[Federal Register Volume 80, Number 27 (Tuesday, February 10, 2015)]
[Notices]
[Pages 7461-7465]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2015-02704]


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ENVIRONMENTAL PROTECTION AGENCY

EPA-HQ-OAR-2002-0050; FRL-9922-75-OAR]


National Emission Standards for Hazardous Air Pollutants 
(Radionuclides); Availability of Updated Compliance Model

AGENCY: Environmental Protection Agency (EPA).

ACTION: Notice of availability.

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SUMMARY: The Environmental Protection Agency (EPA) is announcing the 
availability of Version 4 of the CAP88-PC model. This version may be 
used to demonstrate compliance with the National Emission Standards for 
Hazardous Air Pollutants (NESHAP) applicable to radionuclides. CAP88-PC 
is approved for this use by EPA. Version 4 has many changes and 
improvements from previous versions. The most significant of these 
changes from a user perspective are the incorporation of age-dependent 
radionuclide dose and risk factors for ingestion and inhalation, the 
increase in the number of included radionuclides, and a change in the 
file management system used by the program. Other changes less visible 
to the user include new code architecture, incorporation of numerical 
solvers for the calculation of radioactive decay chains, including the 
ingrowth of decay products during air transport and ground surface 
deposition, enhanced error messages, updated on-line help, and a 
utility for migrating Version 3 datasets, wind files and population 
files to Version 4. The modifications have produced a significant 
improvement in speed and stability for Version 4 relative to Version 3, 
and eliminated the solution approximations used in Version 3.

FOR FURTHER INFORMATION CONTACT: Reid J. Rosnick, Office of Radiation 
and Indoor Air, Radiation Protection Division (6608T), U.S. 
Environmental Protection Agency, 1200 Pennsylvania Avenue NW., 
Washington, DC 20460; telephone number: (202) 343-9200; fax number: 
(202) 343-2304; email address: [email protected].

SUPPLEMENTARY INFORMATION: 

I. General Information

A. Does this action apply to me?

    You may be potentially affected by this action if you are subject 
to the requirements for radionuclide NESHAP found in 40 CFR part 61, 
subpart H. This subpart applies to Department of Energy (DOE) 
facilities.

B. How can I get copies of the model and other related information?

    1. Docket. EPA has established a docket for this action under 
Docket ID No. EPA-HQ-OAR-2002-0050; FRL-9922-75-OAR. Publicly available 
docket materials are available either electronically through 
www.regulations.gov or in hard copy at the Air and Radiation Docket in 
the EPA Docket Center (EPA/DC), EPA West, Room B 102, 1301 Constitution 
Avenue NW., Washington, DC. The EPA Docket Center Public Reading Room 
is open

[[Page 7462]]

from 8:30 a.m. to 4:30 p.m., Monday through Friday, excluding legal 
holidays. The telephone number for the Public Reading Room is (202) 
566-1744, and the telephone number for the Air and Radiation Docket is 
(202) 566-1742.
    2. Electronic Access. You may access this Federal Register document 
electronically through the EPA Web site under the ``Federal Register'' 
listings at http://www.epa.gov/fedrgstr/.
    3. EPA Web site. You may download the CAP88-PC model and 
documentation from EPA's Web site at http://www.epa.gov/radiation/assessment/CAP88/index.html.

II. Background

    On December 15, 1989, EPA promulgated the National Emission 
Standards for Hazardous Air Pollutants (NESHAPs) under section 112 of 
the Clean Air Act to control radionuclide emissions to the ambient air 
from a number of different source categories (54 FR 51654, December 15, 
1989 (Docket EPA-HQ-OAR-2002-0050-0028)). Subpart H of 40 CFR part 61 
is one of the source categories covered in the 1989 final rule. 
Facilities owned and operated by the Department of Energy (DOE) are 
regulated under subpart H. DOE administers many facilities across the 
country, including government-owned, contractor-operated facilities. 
Some of these facilities handle significant amounts of radioactive 
material that could potentially be emitted into the air in various 
chemical and physical states. The purpose of subpart H is to limit 
radionuclide emissions (not including radon) from the stacks and vents 
at DOE facilities so that no member of the public receives an effective 
dose equivalent of more than 10 millirems per year (mrem/yr) or in SI 
units 0.1 millisievert per year (mSv/yr). See 40 CFR 61.92.

III. CAP88-PC Model for Demonstrating Compliance

A. CAP88-PC History

    EPA is today announcing the availability of Version 4 of the CAP88-
PC model for use in subpart H. Section 63.93(a) states: ``To determine 
compliance with the standard, radionuclide emissions shall be 
determined and effective dose equivalent values to members of the 
public calculated using EPA approved sampling procedures, computer 
models CAP-88 or AIRDOS-PC, or other procedures for which EPA has 
granted prior approval.''
    CAP88 (Clean Air Act Assessment Package-1988) is a set of computer 
programs, databases and associated utility programs for estimation of 
dose and risk from radionuclide emissions to the air. CAP88-PC 
implements, on the personal computer platform, modified versions of the 
AIRDOS-EPA and DARTAB codes that were written in FORTRAN 77 and 
executed in a mainframe computing environment. CAP88-PC provides for 
dose and risk assessments of collective populations, maximally-exposed 
individuals and selected individuals. The original CAP88-PC software 
package, Version 1.0 allowed users to perform full-featured dose and 
risk assessments in a DOS environment for the purpose of demonstrating 
compliance with the standard in 40 CFR 61.92; it was approved for 
compliance demonstration in February 1992.
    CAP88-PC Version 2.0 provided a framework for developing inputs to 
perform full-featured dose and risk assessments in a Windows 
environment for the purpose of demonstrating compliance with the 
standard in 40 CFR 61.92. Version 2.0 was approved for compliance 
demonstration in 1999. Version 2.1 included some additional changes 
compared to the DOS version and the previous Windows version 2.0. The 
changes included the addition of more decay chains, improvements in the 
Windows code error handling and a modified nuclide data input form. 
Section 1.6 of the CAP88-PC Version 3 User's Guide provides a summary 
of the changes incorporated into Version 2.1 relative to Version 2.0.
    CAP88-PC Version 3.0, released in 2007, was a significant update to 
Version 2.1. Version 3 incorporated dose and risk factors from Federal 
Guidance Report 13, ``Cancer Risk Coefficients for Environmental 
Exposure to Radionuclides'' (FGR 13) in place of the RADRISK data that 
was used in previous versions. In addition, the CAP88-PC database, the 
user interface, input files and output files were modified to 
accommodate the FGR 13 data formats and nomenclature. Section 1.7 of 
the CAP88-PC Version 3 User's Guide describes the modifications 
incorporated into Version 3 relative to Version 2.1.
    CAP88-PC Version 4 is a significant update to Version 3. While 
keeping the main computer code used to conduct the calculations 
unmodified, modifications have been made to add flexibility, enhance 
stability of the code, and make it easier for the user to use while 
also improving the quality assurance of the modeling. The most 
significant of these changes from a user perspective are the 
incorporation of age-dependent radionuclide dose and risk factors for 
ingestion and inhalation (the use of which is specified by the user), 
the increase in the number of included radionuclides, and a change in 
the file management system used by the program. Other changes less 
visible to the user include new code architecture, incorporation of 
numerical solvers for the calculation of radioactive decay chains, 
including the ingrowth of decay products during air transport and 
ground surface deposition, enhanced error messages, updated on-line 
help, and a utility for migrating Version 3 datasets, wind files and 
population files to Version 4. The modifications have produced a 
significant improvement in speed and stability for Version 4 relative 
to Version 3, and eliminated the solution approximations used in 
Version 3. EPA has implemented an extensive testing and documentation 
program for CAP88-PC Version 4 to address user concerns with past 
versions. This enhanced documentation has allowed for greater 
compatibility with user software quality assurance programs. The total 
number of radionuclides available has been increased from 825 in 
Version 3 to 1,252 in Version 4. The maximum number of radionuclides 
that can be included in any single case is increased from 256 in 
Version 3 to 500 in Version 4.

B. CAP88-PC Model Summary

    All versions of CAP88-PC use a modified Gaussian plume equation to 
estimate the average dispersion of radionuclides released from up to 
six types of sources. The sources may be either elevated stacks, such 
as a smokestack, or uniform sources, such as a pile of uranium mill 
tailings. ``Plume rise'' can be calculated assuming either a momentum 
or buoyant-driven plume. Assessments are made for a circular grid of 
distances and directions for a radius of up to 80 kilometers (50 miles) 
around the source. The Gaussian plume model produces results that agree 
with experimental data as well as any model, is fairly easy to work 
with and is consistent with the random nature of turbulence. Site-
specific information on population location and meteorological 
conditions is provided to CAP88-PC as input files developed by the 
user. The formats for these input files have not changed from the 
original mainframe version of the CAP88 code package.
    CAP88-PC Version 4 is a significant modification intended to 
improve usability, increase stability by complying with the write 
restrictions on system folders, enhance the modeling methodology, 
update the dataset formats, and provide a more maintainable code base 
and documentation set for the future.

[[Page 7463]]

Version 4 now provides age-dependent dose and risk factors and 
introduces a new code architecture that conforms to updated coding 
standards and data formats. The data updates include adoption of the 
ingestion and inhalation age and particle size dependent dose and risk 
factor data supplied by Oak Ridge National Laboratory in the DCFPAK 
Version 2.2 model,\1\ and age-dependent ingestion and inhalation rates 
from the EPA,\2\ The DCFPAK Version 2.2 external dose rate coefficients 
used in CAP88-PC Version 4 are not explicitly age-dependent. The 
external coefficients are calculated for adults but are applicable to 
all age groups.
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    \1\ http://www.epa.gov/radiation/federal/techdocs.html.
    \2\ http://www.epa.gov/ncea/efh/pdfs/efh-complete.pdf.
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    CAP88-PC Version 4 not only adds significant features, but also 
redesigns the user interface (UI) experience to make it more similar to 
that of other programs developed for Microsoft Windows. The application 
uses the Microsoft. Net Framework Version 4, and the Microsoft Visual 
Studio 2010 development environment, to support security and 
connectivity models in Windows 7. The window structure presented to the 
user is in general unchanged from earlier versions but has been updated 
to provide more flexible data entry, to include the new data fields 
mentioned earlier, and to eliminate the use of an intermediate database 
to relate filenames to datasets. The layout of the UI forms has been 
modified to include sub-windows that provide a running record of 
dataset modifications since the dataset was last saved, and provide 
real-time errors and warnings generated by the entry validation tests. 
The database of uptake and radionuclide-specific information is now in 
eXtensible Markup Language (XML) format, making it more accessible to 
the user and to other applications. One consequence of the move to an 
updated development and data environment is the fact that CAP88-PC 
Version 4 can only be installed on Windows XP Service Pack 3 and later 
operating systems.
    The CAP88-PC Version 4 software was developed using a structured 
software engineering methodology that included adoption of a defined 
software architecture, rigorous source control, independent 
verification of source code as it was being implemented, multiple 
phases of testing, and configuration control of the documentation and 
the code as development progressed.
    To conform to Windows 7 security requirements, and to improve 
usability, CAP88-PC Version 4 includes many significant changes to 
input and output file handling. Case-specific input and output data 
files are now stored by default in the user's Windows profile folders, 
rather than in the application's Program Files folder. For example, the 
default primary CAP88-PC Version 4 folder location in Windows 7 would 
be c:\Users\xxxx\Documents\CAP88 for a username of xxxx. This was 
required because Windows Vista and 7 security improvements restrict 
writing files to the Program Files folder.
    CAP88-PC Version 4 input datasets can be stored in their own 
folders, as subfolders of the Datasets folder. As an example, for the 
Modtest dataset included with the Version 4 distribution set, the 
folder holding the dataset and all associated data files and reports 
would be located at c:\Users\xxxx\Documents\CAP88\Datasets\Modtest. 
Datasets are recommended to be put into their own folders, because 
using this data storage structure will make use of the code easier and 
management of case data simpler. Reports (formerly called ``Output'') 
are always stored in the same folder as the dataset. Population and 
wind files can be stored with the dataset or in the default Population/
Wind folders. However, CAP88-PC Version 4 will preferentially use the 
population and wind files located in the dataset. This improves sharing 
dataset information between organizations, and simplifies configuration 
management of cases because all pertinent case records (input and 
report files) are stored together. A user can send a dataset, its 
population and wind files, and its reports to another user, who can 
open them, using CAP88-PC Version 4 or any text editor, confident that 
the proper files are being used.
    As was the case with Version 3, Version 4 is not backward 
compatible, and datasets generated using Version 3 cannot be used 
directly by Version 4. This is the result of many factors, including 
the addition of age-specific data and the inclusion of many more 
nuclides than in previous versions. However, Version 4 includes a 
dataset migration utility that upgrades many Version 3 datasets to the 
Version 4 format. The migration utility runs on first use and is also 
available on demand from the Tools>Options drop-down menu. The 
migration utility will move Version 3 database files, input dataset 
files, population files, and wind files from the format used with the 9 
December 2007 release of Version 3 to their respective Version 4 
formats. The folder locations of the Version 3 files being migrated and 
the locations for the Version 4 files being generated are selectable by 
the user or the utility will select the default locations for those 
files.
    The overall principle of the new architecture was to optimize the 
code by performing data manipulation in the UI and computational 
functions in FORTRAN. CAP88-PC Version 4 has accomplished this by 
having the UI collect the user input data, read the associated 
databases, generate the dose and risk factors from the DCFPAK data, 
then build and write the case dataset. The UI also handles all program 
interactions with the file system. The FORTRAN computational sub-system 
now performs all decay and ground surface buildup calculations along 
with all the air dispersion, deposition, intake, dose and risk 
calculations. The only file manipulation performed by the FORTRAN sub-
system is reading the dataset files and writing report files. The data 
system used in CAP88-PC Version 4 has access to information for all 
1,252 radionuclides contained in DCFPAK Version 2.2, 737 of which have 
internal dose and risk factors. A significant change in Version 4 is 
the fact that radionuclides in the database having external but no 
internal dose factors is flagged to the user during radionuclide 
selection. This is an improvement over Version 3, where the code would 
produce a database read error when encountering a radionuclide having 
an external but no internal dose conversion factors. Flagging these 
radionuclides permits analysis to be performed in situations where only 
the external dose is of concern, but also creates the potential for 
under-reporting dose when a radionuclide with no internal dose factors 
is included in the case. Users must now be aware that when a 
radionuclide has no internal dose factors, an independent method, such 
as surrogates, must be used to account for internal dose resulting from 
intake of these radionuclides in a CAP88-PC Version 4 case.

C. Validation of the CAP88-PC Version 4 Model

    The CAP88-PC Version 4 program represents one of the best available 
validated codes for the purpose of making comprehensive dose and risk 
assessments. The Gaussian plume model used in CAP88-PC to estimate 
dispersion in air is one of the most commonly used models for 
dispersion modeling. It produces results that agree with experimental 
data as well as any model, is fairly easy to work with, and is 
consistent with the random nature of

[[Page 7464]]

turbulence. Version 4 has not modified the basic Gaussian plume 
algorithm used by the AIRDOS module of CAP88-PC, and comparison cases 
between Versions 4 and 3 have been run.
    EPA's Office of Radiation and Indoor Air (ORIA) has reviewed and 
verified through testing the contractor's initial testing and quality 
assurance results. The report \3\ can be found at http://www.epa.gov/radiation/assessment/CAP88/index.html.
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    \3\ EPA-HQ-OAR-2002-0050-0004.
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    The testing report includes a description of the testing of the 
user interface; a description of the six test cases used to test the 
incorporation of age-specific dose factors; a description of the 
seventh test case verifying the calculation of air concentrations and 
working levels for radon-only test cases; a description of the 31 
issues identified by ORIA and the corrective actions that resolved 
those issues; a brief biographical sketch describing the independence 
and qualifications of the independent tester; and conclusions drawn 
from the testing.
    As part of the software testing, the user interface was extensively 
tested. The testing verified that the interface only accepted:
    (1) Positive distances less than or equal to 80 kilometers (km) for 
receptor distances;
    (2) Non-negative release rates;
    (3) Annual precipitation amounts between 0.01 and 500 centimeters 
per year (cm/yr);
    (4) Annual ambient temperatures between -100 and 100 degrees 
Celsius ([deg]C);
    (5) Lid heights between 25 and 10,000 meters (m);
    (6) Non-negative source heights, and positive source diameters or 
areas;
    (7) Non-negative heat release rates, exit velocities and fixed 
plume rises; and,
    (8) Agricultural fractions that summed to unity.
    All issues identified with the interface have been resolved and 
closed.
    Seven test cases were developed to test the capabilities of CAP88-
PC Version 4. Six of these cases involve the calculation of dose and 
risk to an individual or population at the location identified by the 
model as that of the maximally exposed individual (MEI) or specified by 
the user. The testing objectives for these six cases include the 
following verifications:
    (1) Dose factors agree with those calculated using the Dose 
Coefficient Data File Package from Oak Ridge National Laboratory, 
Version 2.2 (DCFPAK2.2) to 1% or less;
    (2) Values of Chi-over-Q ([chi]/Q) agree within 1% with those 
calculated using CAP88-PC version 3.1, including but not limited to the 
direction of the MEI (the calculated values for [chi]/Q showed good 
agreement between Versions 3.1 and 4 in all directions);
    (3) Air concentrations and deposition rates (where applicable) 
agree within 1% with those calculated using CAP88-PC Version 3.1; and,
    (4) Results for dose rates and risks agree within 5% with 
independent calculations; the 5% criteria was used here to allow for 
differences caused by different modeling methods.
    The objective of Test Case 7 was to verify the CAP88-PC Version 4 
calculations of the air concentrations and working levels for radon-
only are consistent with Version 3.1.

D. Limitations of the CAP88-PC Model

    Like all models, there are some limitations in the CAP88-PC system. 
While up to six stacks or sources can be modeled, all the sources are 
modeled as if located at the same point; that is, stacks cannot be 
located in different areas of a facility. The same plume rise mechanism 
(buoyant or momentum) is used for each source. Also, multiple sources 
are treated as uniform. Variation in radionuclide concentrations due to 
complex terrain cannot be modeled. Errors arising from these 
assumptions will have a negligible effect for assessments where the 
distance of exposed individuals is large compared to the stack height, 
area or facility emissions.

E. Use of CAP88-PC Version 4 for Compliance Purposes

    One of the primary requirements driving the production of CAP88-PC 
Version 4 was the desire to incorporate the age-specific dose 
conversion factors and intake rates contained in DCFPAK Version 2.2. 
The code now allows the user to select the ingestion and inhalation 
dose conversion and intake rates from the age groups modeled in DCFPAK 
Version 2.2, infant (100 days old), one-year old, five-year old, ten-
year old, fifteen-year old, and adult. To accommodate this, many 
variables across the entire code have increased dimensionality and the 
dataset structure required significant modification. The need to 
examine the entire code base in order to include age-dependency drove 
the decision to look for a new architecture that would enhance the 
performance and maintenance of CAP88-PC both in Version 4 and future 
versions.
    Additionally, our in-house analysis of calculated doses between 
Versions 3 and 4 has shown that the dose in Version 4 is usually less 
than the dose in Version 3. This is primarily because we have updated 
the intake factors in Version 4 to be consistent with the latest 
version of the EPA Exposure Factors Handbook. Therefore, the user will 
likely see lower calculated doses in Version 4 for the source term and 
receptor.

F. Summary of Changes for CAP88-PC Version 3 to Version 4

    Version 4 of CAP88-PC is a significant update from Version 3. 
CAP88-PC Version 4 not only added significant features, but also 
redesigned the interface to give the user a more standard experience. 
The entire user interface module was re-written for Version 4 using 
VB.Net, the Microsoft.Net Framework Version 4, and the Visual Studio 
2010 development environment, in order to better comply with updated 
code standards in Windows 7 and Windows 8. To conform to recent Windows 
security requirements, and to improve usability, the following 
additional significant changes were made:
Modeling and Architecture
    (1) All DCFPAK Version 2.2 nuclides are included. Nuclides in the 
database having external but not internal dose factors are flagged to 
the user rather than crashing the run. NOTE: the user must account for 
internal dose resulting from intake of these radionuclides using other 
methods, such as surrogates.
    (2) Age-specific data is now returned for dose, risk, and 
inhalation/ingestion rate values.
    (3) Nuclide Release Rates less than 1.000e-25 Ci/yr (e.g., ``0'') 
or greater than 7.92e+28 are no longer allowed. A FORTRAN numerical 
solver is now used to calculate decay-in-flight and ground build up 
concentrations for each sector. The time for decay in flight is 
calculated using the annual Pasquill category-averaged wind speed for 
each direction.
    (4) Up to 500 radionuclides can be included in any case. The 500 
limit includes both the nuclides released by the stacks and their 
progeny.
    (5) Whole body and organ dose and risk factors are from DCFPAK 
Version 2.2. The data include six age groups; infant (100 days old), 1 
year old, 5 years old, ten years old, fifteen years old, and adult.
    (6) Age-specific inhalation and ingestion data developed by the 
U.S. Environmental Protection Agency have been included for the above 
age groups.
    (7) The FORTRAN computational code has been consolidated into one

[[Page 7465]]

module and variable names made consistent throughout the module. Data 
transfer between the routines was streamlined by the use of Include 
statements for COMMON block variables.
    (8) All nuclide-specific data are now stored in eXtensible Markup 
Language (XML) format.
    (9) All significant floating-point calculations have been moved to 
the FORTRAN routines, greatly speeding up the code.
    (10) The code uses the Intel FORTRAN Composer XE 11 compiler that 
permits many of the calculations to be vectorized and multi-threaded to 
take advantage of these capabilities in modern desktop processors.
    (11) The bit-length of variables has been doubled, allowing much 
greater computational ranges for cases with large or small release 
rates.
User Interface
    (1) A traditional document-style interface has been designed, 
similar to major applications with which users are already familiar. 
Users can more easily open, edit and save datasets, population and wind 
files using Windows menus and familiar icons on the application bar.
    (2) Dataset reports are now displayed in, and generated from a 
Reports tab when the dataset is opened. The code is now executed using 
the Report generation button rather than a ``Save and Close'' button. 
The reports to be generated and viewed are selectable from the Reports 
tab. The ``Save and Close'' button from Version 3 has been removed.
    (3) Multiple files (datasets, population files, wind files) can be 
open at once.
    (4) When editing files, changes and errors are displayed in real 
time.
    (5) Editing of nuclides is clearer and easier. In-grid editing is 
allowed, but note that fields are not recorded until the user clicks 
away from the field being edited. A Save performed without first 
clicking away from a field being edited will result in that field's 
data not being saved.
    (6) The application recognizes when a user is opening a Version 3 
file, and launches the migration utility, offering to create a Version 
4 copy of the file.
    (7) The general layout, look, and feel of the user interface are 
similar to that in earlier versions of CAP88-PC in order to ease 
transition to CAP88-PC Version 4.
File Formats
    The dataset file format has changed in Version 4 from Version 3 to 
accommodate the new requirements. The new dataset file format is 
documented both in the Version 4 User's Manual and the on-line help 
files.
    (1) Population and Wind files previously had extended values such 
as State and Census stored in a Microsoft Access database. When 
migrating from Version 3, this data--if available--is stored in the 
file itself. Doing so removed the need for an external database, and 
allowed users to send their custom population/wind files with the 
extended values intact. These changes have been documented in the file 
format description in the Version 4 User's Manual and the on-line help 
files.
    (2) Version 3 population and wind files can still be used in 
Version 4 datasets. Extended values are only added to the pop/wind 
files if they are edited to add them.
    (3) The use of additional applications, such as Microsoft Access, 
to manage data has been eliminated in CAP88-PC Version 4. Radionuclide, 
agricultural, and other data previously held in the Microsoft Access 
database are now in a more portable and more easily accessible XML 
database.
Error Handling
    CAP88-PC Version 4 contains an enhanced internal error logging and 
tracking system. In the case of internal code errors, the code will 
write errors to a file in the Message Log folder located in the same 
folder set as the folder containing the datasets. Sending this file to 
the EPA representative will facilitate troubleshooting.
On-Line Help System
    CAP88-PC Version 4 includes a context-sensitive help system that is 
accessible during operation. The on-line help system is a hypertext 
version of the traditional user manual; the traditional user manual is 
included as part of the release distribution package in pdf format.

    Dated: January 23, 2015.
Jonathan D. Edwards,
Director, Radiation Protection Division, Office of Radiation and Indoor 
Air.
[FR Doc. 2015-02704 Filed 2-9-15; 8:45 am]
BILLING CODE 6560-50-P