[Federal Register Volume 85, Number 44 (Thursday, March 5, 2020)]
[Pages 12917-12920]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2020-04546]



[EPA-HQ-OAR-2002-0050; FRL-10006-13-OAR]

National Emission Standards for Hazardous Air Pollutants 
(Radionuclides), Availability of Updated Compliance Model, CAP88-PC

AGENCY: Environmental Protection Agency (EPA).

ACTION: Notice of Availability.


SUMMARY: Pursuant to section 112 of the Clean Air Act, as amended, the 
Environmental Protection Agency (EPA or Agency) is announcing the 
availability of Version 4.1 of the CAP88-PC model. This version may be 
used to demonstrate compliance with the National Emission Standards for 
Hazardous Air Pollutants (NESHAPs) applicable to radionuclides. CAP88-
PC is approved for this use by the EPA. Version 4.1 includes a number 
of improvements from previous versions, including Version 4.0. The most 
significant of these changes from a user perspective are the 
implementation of a new Wix installer technology that enhances 
compatibility with Windows 10 and future Windows updates, an update in 
the number of included radionuclides and the data for these 
radionuclides, and a change in the manner in which reports are printed.

FOR FURTHER INFORMATION CONTACT: Brian Littleton, 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].


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 NESHAPs found in 40 CFR part 61, 
subpart H. This subpart applies to Department of Energy (DOE or 
Department) facilities.

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

    Docket. The EPA has established a docket for this action under 
Docket ID No. EPA-HQ-OAR-2019-0050. 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 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 website under the ``Federal Register'' 
listings at http://www.epa.gov/fedrgstr/.
    3. EPA website. You may download the CAP88-PC model and 
documentation from the EPA's website at https://www.epa.gov/radiation/cap-88-pc.

II. Background

    On December 15, 1989, the 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 DOE are regulated under subpart H. 
The Department 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

[[Page 12918]]

per year (mrem/yr) or, in SI units, 0.1 millisievert per year (mSv/yr).

III. CAP88-PC Model for Demonstrating Compliance

A. CAP88-PC History

    The EPA is today announcing the availability of Version 4.1 of the 
CAP88-PC model for use in demonstrating compliance with the 
requirements of 40 CFR part 61, subpart H. 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 
    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 40 CFR 61.93(a); 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 40 CFR 
61.93(a). 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. The CAP88-PC User 
Guide provides a summary of the changes incorporated into Version 2.1 
relative to Version 2.0.
    CAP88-PC Version 3.0, released in 2006 (71 FR 8854, February 21, 
2006), 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. Page 9 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, released in 2015 (80 FR 7461, February 10, 
2015), was a significant update to Version 3. While keeping the 
fundamental model unchanged, modifications were 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 were 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. Those modifications 
produced a significant improvement in speed and stability for Version 4 
relative to Version 3 and eliminated the solution approximations used 
in Version 3. The EPA also implemented an extensive testing and 
documentation program for CAP88-PC Version 4 to address user concerns 
with past versions. This enhanced documentation allowed for greater 
compatibility with user software quality assurance programs. The total 
number of nuclides available in Version 4 was increased from the 825 in 
Version 3 to 1,252. The maximum number of nuclides that can be included 
in any single case was increased from the 256 in Version 3 to 500 in 
Version 4.
    CAP88-PC Version 4.1 incorporates the following changes to Version 
    (1) Dose and risk coefficient data have been updated to the values 
supplied by Oak Ridge National Laboratory with the Dose Coefficient 
Data File Package (DCFPAK) Version 3.02 (addition of internal dose 
information for 151 isotopes; updated information for isotopes in vapor 
or gas forms; and additional risk information for many isotopes);
    (2) The ability to print from the Reports tab has been removed 
because of incompatibility of certain characters in the reports with 
some printer drivers. Printing reports can be done by opening the 
report files in any word processor or text editor. The new button opens 
the location of the report files;
    (3) The synopsis file now provides the adjusted fractions of milk, 
meat, and/or vegetables produced in the assessment area, if CAP88-PC 
adjusted them to account for population;
    (4) Enhancements to the user interface code have been made to 
increase performance and/or maintain compatibility with the DCFPAK 
Version 3 data;
    (5) The installer system has been updated for better compatibility 
with Windows;
    (6) Migration utility updates have been made to migrate data from 
Version 3 to Version 4.1 formats; and
    (7) The user interface has been updated to provide automatic 
conversion of Version 4.0 datasets to Version 4.1.
    In summary, Version 4.1 enhances and completes the updates 
initiated under CAP88-PC Version 4.0 and incorporates compatibility for 
newer operating systems.

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 sources. The sources may be either elevated stacks, such as a 
smokestack, or uniform area 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 4.1 is a modification intended to improve 
usability, enhance the modeling methodology, update the dataset 
formats, and provide a more maintainable code base and documentation 
set for the future. Version 4.1 provides age-dependent dose conversion 
factors and lifetime risk factors and uses a code architecture that 
conforms to more recent 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 3.02 model,\1\ and age-
dependent ingestion and inhalation rates from the EPA.

    \1\ https://www.epa.gov/radiation/tools-calculating-radiation-dose-and-risk.

    The CAP88-PC Version 4.1 software was developed using a structured 
software engineering methodology that included adoption of a defined 

[[Page 12919]]

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 10 security requirements, and to improve 
usability, 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.
    CAP88-PC Version 4.1 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 4.1 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 simplify use of the code and 
management of case data. Reports 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 4.1 will preferentially use the population and wind files 
located in the dataset. This improves sharing of 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 
4.1 or any text editor, confident that the proper files are being used.
    As was the case with Versions 3 and 4.0, Version 4.1 is not 
backward compatible, and datasets generated using Versions 3 and 4.0 
cannot be used directly by Version 4.1. 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, both Versions 
4.0 and 4.1 include a dataset migration utility that upgrades many 
Version 3 datasets to the applicable Version 4.0 or 4.1 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 Version 4 architecture was to optimize 
the code by performing data manipulation in the user interface and 
computational functions in FORTRAN. CAP88-PC Versions 4.0 and 4.1 have 
accomplished this by having the user interface 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 user 
interface 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 4.1 has access to information for all 1,252 radionuclides, 
including those for which internal dose and risk factors have been 
added in to DCFPAK Version 3.02.

C. Validation of the CAP88-PC Version 4.1 Model

    The CAP88-PC Version 4.1 program is a well-established and 
validated code 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 turbulence. Version 4.1 has not 
modified the basic Gaussian plume algorithm used by the AIRDOS module 
of CAP88-PC, and comparison cases between Versions 4.0 and 4.1 have 
been run.
    The EPA's Office of Radiation and Indoor Air (ORIA) has reviewed 
the testing report submitted by the contractor and verified the results 
through independent testing. The report can be found at https://www.epa.gov/radiation/cap-88-pc.
    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 
    (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 4.1. 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 DCFPAK 3.02 
from Oak Ridge National Laboratory to 1% or less;
    (2) Values of Chi-over-Q ([chi]/Q) agree within 1% with those 
calculated using CAP88-PC Version 4.0, including but not limited to the 
direction of the MEI (the calculated values for [chi]/Q showed good 
agreement between Versions 4.0 and 4.1 in all directions);
    (3) Air concentrations and deposition rates (where applicable) 
agree within 1% with those calculated using CAP88-PC Version 4.0; and
    (4) Results for dose rates and risks agree within 5% of independent 
calculations; the 5% criterion 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 4.1 
calculations of the air concentrations and working levels for radon-
only are consistent with Version 4.0.

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 six area 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, area 
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.

[[Page 12920]]

E. Use of CAP88-PC Version 4.1 for Compliance Purposes

    In the same manner as CAP88-PC Version 4.0, Version 4.1 allows the 
user to incorporate the age-specific dose conversion factors and intake 
rates contained in DCFPAK Version 3.02. The code allows the user to 
select the ingestion and inhalation dose conversion and intake rates 
from the age groups modeled in DCFPAK Version 3.02: infant (100 days 
old), one-year old, five-year old, ten-year old, fifteen-year old, and 
adult. However, the addition of this capability does not change the 
requirements for compliance to the NESHAPS Subpart H requirements. 
These are clearly stated in 40 CFR part 61 Subpart H. The ability to 
allow the code base to include age-dependency does not impact or imply 
changes to the compliance demonstration.

F. Summary of Changes for CAP88-PC Version 4 to Version 4.1.

    Version 4.1 of CAP88-PC is an update from Version 4.0, and a 
significant upgrade from earlier versions. CAP88-PC Versions 4.0 and 
4.1 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, Windows 8.1. and Windows 10. Specific changes 
from Version 4.0 visible to the user in Version 4.1 include:
User Interface
    (1) The Print button on the Reports tab has been replaced with a 
button that opens the folder holding the report files which may then be 
printed using a word processing program;
    (2) Some labels in the user interface have been modified for 
    (3) The capabilities for migrating datasets from previous versions 
of CAP88-PC have been improved, including automatic conversion of 
Version 4.0 datasets to Version 4.1.
    (1) Some report headers have been modified for clarity;
    (2) The Agricultural Data in the Synopsis report now prints the 
values for the fractions of vegetables, milk, and meat from the 
assessment area used in the calculation, which may have been adjusted 
by CAP88-PC from the input values.
    (1) The dose and risk coefficients have been updated from DCFPAK 
2.2 to those in DCFPAK 3.02 provided by Oak Ridge National Laboratory;
    (2) Internal dose and risk coefficient factors for 151 more 
radionuclides have been added;
    (3) Additional risk coefficient data has been added for more 
radionuclides and chemical forms beyond the additional 151;
    (4) Inhalation coefficients for radionuclides with special chemical 
forms, such as iodine, have been added.
Error Handling
    CAP88-PC Versions 4.0 and 4.1 contain an 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 4.1 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: February 26, 2020.
Lee Ann B. Veal,
Director, Radiation Protection Division, Office of Radiation and Indoor 
[FR Doc. 2020-04546 Filed 3-4-20; 8:45 am]