the case of transportation of radioactive materials: Regulating the transit of 

C-5 
Type A packages through the Mont Blanc Tunnel. Centre d'Etude sur 1'Evaluation de la 

Protection dam le Domaine Nucleaire, Fontenay-aux-Roses, France. 

Kaplan, S. 1986. "On the use of data and judgment in probabilistic risk and safety 

analysis. " Nuclear Engineering Design, 93 : 2. 

Lautkaski, R. and T . Mankamo . 1977. Chlorine transportation risk assessment. 

Valtion Teknillinen Tutkimuskeskus; Ydinvcimatekniikan Lab, Otaniemi, Finland. 

Nayak, P. R., D. B. Rosenfield, and J. H. Hagopian. 1983. Eventprobabilities and 

impact zones for hazardous materials accidents on railroads. U . S . Department of 

Transportation. 

Neuhauser, K. S., and P. C. Reardon. 1986. "A demonstration sensitivity analysis for 

RADTRAN 111. " Waste Management '87, 4 17-422. 

Office of Civilian Radioactive Waste Management. 1991. The Nevada railroad system: 

Physical, operational, and accident characteristics. U .S . Department of Energy. 

Pijawka, K. D., S. Foote, and A. Soesila. 1985. Risk assessment of transporting 

hazardous materials: Route analysis and hazard management. Transportation 

Research Board, National Research Council. 

Raj, P. K. 1988. A risk assessment study on the transportation of hazardous materials 

over the U. S. railroads. U.S. Department of Transportation. 

Raj , P. K., and T. S. Glickman. 1986. Generating hazardous material risk profiles on 

railroad routes. National Research Council. 

Rao, R. K:, E. L. Wilmot, and R. E. Luna. 1982. Non-radiological impacts of 

transporting radioactive material. U. S. Department of Energy. 

Rhoades, R. E., and A. L. Franklin. 1986. Evaluation of methods to compare 

consequences from hazardous materials transportation accidents. U . S . Department of 

Energy. 

Saccomanno, F. F., and S. El-Hage. 1989. "Minimizing derailments of railcars 

carrying dangerous commodities through effective marshalling strategies. " 

Transportation Research Record 1245. Washington, DC: Transportation Research 

Board. 

Saccomamo, J. H., J. H. Shortreed, M. Van Aerde, and J. Higgs. 1989. Comparison 

of risk measures for the transport of dangerous commodities by truck and rail. Institute 

for Risk Research, University of Waterloo, Canada. 
Santa Barbara County Resource Management Department. 1989. Risk assessment for 

gas liquids transporntion from Santa Barbara County. Santa Barbara, CA . 

Slovic, P. 1987. "Perception of risk. " Science, 236, 280-285. 

Smith, D. R., and J. M. Taylor. 1978. Analysis of radiological risks of transporting 

spent fuel and radioactive wastes by truck and by ordinary and special trains. U.S. 

Department of Energy. 

Tomachevsky , E. G., C. Ringot, P. Page, and P. Hubert. 1987. A validation study of 

the INTERZUN model for assessing risks of transportation accidents: Road transport 

of uranium hexafuoride. Transportation Research Board, National Research Council. 

Transportation Research Board. 1983. Risk assessment processes for hazardous 

materials transportation. National Research Council. 

Union Pacific Railroad. 1993. Simulation analysis in-train placement of nuclear cask 

cars. 

U. S . Department of Energy. 1979. Relative consequences of transporting hazardous 

materials-Interim report. 

U.S. Department of Transportation. 1973. Risk analysis in hazardous material 

transportation. 

U. S . Environmental Protection Agency. 1975. Transportation accident risks in the 

nuclear power industry, 1975-2020. 

Wilson, R., and E. A.C. Crough. 1987. "Risk assessment and comparisons: an 

introduction. " Science, 236:4799, 267-270. 

REGULATORY GUIDELINES 

Barber, E. J., and L. K. Hildebrand. 1980. Guidelines for applying criteria to 

designate routes for transporting hazardous materials. U . S . Department of Transportation, Federal Highway Administration. 

LaMortelWilliams Associates. 1987. Dangerous goods truck route screening method 

for Canadian municipalities. Transport of Dangerous Goods Directorate, Transport 

Canada. 

Peat, Marwick, Mitchell, and Co. 1980. Development of criteria to designate routes 

for transporting hazardous materials--Final report. U . S . Department of Transportation, Federal Highway Administration. 
Research and Special Programs Administration. 1992. Guidelines for selecting 

preferred highway routes for highway route controlled quantity shipments of radioactive 

materials. U. S. Department of Transportation. 

ENVIRONMENTAL ASSESSMENT STUDIES 

Hostick, C. J., J. C. Lavender, and B. H. Wakeman. 1992. Time and dose assessment 

of barge shipment and at-reactor handling of a CASTOR V/21 spentfuel storage cask. 

U. S . Department of Energy. 

Schneider, K. J., W. A. Ross, and R. I. Smith. 1988. "Estimated effects on radiation 

doses from alternatives in a spent fuel transportation program." In Proceedings of the 

29th Meeting of the Institute of Nuclear Materials Management. 

Smith, R. I., P. M. Daling, and W. D. Faletti. 1992. Analysis of radiation doses from 

operation of postulated commercial spent fuel transportQtion systems. U. S . Department 

of Energy. 

Unfone, A. J., A. A. Garcia, and R. Stuart. 1978. A generic assessment of barge 

transportation of spent nuclearfuel. Atomic Industrial Forum. 

U. S. Nuclear Regulatory Commission. 1977. Final environmental statement on the 

transportation of radioactive material by air and other modes. 

GENERAL STUDIES 

Abkowitz, M. D., S. B. Abkowitz, and M. Lepofsky. 1989. Analysis of human 

factors effects on the safety of transporting radioactive waste materials. US. 

Department of Energy. 

Abkowitz, M., P. Alford, A. Boghani, J. Cashwell, E. Radwan, and P. Rothberg. 

1991. "State and local issues in transportation of hazardous materials: Toward a 

national strategy. " Transportation Research Record 13 13. 

Abkowitz, M., P.D-M. Cheng, and M. Lepofsky . 1990. "Use of geographic 

information systems in managing hazardous materials shipments. " Transportation 

Research Record 1261. 

Abkowitz, M., and G. List. 1987. "Hazardous materials transportation incidentaccident information systems. " Transportation Research Record 1148. 

The Aerospace Corporation. 1987. Case histories of West Valley spentfuel shipments. 

U. S . Nuclear Regulatory Commission. 
Allen, J.C. 1991. Regulation of hazardous material routing and relationship to risk 

analysis. Air and Waste Management Association. 

Andrews, W. B., B. M. Cole, R. I. Engel, and J. M. Oylear. 1982. Defense waste 

transportation cost and logistics studies. U.S . Department of Energy. 

Batta, R., and S. S. Chiu. 1988. "Optimal obnoxious paths on a network: 

transportation of hazardous materials. " Operations Research 36: 1, 84-92. 

Blum, P. 1985. Trends in shipping spent fuel. Nuclear Engineering International. 

Brentlinger, L. A., S. Gupta, A. M. Plumrner, L. A. Smith, and S. Tzemos. 1989. 

MRS systems study, Task F: Transportation impacts of a monitored retrievable storage 

facility. U. S . Department of Energy. 

Brentlinger, L. A., and P. L. Hofinan. 1988. Nuclear waste transport using 

overweight truck and hefty rail casks. U. S. Department of Energy. 

Carlson, R. D., E. R. Koehl, L. H. Harmon, E. J. Habib, and T. A. Mignone. 1988. 

"Testing TRANSCOM--U.S. Department of Energy's RadMat tracking system. " In 

Proceedings of the 29th Meeting of the Institute of Nuclear Materials Management. 

Cashwell, J. W., K. S. Neuhauser, P. C. Reardon, and G. W. McNair. 1986. 

Transportation impacts of the commercial radioactive waste management program. 

U.S. Department of Energy. 

Cluett, C., and F. A. Morris. 1992. The transportation of radioactive materials 

through urban areas: Social impacts and policy implications. U.S. Department of 

Energy. 

Conference of Radiation Control Program Directors, Inc. 1990. Directory of State 

agencies concerned with the transportation of radioactive material-- With notes on their 

statutory authority and regulations. 

Cook, J. R., W. R. Lahs, and W. H. Lake. 1987. The modal study: The response of 

spent fuel packages to severe transportation accidents. U. S . Nuclear Regulatory 

Commission. 

Durfee, R. C., P. E. Johnson, P. R. Coleman, and D. S. Joy. 1988. Calculation of 

population statistics associated with hazardous material transportation routes. U . S . Department of Energy. 

Elder, H. K. 1983. Intermodal transportation of spentfuel. U.S. Department of 

Energy. 
Electric Power Research Institute. 1986. Safety criteria for spent-fuel transport. 

Federal Emergency Management Agency. 1983. Guidance for developing State and 

Local radiological emergency response plans and preparedness for transportation 

accidents. 

Fisher, A. C., and C. P. Furber. 1992. Railroad infrastructure adequacy for safe 

transportation of spent nuclear fuel. American Nuclear Society. 

General Accounting Office. 1987. NUCLEAR WASTE--Shipping damaged fuel from 

llhree Mile Island to Idaho. U.S. Congress. 

Glickman, T. S. and D. Golding . 1991. For a few dollars more: Public trust and the 

case for transporting nuclear waste in dedicated trains. Washington, DC: Resources 

for the Future. 

Goodman, L. 1992. Transporting nuclear waste: Securing the public trust. 

University of Nevada. 

Goodman, L. S., and R. F. Garrison. 1990. Routing guidelines for rail transport of 

radioactive materials--Is consensus possible ? U.S. Department of Energy. 

Gopalan, R., K. S. Kolluri, R. Batta, and M. H. Karwan. 1990. "Modeling equity of 

risk in the transportation of hazardous materials. " Operations Research, 38: 6, 96 1-973. 

Grella, A. W. 1989. "Reflection upon the nuclear transport regulations as they have 

emerged over the past several decades." Presented at PATRAM ' 89, Washington, DC. 

Halstead, R. J., R. R. Souleyrette, and R. diBartolo. 199 1. Transportation access to 

Yucca Mountain: Critical issues. Nuclear Waste Project Office, Carson City, NV. 

Harwood, D. W., and E. R. Russell. 1990. Present practices of highway 

transportation of hazardous materials. U.S. Department of Transportation, Federal 

Highway Administration. 

Harwood, D. W., E. R. Russell, and J. G. Viner. 1989. Characteristics of accidents 

and incidents in highway transportation of hazardous materials. U.S. Department of 

Transportation, Federal Highway Administration. 

Heimann, D. I. 1980. Potential causes of railroad hazardous materials accidents: A 

statistical analysis (Volume I--Analysis and discussion; Volume 2--Detailed 

calculations). U. S. Department of Transportation. 

Hoess, J. A., and V. J. Drago. 1989. Study of minimum-weight highway transporters 

for spent nuclear fuel casks. U .S . Department of Energy. 
Jones, L. S . 1983. Cargo security: A nuts and bolts approach. Woburn, MA: 

Butterworth Publishers. 

Lahs , W. R. 1987. Transporting spent fuel--Protection provided against severe I 

highway and railroad accidents. U. S . Nuclear Regulatory Commission. 

i Loscutoff, W. V., E. S. Murphy, L. L. Clark, R. W. McKee, and R. J. Hall. 1977. A 

safety and economic study of special trains for shipment of spent @el. US. Department 

of Energy. 

Madsen, M. M., J. M. Taylor, R. M. Ostmeyer, and P. C. Reardon. 1986. 

RADTRAN III. U.S. Department of Energy. 

National Conference of State Legislatures. 1985. Emergency response to radioactive 

materials transportation accidents. Denver, CO . 

Office of Civilian Radioactive Waste Management. 1986. Transporting spent nuclear 

fuel: An overview. U. S . Department of Energy. 

Office of Civilian Radioactive Waste Management. 1990. Preliminary Nevada 

transportation accident characterization study. U .S . Department of Energy. 

Office of Transportation Systems Planning. 1988. Analysis of institutional issues and 

lessons learned from recent spent nuclear fie1 shipping campaigns (1 983-1 987). U. S . 

Department of Energy. 

Pages, P., P. Hubert, P. Gilles, and E. Tomachevsky. 1987. Modijjing the regulation 

for small radioactive package transit through the Mont Blanc Tunnel--Assessment of the 

health and economic impact. U. S . Nuclear Regulatory Commission. 

Price, D. L., J. W. Schmidt, and R. W. Kates. 1981. Multimodal hazardous materials 

transportation in Virginia. Virginia Department of Transportation Safety. 

Puget Sound Council of Governments. 1980. Hazardous materials study for the 

Central Puget Sound Region. Seattle, WA. 

Radwan, A. E., S. Singh, and K. D. Pijawka. 1990. "Projecting hazardous materials 

and wastes in transportation: Conceptual and methodological factors and applications. " 

Transport~tion Research Record 1264. 

"Recommendations for .hazardous materials transportation research and development 

projects." 1983. Transportation Research Circular, No. 267. 

Reno, H. W., R. C. Schmitt, and W. C. Lattin. 1989. "Transporting spent and 

damaged fuel in the United States: Recent experience and lessons learned related to the 
evolving transportation policy of the U.S. Department of Energy." Presented at 

PATRAM ' 89, Washington, DC. 

Research and Special Programs Administration. 198 1. A community model for 

handling hazardous material transportation emergencies. U. S . Department of 

Transportation. 

Research and Special Programs Administration. 1990. 1990 emergency response 

guidebook, guidebook for first response to hazardous materials incidents. U. S. 

Department of Transportation. 

Saccornanno, F. F., and J. H. Shortreed. 1991. "Final specification of corridor 

characteristics. " International Consensus Conference on the Risks of Transporting 

Dangerous Goods. 

Shappert, L. W., C. R. Attaway , et al. 1988. Transportation operationsfunctions of 

the Federal waste management system. U . S . Department of Energy. 

Southern States Energy Board. 1992. Spent fuel and high-level radioactive waste 

transportation report. U. S . Department of Energy. 

S praggins , H . B . 1993. Rail operations and management: Perspectives. U. S . Department of Energy. 

Starr, C., and C. Whipple. 1980. "Risks of risk decisions. " Science, 208, 11 14-1 119. 

Stiegler, J. E., G. C. Allen, and J. W. Cashwell. 1988. Spentfuel transportation 

system limitations and opportunities. U. S . Department of Energy. 

Tobin, R. L., N. K. Meshkov, and R. H. Jones. 1985. Preliminary assessment of 

costs and risks of transporting spent fuel by barge. U.S. Department of Energy. 

U. S . Congress, Office of Technology Assessment. 1986. Transportation of hazardous 

materials. 

U.S. Department of Energy. 1978. Everything you always wanted to know about 

shipping high-level nuclear wastes. 

U.S. Department of Energy. 1986. Spent fuel transport~tion in the United States: 

Commercial spent fuel shipments through December 1984. 

U. S . Department of Energy. 1986. Transuranic waste: Transportation assessment 

and guidance report." 
U.S. Department of Energy. 1987. Monitored retrievable storage submission to 

Congress - Volume I, The proposal. 

U. S . Department of Energy. 1988. Annual radioactive materials transportation legal 

developments report. Washington, DC . 

U. S. Department of Energy. 199 1. Midwestern high-level radioactive waste 

transportation primer. 

U. S. Nuclear Regulatory Commission. 1980. Survey of current State radiological 

emergency response capabilities for transportation related incidents. 

Viebrock, J. M., and N. Mote. 1992. Near-site transportation infrastructure project' 

jinal report. U.S. Department of Energy. 

Vincent, J. A. 1992. Issues concerning spent nuclear fuel transportation systems and 

shipping and receiving facilities interfaces. American Nuclear Society. 

Wentz, C. J. 1992. Ensuring safe transport of nuclear waste: New Mexico's 

experience with WIPP. State of New Mexico, Sante Fe, NM. 

Western Interstate Energy Board. 1991. Rail primer: Legal, technical and business 

aspects of rail transportation. Denver, CO . 

Wooden, D. G. 1986. Railroad transportation of spent nuclear fuel. U.S. Department 

of Energy. 
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Appendix D. 

HAZTRANS* MODEL DESCRIPTION 

MODEL OVERVIEW 

This appendix provides a brief description of the current version and project use of HazTrans, 

a risk management product of Abkowitz and Associates, Inc. (AAI), of Nashville, Tennessee. 

HazTrans, used in this study to perform transportation route risk assessments, is a geographic 

information systems (GIs)-based application, which uses longitude and latitude coordinates to 

combine data that otherwise would be difficult or impossible to integrate. 

HazTrans utilizes computerized highway, rail, and waterway transportation networks, derived 

from federal data maintained at Oak Ridge National Laboratory in Oak Ridge, Tennessee. 

The highway network contains all Interstate, U.S., and state highways, as well as some major 

local arterials. The rail network includes both mainline and branch track and contains 

information on railroad operating rights. The waterway network contains all navigable 

intracoastal and intercoastal waterways (including the Panama Canal), and includes the 

representation of all locks and dams. 

AAI has augmented the network databases with additional attributes, such as travel time, 

accident likelihood, and neighboring population. These attributes have been formed using a 

variety of transportation and demographic information sources and the results of scientifically 

credible transportation research studies. For example, population statistics are calculated 

using the 1990 Census by overlaying the block-level data onto the transportation networks and 

counting the population that resides within proximity of each segment and transfer point. 

Similarly, highway truck accident statistics are derived from a recent Federal Highway 

Administration study focusing on truck transport of hazardous materials. 

ROUTING CRITERIA 

To perform a routing analysis in HazTrans, the user must specify the mode, the origin and 

destination, the criteria to be used to determine the route, and any restrictions that should be 

placed on the route. These features were used in the study to select candidate routes to include 

in the case study sample. 

The criteria used to select a route can be based on a single or weighted combination of 

economic and safety measures. Selecting travel time, for example, as the sole criterion will 

result in the quickest route from the origin to the destination. Safety measures include releasecausing accident likelihood (i.e., the likelihood that there will be an accident that will result in 

a release at some point along the route), population exposure along the route, and a composite 

'HazTrans is a registered trademark of Abkowitz & Associates, Inc., Nashville, Tennessee. 

D-1 
risk measure. Designated routes can also be represented and evaluated in HazTrans using 

special function commands. 

In addition to using differing criteria and weights to select and evaluate candidate routes, 

HazTrans provides the capability to specify various types of route restrictions. These 

restrictions fall into four categories: (1) specific nodes or links, (2) area-wide impacts, 

(3) link groups based on segment attributes, and (4) the location of mode-specific activities. 

HazTrans output provides both segment and route-level statistics. These statistics can be used 

to supply input data to other risk models (e.g . , population, travel times, stop locations, etc., as 

inputs to Radtran 4) or to support HazTrans risk screening models directly. 

APPENDIX D BIBLIOGRAPHY 

Abkowitz, M. D., P.D.M. Cheng, and M. Lepofsky. 1990. "The use of geographic 

information systems (GIs) in managing hazardous materials shipments. " Transportation 

Research Record 126 1. 

Bureau of the Census. 1980. Census of population and housing, 1980: Master area 

reference file (MARF) 2. U. S. Department of Commerce. 

Federal Emergency Management Agency. 1989. Handbook of chemical hczzard analysis 

procedures. U. S . Department of Transportation, U. S. Environmental Protection Agency. 

Harwood, D. W., J. G. Viner, and E. R. Russell. 1990. "Truck accident rate model for 

hazardous materials routing. " Transportation Research Record 1264. 

Research and Special Programs Administration. 1990. Emergenq response guidebook. 

Report No. DOT-P-5800.5. U.S. Department of Transportation. 

Research and Special Programs Administration. 1989. Guidelines for applying criteria to 

designate routes for hazardous materials. U.S . Department of Transportation. 
Appendix E. 

RADTRAN 4 MODEL DESCRIPTION 

MODEL OVERVIEW 

Radtran 4 is a sophisticated computer program developed to evaluate radiological consequences of incident-free transportation, as well as the radiological risks caused by vehicular 

accidents occurring during transportation. Radtran 4 was developed (and is maintained) by 

Sandia National Laboratory (SNL) under contract to the U.S. Department of Energy. The 

following description of Radtran 4 has been compiled from source documents prepared over 

time by Radtran developers. 

SNL developed the original Radtran code in 1977 in conjunction with preparation of NUREG0170, "Final Environmental Statement on the Transportation of Radioactive Material by Air 

and Other Modes." The analytical capabilities of the code were expanded and refined in 

subsequent versions. Radtran 4 contains advances in handling route-related data and in treating multiple-isotope materials. 

The Radtran 4 code is designed to analyze the radiological impact of transporting radioactive 

material and combines meteorological, demographic, health physics, transportation, 

packaging, and material factors to evaluate both incident-free and accident-induced risks. 

EVALUATION METHODOLOGY 

Any evaluation of impacts on the public from transporting radioactive material requires some 

means of assessing health effects. Radtran uses a model based on the U.S. Nuclear Regulatory 

Commission's 1975 report entitled Calculation of Reactor Accident Consequences, which evaluates early fatalities, early morbidities, genetic effects, and latent cancer fatalities. 

Radionuclides being evaluated are first subdivided into two classes: (1) external (outside the 

human body) penetrating radiation hazards and (2) internal radiation hazards from inhaled or 

ingested radioactive material. External sources irradiate the total body, whereas the 

consequences of exposure to internal sources are dependent on the specific organs irradiated. 

External exposure can occur as a result of direct exposure to a localized source, from exposure 

to contaminated surfaces (groundshine), or from penetrating radiation from a passing cloud 

(cloudshine). Direct exposure can occur in either incident-free or accident-induced scenarios. 

Groundshine and cloudshine exposure only occur following accidents. 

Despite requirements designed to minimize exposure, whenever radioactive material is transported, members of the general population are exposed to extremely small doses of external 

penetrating radiation from x-rays, gamma rays, or exposure neutrons. In Radtran 4, the general population is divided into eight population subgroups: (1) crew, (2) passengers, (3) cargo 
handlers, (4) flight attendants, (5) warehouse personnel, (6) people in the vicinity of the 

vehicle while it is stopped, (7) people surrounding the transport link on which the vehicle is 

moving, and (8) people sharing the transport link with the vehicle. Total doses (in personrems) are computed for each of these subgroups. 

Two factors are considered in evaluating the impact of accidents that involve vehicles carrying radioactive shipments: probability and consequence. The probability that an accident 

releasing radioactive material will occur is described in terms of the expected number of accidents of a given severity for each transport mode, together with the package response to such 

an accident. The consequence of an accident is expressed in terms of the potential effects of 

the release of a specified quantity of radioactive material to the environment or the increased 

direct exposure of persons to ionizing radiation resulting from damaged package shielding. 

Risk is defined as the product of probability multiplied by consequence. 

Radtran 4 contains mathematical models of transportation environments; these models have 

been formulated to yield conservative estimates of integrated population dose in a way that can 

be supported by available data. These models neglect features of the transportation environment that either do not affect the calculated risk values or reduce conservatism (e.g., the width 

of the median on divided highways). 

Wherever possible, Radtran 4 combines calculational simplicity with general conservatism. 

For example, all routes by all modes are modeled as linear and flat without grade or curves. 

Also, all highway and rail links are treated as being one lane (or track) in width for the 

purpose of estimating distance to off-link population, but as being two lanes wide (one lane or 

track in each direction) for the purpose of estimating on-link doses. The first treatment is used 

to achieve symmetry (and, hence, mathematical simplicity) around the lane in which the 

shipment is located and is also slightly conservative. The second treatment (one lane in each 

direction) yields the smallest perpendicular distance to the traffic traveling in the opposite 

direction, which again is conservative. The latter treatment also implies that all rail routes are 

modeled as having double tracks, which is another small increment of conservatism for railmode calculations. 

Radtran 4 is designed for evaluating specific routes on a link-by-link basis. This option allows 

the user to independently analyze up to 40 separate route segments for each computer analysis. 

On each segment, the user assigns values representing the following route-related parameters: 

Mode (numerical designator) 

Segment length (km) 

Vehicle velocity (Whr) 

Population density @ersons/km2) 

One-way traffic count (vehicleslhr for all lanes) 

Accident rate (accidentslkm) 

Character designation (rural, suburban, or urban) 

Link type (1 = freeway, 2 = non-freeway, or 3 = other modes). 
The ability to include link-specific information provides the capability to compare risks 

between modes and routes necessary for evaluating the significance of route factors and for 

comparing radiological risks among routing alternatives. 

APPENDIX E BIBLIOGRAPHY 

Fischer, L. E., et al. 1975. Shipping container response to severe highway and railway 

accident conditions. U. S. Nuclear Regulatory Commission, NUREGICR-4829, Vol. 1. 

Madsen, M. M., J. M. Taylor, R. 0. Ostmeyer, and P. C. Reardon. 1986. Radtran III. 

SAND 84-0036. Sandia National Laboratories, Albuquerque, NM. 

Neuhauser, K. S., and F. L. Kanipe. 1992. Radtran 4: Volume 3, User Guide. SAND 889- 

2370, Sandia National Laboratories, Albuquerque, NM. 

Taylor, J. M., and S . L. Daniel. 1977. Radtran: A computer code to analyze transportation 

of radioactive material. SAND 76-0243, Sandia National Laboratories, Albuquerque, NM. 

Taylor, J. M., and S. L. Daniel. 1982. Radtran 11: A revised computer code to analyze 

transportation of radioactive material. SAND 80- 1943, Sandia National Laboratories, 

Albuquerque, NM. ' 

U . S . Nuclear Regulatory Commission. 1975. Calculations of Reactor Accident 

Consequences, Appendix VI to the Reactor Safety Study. WASH- 1400. Washington, DC . 

U.S. Nuclear Regulatory Commission. 1977. Final environmental statement on the transportation of radioactive material by air and other modes. NUREG-0170. Washington, DC. 
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Appendix F. 

DERIVATION OF TRANSPORT RADIATION RISK MODELS 

BACKGROUND 

The development of fundamental relationships for measuring radiation exposure was described 

in Chapter 5 of this report. In this appendix, derivations of the model formulations are 

presented in more detail. 

SCOPE OF THE MODELS 

Radiation risk comprises exposure of the following population groups: 

Off-Link Population--people residing, working, or otherwise congregating in areas 

within the zone of radiation influence from the route of spent nuclear fuel shipment 

On-Link Population-passengers in other vehicles encountered along the route 

Crew-personnel within the immediate vicinity of the cask (e.g., primary crew, 

onboard security personnel, inspectors) 

Population at Stops-transportation workers away from the immediate vicinity of the 

cask (and emergency responders in the case of accidents) and general population 

nearby 

Handling Personnel-workers at an intermodal transfer terminal. 

The risk evaluation models described in this appendix include considerations of the following 

types of risks: 

Incident-free radiological exposure 

Radiological exposure as a result of accident-induced release of nuclear materials into 

the environment. 

MODEL DESCRIPTION 

Assumptions 

In the models presented below, the following assumptions are made: 
The models are applicable to a single mode only; coefficient values are applicable to 

each specific mode. 

The width of radiation effect zones for each mode is a constant. 

An individual shipment contains a single cask; multiple cask shipments are not 

considered. 

Risks to handlers arise only at intermodal transfer facilities. 

Model symbols are defined in the nomenclature appearing at the end of this appendix. 

Incident-Free Exposure Model 

Consider the shipment of a single cask from an origin, 0, to a destination, D, as shown schematically in Exhibit F-1. The total risk from a single shipment is 

where: 

R,,= total risk from incident-free exposure (person-rems) 

R, = risk to off-link population 

R, = risk to on-link population 

R3 = risk to crew 

% = risk to population at stops 

R, = risk to handlers 

Radiation effects are felt within this zone 2 

Exhibit F-1. Schematic Representation of a Shipment Route Attributes 

F-2 
Each component risk is modeled below, consistent with fundamental physical considerations. 

Off-Link Population Exposure. The risk to off-link population is given by 

number of persons average duration of 

Rl = [ exposed over the route exposure of each individual 1 

with 

the number of people exposed = pLW (F-3) 

The premise of this model is that the duration of exposure to an off-link individual is 

inversely proportional to the speed of the vehicle: 

a,' average duration of off-link individual exposure = - 

uv 

where a,' is a constant. 

Note also that 

Hence, 

R1 PLW = a,' x - L 

In this formulation, a,, which combines a,' and W (assumed constant), is also a constant. 

Therefore, the off-link risk is dependent only on the average population density and the 

duration of shipment. 

On-Link Population Exposure. Exhibit F-2' represents a schematic of the on-link traffic 

situation (the highway mode is represented; however, the same schematic is assumed to be 

applicable to the other modes). 

'In Exhibit F-2, subscript 1 represents the traffic moving in the same direction as the spent nuclear fuel 

shipment and subscript 2, the traffic moving in the opposite direction. 

F-3 
7 Zone of Radiation Effects 

/ Cask Vehicle - 

Exhibit F-2. Schematic Representation of the On-Link Traffic Vehicles Being Exposed 

to the Effects of Radiation from a Moving Spent Nuclear 

The radiation exposure risk is given by the equation: 

number of number of on-link duration = [ persons ] x [ vehicles exposed 

per vehicle during the time t, each vehicle 

Fuel Shipment 

The initial development is for traffic moving in the same direction as the shipment. The 

results are then generalized and applied to traffic moving in the opposite direction. 

Taking into consideration traffic in all lanes moving the same direction as the shipment, the 

mean separation distance between vehicles is 

and 
The relative velocity of "same-directionn vehicles with respect to the cask vehicle is 

If the time duration for another - vehicle to pass the cask vehicle is c, then 

1 Substituting the prior equations and simplifying: 

Each on-link vehicle is assumed to be exposed to radiation when it is within + S/2 

longitudinal distance of the cask vehicle. Hence, the duration of exposure for each vehicle 

becomes 

where 2s represents the total length (parallel to the direction of motion of the spent nuclear 

fuel shipment) over which the radiation effects are significant. 

Combining the previous equations, the on-link, same-direction travel exposure risk becomes 

[%I SAME = a'2,1 Np TI WJl 

where a',, is a constant of proportionality. If the on-link vehicle speed (U,) is assumed to be 

a fixed ratio to the cask vehicle speed and the number of passengers per vehicle is constant, 

then the above equation becomes 

From this, the risk is not dependent on the relative speed between the traffic and cask 

vehicle. Therefore, whether a vehicle is moving with the cask vehicle or in the opposite 

direction, the form of equation is the same and the exposure risk to traffic in the opposite 

direction will be 
Equations 17 and 19 can be combined to a single equation of the type 

where T is the mean traffic density (vehicles/hour) on the route. The definition of T involves 

all lanes in the route segment; that is, the mean of the vehicle density crossing a point per 

hour in each direction. 

Evaluation of Traffic Density for Multi-Lane Routes. The traffic density value to be used 

in equations 17, 19, and 20 is calculated as follows. 

Let 

Ti = Traffic count in direction 1, traffic lane i 

Yi = Distance of lane i from the lane in which the spent nuclear fuel shipment is 

moving (this is the distance measured normal to the direction of motion of the 

spent nuclear fuel shipment). 

Case 1: Radiation Zone is Rectangular. The radiation zone is assumed to be rectangular 

along a transport distance of 2s and extends W distance on either side of the cask vehicle. In 

addition, all lanes of traffic on either side of the cask vehicle are assumed to be within a 

distance, W. Under these assumptions 

and 

where m and n represent, respectively, the total number of traffic lanes in directions 1 and 2. 
The total traffic density, T , used in equation 20, is then 

T =T +T2 

Case 2: Radiation Zone is Circular. If the radiation zone surrounding the spent nuclear 

fuel shipment is assumed to be circular with radius S and if all traffic lanes are intersected by 

this circle, then 

and 

The total traffic density T value is again given by equation 23. 

On-Board Crew Exposure. Crew exposure is directly proportional to the average number 

of personnel and the duration of transit: 

number of average duration of 

5 = a3 [ crew, inspectors exposure of each individual 1 

Population Exposure at Stops. The population exposure risk at w 

number of stops avg. number of per- avg. duration] 

R4 = [ over length L sons exposed per stop of exposure 

stops can be estimated by 

The number of stops may be assumed (without significant loss of .generality) to be 

proportional to the total distance of travel. Furthermore, if both the average number of 

people exposed per stop and the average duration of exposure (stopped time) are assumed to 

be constant, then 

where 
a, = coefficient for stop risk 

L, = trip distance. 

Risks to Intermodal Handling Personnel. The handling risk is assumed to occur only for 

intermodal transfers when the casks have to be handled by transportation personnel. Both the 

number of handlers and the average duration of handling are assumed to be constant. Hence, 

the risk itself is considered to be constant, irrespective of the distance of transportation: 

where 

a, = coefficient for handling exposure 

H, = Boolean variable (i.e., equal to 1 for intermodal and 0 for all other modes). 

Total Incident-Free Radiological Risk. Total incident-free radiological risk is then 

expressed as 

The different coefficients are considered constants and are not dimensionally consistent. The 

product of the coefficients and their respective parameter groups, however, have units of 

radiation dosage expressed in person-rems. 

Accident-Induced Radiological Risk Model 

The radiation risk from accident-induced release is calculated as follows. 

R = probability of an X consequence of release 

accident -induced release (in person -rems) 

The probability of release per shipment on a route is expressed by 

where 

probability = [mean accident rate per P(r Act) of release unit length per vehicle 1 

probability of release anywhere on the trip per shipment 

conditional probability of release, given that an accident has taken place 

travel length 
The consequence calculation is somewhat more complicated. The potential dispersal of 

radioactive nuclei in the atmosphere and the associated area of hazard are schematically 

represented in Exhibit F-3. The relationship is 

consequence = number of people average duration 

exposed to the cloud of exposure 

or 

where p' is population density, including both general and occupational population. 

In equation 35, a measure of the duration of exposure is the average time of transit of radionuclides carried by wind across the hazard area. This windward length is estimated to be 

directly proportional to the square root of hazard area. 

Note also that in equation 35 the hazard area, A, is a function of the quantity of radioactive 

materials released into the environment. This quantity depends on both the vehicle payload 

and the severity of the accident. However, if all possible conditional probabilities of release 

of different quantities (i.e., accident severity) are combined, then the term A in equation 35 

can be interpreted as the area corresponding to a mean quantity released and P(r 1 Acc) in 

equation 33 will then correspond to the conditional probability of release of this mean 

quantity. 

Combining equations 33 and 35, and noting that (1) mean conditional release probability is 

independent of the route chosen, (2) mean quantity released is constant over a given mode 

(hence, A is a constant over mode), and (3) wind and other atmospheric conditions are 

constant, the relationship becomes 

where b is the radiological accident coefficient. 

Note that accident release risk has a direct relationship to mean population density, length of 

travel, and mean accident rate. It does not depend on the duration of travel. 

The accident-induced radiological risk calculations presented above are adequate for 

modeling. It should be recognized, however, that they do not fully address a number of 

variables related to modal differences associated with accidents, severities, and cask contents. 
of hazard A 

Exhibit F-3. Schematic of Radioactive Nuclide Dispersion and Hazard to Off-Link 

Population 

NOMENCLATURE 

a Coefficients of various risk terms 

A Radiation dose hazard area (sq. km.) 

b Coefficients of various risk terms 

C Consequence of an accidental radiation release (person-rems) 

H I Boolean with value 1 or 0 

L Total length of the trip (or route length) for the cask vehicle (km) 

m Number of traffic lanes in direction 1 

n Number of traffic lanes in direction 2 

NcZw Average number of crew per vehicle (personnel within 10 meters of the cask) 
Average number of people per vehicle (assumed the same for both directions of 

traffic) 

Total number of vehicles exposed to radiation effects during the transit of the cask 

vehicle (in time t3 

Probability that in a shipment an accident occurs resulting in the release of radionuclides to the atmosphere 

Conditional probability of release given that a traffic accident has occurred 

Total radiation exposure risk per shipment (person-rems) 

Non-accident exposure risk to off-link population (person-rems) 

Non-accident exposure risk to on-link population (person-rems) 

Crew exposure risk in non-accident transportation (person-rems) 

Exposure risk at stops (person-rems) 

Intermodal handling risk (person-rems) 

Along-link distance over which the radiation effects are important either in the front 

or at the back of spent nuclear fuel cask (km) 

Mean accident rate over the entire length per shipment. It is also the probability of 

realizing an accident over a unit distance in a single shipment (#/km) 

Mean traffic fatal accident rate over the entire route 

Mean duration of radiation exposure of each on-link vehicle (r) 

Total duration of the trip for the cask vehicle (hr) 

Mean time between vehicles crossing a specified point on the link (hr) 

Mean traffic density on the mode over the duration of time that the cask vehicle is 

on the route (vehicleslhr) 

Mean speed of cask vehicle = (Llt,) (kmlhr) 

Mean speed of vehicles moving in the same direction of the cask vehicle (kmlhr) 

Mean speed of vehicles moving in the opposite direction of the cask vehicle (Mhr) 

F-11 
W Total width of radiation effect zone along the route corridors (km) 

Yi Cross longitude distance to traffic lane i from the lane in which the SNF cask 

vehicle is moving (center-to-center distance between lanes) 

P Average density of population along the route lying entirely within semi-width Wl2 

on either side of the route (numberlsq. km.) 

P ' p based on consideration of both general and occupational population 

4 Mean separation distance between vehicles moving in the same direction (km) 

42 Mean separation distance between vehicles moving in the opposite direction (km) 

Subscripts 

1 Traffic moving in the direction of the spent nuclear fuel cask vehicle 

2 Traffic moving in the opposite direction of the spent nuclear fuel cask vehicle 
Appendix G. 

DEVELOPMENT OF CASE STUDY INPUT AND OUTPUT 

The purpose of this appendix is to provide a discussion of the information used to generate 

the case study inputs and outputs. The emphasis of this work was to support comparisons of 

safety impacts associated with different mode and route selections, which required several 

adjustments to the information provided to and received from the Radtran 4 analyses as 

described below (for more on Radtran 4, see Appendix E). 

PRIMARY FACTORS 

The primary factors that provide the basis for the case studies include amount of material, 

emergency response, general population, occupational population, accident rate, trip length, 

and shipment duration. As outlined below, values for these factors were obtained from 

HazTrans, except as noted, for each of the 65 routes used in the case study analysis (for more 

on HazTrans, see Appendix D). 

Amount of Material 

Amount of material is quantifiable in the context of this analysis if it is handled as a postprocessing activity once the relationship between primary factors and safety is established on a 

per-shipment basis. The relative payload capacity, as a modal selection factor, becomes a 

consideration when the number of shipments is compared. To extend the interpretation of case 

study results to consider amount of material, the cask payloads used in this analysis were two 

pressurized water reactor (PWR) assemblies per truck and fourteen PWR assemblies per rail 

and barge shipment. One common way to establish equivalency is to assume linearity in the 

radiological impacts per shipment. 

Emer~encv Response 

DOE has developed regional emergency management field offices that can assemble and dispatch qualified response teams to incidents involving nuclear material. The following ten 

regional field offices were identified and located: 

Albuquerque, NM Oak Ridge, TN 

Argonne, IL Richland, WA 

Cincinnati, OH Oakland, CA 

Idaho Falls, ID Aiken, SC 

Las Vegas, NV Brookhaven, NY 
Each office determines the appropriate response and the best method for transporting the 

response unit to the incident site. For this reason, actual response times are very difficult to 

predict. 

As a surrogate measure, emergency response time was represented as the average of the direct 

distance from the nearest field office to each route segment for that route. Distance was 

calculated using curvilinear distance from the nearest field office to the ends of each route 

segment using latitude and longitude coordinates. The segment response distance was taken as 

the average of the response distances to each end of the segment. A weighted average of 

response distances by segment length was then calculated to derive an overall route response 

measure. 

Inherent in the use of "as-the-crow-flies* distances is the possibility of misrepresenting driving 

distance, available access to rail and water modes, or the possibility that teams may fly to the 

incident site. Because the intended purpose in the case study was to establish a surrogate 

measure of the proximity of qualified response to different locations along prospective routes, 

it was felt that the methodology could achieve this purpose given these limitations. I 

General Po~ulation 

Exposure of residential population along transport routes was determined using HazTrans. 

HazTrans contains detailed 1990 Census residential population data by geographic location. 

This database was overlaid onto each case study route segment using common map referencing 

(latitude-longitude coordinates). The population within a half-mile band around the segment 

was counted for the purpose of establishing the population density of interest. Population densities on route segments with fewer than 6 persons/krn2 were defined as rural; greater than 6 

and fewer than 719 persons/km2 were classified as suburban; locations over 719 persons/km2 

were defined as urban. This grouping was formed to accommodate Radtran 4 default input 

requirements. 

The traffic sharing each route was based on assumptions made in previous radiological 

transport studies and in consultation with shippers and carriers. Highway traffic densities 

were based on assuming partially congested use of each roadway and the roadway capacity 

according to its functional classification. The traffic density for rail was assumed to be 2 

trainslhr on mainline tracks and 0.2 traindhr on all other lines. Traffic density on rivers and 

the intercoastal waterway was assumed to be one barge consist per hour; no traffic within 

significant exposure range was assumed for Great Lakes and off-shore locations. 

Occu~ational Population 

Occupational population was assumed to consist of on-board personnel (primarily crew and 

escorts) and inspectors at stops. The size of each group for each mode was obtained from 

telephone conversations with shippers and carriers directly involved in the movement of spent 
nuclear fuel. At the time of the Radtran 4 analyses, barge shipments of spent nuclear fuel had 

yet to occur. Discussions with a barge company and a shipper considering the use of barge 

transport, however, established the number of crew members for possible barge shipments. 

Accident Rate 

Accident rates for each mode and route combination were generated using the HazTrans 

system. HazTrans labels each transport route segment as a particular type, based on its 

functional characteristics, and then assigns a hazardous materials vehicle accident rate 

appropriate for its type that is based on previous scientific studies. Although the accident rates 

are reported on a per-mile basis, they were subsequently converted to a per-kilometer measure 

to accommodate Radtran 4 input requirements. 

Accident rates utilized in the study are provided below: 

Highway 

rural two-lane 

rural multilane undivided 

rural multilane divided 

rural fieeway 

urban two-lane 

urban multilane undivided 

urban multilane divided 

urban one-way street 

urban fieeway 

Rail 

mainline track 

yards 

sidings 

Waterway 

coast 

MS/OH/TNlMO river systems 

open seas, Great Lakes 

2.19 x per vehlmile 

4.49 x loa per vewmile 

2.15 x 10" per vewmile 

0.64 x lo6 per vewmile 

8.66 x per vewmile 

13.92 x 10" per vehlmile 

12.47 x per vewmile 

9.70 x 10" per vewmile 

2.18 x per veldmile 

6.0 x lo-' per car-mile 

2.04 x 10" per car-visit 

2.40 x per car-visit 

1.0 x per vewmile 

1.5 x 10" per vewmile 

0.005 x per veh/mile 

Trip Leneh and Shipment Duration 

Trip lengths were derived directly fiom HazTrans by summing the segment distances composing each route. Shipment duration took into consideration varying operating speeds associated 

with each segment type, subject to mode-specific adjustments associated with stops and delays. 

Stop time and delay assumptions are discussed in the following sections. 
RADTRAN 4 INPUT 

Radtran 4 requires a substantial amount of information to perform a single analysis. 

Exhibit G-1 lists all of the variables used by Radtran 4 along with their corresponding 

descriptions. The variables can be divided into four categories: modeling, material, mode, 

and route. Modeling variables define the type of analyses to be performed and specify the 

amount and type of output to be provided by Radtran 4. Material variables determine the type 

of material being shipped and its properties. Mode variables specify the amount of material 

being shipped, the type of handling and shipment characteristics, and the severity and release 

information for possible accidents. Route variables specify the length, vehicle speed, 

population density, number and length of stops, traffic density, and type of transportation link. 

Exhibit G-1 includes a letter after the name of each variable to designate its type as follows: 

modeling (D), material (T), mode (M), and route (R) variables. 

model in^ Assumptions 

Modeling variables remained constant for all cases. Modeling assumptions included 

Conduct of both incident-free and accident analyses 

Use of eighteen user-supplied time-integrated concentration isopleths and areas representing air dispersion as developed by SNL in their data set [4,1,3], available for 

public use via remote telephone access 

Modeling of freight movements as exclusive-use shipments. 

Material Assum~tions 

Material variables remained constant for all cases. Material assumptions included 

Spent nuclear fuel discharged from the reactor 5 years before transport 

Effective dose rate of 13 millirem/hour, the highest value permitted in Radtran 4. 
Exhibit G-1. Summary of Radtran 4 Variable Descriptions 

TITLE D 

FORM D 

DIMEN 

NISO D 

NSEV D 

NGROUP D 

NRAD D 

NAREAS D 

PAM 

IRNKC D 

IANA D 

IUOF'T D 

ISEN D 

IPSQSB D 

POPDEN R 

PACKAGE 

LABGRP(J) T 

PKGSZl T 

PKGSZ2 T 

SHIPMENT 

LABISO(1) T 

NORMAL 

NMODE M 

FTZNR R 

FTZNS R 

FTZNU R 

VELR R 

VELS R 

VELU R 

CREWNO M 

ADSTCW M 

HANDNO M 

STOPTIM R 

MINST R 

TiMZR R 

FMINCL R 

PDSTM 

RST M 

DISTOR M 

PDSTOR M 

RSTOR M 

PPV M 

FRSHR R 

FCTST R 

FTLFWY R 

TCNTPR R 

TCNTPS R 

TCNTPU R 

RPD M 

Alphanumeric title 

UNIT indites population dose calculation 

Number of isotopes 

Number of accident-severity categories 

Number of physical-chaniial groups 

Number of radii areas used for nondispnal mident analysis 

Number of areas used in dispersion accident adysis 

Flag for placing data on fdc 6 (Default = 1) 

Analysis flag (Default = 3: boh accident and incident-free) 

Shielding options tlag (Default = 2: pnom in bldgs exposed at reduced level) 

Rinting flag (1: @idem-free and accident output tables) 

Dispasal lccidcnt flag (Default = 0: user-supplied time-integntcd concentrations) 

Rural. suburban. and urban population densities (Default = 6,719,3861 peopleflrm? 

Alphanumeric identifiers for physical-chemical groups 

Fit package-size thmhold (Default = 0.5 m) 

Second package-size threshold (Default = 1.0 m) 

Alph~~~lleric isotope designators 

Mode number (1 = mck. 2 = nil. 3 = barge) 

Fraction of ml in rural zone 

Fraclion of travel in suburban zane 

Fraction of travel in urban zone 

Velocity in rural zone Orm/hr) 

Velocity in suburban zone @'r~/hr) 

Velocity in urban zone &nh) 

Number of crew on a shipment 

Avenge dii from ndiition source to crew during shipment (m) 

Number of handlings pn 

Stop rime for shipment (hr) 

Minimum stop time pn trip for shipment (hr) 

Diiindepnaent sop time per trip (kr) 

Minimum numb of nil inspections or classifzations; rail mode only 

Number of pewr~ exposed during slops 

Avenge exposure di when sopped 

Storage time per shipment (hr) 

Number of pnons exposed during slonge for shipment 

Avenge exposure dii during mnge (m) 

Number of persons per vehicle sharing thc vanspon lid 

Fraction of urban travel during rush hour 

Fraction of urban travd on city sveets 

Fraction of rural and suburban vavel on freeways by mode 

One-way a+ffi count in rural zones (vehk) 

One-way vdffz count in suburban tones (vehb) 

One-way tnffz count in urban zones (vehhr) 

Ratio of pcdesvian density to urban residential population dcnsity (Default = 6) 
Exhibit G-1. Summary of Radtran 4 Variable Descriptions (Continued) 

TRANSFER 

GAMMA T 

NEUTRON T 

ACCIDENT 

ARATMZ R 

SEVFRC M 

MATERIAL 

RPCVAL 7 

INGVAL T 

DEFINE 

ISONAMQ T 

ACCDNT(i,k) T 

RELEASE 

RFRAC M 

AERSOL M 

RESP M 

AREADA D 

DFLEV D 

PSPROB D 

OTHER 

RADIST M 

BDF M 

XFARM R 

CULVL M 

BRATE D 

ITRAIN M 

ECONOMIC 

ISOTOPES 

NM M 

Building shiildiig factor for rural zones (Default = 1.0) 

Building shielding factor for suburban zones (Default = 0.87) 

Building shielding factor for urban zones (Default = 0.018) 

Number of flight attendants for commercial passenger-air mode 

Coeffcknu defining gamma component of ndiation dose 

Coeffcimu defining neutron component of radiation dose 

Accident rates (accidentsihn) 

Fraciin of accidents for each spcitied accident severity 

Factors that determine dose to 8 organs per unit of ndmactivity of isotope inhaled 

Factors that determetermke dose to 8 organs per unit of radioactivity of isotope ingested 

Name of isotope 

Isotope spcif~ data 

Fraction of each physicalshemiial group released in accident of each severity 

Fraction of isotope of each dispersion category that is released in aerosol form 

Fraction of aerosoli isotope of each dispenion category that is respirable 

Area of each isodose area (Defaults in Radvan 4 Uxrs Manual) (m') 

Ti-integrated concentration of ndiotmclide in aerosol in each isodose area (Defaults in Raduan 4 Mad) 

Probability of occurrence of each of six Pasquill aunospheric stability categories (Only requhd if IPSQSB = 1) 

Radii that defm the expome annuli used in mndiirsal accident model (m) 

Building dose factor 

Fraction of rural land under ~ltivation 

Cleanup level following an accident (JL!iim') 

Brearh'ig rate (m'ls) 

For rail: 1 = general freight, 2 = dedicated rail 

not used for this evaluation 

Mode (same as NMODE) 

Number of shii 

Number of packages per shipment 

Package dox rate at l m (mmnlhr) 

Fraction of effstive dose rate that is gamma radiation 

Fraction of effstive dose nte chac is neutron radiation 

Material label 

Name of isotope; must be equivalent to name in LABISO atray 

Isotope-specifi curies per package for isotope 

Isotope-speeifi physicalchemical gmup for isotope; ~lst be identical to LABGRP 

Isowpe-specific diirsab'ility category for isotope 

Characterini package dimension for material (m) 

Dii (ion) 
Exhibit G-1. Summary of Radtran 4 Variable Descriptions (Continued) 

LINK 

LMODEQ) R 

LDISTQ) R 

LSPEDQ) R 

LPOPDQ) R 

LVDENQ) R 

LARATQ) R 

LZONEQ) R 

LTYPEQ) R 

Leeend: 

D . modeling variables 

T - material variables 

M -mode variables 

R .route variables 

Mode (same as NMODE) 

Length of link @m) 

Speed of vehicle on li Oan/hr) 

Population density along link @eMns/hn-) 

One-way vehicle density on link (vehhr) 

Accident rare on li (accidenW) 

Zone rypc designator for Iii (R = rural. S = suburban, U = urban) 

Li type designator (1 = freeway. 2 = non-freeway. 3 = all orher) 

Material that was modeled consisted of 15 major isotopes (Note: the isotopes listed do 

not represent the entire inventory present in spent nuclear fuel): 

Cobalt-60 Cesium-137 Plutonium-240 

Krypton-85 Cerium- 144 Plutonium-24 1 

Strontium-90 Europium- 154 Americium-24 1 

Ruthenium- 106 Plutonium-23 8 Americium-243 

Cesium- 134 Plutonium-23 9 Curium-244 

Mode Assumptions 

As necessary, the mode variables were changed between highway, rail, and waterway 

transport. Where the mode variables also reflected material characteristics, such as CIPKG 

(isotope-specific curies per package), rail and waterway values were kept the same because the 

waterway analyses assumed the use of a rail cask. Mode assumptions included 

Existing type and size casks used for both highway and rail shipments 

Highway cask payload of 2 PWR assemblies; rail cask payload of 14 PWR assemblies 

(This provides a 1 to 7 ratio between highway and rail cask carrying capacity.) 

Number of casks per shipment and the number of shipments per mode set to one each 

for all modes 

Accident severities assumed to be different for each mode. Highway and rail severities 

were derived from work performed by Lawrence Livermore National Laboratory for 

the NRC; barge accident severities were adjusted from the rail severity distribution by 
reducing the five higher severity fractions by a factor of five and increasing the lowest 

severity similarly (based on conversations with DOT contractor). 

Normal modal variables defining incident-free exposure determined for each mode 

based on discussions with shippers and carriers; kept constant for all analyses within 

each mode. - 

Route Assumptions 

Route variables were changed as necessary between routes and included all of the arrays listed 

under LINK as well as the NORMAL variables relating to length and number of stops and rail 

interchanges/inspections. The XFARM value was not included in the analyses because the ' 

ingestion risk under the accident risk results has been disabled within Radtran 4 by SNL. 

Note that all other variables indicated as route variables are overridden by the LINK inforrnation. 

The stops and stop times used for each analysis varied by mode and route. For highway 

routes, the assumption was that one inspection occurred at each state line. This was reflected 

in the FMINCL variable. The Radtran 4 default value of 0.01 1 hrlkm was used to represent 

other stop times for this mode. The stop relationships for both dedicated and regular rail were 

obtained from discussions with DOT staff. The independent stop time (TIMZR) was 

incorporated into the dependent stop time (STOPTIM) and was calculated as follows: 

Dedicated: (2 hrs + 8 hrs /classification & inspection)/ total route length 

Regular: (16 hrs + 16 hrs/classification & inspection)/ total route length 

The resulting values were added into the dependent stop times, which were: 

Dedicated: 0.0055 hrdmi for west of the Mississippi River and 0.0073 for east of the 

Mississippi River 

Regular: 0.035 hrs/rni for west of the Mississippi River and 0.047 for east of the 

Mississippi River 

An inspection was also included if the route went more than 1,000 miles without the occurrence of a classification. The stop time for waterborne shipments was calculated as follows: 

Water: (1.5 hrs/lock & dam) / total route length. 

Exhibit G-2 presents the specific variables used for each mode or the source used to obtain 

those variables. In many cases, particularly for the material variables, the variable listed in 

the table represents an array of values for different properties or modal criteria. Standard data 

sets were used for these arrays as referenced in Exhibit G-2. 
Exhibit 6-2. Summary of Radtran 4 Input Used for Case Analyses 

TITLE 

FORM 

DIMEN 

NISO 

NSEV 

NGROUP 

NRAD 

NAREAS 

PARM 

IRNKC* 

IANA* 

IUOPT* 

ISEN 

IPSQSB* 

POPDEN 

PACKAGE 

LABGRP(J) 

PKGSZI ** 

PKGSU*' 

SHIPMENT 

LABISO(1) 

NORMAL 

NMODE 

FTZNR 

FTZNS 

FTZNU 

VELR 

VELS 

VELU 

CREWNOt 

ADSTCW 

HANDNO 

STOPTIM 

MINST 

TlMZR 

FMINCL 

PDST 

RST 

DTSTOR 

PDSTOR 

RSTOR 

PPV 

FRSHR 

FCTST 

FTLFWY 

TCNTPR 

TCNTPS 

TCNTPU 

RPD** 

RR** 

RS** 

RU** 

FNOATT 

highway manrail ded.rail water intermodal 

UNIT UNIT UNIT UNIT UNIT 

not used (in LINK)- ------- Suburban: 719* 

from Transnet TTC developed data set [4,1,3]: same for all modes 

0.5 0.5 0.5 0.5 

1.0 1.0 1.0 1.0 

from Transnet TTC developed data set [4,1,3]: same for all modes 

1 2 2 3 2 

not used (in LINK) ------------------ 0 

nor used (in LINK) ------------------ 1 

not used (m LINK) -- 0 

not used (in LINK) - --- 0 

not used (in LINK) ------------- 1 

not used (in UNK) --- 0 

2 # 2 # 5 # 10 # 0 

3.1 *# 100 # 100 # 60# 0 

0 0 0 0 1 

0.011 *# varies wl route varies wl route varies wl route 0 

0 0 0 0 0 

0 0 0 0 12 # 

varies wl route 2 2 0 1 

50 # not used not used 10 # nor used 

50 # nor used not used 50 # not used 

nor used (assumed no storage)- -- --- not used (assumed no storage) 

not used (assumed no storage) - - 

1.2 3 # 3 # # 0 

nos used (in LINK) 

.05 1.0 1 .O 0 0 

.85 0 0 0 0 

not used (in LINK) -- 0 

not used (in LINK) - ---- 1 

not used (in LINK) --- - 0 

6.0 6.0 6.0 6.0 0 

1 1 1 1 1 

.87 .87 .87 .87 1 

.018 .018 .018 ,018 1 

nor used (air mode nor used) ----- 
Exhibit 6-2. Summary of Radtran 4 Input Used for Case Analyses (Continued) 

TRANSFER 

GAMMA** 

NEUTRON*. as defined on p. 4-8 of Radtran 4 manual: same for all modes 

as defined on p. 4-8 of Radtran 4 manual: same for all modes 

ACCIDENT 

ARATMZ 

SEVFRC 

MATERIAL 

RPCVAL** 

INGVALS* 

DEFINE 

ISONAM(k) 

ACCDNT(i,k) 

RELEASE 

RFRAC 

AERSOL 

RESP 

AREADA** 

DFLEV** 

PSPROB 

OTHER 

RADIST 

BDF** 

XFARM** 

CULVL** 

BRATE8* 

ITRAIN 

ECONOMIC 

ISOTOPES 

NM 

TABSPY(NM) 

PKGSHP(NM,m) 

TIPKG(NM,m) 

FRGAMA(m) 

FRNEUT(m) 

LABMAT(m) 

LINK 

LMODEU) 

LDISTU) 

LSPEDU) 

LWPDU) 

LVDENU) 

LARATU) 

LZONE(i)* 

LTYPEU) 

nor used (in LINK)------ --------------- from Modal Study: see section of table labeled ACCIDENT SEVERITY. . . 

as defined in Radtran 4 data base: same for all modes 

as defined in Radtran 4 data base: same for all modes 

not used (no new isotopes used for these analyses) 

not used (no new isotopes used for these analyses) 

from Transnet TTC developed data set [4,1,3]: same for all modes 

from Transnet TTC developed data set [4,1,3]: same for all modes 

from Transnet TTC developed data set [4,1,3]: same for all modes 

as defined by Radtran 4: same for all modes 

as defined by Radtran 4: same for all modes 

not used (national averages used for user defined dispersion) 

not used (dispersion model used for HLW and NSfl 

8.68-3 8.6E-3 8.68-3 

0.5 0.5 0.5 

0.2 0.2 0.2 

3.3E-4 3.3E-4 3.3E-4 

0 1 2 

not used for these evaluatioru 

-1 -2 -2 -3 

1 1 1 1 

1.0 1.0 1 .o 1.0 

13.0 13.0 13.0 13.0 

1.0 1.0 1.0 1.0 

0.0 0.0 0.0 0.0 

SFUEL SFUEL SFUEL SFUEL 

See section of table labeled ISOTOPE ARRAYS for input values for the following 4 variable groups. 

as in Transnet TTC developed data set [4.1.3]: same for all modes 

data set (4.1.31 exa p. 5.28 Radmn 4 exa. p. 5.28 exa. p. 5.28 

as in Transnet TTC developed data set [4,1,3]: same for all modes 

as in Transnet TTC developed data set [4,1,3]: same for all modes 

5.2 5.2 5.2 5.2 

not used (in UNK) -- 

1 2 

from HazTrans 

from HazTrans 

from HazTrans (112 mile band width - 800 m) 

from HazTrans 

from HazTrans 

R, S, U based on LPOPDQ) r 6, 719, 3861 resp. 

l or2 3 

-2 

1 

1 .o 

13.0 

1 .o 

0.0 

SFUEL 

exa. p. 5.28 

5.2 

nor used 

not used 

nor used 

not used 

not used 

not used 

nor used 

not used 
Exhibit G-2. Summary of Radtran 4 Input Used for Case Analyses (Continued) 

Accident Severity Arrays for All Population Zones 

Level 

MA& 

Hiehwav Rail Water 

1 9.948-01 9.948-01 9.99E-01 

2 4.05EM 2.02E-03 8.10E-06 

3 3.82E-03 2.72843 7.64E-04 

4 1.80E-03 5.55E-04 3.60E-04 

5 1.55E-05 6.14E-04 3.10E-06 

6 9.84E-06 1.25E-04 1.97E-06 

Fractional Release Arrays for Each Severity by IPCGRP 

@OUD 1 Grouo 2 Grouo 3 Grow 4 Groa 

Isotope Arrays 

LIBSAV ClPKG IPCGRP IDlSP 

mwav Rail & Wm 

PKG 1 

PKG2 

PKG4 

PKG5 

PKG3 

PKG3 

PKG4 

PKG4 

PKG4 

PKG4 

PKG4 

PKG4 

PKG4 

PKG4 

PKG4 

* Default values provided within Radtran 4 used. 

** Value not explicitly included in input files but default values within Radtran 4 used. 

t 5 crew members assumed on train; only 2 assumed within exposure to cask. 

# Values obtained from shippers and/or carriers. 

*# Default values used by Radtran confirmed by shippers and/or carriers 

Several "NORMAL" variables are hard-set within Radtran and cannot be changed. These variables are: 

PPH - persons per handling 

D, - distance from handlers to source 

T, - exposure time for handlings 

ri - distance from inspector to source 

Ti - exposure time for inspections 

SF, - shielding factor at rail stops 
RADTRAN 4 OUTPUT 

The output from a Radtran 4 analysis as designed for this study includes incident-free and 

accident-induced radiological risk values calculated in terms of person-rems. The five components of incident-free exposure include (1) crew risk, (2) handler risk, (3) off-link (or 

surrounding) population risk, (4) on-link (or shared facility user risk), and (5) stop risk 

(people exposed during stops). The four components of accident-induced radiological 

exposure are (1) groundshine (from external exposure to deposited particles), (2) inhalation 

(from breathing in particles), (3) resuspension (from inhalation of particles deposited and then 

resuspended), and (4) cloudshine (from external exposure to passing radioactive cloud). 

As indicated previously, shipments were assumed to travel via exclusive-use vehicles requiring 

no storage during transit. This assumption eliminates the calculated risks to passengers 

(exclusive of crew and escorts) and storage personnel. Also, because the ingestion risk calculations have been disabled by SNL within the current version,of Radtran 4, the associated risk 

could not be obtained. This risk is much smaller than the other risks and so would not affect 

the magnitude of the overall accident-induced radiological risk. 

The current version of Radtran 4 limits route-specific analyses to 40 links. Very few of the 

routes analyzed in this case study contained fewer than 40 links. Therefore, each route was 

divided into sets of 40 links and the results from each set were added to compile the final risk 

values. Adjustments were made in cases where exposure was shipment- (and not segment-) 

based so as not to double-count those effects. 

ADJUSTMENTS TO RADTRAN 4 RESULTS 

Because of assumptions within Radtran 4, some modes do not include certain incident-free 

doses, and some doses are calculated differently. Exhibit G-3 addresses the manner in which 

these differences were addressed for the Radtran 4 case study analyses. Exhibit G-3 displays a 

matrix of the incident-free doses for the different modes being evaluated. The numbers within 

the matrix refer to descriptions provided following the matrix. 

NON-RADIOLOGICAL RISKS 

Since Radtran 4 does not model non-radiological transport risks, this measure was derived 

outside of the Radtran 4 methodology using HazTrans and national accident statistics. Nonradiological risk was measured as expected fatalities due to the forces of the vehicular 

accident. National statistics have been compiled for each mode from which fatal accident rates 

can be derived that are relevant for this study. 
Exhibit 6-3. Adjustments to Radtran 4 Results 

Highway 

On-link: opposite direction 1 

On-link: same direction 1 

Off-link 1 

Crew: on board 1 

Crew: inspection 5 

Stops 1 

- Rail Water 

1. Indicates that the dose calculation performed within Radtran 4 was used directly. 

2. Indicates that Radtran 4 does not currently calculate a dose for this mode, and that not doing so is realistic 

because no dosage appears to generally occur here. 

3. Incident-free radiological risk to crew and other on-board personnel is currently calculated only for the 

highway mode. Analysis was performed using the rail mode input file with all mode flags changed from 2 to 

1 (rail to tractor-trailer). The resulting crew on-board dose was added to the original rail inspection dose to 

obtain a find crew dose. 

4. Incident-free radiological risk to crew and other on-board personnel is currently calculated only for the 

highway mode. Analysis was performed using the barge input file with all mode flags changed from 3 to 1 

(water to tractor-trailer). The resulting crew on-board dose was added to the original barge inspection dose to 

obtain a final crew dose. 

5. The crew inspection risk is calculated only for the rail and water modes. Problems were identified within 

Radtran 4 for the rail inspection calculations. The number of inspections has two components, FMINCL 

(minimum number of inspections per shipment) and a constant times the shipment distance. FMINCL was 

included in every link, rather than once per shipment. The modification was to calculate the risk directly, 

replacing the two terms with the actual number of inspections for each route. The resulting inspection crew 

dose was added to the on-board crew dose to obtain a final crew dose. 

6. Radtran 4 results for the rail model stop-risk calculations were modified to account for the following two 

factors. First, a risk value was being calculated only for suburban links. The formulation of the stop risk 

calculation uses the suburban population density for rail yards. Because of this, the code only checks for 

suburban links in calculating the risk. Instead, all links should be considered even if the suburban population 

density is used in place of link-specific density. When this was corrected using a spreadsheet and the linkspecific information, the stop risk was much higher than the other incident-free risks. 

When the equation was re-evaluated, it appeared that the distance-independent stop-time was being summed 

over every link with the distance-dependent calculation. To account for this, the independent stop time was 

divided by the total length of the route and added to the dependent stop time during the input phase. The final 

rail stop risk calculations were performed in a spreadsheet independent of Radtran 4 by using a stop-risk value 

from the Radtran 4 analysis, dividing by the length and population density of the link and multiplying by the 

total length of the route and the suburban population density of 719 persons/km2. 
Conversions to fatal accident rates per shipment-mile were made as follows. Highway heavy 

truck fatal accidents per vehicle-mile have been previously reported in the literature, as have 

train fatal accident rates per train-mile. Derivation of a fatal accident rate per rail cask 

shipment was made by assuming that the average regular train consist has 70 cars and the cask 

car block of 4 cars would assume 4/70 of the train accident rate. The rate for a (single) cask 

shipment via dedicated train was the full train accident rate. Published barge fatal accident 

rates are reported on a per ton-mile basis. Based on conversations with a barge carrier, it was 

concluded that the average dry cargo consist contains 15 barges, each carrying 1,500 tons. 

Conversion to a fatal accident rate per barge-mile was made using this information. All fatal 

accident rates were subsequently converted to a per-kilometer basis. 

DISCUSSION OF RADTRAN 4 RESULTS 

The aforementioned approach represents application of a hybrid tool to assist in forming technical judgments. Consequently, its usefulness depends on the quality of data and relevance of 

assumptions. 

Uncertainties are inherent in radiological risk prediction, especially for the low exposure levels 

associated with spent nuclear fuel transportation and potential accidents associated with its 

transport. Health effects (primarily related to cancer) from exposures to low doses of 

radiation do not appear for several years, and predictions are made using conservative 

estimates based on observed health effects resulting fiom exposures to much higher radiation 

doses at much higher rates. Using risk assessment models does not reduce these uncertainties 

since the output is dependent on the input data and assumptions. 

Using models-that systematically represent the transport of spent nuclear fuel and activities 

associated with that operation, however, does provide a means for conducting a consistent 

comparison of the quantifiable factors and associated risks among different modes and routes 

for representative origin and destination pairs. Therefore, although the absolute effect of 

different factors on the levels of radiation doses and risks for a given mode or route may be 

subject to question, the case study represents a valid framework for examining dependencies 

and variabilities of the primary factors and their relative relationship to public safety. 

Some of the key modeling assumptions contained within Radtran 4 that may significantly 

impact the results of these analyses are listed below. No attempt was made to change these 

assumptions because no basis exists for justifying such changes. They can be subjected to 

sensitivity analysis to gauge their importance to estimation of overall risk values. 

Dedicated rail contains a Radtran 4 default exposure factor of 0.01; for regular rail this 

exposure factor is 0.16. This factor is used to represent the exposure time and distance 

for the inspection crew risk. Highway and water modes were assigned the regular rail 

factor (0.16) for inspection crew risk. 
Stop dose is not calculated the same way for all modes. The rail model is based on the 

suburban population density (719 persons/km2) over a 400-meter radius area. The 

other modes use a specified number of people exposed at a specified average distance. 

The rail stop model uses a shielding factor (0.1) while the other modes do not. This 

effectively reduces the rail stop risk by one order of magnitude. 

The highway model includes pedestrian exposure for urban areas. Rail and water 

modes do not calculate any pedestrian exposure. 

The water mode uses an exposure band from 200 meters to 1000 meters while rail and 

highway use an exposure band of 30 meters to 800 meters to measure surrounding 

population exposure. 

As indicated above, Radtran 4 requires a large amount of information to perform a single 

analysis. The effect of variations of this data is difficult to determine without performing 

detailed sensitivity analyses on each variable. 

Although Radtran 4 includes a sensitivity evaluation for the incident-free risk calculations, this 

evaluation is performed on a link basis for the route-specific option. No overall sensitivity is 

performed for the route. Therefore, use of this information for this study is limited. 

A previous study, however, did assess the sensitivities of the Radtran model for a highway 

routing analysis. Ranked by importance, the parameters having the greatest influence on 

incident-free risk were (1) exposure distance at stops, (2) dose rate conversion factor (KO, 

which is a calculated factor based on the physical size of the container), (3) the transport index 

(TI), (4) number of packages per shipment, (5) number of shipments per year, and (6) trip 

length. Most of those factors, however, are constants in the case study analysis: exposure 

distance at stops was a constant for each mode; KO and TI were constant throughout; and 

number of packages per shipment and number of shipments per year were assumed to be one 

for all cases. The trip length was the only factor that varied with each modehoute 

combination. That study also assessed the sensitivity of accident-induced radiological risk 

calculations to changes in input parameter values for the following critical parameter groups: 

fractions of travel, accident rates, severity fractions, and release fractions. Parameters with 

large associated uncertainties were allowed to vary from the base case values by two orders of 

magnitude or more. Based on the results of that sensitivity study, it was concluded that no 

single parameter or parameter group dominates accident-induced radiological risk. Each of the 

parameter groups were determined to be significant contributors to overall accident-induced 

radiological risk. Increases in these parameters, however, produced disproportionately smaller 

increases in overall risk. It can be inferred, therefore, that the results of the Radtran 4 model 

are stable across wide ranges of input parameter values. Although the results of the sensitivity 

study cannot be applied directly to the primary factors being evaluated in the case analyses, 

they do give some indication of inherently stable tendencies within the Radtran 4 modeling 

environment. 
PRESENTATION OF CASE STUDY FACTOR AND RISK VALUES 

Exhibit G-4 presents summary case study values for both primary factors and radiological and 

non-radiological risks. This information is organized by origiddestination pair and mode. 

The inputs and calculations presented in this exhibit demonstrate that relevant information on 

primary factors can be collected by mode and route; these factors can be applied to a risk 

assessment methodology, and the overall impacts to safety can be quantitatively measured. 

They also show that the values of these primary factors vary considerably across the 

modelroute alternatives and, therefore, have meaningful roles in choosing an option to enhance 

safety. 

The cases are organized by mode in Exhibit G-5, where component and overall risk values are 

presented for incident-free and accident-induced radiological risk, respectively. This information substantiates that risk values also vary considerably by O/D pair, mode, and route, due 

to variations in primary factor values. This exhibit also lends itself to some meaningful 

conclusions concerning the relative magnitudes of risk associated with various shipment 

characteristics. For example, incident-free risk tends to dominate the overall radiological risk 

associated with spent nuclear fuel shipments. In most instances, incident-fiee risk is much 

larger than accident-induced radiological risk. 
Exhibit G-4. Summary Case Study Factor and Risk Values 

O/D Mode 

Pair 

Independent Variables 

Length Population Avg. No. Average Accident Average 

(km) Density of Crew Speed Rate Response 

(perkm2) (kmlhr) (acc./km) Dist. (km) 

Non-Rad 

Risk 

No. of 

Fatalities 

Incident 

Free Risk 

Total 

(Person- ! rem) I 

3.14E-03 

2.21E-02 

I 2.07E-02 

I 2.82E-02 

I 1.53E-02 

I 1.28E-01 I 

2.42E-03 

3.36E-02 

5.08E-02 

I 4.15E-02 

4.81E-02 

4.30E-01 I 

3.08E-02 

6.43E-02 

I 6.11E-02 

I 6.83E-02 

6.22E-01 

5.28E-03 

9.74E-02 

1.12E-01 

1.1lE-01 

I 3.82E-02 

I 1.57E-01 

4.39E-02 

I 1.76E-01 I 

6.57E-02 

I 1.50E-01 

8.08E-02 

7.74E-02 

9.88E-02 

I 6.23E-02 

I 7.01E-01 

I 8.01E-02 

9.24E-01 

I 1.26E-01 

I 3.85E-01 

I 1.77E-01 

I 1.93E-01 

I 1.95E-01 

I 8.52l32 

I 9.25E-01 

2.42E-01 

I 1.35€+00 I 

9.52E-02 

3.22E-01 

I 2.12E-01 

2.33E-01 

I 2.08E-01 

I 1.06E-01 

I 9.58E-01 

I 1.17E-01 

I l.23E+OO 

I 1.23E-01 

I l.23E+OO 

I 

I 

Rad. 

Accident 

Risk 

I Total 

( (person- 

! rem) I 

4.32E-04 

I 1.05E-04 

I 1.01E-04 

I 1.49E-05 

I 4.48E-04 

I 4.48E-04 I 

2.15E-07 

I 9.83E-04 

1.32E-04 

2.03E-04 

I 2.89E-03 

2.89E-03 I 

I 1.71E-03 

6.27E-04 

I 8.02E-05 

4.14E-03 

4.14E-03 

1.44503 

4.23E-04 

1.83E-04 

1.35E-04 

I 4.95E-03 

1 4.95E-03 

4.49E-03 

I 4.49E-03 I 

I 2.26E-03 I 2.M-03 

1.22E-04 

9.22E-05 

I 6.81E-05 

1.96E-03 

1.96E-03 

2.54E-03 

2.54E-03 I 

1 9.56E-03 

I 9.56E-03 

2.06E-04 

I 3.28E-04 

5.19E-05 

3.23E-03 

3.23E-03 

I 1.09E-02 

I 1.09E-02 I 

I 5.40E-03 

I 540E-03 

I 1.51E-03 

I 3.27E-04 

I 5.96E44 

I 8.48E-03 

8.48E-03 

4.98E-03 

4.98E-03 ' 6.64E-03 

6.64E-03 

I 

I 
Pair 

M 

D 

M 

D 

M 

Exhibit E4. Summary Case Study Factor and Risk Values (Continued) 

Independent Variables Non-Rad Incident Rad. 

Risk Free Risk Accident 

Risk 

Length Population Avg. No. Average Accident Average No. of Total i Total 

(km) Density of Crew Speed Rate Response Fatalities I (person- (person- 

(per/km2) (km/hr) (acclkm) Dist. (krn) ! rem) ! rem) 

D - dedicated train (rail) 

M - manifest train (rail) 

H - highway 

W - waterway 

WD - intermodal - barge and dedicated train 

WM - intermodal - barge and manifest train 
Exhibit G-5. Radtran 4 Component and Overall Risks 

-- 

,": Mode 

' ,. Incl&nt Fm Risk (pno~m) Incldanl Frr RII 

Crew Handllnps Off-Unk On-Unk I Total 

''Op j (penon-rem) 

Rad. Acci&nl Rbk (pnormm) , Risk 

Grwnd Inhalation Resuspension Clwdrhine To(al'persw I rem) 
trn Pair Mode 

Exhibit G-5. Radtran 4 Component and Overall Risks (Continued) 

Incident Fns 

lnslded Fns Rlsk (perrorrnm) Rlsk 

Crew Handlings OffUnk Onllnk Stop I 

1 (perno-m) 

I 

I 

6.78E-04 0.00E+00 6.78E-04 0.00E+00 1.78E-03 1 3.14E-03 

6.69E-04 0.00E+00 1 .OlE-05 0.00EWO 1.74E-03 f 2.42E-03 

1 A6E-03 0.00E+00 2.76E-02 0.00E+00 l.74E-03 1 3.08E-02 

1.586-03 0.00E+00 1.85E-03 O.OOE+OO 1 B4E-03 1 528E-03 

I 

7.39E-03 4.86E-02 8.72E-04 1.43E-05 8.85E-03 1 6.57E-02 

2.00E-02 4.86E-02 4.17E-02 6.22E-04 1.53E-02 1 126E-01 

1.83E-02 4.86E-02 7.96E-03 9.58E-05 2.03E-02 I 9.52E-02 

9.52E-02 4.86E-02 6.70E-03 1.10E-03 4.81842 1 2.00E-01 

8.62E-02 4.86E-02 9.78E-04 2.03E-05 1.47E-02 f 1.50E-01 

2.63E-01 4.86E-02 4.37E-02 7.38E-04 2.96E-02 1 3.85E-01 

2.36E-01 4.86E-02 8.02E-03 7.67E-05 2.93E-02 1 3.22E-01 

1.43E+00 4.86E-02 6.18E-03 7.338-04 8.28E-02 f 1.57E-0 

Rad. Accident 

Rad. Accldent Rlsk (personram) Risk 

I 

Ground Inhallon Resuspension CloudrMm 1 'pcmon- nml 

Leaend: 

D - dedicated train (rail) 

M - manifest train (rail) 

H -highway 

W - waterway 

WD - intennodal - barge and dedicated train 

WM - intennodal - barge and manifest train 
APPENDIX G BIBLIOGRAPHY 

Federal Emergency Management Agency. 1989. Handbook of chemical hazard analysis 

procedures. U.S. DOT and U.S. EPA. 

Fischer, E. E., et al. 1987. Shipping container response to severe highway and railway 

accident conditions. U. S. Nuclear Regulatory Commission, NUREGICR-4829, Val. 1. 

Harwood, D. W., J. G. Viner, and E. R. Russell. 1990. "Truck accident Fate model for 

hazardous materials routing. " Transportation Research Record 1264, 12-23. 

ICF, Inc. 1989. Nuclear waste: Is there a need for federal interim storage? Monitored 

Retrievable Storage Review Committee. 

Neuhauser, K. S., and P. C. Reardon. 1986. A demonstration sensitivity analysis for 

Radtran 3. SAND 85- 100 1, Sandia National Laboratories. 

Neuhauser, K. S., and F. L. Kanipe. 1992. Radtran 4: Volume 3, User Guide. SAND 

89-2370, Sandia National Laboratories. 

U.S. Department of Energy. 1992. Summary listing of EM facilities by field ofice and 

installation. Office of Environmental Restoration and Waste Management. 

U . S . Department of Transportation. 1990. National Transportation Strategic Planning Study 

(h'TSPS) . 

U. S . Nuclear Regulatory Commission. 1977. Final environmental statement on the 

transportation of radioactive material by air and other modes. NUREG-0170. 
Page intentionally left blank. 
Appendix H. 

MODEL ESTIMATION USING CASE STUDY ANALYSIS RESULTS 

This appendix describes the use of the results of the case study database to statistically estimate 

model (i.e., equation) coefficients for the radiological risk models presented in Chapter 5. 

Model (i.e., equation) estimation was performed in order to develop a more detailed look at 

the relationship of primary factors to the risk components of public safety and to examine the 

sensitivity of risk components to individual factors and factor coefficients. 

MODELING APPROACH 

The database comprised of the inputs and outputs of case,studies contains values for the 

independent variables (primary factors) and dependent variables (incident-free and accidentinduced radiological risks, respectively). Multiple linear regression analysis was considered as 

the initial means of model estimation. A close examination of the terms contained in the 

incident-free model equations revealed, however, several terms with common factors (e.g., t,) 

or terms that intuitively would be highly correlated. A subsequent correlation analysis of 

independent and dependent variables by mode confirmed this observation. The appearance of 

correlation of terms and factors typically leads to coefficient estimation problems due to multicolinearity, resulting in estimates lacking statistical confidence and often possessing improper 

signs. 

To address this concern, model estimation was designed around the use of single variable 

linear regression, estimating the coefficient of each term independently, using the primary 

factors included in the term as the independent variables and the incident-free risk component 

as the dependent variable. This approach was also intuitively appealing since each term was 

derived independently to represent a specific incident-free risk component. 

Evaluation of the quality of the regression analysis results was governed~by the following criteria: (1) the overall goodness of fit, as measured by the adjusted R2, (2) proper signs for the 

estimated coefficients, and (3) statistical confidence in each coefficient estimate, as measured 

by the t-statistic. A coefficient estimate was considered significant if the magnitude of the tstatistic exceeded the value corresponding to a 95 percent confidence that the coefficient value 

is significantly greater than zero. This value from the tdistribution varies by sample size and 

degrees of freedom, and therefore by mode in this case study. Corresponding t-values for 

each mode based on the case study sample size are: 

Threshold 

Mode t-Value 

Highway 

RegularlDedicated Rail 

Waterway 

Intermodal 
Separate models were estimated by mode. The model results and statistical measures are 

presented for incident-free risk by mode in Exhibits H-1 through H-5, respectively. The 

radiological accident risk model results and statistical measures for each mode appear in 

Exhibit H-6. These results are evaluated, in turn, in the following discussion. 

MODEL COEFFICIENT DERIVATIONS 

This section presents the results of the regression analysis performed to estimate incident-free 

and radiological accident risk model coefficients, respectively. 

Hi~hwa~ Incident-Free Risk 

The highway incident-free risk model estimation results appear in Exhibit H-1. Each 

coefficient, its corresponding value, t-statistic, and adjusted R2 are presented. In addition, the 

mean value of the independent variable associated with each coefficient (consisting of primary 

factor values) is presented along with the estimated intercept (constant) and the mean value of 

the dependent variable (incident-free risk component). 

Exhibit H-1. Highway Incident-Free Risk Model 

Mean Value of Mean Value 

Risk Coefficient Independent of Dependent 

Coefficient Component Value +Statistic Adjusted R' Variable Constant t-Statistic Variable 

a! off-link pop. 1.48 x lod 8.92 .781 912.29 @o 3.48 x 1W 1.73 .002 (R,) 

a2 on-link pop. 1.26 x lo4 11.32 ,852 151.81 (T PLL) 7.76 x lo-' 0.36 .020 (R2) 

a3 crew 1.73 x 105 54.41 ,993 58.09 (N-tJ 8.02 x 1W3 3.29 .I08 (R,) 

a, pop. at stops 3.18 x 10" 872.14 .999 1379.27 (L) 1.11 x lo4 1.67 .044 (R,) 

R,, (highway) = 1.48 x lo4 p t,+ 1.26 x lo4 T fL/L + 1.73 x 105 N,, t, + 3.18 x lW5 L + 9.26 x 10'' 

All four coefficients in the highway incident-free risk model have the expected sign and are 

statistically significant. In addition, each coefficient and associated term is able to explain 

over 75 percent of the variation in its respective risk component. The component terms are 

grouped to present the overall derived expression for highway incident-free risk, RIFE 

(highway), at the bottom of Exhibit H-1. 

In reviewing the mean values of the independent and dependent variables, a few items are 

notable. First, the independent variable associated with a, is large for highway (relative to 

other modes) because of the higher traffic densities of shared-facility users in highway 

operations. Similarly, the relatively low value for the a, associated term is due to smaller 

crew sizes for truck shipments. Finally, the overall contribution of a, and its term to highway 

incident-free risk is probably due to lower population densities along the interstates, where 

wider right-of-way is part of the facility design. 
Re~ular Rail Incident-Free Risk 

Exhibit H-2 presents the regular rail incident-free model estimates and statistical information. 

As in the case of highway, all coefficient estimates exhibit the expected signs, are statistically 

significant and have high adjusted R2. The resulting equation at the bottom of Exhibit H-2 is a 

composite representation of regular rail incident-free risks for spent nuclear fuel shipments. 

Exhibit H-2. Regular Rail Incident-Free Risk Model 

Mean Value of Mean Value 

Risk Coefficient Independent of Dependent 

Coefficient Component Value t-Statistic AdjustedR1 Variable Constant t-Statistic Variable 

a, off-link 5.95 x lod 15.26 .943 3128.24 (ptJ -3.58 x 1W -0.26 ,018 (RJ 

a2 on-link 1.12 x 10" 12.97 .923 0.68 (T PLL) 7.93 x I@" 1.17 .001(R2) 

a, crew 7.6) x 10" 8.06 .820 82.20 (N,~J 1.14 x 10" 1.26 ,074 (R,) 

a, pop. at stops 2.49 x 10J 15.31 ,943 2010.00 (L) 1.32 x 10" 3.39 ,063 (R,) 

R,, (regularrail) = 5.95 x 104p t, + 1.12 x 10" T PL/L + 7.64 x lo4 N, t, + 2.49 x 10'' L + 2.43 x 1W2 

One item of note is the relatively large value of the incident-free risk term associated with 

crew exposure in contrast to the dedicated rail model. This is due to the crew exposure factor 

of 0.16 used in Radtran 4 for regular rail in contrast to a factor of 0.01 for dedicated rail. 

Although the other modes used a similar exposure factor of 0.16, the number of inspections is 

generally much smaller relative to rail operations. 

Dedicated Rail Incident-Free Risk 

The dedicated rail incident-free risk model estimate and associated statistics appear in 

Exhibit H-3. Similar findings as reported previously apply here as well, in terns of model 

goodness of fit and coefficient signs and significance. The overall model as presented at the 

bottom of Exhibit H-3 represents the entire derivation for dedicated rail incident-free risk for 

spent nuclear fuel shipments. 

Exhibit H-3. Dedicated Rail Incident-Free Risk Model 

Mean Value of Mean Value 

Risk Coefficient Independent of Dependent 

Coefficient Component Value t-Statistic Adjusted R2 Variable Constant t-Statistic Variable 

a, off-link 4.75 x 106 28.15 .982 3965.50 @t,) -1.02 x lo4 -0.13 ,019 (R,) 

% on-link 7.61 x lo4 25.27 .978 1.12 (T PL/L) 7.16 x 10" 1.77 .001 (R2) 

crew 9.84 x lod 18.76 .962 210.87 (N-tJ 1.11 x 10" 8.45 .003 (R,) 

a, pop. at stops 9.13 x 104 10.95 ,895 2010.00 (L) 5.51 x 10' 2.75 .024 (K) 

R,, (dedicated rail) = 4.75 x lo4 p t, + 7.61 x lW T PL/L + 9.84 x 106 N, t, + 9.13 x lo4 L + 6.59 x 105 
Waterwav Incident-Free Risk 

Because of the nature of waterborne transport, this model specification did not hclude on-link 

population exposure on the Gulf, Great Lakes, and oceans. A Boolean variable (0 for 

waterway; 1 otherwise) was included in the final model to account for this feature, thus 

removing the a, term from the waterway model specification. Results of the waterway 

incident-free risk model estimation appear in Exhibit H-4. Model estimation statistics for offlink population risk are quite favorable, in contrast to an improper sign for the crew risk 

model coefficient and poor t-statistics for both crew risk and stop risk. The small sample size 

for waterway may be contributing to this effect. Fortunately, off-link population is the 

dominant independent variable in contributing toward the magnitude of waterway incident-fiee 

risk. 

Exhibit H-4. Waterway Incident-Free Risk Model 

Mean Value of Mean Value 

Risk Coefficient Independent of Dependent 

Coeftrcient Component Value t-Statistic Adjusted R' Variable Constant t-Statistic Variable 

a, off-link 1.15 x IOd 67.08 999 6701.16 @t,) -1.64 x lo4 -0.79 (RI) 

a1 crew -2.59 x 10'" -0.23 -.458 489.26 kt,) 4.05 x lo4 0.24 (R3) 

a, pop. at stops 5.78 x 10d 0.65 -.240 487.38 (L) 1.75 x 10“ 34.43 ,002 (&) 

R,, (waterway) = 1.15 x 104p t+ 2.59 x 1@'O N, t, + 5.78 x 10" L + 1.99 x 10" 

Interm' odal Incident-Free Risk 

As noted in Exhibit H-5, all intermodal incident-free risk model coefficients have the expected 

sign; however, the a, and a, coefficient estimates are not statistically significant. This is of 

concern, given the relatively large contribution of a, and its associated term in the overall risk 

expression. The low value of the adjusted R, is a result of the fact that the on-link exposure 

only exists on the rail portions of the intermodal trip. Given the strong statistical strength of 

the other incident-free risk models and the a, (handling) term in the intermodal model, it may 

be preferable to model intermodal risks as the sum of the following three components: (1) 

Exhibit H-5. Intermodal Incident-Free Risk Model 

Mean Value of Mean Value 

Risk Coefficient Independent of Dependent 

Coeftrcient Component Value t-Statistic Adjusted Ra Variable Constant t-Statistic Variable 

a1 off-link 1.95 x lod 16.43 .975 8647.63 @t,) -2.35 x 10' -1.65 .015 (RJ 

a2 on-link 2.86 x 10" 1.00 .001 13.59 (T t2,L) 3.68 x I@' 0.09 .0004 (R,) 

a, crew 2.32 x lod 0.18 -.I60 1763.21 (N-t,) 8.28 x 10' 0.36 .012 (RJ 

a, pop. at stops 1.29 x 10" 4.99 .773 2961.27 (L) -7.22 x 105 -0.83 ,031 (RJ 

4 handling 4.90 x 105 da da 1.00 (HI) da da .049 ($) 

R,, (intermodal) = 1.95 x lo4 p t + 2.86 x 10" T t2,2/L + 2.32 x 104 N, t + 1.29 x 10" L + 4.77 x 10" 
originating mode, (2) intermodal transfer, using the a, handling term only, and (3) delivery 

mode. 

Accident-Induced Radiolo~cal Risk Models 

All the accident-induced radiological risk model estimation results are presented by mode in 

Exhibit H-6. In all cases, the b, coefficient estimates have the expected sign. Coefficient 

statistical significance and overall goodness of fit as measured by the adjusted R2 are also 

good, with the exception of the waterway radiological accident risk model. Fluctuations in 

population exposure as a function of width of the waterway and the small sample size are the 

likely causes of this problem. In general, however, the estimated equations appear to be useful 

predictors of radiological accident risk values for spent nuclear fuel shipments. 

Exhibit H-6. Accident-Induced Radiological Risk Model 

Mean Value of Mean Value of 

Independent Dependent 

Mode Coefficient Coefficient Value t-Statistic Adjusted R' Variable Constant t-Statistic Variable 

Highway b, 1.55 x 10.' 9.20 .792 .046 @LSJ -2.35 x lW -2.32 .0005 

R, (highway) = 1.55 x I@'@ L SJ - 2.35 x lo4 

Regular Rail' b, 7.19 x 10" 11.41 ,902 .089 @LSJ -6.74 x lo4 -1.08 .OM 

RAa(regularhain)=7.19x 1w2(pLSJ-6.74~ l(r 

Dedicated Rail' bl 7.19 x 105 11.41 .902 .089 (pLSJ -6.74 x 10' -1.08 .006 

R, (dedicated hain) = 7.19 x 10' (p L SJ - 6.74 x 104 

Waterway b~ 6.89 x lo4 1 SO .295 SO3 @LSJ 5.49 x l(r 1.33 ,001 

R, (waterway) = 6.89 x lo4 (p L SJ + 5.49 x lo4 

Intermodal 'A 8.41 x lw3 4.40 ,724 ,474 @LSJ 1.46 x 1 w3 1.40 .005 

RA,,(intermoda1)=8.41 x lw3@LSJ+ 1.46~10.' 

'Equation estimated using overall national rail accident rate. 
Page intentionally left blank. 
Appendix I. 

DOT RESPONSE TO COMMENTS ON THE DECEMBER 1993 DRAFT 

REPORT 

INTRODUCTION 

This appendix reviews and responds to the comments submitted by the public on the draft 

report "Identification of Factors for Selecting Modes and Routes for Shipping High-Level 

Radioactive Waste and Spent Nuclear Fuel," December 1993. 

The U.S. Department of Transportation (DOT) was directed by Section 15 of HMTUSA to 

undertake a Mode and Route Study. The purpose of this study was " . . .to determine which 

factors, if any, should be taken into consideration by shippers and carriers in order to select 

routes and modes which, in combination, would enhance overall public safety related to the 

transportation of high-level radioactive waste and spent nuclear fuel." The Act also directed 

the U.S. Department of Transportation to "...include notice and opportunity for public 

comment. . . . " 

The draft report, "Identification of Factors for Selecting Modes and Routes for Shipping HighLevel Radioactive Waste and Spent Nuclear Fuel," December 1993, was made available by the 

DOT for public comment and was formally announced in the Federal Register, December 30, 

1993, p. 69450. 

Thirteen responses were received in the response docket (see Exhibit 1-1). The majority of the 

commentors were governmental organizations (or contractors acting on their behalf). Of the 

four cornmentors who were not governmental organizations, two were industry organizations 

(one representing the electric power industry and the other representing the railroads), one was 

a railroad, and one was a consultant acting on his own behalf. 

The major issues raised in the comments are summarized below, organized by subject area. 

The response of the DOT, in italics, follows each issue. 

STUDY OaTECTIVES 

Focus on NWPA Shipments 

Several commentors argued that the report should specifically address the upcoming mode and 

route decisions for Nuclear Waste Policy Act (NWPA) shipments, to both the national 

repository and the Monitored Retrievable Storage (MRS) facilities, directly and in detail. 
Exhibit 1-1. Cornmentors on the December 1993 Draft Report 

Association of American Railroads (AAR) 

Board of Education, Ballston Spa (NY) Central School District 

Clark County, Nevada, Department of Comprehensive 

Planning, Nuclear Waste Division 

Edison Electric Institute (EEI), Nuclear Waste and 

Transportation Program 

Intertech Services Corp. on behalf of White Pine County, 

Nevada, Board of White Pine Commissioners 

Intertech Services Corp. on behalf of Lincoln County 

Commissioners and the Caliente City Council 

Jefferson, Robert M., consultant 

State of Nevada, Agency for Nuclear Projects, Nuclear Waste 

Project Office 

State of New Mexico, Energy, Minerals and Natural Resources 

Department, Radioactive Waste Consultation Task Force 

State of Tennessee, Department of Environment and 

Conservation, Division of Radiological Health 

Union Pacific Railroad Company 

United States Department of Energy, Office of Technology 

Development, Office of Special Programs, Transportation 

Management Division 

Western Interstate Energy Board (WIEB), High-Level 

Radioactive Waste Committee 
They alleged that the legislative history shows that this was Congress' focus and "explicit 

technical assistance.. .is sorely needed. " On the other hand, another commentor stated that the 

study should not focus on the repository shipments, because MRS and other shipping 

campaigns will occur well before those shipments commence. 

DOT Response: 

The DOT acknowledges the concern, especially among western states, about the modes 

and routes that the U.S. Department of Energy (DOE) would use to transport shipments 

to a repository location in Nevada. DOT has sought to keep this initial study generic 

so that the findings would be useful for planning ongoing shipments and 

intra/interutility transfer shipments in the near term, as well as NWPA shipments 

further in the future. For the latter, guidance provided by this study may facilitate both 

the establishment of mode/route selection policies for DOE, and agreement among 

DOE, carriers, and representatives of the public interest regarding specflc routes to 

the MRS and repository. 

STUDY SCOPE 

Environmental Protection as Part of the Definition of "Public Safetv" 

One cornmentor stated that expanding "public safety" to include the environment is 

unnecessary because "the study assumes that accidents which impact the environment might 

eventually impact the safety of the public.. . . " Another commented that incorporating 

"environment" without a proper definition creates yet another roadblock to transporting 

radioactive material (RAM). 

DOT Response: 

Not all of the links between environmental contamination and human health are 

necessarily direct, known, or fully understood. Excluding environmental 

contamination, however, essentially limits the effects of a release to human exposure at 

the time of the accident. The goal of minimizing exposure of the environment was 

therefore included as part of the "overall public safety" objective to acknowledge 

potential indirect, long-term efSects on human health of a radioactive material release. 

A working dejinition and unit@) of measure for environmental exposure/contamination 

would need to be developed if it is to be a selection factor. Although, the study 

recognizes the merits of this selection factor, resources were insuficient to recommend 

both a dejinition of sensitive environmental areas and a practical unit of measure. This 

is an area needing further research. 
Perceived and Other Non-Calculable Risks 

Several non-calculable factors, including perceived risk, drew much more attention than other 

defined issues. Some cornmentors alleged that the perceived risk and public confidence are 

significant factors in planning and implementing safe RAM transport and thus warranted 

greater discussion. It was also suggested that the study might recommend the development of 

ways to incorporate non-calculable risks into traditional risk models. Another commentor 

asserted that "regulatory policy should not be based on risk perception, but rather on objective 

and measurable criteria." 

DOT Response: 

The term "perceived risk" could refer to either a specijic aspect of safety or a general 

concern about the transportQtion of RAM. A perceived risk often refers to a specijic 

concern/hazard (e.g., a rail line through a high vandalism area or a highway route 

that passes near a large hospital) that affected parties believe has not received proper 

consideration, ofen because it cannot be readily addressed by traditional, quantitative 

risk assessment methods. This type of perceived risk is so case-speczjic that it is not 

suitable for use as a general selection factor. Perceived risk may also refer to general 

concerns about the safety of shipping RAM that are not specifically recognized or 

considered by conventional criteria. Where this concern is directed at completely 

prohibiting transporiation or exporting the risk to other jurisdictions, perceived risk 

cannot be a selection factor because the parties advancing such concern seek to avoid 

the selection of mode and route entirely. Where the need to transport over a given 

corridor is acknowledged, however, perceived risk could influence mode choice if one 

mode is believed to be safer than another. Even so, it cannot be a definitive selection 

factor, since there is no objective, measurable criterion on which to base a choice. 

It is appropriate for state or local government and other entities representing public 

interests to identi& and advance such concerns about perceived risks. In a joint 

decision making process (among shippers, carriers, and representatives of public 

interests), perceived risks would be considered when arriving at a final choice among a 

set of viable options identijied by shippers and carriers using the selection factors 

recommended by this report. 

Treatment of the Cask 

If, as one commentor asserted, "safety is in the package" and thus "selection of mode and 

route will have little to do with enhancing safety," the study might be considered flawed 

because it overlooks the role of the cask in transport safety. 

Another commentor noted that the report does not deal directly with cask integrity and the 

accidents and forces that can cause casks to fail. It only addresses the probability of an 

accident and the consequences of a release, not the likelihood of a release accident. 
DOT Response: 

The use of a certified cask and the level of safety it acfords was assumed by the 

Department of Transportation to be consistent for all modes and routes, given the 

uniform mechanical and thermal performance standards for all casks (10 CFR 71) and 

assuming that the accident environment is essentially the same for all modes. ' 

MODEIROUTE SELECTION FACTORS 

Sifmificance of Anv Factors, Given the Safetv Afforded bv the Cask and Com~liance with 

Other Safetv Regulations 

One commentor observed that "DOT's decision not to preclude use of any particular mode for 

SNF shipments reflects DOT's conclusion that an adequate level of public safety is afforded 

for shipments by any mode, provided that the shipper and carrier comply with applicable 

regulations. " 

DOT Response: 

The Hazardous Materials Transportation Uniform Safety Act (HMTUSA) is concerned 

about selection of modes and routes that "would enhance overall public safety" for, it 

is presumed, transportation in certified casks in compliance with existing regulations. 

DOT's position must be that truck, rail and barge modes do provide adequate safety if 

regulations are complied with.2 "Adequate" safety, however, does not mean "equal" 

safety. This report was intended to identify primary factors that aflect the safety of 

transportation performed in compliance with all regulations. 

Suggest Additional Mode and Route Selection Factors 

Among the additional mode and route selection factors mentioned in the comments were 

aspects of modelroute combinations that would bring the cask near other hazards, such as 

hazardous materials on either the same train or other vehicles on the same route. 

?he NRC report entitled "Shipping Container Response to Severe Highway and Railway Accident Conditions" 

(1987) evaluated the accident environment for each mode. It found that the percentage of accidents exceeding the 

10 CFR 71 mechanical and thermal loading conditions (i.e., accidents that could "create a radiological hazard to 

the public") is 0.6% for both truck and for rail (adjusted for thermal performance). Severe loading, however, 

was determined to be more likely in rail accidents (0.012% of rail accidents vs. 0.001 % for truck). Nevertheless, 

when cask payloads and consequences were considered, risk per accident was comparable for both modes (results 

adjusted to yield a risk per fuel assembly basis). Given those fmdigs, it appears that the accident environment is 

fairly comparable for truck and rail and therefore is not a significant factor in mode choice. There is presently no 

similar analysis of the accident environment for barge transport. 

'Air transport of certain shipments of radioactive material& prohibited or restricted by 10 CFR 71.88 and 73.24. 
DOT Response: 

The comparative safety of dedicated trains (only RAM shipments) and regular trains, 

which may contain hazardous materials, is the subject of an ongoing DOT study 

mandated by Congress. Congressional action on that subject may ultimately affect 

modal use. 

Another additional mode and route factor mentioned in the comments was proximity to 

schools. 

DOT Response: 

Nearness of a route(s) to special facilities with large populations that may be dificult 

to evacuate would only be considered if the better routing alternatives were essentially 

equivalent with respect to the overall risks to the public. Note that proximity to special 

facilities was considered in this study to be a subset of general population exposure. 

(See also the DOT response on 'perceived risks" in Section 3.2). 

Other mode and route factors mentioned were the characteristics of specific routes, including 

those of a temporary (e.g., construction) or seasonal nature, and specific locations where risk 

contributors occur (e.g., severe slope or dangerous crossing). 

DOT Response: 

The data on accident rates, a primary factor, would reflect substantial hazards 

associated with seasonal weather or particularly dangerous locations, if the data are by 

route segment. If a more generic accident rate is used, however, a selected set of 

candidate routes might need to be examined for such hazards before making the_final 

selection. Temporary hazards would not be reflected in accident data and so would 

appropriately be considered for tactical changes to routing in certain circumstances. 

Finally, some cornmentors mentioned, as additional mode and route factors, the effects of 

operational restrictions, such as speed limits and time-of-day transit of cities. 

DOT Response: 

The potential for altering the normal operation of a mode to @resumably) improve 

safety varies somewhat. Certainly, it is dificult or impossible to change the operation 

of a non-exclusive use, scheduled vehicle, such as a regular train; but for most 

mode/route choices, operational changes or restrictions are possible. Speed limits may 

reduce accident severity, but may increase accident likelihood at the same time, if the 

vehicle disrupts the normal flow of traflc. The time of day that a vehicle transits a city 

(e.g., late night/early morning) may reduce accident likelihood and exposure of the 

general population, but also lengthens trip duration and consequently increases 

exposure of the crew and those people near stops. Since the net effect on public safety 
cannot be predicted except for a particular time or one particular route, the ability to 

apply operational adjustments cannot be a primary mode/route selection factor. 

Failure to Weight Factors to Reflect Relative Effect on Risk 

A commentor observed that the Report starts off by saying it will "assess the degree to which 

the various factors affect overall public safety.. . . " The Report later states, however, that "No 

attempt has been made to weight these factors.. . . " Another commentor said that the "study 

must address the degree to which each factor, and various combinations of factors, contribute 

to the enhancement of overall public safety. " 

DOT Response: 

Weights, which reflect the relative importance of each primary selection factor, could 

simplz~ the selection of modes and routes by focusing attention on the (typically) more 

important factors. They could also provide the basis for a 'Iformula" that could produce ajigure of merit for each mode/route combination. There are several very serious 

dificulties, however, that prevented an attempt to weight the primary factors. 

A fundamental issue in assigning weights is the treatment of radiological risk versus 

non-radiological risk. In risk assessments, the non-radiological risk is typically found 

to be many times greater than radiological risk. Therefore, if radiological and nonradiological risks are treated as equally important (i.e., unweighted), the factors that 

aflect non-radiological risk would determine the modehoute selection @rimarily 

accident rate). This approach, however, seems to ignore concerns over radiological 

risk. To avoid this problem, non-radiological risk must either be treated as less 

important (i. e., weighted much less) than radiological risk or eliminated from 

consideration. If, on the other hand, overall radiological risk is the principal concern, 

then the factors that generally rule mode/route selection are those that drive incidentfree radiological risk @rimarily trip duration), because it is usually much greater than 

that associated with accidents. But it is the consequences of an accident that are 

usually the focus of public concern. Consequently, most risk assessments treat 

radiological and non-radiological risk separately. Weighting of selection factors 

dependsjirst and foremost on the importance (weight) assigned to the three main 

categories of risk, and that is a deliberative policy matter and is not conducive to being 

simplified or generalized. 

An additional complication is that the influence each primary factor has on the types of 

risk varies from mode to mode, as was demonstrated in the sensitivity analysis conducted as part of this study. For example, length of the route has a widely varying eflect on 

incident-free radiological risk. It is a primary determinant for both dedicated and 

manifest train modes, has a modest egect for highway, and virtually none for 

waterway. Therefore, it is inappropriate to assign a single weight to a factor that 

would apply to all modes. 
LOGISTICS OF A SHIPPING CAMPAIGN 

Amount of Material to Be Shipped (As It Affects Mode Choice) 

To one commentor, the amount of material to be shipped is "hardly worth mentioning", 

because cask availability and modal access often dictate mode choice regardless of the amount 

to be shipped, while another commentor states that mode choice is based primarily upon modal 

access and the amount of material to be shipped. 

DOT Response: 

Mode choice is limited to those modes that can actually access the shipment origin 

and/or destination. Highway access is universal. In most shipping situations, 

however, there would be at least one alternative to trucking. Recent DOE studies 

determined that over two-thirds of nuclear power plants assessed were sewed by rail 

and/or barge and that most could handle these heavier casks. In addition, cask 

availability is expected to be less of a constraint on mode choice in the future, when 

large numbers of both truck and rail/barge casks are produced. Consequently, there 

will often be a choice of modes for a shipping campaign and, in those cases, the 

amount of material to be shipped would be a very important consideration. 

Single vs. Multiple Cask Shipments 

One commentor faulted the study for not reaching "any conclusions about the impact on safety 

of multi-cask car shipments by rail versus single cask shipments by rail or truck. " The 

commentor stated that "the safety of a limited number of multi-cask car train shipments which 

are subject to special preparations (e.g., track inspection, escorts, on-board emergency 

response) [should be] compared to many general commerce train shipments without special 

preparations; and the safety of truck convoys versus single truck shipments" should be 

assessed. Also, another commentor said, "The decision to assume a single cask per shipment 

appears to be ill-conceived, contributing little to resolution of a critical issue in the current 

debate on modelroute selection (i.e., potential benefits associated with multiple cask 

shipments). " 

DOT Response: 

For simplicity's sake, a single cask shipment basis was used in the original case study 

presented in the December 1993 draft report. Another primary factor, amount of 

material to be shipped, has been added in the revised report to reflect the capability of 

3A recent DOE review of modal access to power plants (see J.M. Viebrock and N. Mote , "Near-Site 

Transportation Infrastructure Project Final Report," Nuclear Assurance Corp. for US DOE, Norcross, GA, 

DOElCH/10441-1, February 1992) found that over two thirds of the sites assessed are rail andlor barge capable. 

A contemporary DOE study (Facility Interface Capability Assessment) showed that most facilities can handle the 

heavier railharge casks. 
a single railbarge cask to accommodate more fuel assemblies than a truck cask. 

Results presented in the revised report show that reducing the number of shipments by 

using the larger cask cuts the overall risk dramatically. By implication,handling more 

than one cask per train or barge would reduce risks further. For example, adding a 

second cask to a dedicated train would cut the non-radiological risks per cask in half, 

since only one train would be operated to transport both casks. Furthermore, adding a 

cask to the train reduces incident-free radiological risk, as well. Exposure of onboard 

personnel is cut because each cask shields a portion of the other cask's radiation and 

the average distances between the casks and those people increases. 7;hese and other 

effects can be incorporated when and if multiple-cask shipments are considered for a 

specific shipping campaign. 

CASE STUDIES 

General Limitations of Probabilistic Risk Models 

One commentor observed that "computer models have significant limitations in performing 

risk assessments. These models can assist in preliminary selection of routes. But, as a 

comprehensive tool they fall short on two points: the most complete model will never be 

complete enough to make it immune to some criticism on a technical basis and the addition or 

subtraction of risk factors will never be complete. The data requirements for extensive models 

will push costs higher as potential benefits remain static. These models also are incomplete 

because they will never be credible to people at risk without some involvement on their part." 

In turn, another commentor faulted the study for its "uncritical reliance upon probabilistic risk 

models. . . . " 

DOT Response: 

The limitations of risk models were apparent when this study was planned. Therefore, 

the study incorporated several alternative and complementary analytic techniques: (I) 

the hierarchical analysis of a comprehensive listing of candidate factors, (2) 

deliberations of the Technical Advisory Group, (3) the derivation of risk equations, and 

(4) case studies. Also, an overall qualitative assessment of the identified factors was 

conducted. 

Risk models should be viewed as contributing to, but not dictating, the selection of 

modes and routes. There are many important qualitative considerations that they are 

not able to address. 

Assumptions and Data Used in the Case Studv Analvsis 

The case study analysis assumed that all trains hauling spent fuel operate at 35 mph. 
DOT Response: 

While one commentor contends that it is not a realistic assumption to state that all 

railroads follow the 35 mph guideline of the Association of American Railroads (MR), 

waybills for all DOD shipments specifi a speed limit of 35 mph and it appears that rail 

carriers uniformly comply with this requirement. Also, carriers generally follow the 

AAR guideline for other RtFM shipments. The principal exception is the Union Pacij?c, 

which limits shipments on its lines to 50 mph. Therefore, assuming a limit of 35 mph is 

not an unrealistic simplification. 

National average accident rates, rather than route-specific rates were used in the case study 

analysis. 

DOT Response: 

Accident rate data for the specijic mode/route combinations being examined in the case 

studies would have been preferred. Much of this information is not readily available. 

Even if had been available, using link-specijic data for the 65 mode/route combinations 

would have been a formidable undertaking. Consequently, accident rates typical of 

various types of highway, rail, and water links were used. This approach adequately 

served the purposes of the case studies. The use of route-specijic accident data is 

certainly more feasible and warranted for detailed mode/route studies for a given 

shipping campaign. 

CONCLUSION 

Section 15 of HMTUSA directed the DOT to include "notice and opportunity for public 

comment." This appendix has reviewed the major issues brought up by those who commented 

on the December 1993 draft report. 

A majority of the 13 responses were from governmental organizations (or contractors acting 

on their behalf). The comments in these responses fell into five broad categories: study 

objectives, study scope, modelroute selection factors, the logistics of a shipping campaign, and 

the case studies. Each of these categories included one or more issues relating to the 

movement of high-level radioactive waste and spent nuclear fuel. Each of those issues has 

been addressed in this appendix. 

All of the comments received were given due consideration in the preparation of the final 

Mode and Route Study report. Where appropriate and feasible, the revised report incorporates 

changes resulting from DOT'S review of the public comments on the December 1993 draft 

report.