Radionuclide Screening Rev 01, ICN 00

ANL-WIS-MD-000006

August 2002

1. PURPOSE
The waste forms under consideration for disposal in the proposed repository at Yucca Mountain 
contain scores of radionuclides (Attachments V and VI). It would be impractical and highly 
inefficient to model all of these radionuclides in a total system performance assessment (TSPA). 
Thus, the purpose of this radionuclide screening analysis is to remove from further consideration 
(screen out) radionuclides that are unlikely to significantly contribute to radiation dose to the 
public from the proposed nuclear waste repository at Yucca Mountain. The remaining nuclides 
(those screened in) are recommended for consideration in TSPA modeling for license 
application. This analysis also covers radionuclides that are not screened in based on dose, but 
need to be included in TSPA modeling for other reasons. For example, U.S. Environmental 
Protection Agency (EPA) and U.S. Nuclear Regulatory Commission (NRC) regulations require 
consideration of the combined activity of Ra-226 and Ra-228 in groundwater (40 CFR 197.30, 
10 CFR 63.331). Also, Cm-245, Pu-241, and U-235 decay indirectly to potentially important 
radionuclides, and are not identified by the screening analysis as important. 
The radionuclide screening analysis separately considers two different postclosure time periods: 
the 10,000-y regulatory period for the proposed repository at Yucca Mountain and the period 
after 10,000 y up to 1 million y after emplacement. The incremental effect of extending the 
screening for the regulatory period to 20,000 y is also addressed. Four release scenarios are 
considered: (1) the nominal scenario, which entails long-term degradation of disposal containers 
and waste forms, (2) a human-intrusion scenario, (3) an intrusive igneous event, and (4) an 
eruptive igneous event. Because the first three scenarios require groundwater transport, they are 
called groundwater scenarios below. The screening analysis considers the following waste 
forms: spent boiling water reactor (BWR) fuel, spent pressurized water reactor (PWR) fuel, U.S. 
Department of Energy (DOE) spent nuclear fuel (DSNF), and high-level waste (HLW). Average 
and outlying (high burnup, high initial enrichment, low age, or otherwise exceptional) forms of 
each waste-form type are considered. This analysis has been prepared in accordance with a 
technical work plan (BSC 2002c). 
In a review of Revision 00 of this radionuclide screening analysis, the NRC found that 
processes that affect transport in the biosphere, such as uptake by plants and bioaccumulation 
are not accounted for and that the direct exposure pathway is not accounted for (Beckman 
2001, Section 5.3.2.1). The NRC also found that the solubility and sorption classes were too 
broadly defined, noting, for example, that Se is in the same solubility and sorptivity groups as Np 
and U, yet is more soluble than Np and U by several orders of magnitude (Beckman 2001, 
Section 5.3.2.1). This revision seeks to build upon the strengths of the earlier screening method 
while responding to the specific concerns raised by the NRC and other reviewers. In place of 
simple inhalation and ingestion dose conversion factors, the revised radionuclide screening uses 
screening factors that also take into account soil accumulation, uptake by plants, exposure to 
contaminated ground, and other features of the biosphere that were neglected in the previous 
screening. Whereas the previous screening analysis allowed only two solubility classes (soluble 
and insoluble), the revised screening introduces an intermediate solubility class to better 
segregate the radionuclides into transport groups. 

2. QUALITY ASSURANCE
An activity evaluation (BSC 2002c, Attachment I, Activity Evaluation for Waste Form Modeling 
and Analysis for LA), which was prepared in accordance with AP-2.21Q, Quality 
Determinations and Planning for Scientific, Engineering, and Regulatory Compliance Activities, 
determined that the Quality Assurance (QA) program applies to the activity under which this 
analysis was developed. Control of the electronic management of information was accomplished 
in accordance with the controls specified by BSC (2002c, Attachment III). The analysis was 
prepared in accordance with AP-SIII.9Q, Scientific Analyses and AP-3.15Q, Managing 
Technical Product Inputs. 
3. USE OF SOFTWARE 
3.1 SOFTWARE APPROVED FOR QUALITY ASSURANCE (QA) WORK 
RadNuScreen 1.0 (BSC 2002a), which was obtained from Software Configuration Management, 
was used for the screening analysis. RadNuScreen 1.0 is appropriate for the application because 
it was designed specifically for use in this radionuclide screening analysis. RadNuScreen 1.0 is 
qualified and was used within the range of validation in accordance with AP-SI.1Q, Software 
Management. The software was used on a Dell Optiplex GX240 personal computer (central 
processing unit number 150418) with Excel 97 SR-2 and the Windows 2000 operating system. 
Input and output workbook files are provided in Attachment VI, with a listing of contents in 
Attachment V. Except for the Screening Summary file, which is an output summary, the first 
two worksheets in each workbook file provide the inputs, while the remaining worksheets 
provide the outputs. 
3.2 COMMERCIAL OFF-THE-SHELF SOFTWARE USED 
Microsoft Excel 97 SR-2, a commercially available spreadsheet software package, was used to 
process RadNuScreen inputs and results and to display information in graphical form. Excel is 
appropriate for the application because the calculations require simple mathematical expressions 
and operations that are standard in Excel to derive the results and because Excel has built-in 
graphical capabilities. The specific built-in functions of Excel that were used for calculations are 
described at the point of use. 

4. INPUTS
4.1 DATA AND PARAMETERS 
4.1.1 Project-generated usage factors (Table 1) are taken from Disruptive Event Biosphere 
Dose Conversion Factor Analysis, ANL-MGR-MD-000003 REV 01 (CRWMS M&O 
2001a, Section 6.5.3) and Nominal Performance Biosphere Dose Conversion Factor 
Analysis, ANL-MGR-MD-000009 REV 01 (CRWMS M&O 2001c, Section 6.5). The 
inputs are appropriate for use in the screening analysis because they pertain to the local 
biosphere (or are generic values that have been found appropriate to represent the local 
biosphere) and are the most recent available at the time of this analysis. 
Table 1. Project-Generated Usage Factors 
Description Value Reference 
Swimming and boating exposure 0 h/y CRWMS M&O 2001c, Table 8 
Shoreline exposure 0 h/y CRWMS M&O 2001c, Table 8 
Soil exposure for the groundwater scenarios 3,387 h/y CRWMS M&O 2001c, Table 8 
DTN: MO0010SPAAAM01.014 
Soil exposure for the eruptive igneous scenario 3,387 h/y CRWMS M&O 2001a, Table 10 
DTN: MO0010SPAAAM01.014 
Drinking water consumption 752.85 L/y CRWMS M&O 2001c, Table 8 
DTN: MO0007SPADMM05.002 
Consumption of locally raised fish 0.47 kg/y CRWMS M&O 2001c, Table 8 
DTN: MO0007SPADMM05.002 
Combined consumption of locally grown leafy and root vegetables, 
fruit, and grain 
39 kg/y CRWMS M&O 2001c, Table 8 
DTN: MO0007SPADMM05.002 
Consumption of locally produced milk 4.14 kg/y CRWMS M&O 2001c, Table 8 
DTN: MO0007SPADMM05.002 
Combined consumption of locally produced beef, poultry, and eggs 10.41 kg/y CRWMS M&O 2001c, Table 8 
DTN: MO0007SPADMM05.002 
Inadvertent ingestion of soil 50 mg/d CRWMS M&O 2001c, Table 8 
DTN: MO0010SPAPET07.004 
Inhalation exposure 6,073.5 h/y CRWMS M&O 2001a, Table 10 
DTN: MO0010SPAAAM01.014 
Chronic breathing rate 23 m3/d DTN: MO0010SPAAAM01.014 
Chronic and acute plume exposure 0 h/y CRWMS M&O 2001a, Table 10 
4.1.2 Half-lives for radioactive decay are primarily taken from Parrington et al. (1996), which 
is appropriate for use in this analysis because it is recognized as established fact in the 
Accepted Data database. For Se-79, a different source is used (Assumption 5.3). Except 
for Se-79, the only reason the half-lives are needed is to distinguish radionuclides with 
half-lives greater than or equal to 10 y from those with half-lives less than 10 years. 
Therefore, the half-lives used are sometimes rounded to the nearest year (Table 2), which 
results in 0-y half-lives for a number of nuclides. Table 2 covers all of the nuclides for 
which activities were calculated in the activity calculations that feed the screening 

analysis (see Assumptions 5.4, 5.11, and 5.12) and is a complete list of the radionuclides 
that were considered in the screening analysis. As indicated in Table 2, a few of the 
extremely long-lived nuclides are listed as stable by Parrington et al. (1996). 
Table 2. Half-lives Used To Discriminate Between Long-lived (=10 y) and Short-lived Radionuclides 
Nuclide Half-life (y) Nuclide Half-life (y) Nuclide Half-life (y) Nuclide Half-life (y) 
Ac-225 0 Co-58 0 Pb-212 0 Sm-148 Stable 
Ac-227 22 Co-60 5 Pb-214 0 Sm-149 Stable 
Ac-228 0 Cs-134 2 Pd-107 6,500,000 Sm-151 90 
Ag-108 0 Cs-135 2,300,000 Pm-145 18 Sn-113 0 
Ag-108m 130 Cs-137 30 Pm-146 6 Sn-119m 1 
Ag-109m 0 Eu-150 36 Pm-147 3 Sn-121 0 
Ag-110 0 Eu-152 14 Po-210 0 Sn-121m 55 
Ag-110m 1 Eu-154 9 Po-211 0 Sn-123 0 
Am-241 433 Eu-155 5 Po-212 0 Sn-126 250,000 
Am-242 0 Fe-55 3 Po-213 0 Sr-90 29 
Am-242m 1,141 Fr-221 0 Po-214 0 Tb-160 0 
Am-243 7,370 Fr-223 0 Po-215 0 Tc-98 4,200,000 
Ar-39 269 Gd-152 1.1E+14 Po-216 0 Tc-99 213,000 
At-217 0 Gd-153 1 Po-218 0 Te-123m 0 
Ba-133 11 H-3 12 Pr-144 0 Te-125m 0 
Ba-137m 0 Ho-166m 0 Pr-144m 0 Te-127 0 
Bi-210 0 I-129 15,700,000 Pt-193 60 Te-127m 0 
Bi-211 0 In-113m 0 Pu-236 3 Th-227 0 
Bi-212 0 K-40 1.27E+09 Pu-238 90 Th-228 2 
Bi-213 0 Kr-85 11 Pu-239 24,100 Th-229 7,300 
Bi-214 0 La-138 1.05E+11 Pu-240 6,560 Th-230 75,400 
Bk-249 1 Mn-54 1 Pu-241 14 Th-231 0 
C-14 5,715 Mo-93 3,500 Pu-242 375,000 Th-232 1.4E+10 
Ca-41 103,000 Nb-91 700 Pu-243 0 Th-234 0 
Ca-45 0 Nb-93m 16 Ra-223 0 Tl-206 0 
Cd-109 1 Nb-94 20,000 Ra-224 0 Tl-207 0 
Cd-113 9E+15 Nb-95 0 Ra-225 0 Tl-208 0 
Cd-113m 14 Nb-95m 0 Ra-226 1,599 Tl-209 0 
Ce-139 0 Nd-144 Stable Ra-228 6 Tm-171 2 
Ce-142 Stable Ni-59 76,000 Rb-87 4.88E+10 U-232 70 
Ce-144 1 Ni-63 100 Rh-102 3 U-233 159,200 
Cf-249 351 Np-235 1 Rh-106 0 U-234 246,000 
Cf-250 13 Np-236a 155,000 Rn-219 0 U-235 7.04E+08 
Cf-251 900 Np-237 2,140,000 Rn-220 0 U-236 23,420,000 
Cf-252 3 Np-238 0 Rn-222 0 U-237 0 
Cl-36 301,000 Np-239 0 Ru-106 1 U-238 4.47E+09 
Cm-242 0 Pa-231 32,800 Sb-125 3 Y-90 0 
Cm-243 29 Pa-233 0 Sb-126 0 Y-91 0 
Cm-244 18 Pa-234 0 Sb-126m 0 Zn-65 1 
Cm-245 8,500 Pa-234m 0 Se-79 1,100,000 Zr-93 1,500,000 
Cm-246 4,760 Pb-209 0 Sm-145 1 Zr-95 0 
Cm-247 15,600,000 Pb-210 23 Sm-146 1.03E+08 
Cm-248 348,000 Pb-211 0 Sm-147 1.06E+11 
NOTE: Some values are rounded to the nearest year. Primary source is Parrington et al. (1996). Source for Se-79 is 
Assumption 5.3. 
ANL-WIS-MD-000006 REV 01 9 August 2002 

4.2 CRITERIA 
There are no criteria specifically for radionuclide screening in the requirements documents. The 
present document addresses the NRC criteria that are specified in the Issue Resolution Status 
Report Key Technical Issue: Container Life and Source Term, Rev. 3 (Beckman 2001, Section 
5.3.2.1). 
4.2.1 
Total System Performance Assessment adequately incorporates important design 
features, physical phenomena, and couplings and uses consistent and appropriate 
assumptions throughout the radionuclide release rates and solubility limits abstraction 
process. (Beckman 2001, Section 5.3.2.1). 
4.2.2 
The Total System Performance Assessment abstraction on radionuclide release rates 
and solubility limits provides sufficient, consistent design information on [waste 
packages] and engineered barrier systems. For example, inventory calculations and 
selected radionuclides are based on the detailed information provided on the 
distribution (both spatially and by compositional phase) of the radionuclide inventory 
within the various types of HLW. (Beckman 2001, Section 5.3.2.1). 
4.3 
CODES AND STANDARDS 
There are no codes or standards directly associated with this analysis. The following sections of 
10 CFR 63 (Disposal Of High-Level Radioactive Wastes In A Geologic Repository At Yucca 
Mountain, Nevada) are relevant to the use of the results from analysis in total system 
performance assessment: 113 (Performance objectives for the geologic repository after 
permanent closure), 114 (Requirements for performance assessment), 331 (Separate standards 
for protection of groundwater), 332 (Human intrusion scenario), and 341 (Projections of peak 
dose). Also relevant to the use of the results from analysis in total system performance 
assessment is 40 CFR 197 (Protection of Environment: Public Health and Environmental 
Radiation Protection Standards for Yucca Mountain, Nevada). 

5. ASSUMPTIONS
5.1 
The analysis is deterministic. In particular, fixed values (not uncertainty distributions) 
are assumed for the screening factors (see Assumptions 5.2 and 5.8). Because of this 
assumption, some radionuclides that could contribute a significant fraction of the dose in 
unlikely circumstances (that is, if extreme values were drawn from uncertainty 
distributions for certain screening factors) could be screened out. The rationale for this 
assumption is that using a single representative screening factor for each radionuclide 
serves the purpose of this analysis, which is to screen out radionuclides that are unlikely 
to significantly contribute to radiation dose. This assumption does not require further 
confirmation because its limitations have been stated and it is consistent with the purpose 
of the screening analysis. This assumption is used throughout Section 6. 
5.2 
Air screening factors from National Council on Radiation Protection (NCRP) Report No. 
123, Screening Models for Releases of Radionuclides to Atmosphere, Surface Water, and 
Ground (NCRP 1996, Table B.1)adjusted to reflect the local biosphereare assumed 
sufficiently representative of human dose effects for the eruptive igneous scenario to be 
used in the screening analysis. The usage factors built in to the NCRP screening factors, 
that is, the assumed times spent in various activities such as gardening and bathing or the 
quantities of water or food products consumed, are not necessarily appropriate for local 
conditions. The NCRP screening factors are adjusted for use in the present analysis by 
replacing the NCRPs generic usage factors (NCRP 1996, Table 7.1) with project-
generated usage factors (Section 4.1.1). Attachment II describes the development of the 
screening factors resulting from this assumption. An anomalously high value for the 
Np-236a air screening factor was discovered during the scoping calculations for this 
analysis; a corrected value is developed for the screening analysis as described in 
Attachment II. The rationale for the corrected Np-236a screening factor, which is strong 
enough to justify a claim that further confirmation is not required, is provided in 
Attachment II. The rationale for using the adjusted air screening factors is as follows. 
The eruptive volcanic event bypasses the groundwater and injects radioactive 
contamination directly into the atmosphere, which then settles to the earth. Pathways 
considered by the NCRP air screening factors include inhalation and exposure to 
contaminated soil; consumption of contaminated crops and soil; and consumption of milk 
and meat from animals that consume contaminated forage (NCRP 1996, Section 8.2.1). 
A neglect of these factors in the previous radionuclide screening drew comments from 
the NRC, which noted that processes that affect transport in the biosphere, such as 
uptake by plants and bioaccumulation are not accounted for and that the direct 
exposure pathway is not accounted for (Beckman 2001, Section 5.3.2.1). 
Although the NCRP screening factors account for inhalation and the other exposure 
pathways of interest for the volcanic scenario, they were not developed for volcanic 
eruptions. Inhalation is expected to be the dominant pathway for all but four of the 17 
radionuclides considered in the site-recommendation analysis for the eruptive igneous 
scenario (CRWMS M&O 2001a, Section 6.6). Therefore, it is important to ensure that 
the screening factors developed for the screening analysis give appropriately high relative 

weight to the inhalation pathway. The four radionuclides for which the inhalation 
pathway is not expected to dominate are Sr-90, Cs-137, Pb-210, and Ra-226 (CRWMS 
M&O 2001a, Section 6.6). The screening factors developed in the present analysis also 
show relatively low contributions from the inhalation pathway for these radionuclides 
(Table 3). For the remaining radionuclides, the inhalation pathway dominates (Table 3), 
with inhalation contributions comparable to those developed for the site-recommendation 
biosphere dose conversion factors (CRWMS M&O 2001a, Tables 16 through 20). Thus, 
the screening factors developed in Attachment II give appropriate weight to the inhalation 
pathway. 
Table 3. Relative Contribution of the Inhalation Pathway for the Eruptive Screening Factors 
Contribution to the 
Nuclide 
Screening Factor from 
Inhalation (percent)a 
Sr-90 8.9 
Cs-137 0.1 
Pb-210 10.6 
Ra-226 5.6 
Ac-227 95.1 
Th-229 97.3 
Th-230 98.1 
Pa-231 85.2 
U-232 85.2 
U-233 96.2 
U-234 96.2 
Pu-238 86.9 
Pu-239 87.3 
Pu-240 87.3 
Pu-242 86.3 
Am-241 86.7 
Am-243 81.8 
aThe percent contributions are calculated from the 
table in Attachment II as the value from Column 1 
times 0.73 (the adjustment factor for inhalation 
developed in Attachment I) divided by the value in 
the last column. 
In light of the error in the NCRP report for the ground-irradiation dose coefficient of 
Np-236a, Attachment III provides an evaluation of the ground-irradiation, inhalation, and 
ingestion dose coefficients that the NCRP report uses to develop air screening factors. 
Attachment III shows that the dose coefficients used are similar in magnitude to other 
published dose coefficients. 
The results of the screening analysis are not sensitive to uncertainties in this assumption 
because results that screened out radionuclides known to be important or a failure to 
screen out radionuclides not previously suspected of being at least marginally important 
would be viewed skeptically. Thus, the worst-case consequence of uncertainties in the 

air screening factors is that marginally important radionuclides could be inappropriately 
screened out. The rationale for this assumption is strong enough to justify a claim that 
further confirmation is not required. This assumption is used in Sections 6.2, 6.3, 6.5, 
and 6.7; and Attachment II. 
5.3 
The half-life for radioactive decay of Se-79 is assumed to be 1.1  106 y. The rationale 
for this assumption is that it is based on a direct measurement technique and is not subject 
to the error that affected some earlier estimates (Songsheng et al. 1997). The calculations 
that provide input activities to the screening analysis used 330,000 y as the half-life for 
Se-79 (calculated from activities in the years 1,002,030 CE and 2130 CE as [1,002,030 -
2,130 y] / ln [1.85  103 Ci / 2.26  102 Ci], CRWMS M&O 2000c, p. I-2). Parrington et 
al. (1996) gives a half-life of 650,000 y, but some earlier sources give an even lower 
value. For example, Weast (1978, p. B-291) gives 65,000 y. The worst-case 
consequence of uncertainties in this assumption is that marginally important 
radionuclides could be inappropriately screened out. This assumption is used in Sections 
4.1.2, 6.2.3, 6.3, 6.7; and Attachment IV to correct the activity for Se-79. 
5.4 
It is assumed that the as-built characteristics of PWR and BWR assemblies and the 
calculated average and outlying radionuclide activities as functions of time that were 
developed by CRWMS M&O (1999a, Assumption 3.1, Section 5.5.3, and Attachment 
XV; 1999b, Assumption 3.1, Section 5.5, and Attachment X) are adequate for the 
screening analysis. The characteristics of the average CSNF waste forms were 
determined by weighted averages from the projected CSNF waste stream of the 
enrichments, burnups, and ages, where the weights are the numbers of assemblies with a 
given value of each characteristic in the waste stream. The characteristics of the outlying 
CSNF waste forms are the maximum burnup, the maximum initial enrichment, and the 
minimum age in the waste stream for each fuel type. The activities are listed in 
Attachment VI in the corresponding Excel workbooks for the 10,000-y regulatory period 
and beyond (see Attachment V for a listing). The rationale for this assumption, which is 
strong enough to justify a claim that further confirmation is not required, is that this 
information is the most recent available at the time of this analysis and was developed in 
accordance with the OCRWM quality assurance program. The possible consequences of 
uncertainties in this assumption are addressed in Section 6.5. This assumption is used in 
Sections 4.1.2, 6.2, and 6.3. 
5.5 
It is assumed that screening radionuclides at 95 percent of the cumulative radionuclide-
screening product under the identified release scenarios is adequate for TSPA. For a 
given radionuclide in the repository inventory, the radionuclide-screening product is 
defined as the product of the radionuclides screening factor (Assumptions 5.2 and 5.8) 
and the activity of the radionuclide in the inventory. The cumulative screening product 
for a given radionuclide is computed by ranking the screening products from largest to 
smallest and summing them starting with the largest and adding the next largest until the 
screening product of the given radionuclide has been included in the sum. Screening at 
95 percent means that the ranked radionuclides that contributed up to 95 percent of the 
maximum cumulative radionuclide-screening product are considered potentially 
important (see Section 6.2.1 for further explanation). The rationale for this assumption is 
as follows. 

Radionuclide screening implies that a subset of the full inventory of radionuclides will be 
modeled in TSPA and, therefore, that the dose contributions from some radionuclides 
will not be included in the dose projections. The radionuclide-screening product for each 
radionuclide is meant to be roughly proportional to the dose. Choosing a high but not 
excessively conservative cutoff serves the purpose of this analysis, which is to screen out 
radionuclides that are unlikely to significantly contribute to radiation dose. To assess the 
effect of variation of the screening cutoff, a fine-screen test was conducted with a 99 
percent cutoff (Section 6.3). This assumption does not require further confirmation 
because its limitations have been stated and it is consistent with the purpose of the 
screening analysis. This assumption is used in Sections 6.2, 6.3, and 6.5. 
5.6 The sorption classes given by the columns of Table 4 are assumed for the groundwater 
scenarios. The rationale for this assumption, which is strong enough to justify a claim 
that further confirmation is not required, is as follows. With the exception of some 
adjustments (to be detailed below), the classification corresponds to the NCRP 
assignment of freshwater sorption adjustment factors in a report that addresses screening 
techniques for releases of radioactive materials to the environment (NCRP 1996, Table 
6.1). 
The NCRP report assigns dimensionless adjustment factors of 0, 0.1, 1, and 10 to adjust 
the dose contributions from radionuclides in shoreline deposits (NCRP 1996, pp. 69 & 
70). Initial classifications are made here by assigning a correspondence as follows: the 
Low sorption class (L) corresponds to the 0 and 0.1 adjustment factors from the NCRP 
report; Medium (M) corresponds to an adjustment factor of 1; High (H) corresponds 
to an adjustment factor of 10. The NCRP derived the sorption adjustment factors from 
summary data on sorption to sediments at freshwater and marine shorelines. 
The NCRP freshwater adjustment factors are used as an initial basis for the sorption 
classifications because NCRP freshwater values provide a rough but consistent indicator 
of sorptivity under freshwater conditions. Corroboration of this assumption is provided 
by project-generated sorption-coefficient distributions recommended for unsaturated and 
saturated conditions (CRWMS M&O 2001e, Tables 2a and 2b). Note that the 
recommended sorption-coefficient distributions are consistent with the classifications 
derived from the NCRP report for Cl, I, and Tc (Low); C, Ni, Np, Pa, Se, Sr, and U 
(Medium); and Ac, Am, Pb, Pu, Sm, Th, and Zr (High). Note also that, although Cs, Nb, 
and Ra were assigned sorption adjustment factors of 1 in the NCRP report, it is more 
consistent with recommended site-specific sorption values to assign Cs, Nb, and Ra to the 
High sorption class. Although the NCRP report gives sorption adjustment factor of 0.1 
for Cd, Cd was placed in the High sorption class due to evidence (EPA 1999, Vol. II: 
Table 5.4) that indicates that the range of Cd sorptivity more closely resembles the range 
of other elements assigned to the High sorption class (CRWMS M&O 2001e, Tables 2a 
and 2b). Tin, which was assigned a sorption adjustment factor of 1 in the NCRP report, 
could reasonably have been placed in either the High or Medium classes based on the 
distributions presented by CRWMS M&O (2001e, Tables 2a and 2b). Tin was placed in 
the High sorption class due to evidence that Sn is highly sorbing compared to Se and U 
under a range of geochemical conditions (Ticknor et al. 1996, Abstract, p. 24, Table 11; 
Crowe and Vaniman 1985, pp. 33 through 37). 

It is recognized that sorptivity may vary depending on water chemistry, temperature, 
nature of the surrounding rock, and other variables. Class assignments are insensitive to 
uncertainties in sorptivity because only a rough division into three sorption classes has 
been done. The results of the screening analysis are insensitive to uncertainties in class 
assignments because the most important radionuclides have high enough radionuclide-
screening products that they will not be screened out regardless of their assigned class. 
At worst, this assumption could lead marginally important radionuclides to be improperly 
screened out. This assumption is used in Sections 6.2.1, 6.2.4, 6.2.6, 6.3, and 6.6. 
Table 4. Assumed Solubility and Sorption Classes for the Screening Analysis 
Solubility 
Class 
Sorption Class 
Low (L) Medium (M) High (H) 
High (H) 
Ar, Cl, H, 
I, K, Kr, 
Rb, Tc 
C, 
Se, Sr 
Cs 
Medium (M) Mo 
Ag, Ba, Ca, 
Eu, Gd, La, 
Ni, Np, U 
Ac, Am, Cf, 
Cm, Pd, Pm, Pu, 
Ra, Sm, Th, Tm 
Low (L) Pa, Pt 
Cd, Nb, 
Pb, Sn, Zr 
5.7 The solubility classes given by the rows of Table 4 are assumed for the groundwater 
scenarios. The solubility classifications roughly reflect the ability of solubility limits to 
restrict mobilization and transport to the accessible environment. It is recognized that 
solubility may vary over several orders of magnitude depending on water chemistry, 
temperature, composition of the surrounding rock, and other variables. Rough definitions 
of the solubility classes are: High (H): greater than 0.1 mol/L (or mol/kg); Medium (M): 
less than 0.1 but greater than 10-6 mol/L (or mol/kg), Low (L): less than 10-6 mol/L (or 
mol/kg). The rationale for the class assignments is provided in Table 5. The rationale for 
this assumption is strong enough to justify a claim that further confirmation is not 
required. 
For the most important elements, other project documents provide corroborating 
information for the class assignments (Table 5). For some of the less important elements, 
due to their apparent lack of importance to repository performance, little project work has 
been done to estimate solubility under site-specific conditions. In these cases, 
approximate solubilities for plausible controlling solids were used in the spirit in which 
the projects solubility investigations have been conducted (BSC 2001b, Sections 6.1.2, 
6.1.8). Class assignments are not sensitive to uncertainties in solubility limits because the 
solubility classes span several orders of magnitude. The results of the screening analysis 
are insensitive to uncertainties in class assignments because the most important 

radionuclides have high enough radionuclide-screening products that they will not be 
screened out regardless of their assigned class. At worst, this assumption could lead 
marginally important radionuclides to be improperly screened out. This assumption is 
used Sections 6.2.1, 6.2.5, 6.2.6, 6.3, and 6.6. 
5.8 Freshwater screening factors provided by NCRP Report No. 123, Screening Models for 
Releases of Radionuclides to Atmosphere, Surface Water, and Ground (NCRP 1996, 
Table C.1)adjusted to reflect the local biosphereare assumed sufficiently 
representative of biosphere transport and human dose effects for the nominal, human-
intrusion, and intrusive igneous scenarios (the groundwater scenarios) to be used in the 
screening analysis. In the present analysis, the screening factors are adjusted by 
replacing the generic usage factors (NCRP 1996, Table 7.1) with project-generated usage 
factors (Section 4.1.1). An anomalously high value for the Np-236a freshwater screening 
factor was discovered during the scoping calculations for this analysis; a corrected value 
is developed for the screening analysis as described in Attachment I. The rationale for 
this assumption, which is strong enough to justify a claim that further confirmation is not 
required, is as follows. 
The nominal, human-intrusion, and intrusive igneous scenarios entail the transport of 
radionuclides to the accessible environment through groundwater (in contrast, the 
eruptive volcanic event bypasses the groundwater and injects radionuclides directly into 
the atmosphere). The freshwater screening factors include dose from: exposure to 
irrigated soil; consumption of drinking water, irrigated crops, and soil; consumption of 
milk and meat from animals that consume irrigated forage; and consumption of 
freshwater fish (NCRP 1996, Section 8.2.2). A neglect of these factors in the previous 
radionuclide screening drew comments from the NRC, which noted that processes that 
affect transport in the biosphere, such as uptake by plants and bioaccumulation are not 
accounted for and that the direct exposure pathway is not accounted for (Beckman 
2001, Section 5.3.2.1). The generic usage factors built in to the NCRP screening factors, 
that is, the assumed times spent in various activities such as gardening and bathing or the 
quantities of water or food products consumed, apply to a generic biosphere. NCRPs 
development of the freshwater screening factors acknowledges the use of agricultural 
irrigation, so the resulting screening factors were intended to apply to climates where 
irrigation is practiced. Irrigated soil has high water content during irrigation, when 
sorption is important, so it is appropriate to apply the freshwater sorption adjustment 
factors that were discussed in Assumption 5.6 there. The sorption adjustment factors do 
not play any role in the pathways for ingestion of water, soil, or locally produced 
terrestrial food. Attachment I describes the development of screening factors based on 
the replacement of the NCRP usage factors by project-generated values. 
The inhalation pathway is not considered in the groundwater scenarios. This is consistent 
with the findings of project documentation of biosphere dose conversion factors. For the 
nominal scenario, the inhalation pathway contributes at most a few tenths of a percent to 
the dose for any of the radionuclides considered (CRWMS M&O 2001c, Table 15). 

Element Rationale for Solubility Class Assignment 
High (> ~0.1 mol/L) 
Ar, Kr Transport of noble gasses is not restricted by solubility limits because they can travel in the gaseous phase. 
Cl Forms naturally occurring, highly soluble ionic compounds with alkali metals, for example, KCl (sylvite) and NaCl (halite) 
(Weast 1978, B-150, B-165; Pauling 1970, Figure 13-3, Section 13-4). 
H, K, Rb Form compounds with halogens, for example, KCl (sylvite), RbCl, and HCl, which are highly soluble (Weast 1978, B-123, 
B-150, B-157; Pauling 1970, Figure 13-3, Section 13-4). 
C, Cs, I, Highly soluble (BSC 2001b, pp. 54 & 55). 
Sr, Tc 
Se Highly soluble, most likely solubility of 0.1 mol/L (CRWMS M&O 1998, Table 6-32, p. 6-84). 
Medium (> ~10-6 mol/L; < ~0.1 mol/L) 
Mo With naturally occurring molybdite (MoO3) as the controlling solid, in cold water, solubility = (0.1 g/100 cc ) / (143.94 
g/mol)  1000 cc/L = 710-3 mol/L (Weast 1978, p. B-139, CRWMS M&O 2001d, Section 6.3.4). 
Ag With naturally occurring horn sliver (AgCl) as the controlling solid, in cold water, solubility = (8.910-5 g/100 cc)/(143.32 
g/mol)  1000 cc/L = 6.210-6 mol/L (Weast 1978, pp. B-52, B-53, B-162). 
Ba 
Taking naturally occurring barite (BaSO4) as controlling, the solubility of Ba in cold water is about (210-4 g/100 cc ) / 
(233.4 g/mol)  1000 cc/L = 910-2 mol/L (Weast 1978, pp. B-11, B-99), which is on the upper end of the M class. 
According to another source, BaSO4 has a solubility of less than about 10-2 mol/L (Pauling 1970, Section 13-4), which 
places Ba solidly in the M class. 
Ca 
Taking CaCO3 as the controlling solid, note that J-13 water is saturated or nearly so in CaCO3 and has 13 mg/L Ca, that 
is, 13 mg/L / [(1000 mg/g)  (40 g/mol)] = 3.3 10-4 mol/L (MO0006J13WTRCM.000). Also, the solubility of CaCO3 in cold 
water is about (0.0014 g/100 cc ) / (100.09 g/mol)  1000 cc/L= 1.410-4 mol/L (Weast 1978, p. B-105). One could argue 
that near saturation would inhibit the dissolution of Ca in the waste form. However, Ca is assigned to M because the M 
class spans several orders of magnitude and because percolating unsaturated storm water could transport Ca. 
La, Pm, Lanthanides have similar chemical properties (Cotton 1999, Section 19.1) and Gd is assigned to M. 
Eu, Tm 
Gd Taking GdOHCO3 as the controlling solid gives a solubility of about 10-6 mol/L at neutral pH and normal atmospheric 
partial pressure of CO2 (CRWMS M&O 1997, Table C-1). 
Ni Loguniform distribution from 1.410-6 to 3.1 mol/L (mean = (1.410-63.1) = 2.110-3 mol/L) (CRWMS M&O 2000d, Table 
19, p. 41). 
Np Solubility 4.2810-5 mol/L at pH 7 and CO2 fugacity 10-3 bar (BSC 2001b, Table 14). 
U Solubility 2.04 mg/L at pH 7 and 30 C (BSC 2001b, Table 10). For approximate atomic weight 238, this is (2.04 mg/L) / 
(238 g/mol)  (10-3 g/mg) = 8.6 10-6 mol/L. 
Ac, Cf Actinides have similar chemical properties (Cotton 1999, Section 20.1) and Th, U, Np, Pu, and Am are assigned to M. 
Am A solubility of 1.810-6 mol/L at pH 7 and CO2 fugacity of 10-3 bar is suggested for Am (BSC 2001b, Table 17). 
Cm, Sm Assigned to M as Am analogs (CRWMS M&O 2000d, p. 40). 
Pd Loguniform distribution from 9.410-6 to 9.410-2 mol/L (CRWMS M&O 1998, Table 6-32). 
Pu Solubility 2.2210-4 mol/kg at pH 7 and CO2 fugacity 10-3 bar (BSC 2001b, Table 16). 
Ra Solubility 2.310-6 mol/L is recommended (BSC 2001b, p. 54, Table 19). 
Th Solubility 1.010-5 mol/L is recommended (BSC 2001b, p. 54, Table 19). 
Low (< ~10-6 mol/L) 
Pa A loguniform distribution from 10-10 to 10-5 mol/L (mean = 3.210-8 mol/L) is given (BSC 2001b, p. 55, Table 19). 
Pt Pt is chemically unreactive and is found in nature in native alloys (Pauling 1970, Section 20-7). Because elemental Pt is 
insoluble even in hydrochloric and nitric acids (Weast 1978, p. B-42.), Pt is placed in L. 
Sn Solubility 5.0 10-8 mol/L is suggested (CRWMS M&O 2000d, p. 42, Table 19). 
Cd 
Cd concentrations in natural waters saturated with respect to otavite (CdCO3) may be as high as 0.25 ppm (or mg/kg) 
(Carroll et al. 1998, p. 960 & Figure 3E), that is 0.25 mg/kg / [(1000 mg/g)  (112 g/mol)] = 2.2 10-6 mol/kg, though Cd 
concentrations this high in natural waters are rare (Langmuir 1997, Table 8.13). Taking otavite as the controlling solid, 
the solubility cited (2.2 10-6 mol/kg) would place Cd roughly at the bottom of M. However, because a solid solution of 
otavite and calcite (CaCO3) may greatly reduce Cd solubility (Langmuir 1997, pp. 14 & 15), Cd is placed in L. 
Nb Solubility 1.0 10-7 mol/L is suggested (CRWMS M&O 2000d, p. 41, Table 19). 
Pb Loguniform distribution from 10-10 to 10-5 mol/L (mean = (10-1010-5) = 3.210-8 mol/L) (BSC 2001b, p. 55, Table 19). 
Zr Solubility 6.810-10 mol/L is suggested (CRWMS M&O 2000d, p. 41, Table 19). 

In light of the error in the NCRP report for the ground-irradiation dose coefficient of 
Np-236a, Attachment III provides an evaluation of the dose coefficients that the NCRP 
report uses to develop freshwater screening factors. Attachment III shows that the dose 
coefficients used are similar in magnitude to other published dose coefficients. 
The results of the screening analysis are not sensitive to uncertainties in this assumption 
because results that screened out radionuclides known to be important or a failure to 
screen out radionuclides not previously suspected of being at least marginally important 
would be viewed skeptically. Thus, the worst-case consequence of uncertainties in the 
groundwater screening factors is that marginally important radionuclides could be 
inappropriately screened out. This assumption is used in Sections 6.2, 6.3, 6.5, and 6.7; 
and Attachment I. 
5.9 It is assumed that radionuclides with half lives less than 10 y that are not decay products 
of other radionuclides in the waste inventory will not contribute significantly to the dose 
in the groundwater scenarios. This assumption is implemented by a logical feature of the 
RadNuScreen software, which ignores direct contributions from radionuclides with half-
lives less than a user-specified cutoff. The rationale for this assumption, which is strong 
enough to justify a claim that further confirmation is not required, is as follows. 
The first time considered for the screening analysis is 100 y after emplacement. This is at 
least 10 half-lives for radionuclides with half-lives of 10 y or less, by which time only a 
miniscule fraction of the original activity (0.510 @ 10-3) is left. In-growth of decay 
products, regardless of half-life, is accounted for by the screening factors (NCRP 1996, 
Section 8.2.2). For the NCRP screening factors, the period assumed for accumulation in 
soil is 30 y (NCRP 1996, Section 8.2.2). The number of atoms Nd of a radionuclide 
produced by the decay of its parent when the daughter is initially absent is given by 
l 
p
Nd (t) = N 0[exp(-l pt) -exp(-l t)], 
-l
l
dpp d 
where N0p is the initial number of atoms of the parent, lp and ld are the decay constants 
of the parent and daughter, and t is time (adapted from Faure 1986, Equation 4.21). Note 
that the number of parent atoms as a function of time is given by Np(t) = N0p exp(-lpt), so 
that 
l 
p
Nd (t) = 
ld -l p 
Np (t1){ -[exp(l p -ld )t]}. 
For in-growth of a daughter product with a short half-life compared to the parent, the 
number of parent atoms can be considered nearly constant during the short times under 
consideration and the decay constant for the parent is much less than that of the daughter 
such that lp -ld @ -ld. Under these circumstances, the number of daughter atoms is 
approximately proportional to 1 - exp(-ldt). For three or more half-lives of in-growth 
time (30 y with a half-life of 10 y), t  3(ln 2)/ld, the fraction of the equilibrium quantity 
generated equals or exceeds 1  exp[-3 (ln 2)] = 87.5%. If two or more radioactive 

daughters are produced, the situation is more complex, but this calculation indicates that 
30-y or greater in-growth times should capture sufficient contributions from the ingrowth 
of radionuclides with half-lives less than 10 y whose direct contributions are 
neglected. The results of the screening analysis are insensitive to uncertainties in this 
assumption because there are few radionuclides in the waste inventory with half-lives 
near 10 y (Table 2). This assumption is used in Sections 6.2, 6.2.3, 6.3, and 6.6; and 
Attachment III. 
5.10 The groundwater and eruptive screening factors for Ce-142, Nb-91, Nd-144, Po-212, 
Sm-148, and Sm-149, are assumed equal to zero. The NCRP report does not provide 
screening factors or dose coefficients for these nuclides or it lists the values as zero 
(NCRP 1996, Tables A.1, B.1, and C.1). Federal Guidance Report No. 11 and 12 do not 
cover them or give zero values for dose coefficients (Eckerman et al. 1988; Eckerman & 
Ryman 1993). The rationale for this assumption, which is strong enough to justify a 
claim that further confirmation is not required, is as follows. 
Because the scope of the references cited is extensive, radionuclides that are omitted from 
these references are not likely to be important sources of radiation exposure. Further 
corroboration is provided as follows. Ce-142 is stable according to Parrington et al. 
(1996). Nb-91 decays to a stable daughter almost exclusively by electron capture 
(Parrington et al. 1996) with little emission of radiation (about 10 keV, Firestone and 
Shirley 1996, Vol. 1, energy diagram on p. 580). Nd-144 has a half-life so long (2.38  
1015 y) that it may be considered stable (Parrington et al. 1996). Po-212 has effective 
dose coefficients of zero (NCRP 1996, Table A.1). Sm-148 has a half-life so long (7  
1015 y) that it may be considered stable (Parrington et al. 1996). Sm-149 is stable 
according to Parrington et al. (1996). The worst-case consequence of uncertainties in this 
assumption is that marginally important radionuclides could be inappropriately screened 
out. This assumption is used in Section 6.2.1 and Attachments I and II. 
5.11 It is assumed that the calculated average and outlying radionuclide activities for 
DSNF as functions of time that were developed by CRWMS M&O (2000b, Tables 2 
through 7) are adequate for the screening analysis. For average DSNF, the activities used 
in the screening are the total inventories of each radionuclide for all DSNF. For outlying 
DSNF, the activities are the total inventories for each radionuclide in spent 
uranium/thorium carbide fuel. Uranium/thorium carbide fuel was chosen as the outlying 
DSNF waste form for the screening calculations because it contains substantial activities 
of U-233 and Th-230, whose potential importance to dose should be evaluated. The 
activities are listed in Attachment VI in the corresponding Excel workbooks for the 
10,000-y regulatory period and beyond (see Attachment V for a listing). The rationale 
for this assumption, which is strong enough to justify a claim that further confirmation is 
not required, is that this information is the most recent available at the time of this 
analysis and was developed in accordance with the OCRWM quality assurance program. 
The possible consequences of uncertainties in this assumption are addressed in Section 
6.5. This assumption is used in Sections 4.1.2, 6.2, and 6.3. 
5.12 It is assumed that the calculated average and outlying radionuclide activities for 
HLW as functions of time that were developed by CRWMS M&O (2000c, Attachments I 

and II) are adequate for the screening analysis. For average HLW, the activities used in 
the screening are the total inventories of each radionuclide for all HLW. For outlying 
HLW, the activities are the totals for HLW glass from the Savannah River Site. HLW 
from Savannah River was chosen as the outlying HLW waste form due to its high total 
activity per canister as compared to glass from the other sites where HLW will be 
produced (CRWMS M&O 2000c, Table 6-1). The activities are listed in Attachment VI 
in the corresponding Excel workbooks for the 10,000-y regulatory period and beyond 
(see Attachment V for a listing). The rationale for this assumption, which is strong 
enough to justify a claim that further confirmation is not required, is that this information 
is the most recent available at the time of this analysis and was developed in accordance 
with the OCRWM quality assurance program. The possible consequences of 
uncertainties in this assumption are addressed in Section 6.5. This assumption is used in 
Sections 4.1.2, 6.2, and 6.3. 

6. SCIENTIFIC ANALYSIS DISCUSSION 
6.1 PREVIOUS RADIONUCLIDE SCREENING ACTIVITIES 
Oversby (1987) conducted early work on radionuclide screening related to the proposed Yucca 
Mountain repository. Radionuclide screening was required for a series of total system 
performance analyses including the 1993 TSPA (Wilson et al. 1994), the 1995 TSPA (CRWMS 
M&O 1995), the TSPA for viability assessment (DOE 1998), and the TSPA for site 
recommendation (CRWMS M&O 2000e). Other organizations, including the NRC and the 
Electric Power Research Institute (EPRI), have conducted performance assessments, which 
required radionuclide screening (for example, Wescott et al. 1995 and EPRI 2002). The results 
of the cited radionuclide screening activities are provided in Table 6. 
The formal screening method that was introduced in REV 00 of the present analysis (CRWMS 
M&O 2000a, Section 4) drew favorable comments from the NRC (Beckman 2001, Section 
5.3.2.1): 
This clear description of the screening process used to identify important radionuclides is an improvement 
in the transparency of the TSPA. Also, consideration of important radionuclides for the human intrusion 
and igneous event scenarios in the inventory abstraction AMR is an improvement in the comprehensiveness 
of the analysis.  The approach appears to account for all waste types that will be emplaced in the 
repository and seems complete in this regard. 
However, the NRC also provided constructive criticism (Beckman 2001, Section 5.3.2.1). This 
revision seeks to build upon the strengths of the earlier screening method while responding to 
comments by the NRC. Specific comments and how they are addressed in the present analysis 
were mentioned in Section 1, are brought to light in the following discussion and the supporting 
assumptions from Section 5, and are treated fully in Section 6.7.1. 
6.2 CONCEPTUAL BASIS 
6.2.1 Summary of the Screening Process 
The screening analysis considers four release scenarios (nominal, human intrusion, intrusive 
igneous, and eruptive igneous) and two time periods (the 10,000-y regulatory period and the 
period after 10,000 y up to 1 million years). The nominal scenario envisions the gradual 
deterioration of the disposal containers, the subsequent exposure of the waste to the potentially 
corrosive effects of the environment, and the natural transport of radioactive contaminants 
through unsaturated and saturated groundwater to the accessible environment, where the 
groundwater is withdrawn by the human population. The human-intrusion scenario considers the 
possibility that future inhabitants of the Yucca Mountain area might drill down into the 
repository, through a waste package, and down to the water table. Under the human-intrusion 
scenario (as compared to the nominal scenario), the waste would be exposed to the environment 
sooner and radioactive contaminants would have a quicker path to the saturated groundwater 
through the postulated borehole. The intrusive igneous scenario envisions the intrusion of 
magma into the repository where it damages waste packages, making radioactive contaminants 
available for transport in the unsaturated groundwater zone. As noted above, the nominal, 

Nuclide 
TSPA 
1993a 
TSPA 
1995b 
TSPA for 
viability 
assessmentc 
TSPA for site 
recommendationd NRCe EPRIf 
Ac-227 Ac-227 Ac-227 Ac-227 
Ag-108m Ag-108m 
Am-241 Am-241 Am-241 Am-241 Am-241 Am-241 
Am-242m Am-242m Am-242m 
Am-243 Am-243 Am-243 Am-243 Am-243 
C-14 C-14 C-14 C-14 C-14 C-14 
Cl-36 Cl-36 Cl-36 Cl-36 
Cm-243 Cm-243 
Cm-244 Cm-244 Cm-244 
Cm-245 Cm-245 Cm-245 Cm-245 
Cm-246 Cm-246 Cm-246 Cm-246 
Cs-135 Cs-135 Cs-135 Cs-135 Cs-135 
Cs-137 Cs-137 Cs-137 Cs-137 
I-129 I-129 I-129 I-129 I-129 I-129 I-129 
Mo-93 Mo-93 
Nb-93m Nb-93m 
Nb-94 Nb-94 Nb-94 Nb-94 Nb-94 
Ni-59 Ni-59 Ni-59 Ni-59 
Ni-63 Ni-63 Ni-63 
Np-237 Np-237 Np-237 Np-237 Np-237 Np-237 Np-237 
Pa-231 Pa-231 Pa-231 Pa-231 Pa-231 Pa-231 
Pb-210 Pb-210 Pb-210 Pb-210 Pb-210 
Pd-107 Pd-107 Pd-107 
Pu-238 Pu-238 Pu-238 Pu-238 
Pu-239 Pu-239 Pu-239 Pu-239 Pu-239 Pu-239 Pu-239 
Pu-240 Pu-240 Pu-240 Pu-240 Pu-240 Pu-240 
Pu-241 Pu-241 Pu-241 
Pu-242 Pu-242 Pu-242 Pu-242 Pu-242 Pu-242 
Ra-226 Ra-226 Ra-226 Ra-226 Ra-226 Ra-226 
Ra-228 Ra-228 Ra-228 
Se-79 Se-79 Se-79 Se-79 Se-79 Se-79 
Sm-151 Sm-151 Sm-151 
Sn-121m Sn-121m 
Sn-126 Sn-126 Sn-126 Sn-126 
Sr-90 Sr-90 Sr-90 
Tc-99 Tc-99 Tc-99 Tc-99 Tc-99 Tc-99 Tc-99 
Th-229 Th-229 Th-229 Th-229 Th-229 
Th-230 Th-230 Th-230 Th-230 Th-230 Th-230 
Th-232 Th-232 Th-232 Th-232 
U-232 U-232 U-232 
U-233 U-233 U-233 U-233 U-233 
U-234 U-234 U-234 U-234 U-234 U-234 U-234 
U-235 U-235 U-235 U-235 U-235 
U-236 U-236 U-236 U-236 U-236 
U-238 U-238 U-238 U-238 U-238 U-238 
Zr-93 Zr-93 Zr-93 Zr-93 
SOURCES: aWilson et al. 1994, Table 5-11; bCRWMS M&O 1995, Tables 3.7-1 & 3.7-2; cDOE 1998, Table 3.14;
dCRWMS M&O 2000a, Table 34; eWescott et al. 1995, Table 5.1; fEPRI 2002, Section 6.5.
ANL-WIS-MD-000006 REV 01 22 August 2002 

For the groundwater scenarios, the screening process first requires a subdivision of the complete 
set of radionuclides for a given waste form into screening sets according to transport 
characteristics of each radionuclide (Sections 6.2.4 through 6.2.6, Assumptions 5.6 and 5.7). It 
then ranks radionuclides within a screening set according to the product of the activity in the 
waste form and a screening factor corresponding to each radionuclide without regard to 
solubility or sorption (Assumptions 5.2 and 5.8). Because radionuclide mobilization and 
transport under the eruptive scenario do not require groundwater transport, which may sort 
elements according to sorption and solubility, no subdivision according to groundwater transport 
characteristics is needed for the eruptive scenario. 
The radionuclide screening is based on the premise that the products of the activity inventories 
and the screening factors indicate the relative importance of each radionuclide with respect to the 
radiation dose that a person near the repository might receive. The units of the product of 
activity and screening factor need not correspond to a dose to an individual, so long as the units 
are consistent across radionuclides within a waste form and the product provides a measure of 
relative importance. For example, a valid pair of units is activity in Ci and screening factor in 
(Sv/y) / (Bq/m3), which corresponds to the groundwater scenarios (Assumption 5.8). The 
resulting units Ci  (Sv/y) / (Bq/m3) do not correspond to the dose to an individual, but the 
product still provides a measure of relative importance because it is proportional to dose under 
the assumptions of the screening for a particular screening time and waste form. Air and 
freshwater screening factors from NCRP Report 123, adjusted to reflect project-generated usage 
factors, are used as screening factors in the screening analysis (Assumptions 5.2 and 5.8). In a 
few cases, screening factors are approximated as zero (Assumption 5.10). 
A radionuclide is screened out for a particular screening set and waste form at a particular time if 
the sum of its screening product and those of the radionuclides below it in rank fails to contribute 
5 percent (Assumption 5.5) of the total of the screening products within the screening set. The 
complement of this fraction (95 percent) may be called the screening-product cutoff fraction. As 
described in Section 6.2.3, the screening is performed at a number of screening times for each 
waste form. A radionuclide that is screened out for all screening times and for all screening sets 
in which it is included is considered screened out for the waste form. A radionuclide that is 
screened out for all waste forms is screened out generally. 
The following sections describe how the screening analysis accounts for exposure time and 
variation in waste package contents, how the screening sets are determined for the groundwater 
scenarios, and how the RadNuScreen software performs the screening. 
6.2.2 Accounting for Variations in Waste Packages 
Some waste packages will contain spent BWR fuel only while others will contain spent PWR 
fuel only. Some will contain canisters of vitrified HLW only and others will contain a mixture of 
canisters, each of which contains either DSNF or HLW. In addition, the design of the disposal 
container and the non-fuel internals varies according to intended contents. Under such 
conditions, the random failure of only a few waste packages or systematic differences in breach 
time or radionuclide transport characteristics that depend on waste form or waste package type 
could mean that any of the several waste forms could independently determine the most 
important radionuclides. Therefore, the screening calculation is performed separately for BWR, 

6.2.3 Accounting for Time of Exposure 
Due to radioactive decay and in-growth, the makeup of the waste changes over time. Therefore, 
the screening analysis is performed independently at a number of times, which span the 
regulatory and post-regulatory periods and are approximately evenly spaced on a logarithmic 
scale (at multiples of roughly two to three). For the 10,000-y regulatory period, the screening 
times are 100 y, 200 y, 300 y, 500 y, 1,000 y, 2,000 y, 5,000 y, and 10,000 y after emplacement. 
An independent screening for times after the regulatory period is conducted with screening times 
at 20,000 y, 30,000 y, 100,000 y, 300,000 y, and 1 million y after emplacement. These sets of 
screening times capture the main features of the changing relative activities of dominant 
radionuclides (Benedict et al. 1981, Figure 11.29). To be screened out for the 10,000-y 
regulatory period, a radionuclide must be screened out at all times less than or equal to 10,000 y. 
Likewise, for the screening analysis for times after 10,000 y, to be screened out generally, a 
radionuclide must be screened out at all times greater than 10,000 y. A separate screening at 
20,000 y only is conducted to address the effect of extending the regulatory-period screening out 
to 20,000 y. 
Except for Se-79, projecting the makeup of the waste as a function of time up to 1 million years 
after emplacement is not part of this analysis, but is provided as input (Assumptions 5.4, 5.11, 
and 5.12). An activity correction factor for Se-79 is used to correct the erroneous half-life that 
was used in the activity calculations (Assumption 5.3). The correction factor reduces the Se-79 
activity throughout the regulatory period by a factor of about 0.3. At 1 million years, the 
correction factor is about 1.3 (Attachment IV). 
As a simplification that avoids the need to classify short-lived elements into sorption and 
solubility classes, radionuclides with half-lives less than 10 y are not considered as direct 
contributors to dose in the groundwater scenarios (Assumption 5.9). 
6.2.4 Accounting for Sorption 
For groundwater scenarios, elements are grouped into three sorption classes: high (H), medium 
(M), and low (L) (Assumption 5.6). Different modes of transport to the accessible environment 
may sort chemical elements according to sorption class (Table 7). The screening analysis allows 
for the possibility that any of the identified modes of transport may predominate at any time. 
Under some conditions, fracture flow may allow highly sorbing elements to be transported by 
colloids while low-sorbing and medium-sorbing elements travel in solution (Table 7, first row 
after header). Under more restrictive fracture-flow conditions, highly sorbing elements may 
attach to fracture walls and colloids may be filtered out, so that highly sorbing elements are 
discriminated against while medium-sorbing and low-sorbing elements travel in solution (Table 
7, second row). Matrix flow discriminates in favor of low-sorbing elements due to the prolonged 
intimate contact of the groundwater with the rock matrix during which medium-sorbing and 
highly sorbing elements are likely to sorb to the fracture walls or to colloids, which are likely to 
be filtered out (Table 7, last row). The sorption class combinations identified in Table 7 are used 
to form screening sets as described in Table 8. 

Groundwater Flow Conditions Favored Sorption Classes 
Fracture flow, rich in colloids High, Medium, and Low 
Fracture flow, low in colloids Medium and Low 
Matrix flow (no colloids) Low 
6.2.5 Accounting for Solubility 
In the groundwater scenarios, solubility affects the ability of an element in the waste form to 
mobilize within the degraded waste package and transport through groundwater to the accessible 
environment. The greater the solubility of an element, the greater the likelihood that its isotopes 
will be mobilized sufficiently to affect repository performance. For this analysis, elements are 
grouped into three solubility classes: high (H), medium (M), and low (L) (Assumption 5.7). The 
solubility and sorption classes are used to form screening sets as described in Table 8. The three 
solubility classes serve to divide the elements into sets based on alternative low-solubility 
cutoffs. Thus, with no consideration of solubility, all three classes are included H, M, and L (see 
the first row of Table 8). A relatively high solubility cutoff discounts only the least soluble 
elements, leaving H and M solubility elements to be considered together (Table 8, second row). 
The most restrictive sets consider only the most soluble elements as possible contributors to dose 
(Table 8, last row). Within each screening set, no further account is taken of differences in 
solubility. In effect, within each screening set, solubility limits do not apply. Instead, the 
screening analysis represents each radionuclide in proportion to its fraction of the inventory, not 
in accordance with solubility limits that might apply to the element in question. 
The previous screening analysis allowed only two groups: soluble and insoluble. Introducing an 
intermediate solubility group in this revision addresses the NRCs claim that transport groupings 
were too broad. NRC observed, for example, that Se is in the same solubility and sorptivity 
groups as Np and U, yet is more soluble than Np and U by several orders of magnitude 
(Beckman 2001, Section 5.3.2.1). 
6.2.6 Determining the Screening Sets 
The considerations given in Sections 6.2.4 and 6.2.5, along with the solubility and sorption 
classes developed in Assumptions 5.6 and 5.7, result in a rule for combining solubility and 
sorption classes into screening sets for the groundwater scenarios. That is: consider the 
combinations of the solubility groupings H, M, and L; H and M; and H with the sorption 
groupings H, M, and L; M and L; and L. Table 8 provides descriptions of the nine resulting 
screening sets. The elements included in each screening set are given in Table 9. 

Solubility Class 
Combinations 
Sorption Class Combinations 
H, M, & L M & L L 
H, M, & L 
Colloidal transport is 
important; solubility 
limits do not inhibit 
mobilization or 
transport. 
Colloidal transport is not 
important, highly sorbing 
elements are immobilized, but 
medium sorbing elements are 
allowed to pass; solubility limits 
do not inhibit mobilization or 
transport. 
Colloidal transport is not 
important, highly and moderately 
sorbing elements are immobilized, 
but low sorbing elements are 
allowed to pass; solubility limits do 
not inhibit mobilization or 
transport. 
H & M 
Colloidal transport is 
important but 
solubility limits inhibit 
mobilization of the 
least soluble 
elements. 
Colloidal transport is not 
important, highly sorbing 
elements are immobilized, but 
medium sorbing elements are 
allowed to pass; however, 
solubility limits inhibit 
mobilization of the least soluble 
elements. 
Colloidal transport is not 
important, highly and moderately 
sorbing elements are immobilized, 
but low sorbing elements are 
allowed to pass; however, 
solubility limits inhibit mobilization 
of the least soluble elements. 
H 
Colloidal transport is 
important but 
solubility limits inhibit 
mobilization of all 
but the most soluble 
elements. 
Colloidal transport is not 
important, highly sorbing 
elements are immobilized, but 
medium sorbing elements are 
allowed to pass; however, 
solubility limits inhibit 
mobilization of all but the most 
soluble elements. 
Colloidal transport is not 
important, highly and moderately 
sorbing elements are immobilized, 
but low sorbing elements are 
allowed to pass; however, 
solubility limits inhibit mobilization 
of all but the most soluble 
elements. 
Table 9. Lists of Elements in Each Screening Set 
Solubility Class 
Combinations 
Sorption Class Combinations 
H, M & L M & L L 
H, M & L 
Ac, Ag, Am, Ar, Ba, C, Ca, Cd, Cf, Cl, Cm, 
Cs, Eu, Gd, H, I, K, Kr, La, Mo, Nb, Ni, Np, 
Pa, Pb, Pd, Pm, Pt, Pu, Ra, Rb, Se, Sm, 
Sn, Sr, Tc, Th, Tm, U, Zr 
Ag, Ar, Ba, C, Ca, Cl, Eu, Gd, 
H, I, K, Kr, La, Mo, Ni, Np, Pa, 
Pt, Rb, Se, Sr, Tc, U 
Ar, Cl, H, I 
K, Kr, Mo, 
Rb, Tc 
H & M 
Ac, Ag, Am, Ar, Ba, C, Ca, Cf, Cl, Cm, Cs, 
Eu, Gd, H, I, K, Kr, La, Mo, Ni, Np, Pd, Pm, 
Pu, Ra, Rb, Se, Sm, Sr, Tc, Th, Tm, U 
Ag, Ar, Ba, C, Ca, Cl, Eu, Gd, 
H, I, K, Kr, La, Mo, Ni, Np, Rb, 
Se, Sr, Tc, U 
Ar, Cl, H, I, 
K, Kr, Mo, 
Rb, Tc 
H 
Ar, C, Cl, Cs, H, I, K, 
Kr, Rb, Se, Sr, Tc 
Ar, C, Cl, H, I, K, Kr, 
Rb, Se, Sr, Tc 
Ar, Cl, H, I, 
K, Kr, Rb, Tc 
SOURCE: Assumptions 5.6 and 5.7. 
6.2.7 Operational Description of the Screening Software 
The purpose of RadNuScreen is to perform the calculations, rankings, and screenings that are 
required for the screening analysis described in Section 6.2.1. The fundamental calculation 
performed by the software is to multiply the activity of a radionuclide by a screening factor. The 
resulting product may be called a screening product. As the basic screening operation, 
RadNuScreen ranks radionuclides based on the magnitudes of the screening products, sums the 
screening products in rank order to form the cumulative screening product for each radionuclide, 
and applies a screening cutoff limit. The software performs the basic screening operation for two 

RadNuScreen requires the user to provide the inputs listed below. For further information on 
RadNuScreen, see the Software Management Report (BSC 2002b). 
 The activity of each radionuclide in each waste form at each screening time. 
 Groundwater and eruptive screening factors for each radionuclide under consideration. 
 Solubility and sorption classes for each radionuclide. Three solubility classes (High, 
Medium, and Low) and three sorption classes (High, Medium, and Low) are allowed. 
 Compositions of the groundwater screening sets as combinations of solubility and sorption 
classes (see, for example, the column and row headers of Table 9). 
 Coarse-screen and fine-screen cutoff levels (95 and 99 percent were used in the present 
screening analysis). 
 Decay half-lives for each radionuclide and the half-life cutoff that RadNuScreen will use to 
discriminate between long- and short-lived radionuclides. Except for the optional Se-79 
correction, RadNuScreen uses half-lives only to exclude short-lived radionuclides from the 
groundwater screening. The specified half-lives and half-life cutoffs have no effect on the 
eruptive screening. 
6.3 RESULTS 
6.3.1 10,000-Year Regulatory Period 
The screening results for the 10,000-y regulatory period, which were produced using 
RadNuScreen 1.0, are provided in Table 10. Table 2 provides a complete list of the 
radionuclides that were considered in the screening analysis. Attachment VI (a compact disk) 
provides Excel workbook files that list the inputs for RadNuScreen 1.0 and provide detailed 
results for every waste form and screening time; Attachment V lists the contents of the compact 
disk. A file that summarizes the results for each waste form is also included. The formal 
screening was conducted using a screening-product cutoff of 0.95. The results listed for a 0.99 
cutoff allow the reader to identify the marginally important radionuclides. The marginally 
important radionuclides might not have been screened out, had inputs or assumptions been 
significantly different. The rightmost two columns give the unions of the groundwater and 
eruptive sets. Note that the totals for the groundwater set and the totals of the unions of sets are 
the same for the 95 percent cutoff; therefore, the eruptive set does not contain any radionuclides 
that are not members of the groundwater set. For the eruptive scenario at 99 percent cutoff, three 
new marginally important radionuclides are introduced as compared to the groundwater set 
(Ac-225, Ra-225, and Th-228). The intended use of the screening results is discussed in Section 
7. Refer to Section 5 for a list of underlying assumptions. 

6.3.2 Incremental Effect of Including the 20,000-Year Screening Time 
With a 0.95 screening-product cutoff, no additional radionuclides are screened in if times up to 
20,000 y are considered along with screening times within the 10,000-y regulatory period. With 
a 0.99 cutoff, no additional marginally important radionuclides are identified for the groundwater 
scenarios, but three additional marginally important radionuclides are identified for the igneous 
eruptive scenario: Cm-245, Ra-226, and Th-230. Attachment VI (a compact disk) provides 
Excel workbook files that list the inputs for RadNuScreen 1.0 and provide detailed results for 
every waste form at the 20,000-y screening time; Attachment V lists the contents of the compact 
disk. A file that summarizes the results for each waste form is also included. 
6.3.3 Times Beyond the Regulatory Period Up To 1 Million Years 
The screening results from RadNuScreen 1.0 for times beyond the 10,000-y regulatory period, up 
to 1 million years after emplacement, are provided in Table 11. Table 2 provides a complete list 
of the radionuclides that were considered in the screening analysis. Attachment VI (a compact 
disk) provides Excel workbook files that list the inputs for RadNuScreen 1.0 and provide 
detailed results for every waste form and screening time; Attachment V lists the contents of the 
compact disk. A file that summarizes the results for each waste form is also included. The 
formal screening was conducted using a screening-product cutoff of 0.95. The results listed for a 
0.99 
cutoff allow the reader to identify the marginally important radionuclides. The rightmost 
two columns give the unions of the groundwater and eruptive sets. Note that the totals for the 
groundwater set and the totals of the unions of sets are the same for the 95 percent cutoff; 
therefore, the eruptive set does not contain any radionuclides that are not members of the 
groundwater set. For the eruptive scenario at 99 percent cutoff, four new marginally important 
radionuclides are introduced as compared to the groundwater set: Ac-225, Cm-245, Ra-225, and 
Th-228. The intended use of the screening results is discussed in Section 7. Refer to Section 5 
for a list of underlying assumptions. 
6.4 
OTHER SCREENING FACTORS CONSIDERED AND REJECTED 
In the course of developing the screening analysis, two alternative sets of screening factors were 
considered and rejected. First, unadjusted screening factors directly from NCRP (1996) were 
considered. It was found that the NCRP screening factors, which were not intended to apply 
specifically to a sparsely populated arid environment, overemphasized some pathways (in 
particular, consumption of fish, milk, and soil), as can be easily seen in retrospect from the 
adjustment factors calculated in Attachments I and II (Table I-1). 
Second, a hybrid set of screening factors, based on biosphere dose conversion factors from 
Yucca Mountain viability-assessment and site-recommendation studies, where available, and 
NCRP screening factors wherever project-generated dose conversion factors were unavailable, 
was considered. The presumed advantage of the hybrid approach was that the forty or so most 
important radionuclides would be represented by project-generated screening factors and the 
NCRP factors would apply only to the less important radionuclides. However, it was found that 
differences in methods used in the various sources, such as treatments of radionuclide buildup in 
soil and the relative importance of exposure pathways, precluded the development of an 
internally consistent set of screening factors. 

Table 10. Screening Results for the 10,000-Year Regulatory Period 
Screening Results by Transport Scenario and 
Screening Product Cutoff Fraction 
Union of Sets for 
Radionuclide 
Groundwater 
Scenarios 
Eruptive Igneous 
Scenario 
Groundwater and Eruptive 
Scenarios 
0.95 0.99 0.95 0.99 0.95 0.99 
Ac-225 Ac-225 Ac-225 
Ac-227 Ac-227 Ac-227 Ac-227 Ac-227 Ac-227 Ac-227 
Am-241 Am-241 Am-241 Am-241 Am-241 Am-241 Am-241 
Am-243 Am-243 Am-243 Am-243 Am-243 Am-243 Am-243 
C-14 C-14 C-14 C-14 C-14 
Cl-36 Cl-36 Cl-36 
Cm-244 Cm-244 Cm-244 Cm-244 
Cs-135 Cs-135a Cs-135 Cs-135 Cs-135 
Cs-137 Cs-137a Cs-137 Cs-137 Cs-137 Cs-137 Cs-137 
I-129 I-129 I-129 I-129 I-129 
Ni-63 Ni-63 Ni-63 
Np-237 Np-237 Np-237 Np-237 Np-237 Np-237 
Pa-231 Pa-231 Pa-231 b Pa-231 Pa-231 Pa-231 
Pb-210 b Pb-210 b Pb-210 
Pu-238 Pu-238 Pu-238 Pu-238 Pu-238 Pu-238 Pu-238 
Pu-239 Pu-239 Pu-239 Pu-239 Pu-239 Pu-239 Pu-239 
Pu-240 Pu-240 Pu-240 Pu-240 Pu-240 Pu-240 Pu-240 
Pu-241 Pu-241 Pu-241 
Pu-242 Pu-242 Pu-242 Pu-242 
Ra-225 Ra-225 Ra-225 
Ra-226 Ra-226a Ra-226 Ra-226 Ra-226 
Sn-126 Sn-126 Sn-126 Sn-126 
Sr-90 Sr-90a Sr-90 Sr-90 Sr-90 Sr-90 Sr-90 
Tc-99 Tc-99 Tc-99 Tc-99 Tc-99 Tc-99 
Th-228 Th-228 Th-228 
Th-229 Th-229 Th-229 Th-229 Th-229 Th-229 Th-229 
Th-232 Th-232 Th-232 
U-232 U-232 U-232 U-232 U-232 U-232 U-232 
U-233 U-233 U-233 U-233 U-233 U-233 U-233 
U-234 U-234 U-234 U-234 U-234 U-234 U-234 
U-235 U-235 U-235 
U-236 b U-236 U-236 
U-238 U-238 U-238 U-238 U-238 
Counts 20 30 12 21 20 33 
NOTES: aWas screened out under REV 00 (BSC 2001a, Table 37) for the nominal scenario. 
bWas not screened out under REV 00 (BSC 2001a, Table 37) for the corresponding 
scenario. 

Screening Results by Transport Scenario and 
Screening Product Cutoff Fraction 
Union of Sets for 
Radionuclide 
Groundwater 
Scenarios 
Eruptive Igneous 
Scenario 
Groundwater and 
Eruptive Scenarios 
0.95 0.99 0.95 0.99 0.95 0.99 
Ac-225 Ac-225 Ac-225 
Ac-227 Ac-227 Ac-227 Ac-227 Ac-227 Ac-227 Ac-227 
Am-243 Am-243 Am-243 Am-243 Am-243 Am-243 Am-243 
C-14 C-14 a C-14 C-14 C-14 
Cl-36 Cl-36 a Cl-36 Cl-36 Cl-36 
Cm-245 Cm-245 Cm-245 
Cs-135 Cs-135 a Cs-135 Cs-135 Cs-135 
I-129 I-129 I-129 I-129 I-129 
Nb-94 Nb-94 Nb-94 
Np-237 Np-237 Np-237 Np-237 Np-237 Np-237 Np-237 
Pa-231 Pa-231 Pa-231 Pa-231 Pa-231 Pa-231 Pa-231 
Pb-210 Pb-210 Pb-210 Pb-210 Pb-210 Pb-210 Pb-210 
Pu-239 Pu-239 Pu-239 Pu-239 Pu-239 Pu-239 Pu-239 
Pu-240 Pu-240 Pu-240 Pu-240 Pu-240 Pu-240 Pu-240 
Pu-242 Pu-242 Pu-242 Pu-242 Pu-242 Pu-242 Pu-242 
Ra-225 Ra-225 Ra-225 
Ra-226 Ra-226 Ra-226 Ra-226 Ra-226 Ra-226 Ra-226 
Se-79 Se-79 a Se-79 Se-79 Se-79 
Sn-126 Sn-126 a Sn-126 Sn-126 a Sn-126 Sn-126 Sn-126 
Tc-99 Tc-99 Tc-99 Tc-99 a Tc-99 Tc-99 Tc-99 
Th-228 Th-228 Th-228 
Th-229 Th-229 Th-229 Th-229 Th-229 Th-229 Th-229 
Th-230 Th-230 Th-230 Th-230 Th-230 Th-230 Th-230 
Th-232 Th-232 a Th-232 Th-232 Th-232 Th-232 Th-232 
U-233 U-233 U-233 U-233 U-233 U-233 U-233 
U-234 U-234 U-234 U-234 U-234 U-234 U-234 
U-235 U-235 U-235 U-235 
U-236 U-236 U-236 U-236 U-236 U-236 U-236 
U-238 U-238 U-238 U-238 U-238 U-238 U-238 
Counts 23 25 18 23 23 29 
NOTES aWas screened out under REV 00 (BSC 2001a, Table 37) for the corresponding scenario. 
6.5 UNCERTAINTIES 
The radionuclide screening analysis has been performed against a backdrop of several previous 
Yucca Mountain TSPAs and reviews by the NRC and an international peer review panel (Riotte 
2001). The results of the radionuclide screening analysis are not sensitive to uncertainties in 
input values or assumptions because the results of the screening analysis are partly known ahead 

of time (based on other TSPAs and on Revision 0 of this screening analysis). Screening out a 
radionuclide known to be important or a failure to screen out a radionuclide not previously 
suspected of being at least marginally important would be viewed skeptically. Before 
finalization of the screening analysis, an inquiry into the unexpected result would lead either to 
an explanation and confirmation of the unexpected result or to a discovery that some fault with 
the inputs or the screening method required correction. An example of this sequence of events 
happened during the scoping calculations when Np-236a was unexpectedly screened in: errors in 
the screening factors for Np-236a were discovered and corrected (Assumptions 5.2 and 5.8 and 
Attachments I and II). 
The worst-case consequence of uncertainties in the inputs or assumptions is that marginally 
important radionuclides could be inappropriately screened out. To highlight radionuclides that 
are of marginal importance, and might have made the 95 percent cut under a different set of 
assumptions (such as solubility- and sorption-class assignments; screening factors; and 
characteristics of the average and outlying waste forms), a finer screening was conducted at a 
screening-product cutoff fraction of 99 percent (Assumption 5.5). 
6.6 ADDITIONAL RADIONUCLIDES RECOMMENDED 
6.6.1 Separate Groundwater Protection Standard 
U.S. Environmental Protection Agency (EPA) regulations (40 CFR 197.30) and the separate 
groundwater protection standard in 10 CFR 63.331 set limits on: 
1. 
The combined activity of Ra-226 and Ra-228 in groundwater 
2. 
Gross alpha activity (including Ra-226 but excluding radon and uranium) 
3. 
Dose from combined beta and photon emitting radionuclides in groundwater. 
The first item requires the addition of Ra-228 to the list of radionuclides that must be included in 
the radionuclide inventory and tracked for TSPA. 
The second item is concerned only with alpha decay. The screening analysis used dose 
considerations to identify the important radionuclides, including alpha emitters. Because dose is 
the best measure of the relative importance of alpha emitters from the human perspective, the 
same screening is appropriate to identify the radionuclides to be included in a gross-alpha 
calculation. However, some of the screened-in radionuclides will be in secular equilibrium with 
short-lived daughter products that were screened out as primary contributors. To show 
compliance with the gross-alpha regulation, it will be necessary to include appropriate 
equilibrium activity contributions for the short-lived decay products. The short-lived products 
will not need to be transported in the TSPA and their equilibrium activities can be computed 
from the activities of the parents, so it is not necessary to list them here or to include them in the 
radionuclide inventory. Long-lived decay products of important radionuclides have either been 
screened in or out. If they have been screened in, their alpha activities and those of their short-
lived daughters will be counted in the gross-alpha calculation. If they have been screened out, 
they need not be considered in the gross-alpha calculation because the screening analysis showed 
them and their short-lived daughters to be unimportant. 

6.6.2 Precursors of Other Recommended Radionuclides 
Some radionuclides that are precursors of important radionuclides are not necessarily identified 
by the screening analysis as potentially important. Table 12 provides a systematic examination 
of the radionuclides screened in according to the 95 percent cutoff (Table 10 and Table 11) and 
of Ra-228, which is needed for the groundwater protection standard. The additional 
radionuclides in the last column should be accounted for in the inventory, either by direct 
inclusion, or by appropriate augmentation of the daughter product. 
Table 12. Additional Radionuclides Needed for Accurate Accounting of Those Screened In 
Nuclide 
Examined Discussion 
Additional 
Nuclides 
Ac-227 Daughter of Pa-231, which is screened in (See Table Note). 
Am-241 Cm-245Pu-241Am-241. Cm-245 has a half-life much greater than that of Am-241 
and can provide a source of Am-241. Toward the end of the regulatory period, Am-241 
is in secular equilibrium with Cm-245 (See Table Note). Also, Bk-245Am-241, but 
Bk-245 does not appear in the waste forms used for the screening analysis. 
Pu-241 
Cm-245 
Am-243 Bk-247Am-243, but Bk-247 does not appear in the waste forms used for the 
screening analysis (See Table Note). Also, Cm-247Pu-243 Am-243. Pu-243 has a 
half-life less than one year and need not be included in the inventory because it is 
merely serving as a conduit for the decay of Cm-247 to Am-243. Cm-247 has a half-life 
of more than 15 million years and therefore would provide a nearly constant source of 
Am-243 throughout the period of this analysis. However, Cm-247 does not appear in 
the waste forms used for the screening analysis except in DSNF, where its activity is a 
very small fraction of the Am-243 activity throughout the period of analysis; therefore, 
Cm-247 need not be included in the inventory. 
C-14 Activation product; not produced by the decay of anything in the waste forms used for 
the screening analysis. 
Cl-36 Activation product; not produced by the decay of anything in the waste forms used for 
the screening analysis. 
Cs-135 Fission product; not produced by the decay of anything in the waste forms used for the 
screening analysis 
Cs-137 Fission product; not produced by the decay of anything in the waste forms used for the 
screening analysis 
I-129 Fission product; not produced by the decay of anything in the waste forms used for the 
screening analysis 
Np-237 Decay product of Am-241, which is screened in. Also produced by decay of U-237, 
which is produced by a minor branch of the decay of Pu-241. U-237 has a half-life less 
than 1 year and need not be included in the initial inventory because it is merely serving 
as a conduit for the decay of Pu-241 to Np-237. Pu-241 is listed above as needed for 
the inventory. 
Pa-231 U-235Th-231Pa-231. Th-231 has a half-life less than 1 y and need not be included 
in the initial inventory because it is merely serving as a conduit for the decay of U-235 
to Pa-231. U-235 is present in the waste forms used for the screening analysis for all 
waste forms and its inventory is needed to accurately project the inventory of Pa-231, 
especially for times beyond the regulatory period. 
U-235 
Pb-210 Ra-226Pb-210 through a series of short-lived radionuclides that need not be included 
in the inventory. Ra-226 is screened in wherever Pb-210 is screened in. 

Table 12. Additional Radionuclides Needed for Accurate Accounting of Those Screened In (continued) 
Nuclide 
Examined Discussion 
Additional 
Nuclides 
Pu-238 Am-242mAm-242Cm-242Pu-238. Cm-242 and Am-242 have half-lives less than 
1 y and need not be included in the inventory because they are merely serving as a 
conduit for the decay of Am-242m to Pu-238. Also Am-242mNp-238Pu-238. 
Np-238 has a half-life of less than 1 y and need not be included in the inventory. 
Am-242m has a longer half-life than Pu-238, so could conceivably provide a source of 
Pu-238 worth tracking in TSPA. However, although Am-242m shows up in BWR, 
DSNF, HLW, and PWR waste forms, in each case, the Am-242m activity is negligible 
compared to that of Pu-238. 
Pu-239 Am-243Np-239Pu-239. Np-239 has a half-life less than 1 y and need not be 
included in the inventory. Am-243 is screened in. Also, Cm-243Pu-239. Cm-243 
appears in BWR, DSNF, HLW, and PWR waste forms, but in each case, the Cm-243 
activity is negligible compared to that of Pu-239. 
Pu-240 Cm-244Pu-240. Cm-244 has a half-life much shorter than that of Pu-240. For that 
reason, its initial activity would have to be much greater than that of Pu-240 to 
significantly affect the activity of Pu-240. This claim can be verified as follows. A 
necessary condition for the inventory of the parent radionuclide to significantly affect 
that of the daughter is that the number of atoms in initial inventory for the parent Np be 
at least comparable to that of the daughter, Nd. That is, Np @ Nd or Np > Nd. In this 
case, because the half-life of the parent is much less than that of the daughter, the 
relationship between the decay constants is lp >> ld. Given the required relationship of 
the numbers of atoms Np and Nd, the necessary condition stated in terms of activities 
(A=Nl) is Nplp >> Ndld. As it happens, the necessary condition is not met because the 
initial Cm-244 activity in the waste forms that were used for the screening analysis is 
less than the initial Pu-240 activity. Therefore, Cm-244 need not be included in the 
inventory. 
Pu-242 Cm-246Pu-242. Cm-246 has a half-life much shorter than that of Pu-242. For that 
reason, its activity would have to be much higher than that of Pu-242 to significantly 
affect the activity of Pu-242. (See the discussion for Pu-240 for a justification of this 
claim.) As it happens, the initial Cm-246 activity in the waste forms that were used for 
the screening analysis is less than the initial Pu-242 activity. Therefore, Cm-246 need 
not be included in the inventory. 
Ra-226 Decay product of Th-230, which is screened in. 
Ra-228 Decay product of Th-232, which is screened in. 
Se-79 Fission product; not produced by the decay of anything in the waste forms used for the 
screening analysis 
Sn-126 Fission product; not produced by the decay of anything in the waste forms used for the 
screening analysis 
Sr-90 Fission product; not produced by the decay of anything in the waste forms used for the 
screening analysis 
Tc-99 Fission product; not produced by the decay of anything in the waste forms used for the 
screening analysis 
Th-229 Decay product of U-233, which is screened in. 
Th-230 Decay product of U-234, which is screened in. 
Th-232 Decay product of U-236, which is screened in. 
U-232 Decay product of Pu-236, which has a half-life of about 3 y. With such a short half-life, 
by the time the waste is received at the repository, most of the Pu-236 will have 
decayed to U-232. In any case, Pu-236 has a half-life much shorter than that of U-232. 
For that reason, its activity would have to be much higher than that of U-232 to 
significantly affect the activity of U-232. (See the discussion for Pu-240 for a 
justification of this claim.) As it happens, the initial Pu-236 activity in the waste forms 
that were used for the screening analysis is less than the initial U-232 activity. 
Therefore, Pu-236 need not be included in the inventory. 

Table 12. Additional Radionuclides Needed for Accurate Accounting of Those Screened In (continued) 
Nuclide 
Examined Discussion 
Additional 
Nuclides 
U-233 Np-237Pa-233U-233. Np-237 is screened in. Pa-233 has a half-life less than 1 y 
and need not be included in the inventory. 
U-234 U-238Th-234Pa-234U-234. U-238 is screened in. Pa-234 and Th-234 have 
half-lives less than 1 y and need not be included in the inventory. 
U-236 Decay product of Pu-240, which is screened in. 
U-238 Decay product of Pu-242, which is screened in. 
NOTE: See Parrington et al. (1996) for decay relationships. See Table 2 for half-lives. See Attachment VI for 
activities in the waste forms used in the screening analysis. 
6.7 RESPONSES TO COMMENTS FROM EXTERNAL REVIEWS 
6.7.1 Nuclear Regulatory Commission 
As has been mentioned above (Section 6.1), the NRC provided a constructive critique of the 
previous revision of the radionuclide screening analysis (Beckman 2001, Section 5.3.2.1). 
Partial responses to the NRCs comments are scattered throughout the present analysis. The 
NRC comments are stated more fully here, and responses are provided. 
Comment: First, the product of the inventory and the inhalation and ingestion DCFs for the 
radionuclide are not directly related to the risk that the radionuclide poses to the critical group, 
even when the solubility and transport properties in the geosphere of the radionuclide are 
accounted for. Processes that affect transport in the biosphere, such as uptake by plants and 
bioaccumulation, are not accounted for using this methodology. Also, the direct exposure 
pathway is not accounted for by this approach. Thus, radionuclides for which ground shine 
constitutes a significant exposure pathway, such as Nb-94 and Sn-126, could be inappropriately 
screened using this methodology. 
Response: The use of the adjusted NCRP screening factors (Assumptions 5.2 and 5.8) answers 
this concern by accounting for the effects of the biosphere (including uptake by plants, 
bioaccumulation, and direct exposure). Furthermore, the relative contribution of each biosphere 
pathway is appropriately weighted by project-generated usage factors (Section 4.1.1, 
Assumptions 5.2 and 5.8). 
Note that, consistent with NRCs observation above, Sn-126 is screened in after the regulatory 
period for the groundwater and igneous eruptive scenarios (Table 11). Despite inclusion of the 
direct exposure pathway in this screening analysis, Nb-94 is screened out for all scenarios and 
time periods; however, Nb-94 is of marginal significance for the groundwater scenario after the 
regulatory period (Table 10 and Table 11). An examination of Table 9 will confirm that Nb and 
Sn appear in only one groundwater screening set owing to their high sorptivity and low 
solubility. Thus, the only way for Sn-126 and Nb-94 to be screened in is to prevail in 
competition with all other radionuclides. 
Comment: Second, the grouping of radionuclides based on solubility and transport properties 
appears to be too broad. Dividing the radionuclides into only two groups of solubility classes 

and three groups of transport classes can lead to the grouping of radionuclides that do not really 
behave similarly under repository conditions and the masking of potentially important 
radionuclides. For example, Se-79, which has been screened from the analysis, is grouped in the 
soluble and moderately sorbing transport group. This group also contains elements such as Np 
and U, which have significantly larger DCFs [dose conversion factors] than Se. However, Se is 
more soluble than Np and U by several orders of magnitude and also is transported much more 
quickly than Np and U. Thus, Se could pose a much greater risk to the critical group than Np or 
U, especially at early times, but be screened from the analysis. 
Response: The revised analysis reevaluates and revises the solubility and sorption 
classifications, using project studies for corroboration wherever possible, and introduces an 
intermediate solubility class (Assumptions 5.6 and 5.7, Sections 6.2.4 and 6.2.5). One effect of 
the revised groundwater transport classifications is that Se is in the high solubility class, while U 
and Np are in the intermediate solubility class (Table 4). Although Se is now classed separately 
from U and Np, Se-79 is screened out during the regulatory period (Table 10). Selenium-79 
becomes potentially important after the regulatory period for the groundwater scenarios (Table 
11). 
Comment: Also, there does not seem to be any proposed methodology to investigate the effect 
of certain radionuclides such as Se-79 that have been identified in previous DOE and NRC 
TSPAs as important but have not been identified as important using the proposed methodology. 
Response: An investigation of the potential effects of screened-out radionuclides is beyond the 
scope of the radionuclide screening analysis. However, it is hoped that the improved methods 
introduced in this revision will allay concerns that radionuclides of more than marginal 
importance could have been improperly screened out. For further discussion on this topic, see 
the response to the first comment in Section 6.7.2. As an aside with respect to Se-79 (the 
radionuclide used as an example in the comment), some of the earlier studies used an 
erroneously low half-life, which then led to overstatement of the Se-79 activity during the 
regulatory period (Assumption 5.3, Attachment IV). The present screening analysis corrects for 
the erroneous Se-79 half-life that was used in the activity calculations (Section 6.2.3). 
Comment: Finally, the inventory abstraction AMR does not indicate how radionuclides not 
considered important to performance in themselves, but that generate daughter products 
important to performance, will be accounted for. 
Response: Significant sources of the potentially important radionuclides that were identified by 
the screening analysis are listed in Table 12. For further discussion on a related topic, see the 
response to the second comment in Section 6.7.2. 
6.7.2 International Peer Review Panel 
In the summer of 2001, an international panel reviewed site recommendation documents at the 
request of the DOE. The panel was jointly organized by the Nuclear Energy Agency of the 
Organization for Economic Cooperation and Development, and the International Atomic Energy 
Agency of the United Nations. The final report (OECD 2002, Section 3.3) provides comments 
on the radionuclide screening that was performed for site recommendation. 

Comment: The [international review team] notes that some radionuclides (such as Cl-36 and 
Cs-135) that feature as important in other international studies [OECD 1997] were screened out 
after the TSPA-1995.  For instance, Cl-36 has been screened out because it is not a fission 
product. However, it is produced by neutron activation of contaminating Cl in the fuel. It has 
been shown to be an important contributor to dose in, for instance, the Canadian program 
(Johnson et al. 1995). 
Response: A study that was cited by the international review team (OECD 1997, Section 2.11) 
identifies the radionuclides that contributed most to dose rate in the reference cases of ten 
repository performance assessment studies. The ten studies vary with respect to waste form, 
geologic media, repository concept, and purpose of the assessment, so there is no reason to 
expect precisely the same radionuclides to be important for every study. Nevertheless, there are 
many similarities in influential variables such as initial waste inventories, geological processes, 
and characteristics of the biosphere, which make it useful to compare the results of the ten 
studies with the results of the present screening. For comparisons of results, take the screening 
for the groundwater scenarios as the reference case for the present screening. Of the 20 
radionuclides collectively identified by the ten studies, 13 were screened in for groundwater 
scenarios during the 10,000-y regulatory period: Ac-227, Am-243, C-14, Cs-135, I-129, Np-237, 
Pa-231, Pu-239, Pu-240, Ra-226, Tc-99, Th-229, U-233. Four more were screened in for times 
up to 1 million years: Cl-36, Pu-242, Se-79, and U-236. The two radionuclides that were 
specifically mentioned in the comment (Cs-135 and Cl-36) are discussed below. The three 
radionuclides that were identified as important by one or more of the ten studies but screened out 
by the present analysis (Nb-94, Pd-107, and Ra-223) are also discussed below. 
In the revised screening, Cs-135 is screened in for the groundwater scenarios and screened out 
for the eruptive scenario (Table 10 and Table 11). The fine-screen test (based on the 99 percent 
screening-product cutoff) does not identify Cs-135 as even marginally important in the eruptive 
scenario. 
For the Canadian repository concept, Johnson et al. (1995, Abstract) found that the estimated 
radiological risks from Cl-36 are forty times lower than from I-129 at [10,000 y]. Consistent 
with that observation, Cl-36 is screened out by the present screening, except for the groundwater 
scenarios in the period beyond 10,000 y. However, the fine-screen test indicates that Cl-36 is 
potentially of marginal importance in the groundwater scenarios during the 10,000-y regulatory 
period (Table 10). In the activity calculations that feed the present and previous revisions of the 
screening analysis, Cl-36 appears in commercial fuel as an activation product due to a 5.3-ppm 
Cl impurity in the fuel (CRWMS M&O 1999a, Table 14; CRWMS M&O 1999b, Table 4). 
Only one of the ten studies found Nb-94 to be a major contributor to dose. This apparent lack of 
importance is consistent with its insignificance as a fission product (Parrington et al. 1996), its 
consequently limited inventory as a neutron-activation product of the niobium present in 
zirconium based cladding, and niobiums tendency to exhibit low solubility and high sorptivity 
(Table 4). In the present screening analysis, Nb-94 is screened out for all scenarios and times 
(Table 10 and Table 11). However, Nb-94 is found to be potentially of marginal importance for 
the groundwater scenarios after the regulatory period. 

One of the ten studies found Pd-107 and Ra-223 to be important contributors to dose. 
Palladium-107 is a low-yield fission product (Parrington et al. 1996) with a relatively low 
groundwater screening factor (Table I-2). In the present screening analysis, Pd-107 is screened 
out for all scenarios and times, and is not identified as marginally important by the fine-screen 
test. Radium-223 has a half-life less than 10 y (Table 2), so it is accounted for in the 
groundwater scenarios only as a decay daughter (Assumption 5.9) from parents such as Ac-227 
(Parrington et al. 1996). Thus, the logic of the screening process for the groundwater scenarios 
makes it impossible to screen in Ra-223. The selection of radionuclides in the eruptive scenario 
is not restricted by half-life; nevertheless, Ra-223 was screened out at all times for the eruptive 
scenario and was not identified as marginally important by the fine-screen test. 
Although Cm-245, Cm-246, and Ni-59 were not mentioned in the NRC or international reviews, 
the NRC included them in its iterative performance assessment (Table 6). None of the ten 
studies under discussion (OECD 1997, Table 2), which include the NRCs iterative performance 
assessment, found Cm-245, Cm-246, or Ni-59 to be important contributors to dose, as can be 
seen from the listing earlier in this response. 
Comment: Furthermore, it is noted that the biosphere dose conversion factors used in screening 
out radionuclides did not properly account for short-lived daughters of long-lived parents when 
determining whether to screen out the parent. 
Response: For the groundwater screening, direct contributions from radionuclides with half-
lives less than 10 y are not included (Assumption 5.9). However, the adjusted NCRP screening 
factors allow for radioactive in-growth during a 30-y period of radionuclide accumulation in the 
soil. For the eruptive screening, direct contributions from all radionuclides are accounted for 
regardless of longevity, and indirect contributions due to in-growth are accounted for by a 30-y 
soil accumulation period. Thus, the revised screening avoids the possibility that a radionuclide 
could be screened out because its short-lived decay products had not been accounted for, as was 
possible under the previous revision. 
For a response to a related comment, see the response to the final NRC comment above. 

7. CONCLUSIONS
The radionuclide screening analysis separately considers two different postclosure time periods: 
the 10,000-y regulatory period for the proposed repository at Yucca Mountain and the period up 
to 1 million y after emplacement. The incremental effect of extending the screening for the 
regulatory period to 20,000 y is also addressed. Four release scenarios are considered: (1) the 
nominal scenario, (2) the human-intrusion scenario, (3) an intrusive igneous event, and (4) an 
eruptive igneous event. The screening analysis considers spent boiling water reactor fuel, spent 
pressurized water reactor fuel, U.S. Department of Energy spent nuclear fuel, and high-level 
radioactive waste. Average and outlying (that is, high burnup, high initial enrichment, low age, 
or otherwise exceptional) forms of each waste-form type are considered. The screening factors 
used for the analysis account for the influence of the biosphere and are consistent with the 
characteristics of the receptor based on the local population. 
The screening analysis has shown that the radionuclides listed in Table 13 may substantially 
affect repository performance for the exposure scenarios and times listed. These radionuclides 
should be considered in total system performance assessment modeling for license application. 
Extending the screening for the regulatory period to include the 20,000-y screening time does not 
add any radionuclides to the lists for regulatory period as presented in Table 10. While the 
purpose of the analysis is to identify all of the radionuclides of major importance to dose and 
virtually all of the marginally important radionuclides, it is recognized that some radionuclides 
that could contribute a marginally significant fraction of the dose in unlikely circumstances 
might have been screened out. For this reason, a fine-screen test was conducted (Table 10, Table 
11). See Section 6.5 for a discussion of the effect of uncertainties on the results of the screening 
analysis. 
In addition to the radionuclides identified by the screening analysis, four other radionuclides 
(Pu-241, Cm-245, Ra-228, and U-235) should be included in the radionuclide inventory, either 
by direct inclusion, or by appropriate augmentation of the daughter product, as discussed in 
Section 6.6. 

Table 13. Results of the Screening Analysis 
Radionuclide 
Nominal, Human-Intrusion, and 
Intrusive Igneous Scenarios Eruptive Igneous Scenario 
102 to 2  104 
years 
2  104 to 106 
years 
102 to 2  104 
years 
2  104 to 106 
years 
Ac-227 Ac-227 Ac-227 Ac-227 Ac-227 
Am-241 Am-241 Am-241 
Am-243 Am-243 Am-243 Am-243 Am-243 
C-14 C-14 C-14 
Cl-36 Cl-36 
Cs-135 Cs-135 Cs-135 
Cs-137 Cs-137 Cs-137 
I-129 I-129 I-129 
Np-237 Np-237 Np-237 Np-237 
Pa-231 Pa-231 Pa-231 Pa-231 
Pb-210 Pb-210 Pb-210 
Pu-238 Pu-238 Pu-238 
Pu-239 Pu-239 Pu-239 Pu-239 Pu-239 
Pu-240 Pu-240 Pu-240 Pu-240 Pu-240 
Pu-242 Pu-242 Pu-242 
Ra-226 Ra-226 Ra-226 Ra-226 
Se-79 Se-79 
Sn-126 Sn-126 Sn-126 
Sr-90 Sr-90 Sr-90 
Tc-99 Tc-99 Tc-99 Tc-99 
Th-229 Th-229 Th-229 Th-229 Th-229 
Th-230 Th-230 Th-230 
Th-232 Th-232 Th-232 
U-232 U-232 U-232 
U-233 U-233 U-233 U-233 U-233 
U-234 U-234 U-234 U-234 U-234 
U-236 U-236 U-236 
U-238 U-238 U-238 U-238 
Counts 20 23 12 18 
NOTES: Extending the screening for the regulatory period to include the 20,000-y 
screening time does not add any radionuclides to the screening lists for 
regulatory period (see Section 6.3.2). 
See Section 6.6 for a discussion of additional radionuclides that should 
be included in the radionuclide inventory: Pu-241, Cm-245, Ra-228, and 
U-235. 

8. INPUTS AND REFERENCES
8.1 DOCUMENTS CITED 
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01. Las Vegas, Nevada: CRWMS M&O. ACC: MOL.19980422.0911. 
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Through the Engineered Barrier System." Chapter 6 of Total System Performance Assessment-
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CRWMS M&O 1999a. BWR Source Term Generation and Evaluation. BBAC00000-01717-
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Vegas, Nevada: CRWMS M&O. ACC: MOL.20001130.0002. 
CRWMS M&O 2000b. Radionuclide Inventories for DOE SNF Waste Stream and 
Uranium/Thorium Carbide Fuels. CAL-MGR-NU-000003 REV 00. Las Vegas, Nevada: 
CRWMS M&O. ACC: MOL.20000412.0764. 
CRWMS M&O 2000c. Source Terms for HLW Glass Canisters. CAL-MGR-NU-000002 REV 
01. Las Vegas, Nevada: CRWMS M&O. ACC: MOL.20000823.0004. 
CRWMS M&O 2000d. Summary of Dissolved Concentration Limits. ANL-WIS-MD-000010 
REV 00. Las Vegas, Nevada: CRWMS M&O. ACC: MOL.20000525.0372. 
CRWMS M&O 2000e. Total System Performance Assessment for the Site Recommendation. 
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MOL.20001220.0045. 
CRWMS M&O 2001a. Disruptive Event Biosphere Dose Conversion Factor Analysis. 
ANL-MGR-MD-000003 REV 01. Las Vegas, Nevada: CRWMS M&O. ACC: 
MOL.20010125.0233. 
CRWMS M&O 2001b. Environmental Transport Parameter Analysis. ANL-MGR-MD-000007 
REV 00 ICN 01. Las Vegas, Nevada: CRWMS M&O. ACC: MOL.20010208.0001. 
CRWMS M&O 2001c. Nominal Performance Biosphere Dose Conversion Factor Analysis. 
ANL-MGR-MD-000009 REV 01. Las Vegas, Nevada: CRWMS M&O. ACC: 
MOL.20010123.0123. 
CRWMS M&O 2001d. Pure Phase Solubility Limits - LANL. ANL-EBS-MD-000017 REV 00 
ICN 01. Las Vegas, Nevada: CRWMS M&O. ACC: MOL.20010126.0005. 

CRWMS M&O 2001e. Unsaturated Zone and Saturated Zone Transport Properties (U0100). 
ANL-NBS-HS-000019 REV 00 ICN 1. Las Vegas, Nevada: CRWMS M&O. ACC: 
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Viability Assessment of a Repository at Yucca Mountain. DOE/RW-0508. Washington, D.C.: 
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Soil, Exposure-to-Dose Coefficients for General Application, Based on the 1987 Federal 
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Ingestion. EPA 520/1-88-020. Federal Guidance Report No. 11. Washington, D.C.: U.S. 
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Publications. TIC: 252385. 
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(DOE/OCRWM), November 2, 2001, with enclosure. ACC: MOL.20011113.0240. 
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Shilin, L. 1997. "Determination of the Half-Life of 79Se with the Accelerator Mass Spectrometry 
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Wilson, M.L.; Gauthier, J.H.; Barnard, R.W.; Barr, G.E.; Dockery, H.A.; Dunn, E.; Eaton, R.R.; 
Guerin, D.C.; Lu, N.; Martinez, M.J.; Nilson, R.; Rautman, C.A.; Robey, T.H.; Ross, B.; Ryder, 
E.E.; Schenker, A.R.; Shannon, S.A.; Skinner, L.H.; Halsey, W.G.; Gansemer, J.D.; Lewis, L.C.; 
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Summary and two volumes. Albuquerque, New Mexico: Sandia National Laboratories. ACC: 
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8.2 CODES, STANDARDS, REGULATIONS, AND PROCEDURES 
10 CFR 63. 2002. Energy: Disposal of High-Level Radioactive Wastes in a Proposed Geologic 
Repository at Yucca Mountain, Nevada. Readily available. 
40 CFR 197. 2001. Protection of Environment: Public Health and Environmental Radiation 
Protection Standards for Yucca Mountain, Nevada. Readily available. 
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and Regulatory Compliance Activities. [Washington, D.C.]: U.S. Department of Energy, Office 
of Civilian Radioactive Waste Management. ACC: MOL.20010212.0018. 
AP-3.15Q, Rev. 1, ICN 2. Managing Technical Product Inputs. Washington, D.C.: U.S. 
Department of Energy, Office of Civilian Radioactive Waste Management. ACC: 
MOL.20020423.0155. 
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Energy, Office of Civilian Radioactive Waste Management. ACC: MOL.20020212.0254. 
AP-SI.1Q, Rev. 3, ICN 4. Software Management. Washington, D.C.: U.S. Department of 
Energy. ACC: MOL.20020520.0283. 
AP-SIII.9Q, Rev. 0, ICN 1. Scientific Analyses Washington, D.C.: U.S. Department of Energy, 
Office of Civilian Radioactive Waste Management. ACC: MOL.20020404.0083. 
8.3 SOURCE DATA, LISTED BY DATA TRACKING NUMBER 
MO0006J13WTRCM.000. Recommended Mean Values of Major Constituents in J-13 Well 
Water. Submittal date: 06/07/2000. 
MO0007SPADMM05.002. Distributions, Mean, Minimum, and Maximum Consumption Levels 
of Locally Produced Food by Type and Tap Water for the Amargosa Valley Receptor of Interest. 
Submittal date: 07/31/2000. 
MO0010SPAAAM01.014. Input Parameter Values for External and Inhalation Radiation 
Exposure Analysis. Submittal date: 10/02/2000. 
MO0010SPAPET07.004. Environmental Transport Parameters. Submittal date: 10/03/2000. 

SCREENING FACTORS FOR GROUNDWATER SCENARIOS 
(8 pages) 
DEVELOPMENT OF GROUNDWATER SCREENING FACTORS 
As stated in Assumption 5.8, freshwater screening factors for various pathways from NCRP 
Report 123 are used as the basis of screening factors in the screening analysis. The usage factors 
that are built in to the NCRP screening factors, that is, the assumed times spent in various 
activities such as gardening and bathing or the quantities of water or food products consumed, 
are not necessarily appropriate for local conditions. The NCRP screening factors are adjusted 
here by replacing the generic usage factors (NCRP 1996, Table 7.1) with usage factors 
developed in project documents (Section 4.1.1). The following sections describe the 
development of adjustment factors (Table I-1) for each additive component from the NCRP 
report (NCRP 1996, Table C.1). The adjusted total screening factor (Table I-2) is the sum of the 
products of the components and their adjustment factors. Table I-2 provides a complete list of 
the radionuclides considered in the screening calculation along with the corresponding 
groundwater screening factors. 
Table I-1. Adjustment Factors for Groundwater and Eruptive Scenarios 
Pathway Description Applicable Scenarios Adjustment Factor 
Gardening and shoreline activities Groundwater 0.23 
Consumption of drinking water Groundwater 0.94 
Consumption of fish Groundwater 0.024 
Consumption of vegetables Groundwater & Eruptive 0.2 
Consumption of milk Groundwater & Eruptive 0.014 
Consumption of meat Groundwater & Eruptive 0.1 
Inadvertent ingestion of soil Groundwater & Eruptive 0.05 
Inhalation Eruptive 0.73 
Contaminated ground Eruptive 0.42 
Swimming and boating 
The agricultural community in Amargosa Valley, which serves as the model for the receptor, 
does not have many opportunities to engage in swimming and boating. Swimming and boating 
are not considered in the development of biosphere dose conversion factors (CRWMS M&O 
2001c, Section 6.3.1, Table 8), so they are not considered in this screening analysis. In effect, 
the adjustment factor for swimming and boating is zero. 

The screening factor for gardening and shoreline activities is calculated in the NCRP report in 
accordance with its Equations 8.11 and 8.12 (NCRP 1996). These two contributions are reported 
together in Table C.1 (NCRP 1996), so it is necessary to treat them together here. The nuclide-
independent adjustment is performed as follows. 
F S = F adj(SF shore + SF irrad soil, )
S& G 
N Eq. I-1 
U F  ir so
s 
= ( sh F W + U F  
)[(U F sh F W + U F ) BC (li , t b)DF , Dir iF , d i ]
U F sh F W + U F s ir so 
i =1
s ir so 
The adjustment factor is the initial multiplier in Eq. I-1. Multiplication by the adjustment factor 
replaces the usage factors in the NCRP report (NCRP 1996, Table 7.1) with the projects 
identified by the prime symbol. NCRP usage factors are as follows U sh = 2000 h/y is the time 
spent annually on the shoreline; U so = 500 h/y is the time spent annually in irrigated fields or 
gardens (NCRP 1996, Table 7.1). Best estimates of the corresponding quantities from project 
documents are as follows: U sh = 0 h/y, U so = 3387 h/y (Section 4.1.1). The other quantities 
needed to calculate the adjustment factor are the shoreline deposition velocity F s = 0.07 m/d 
(NCRP 1996, p. 69), the shoreline width factor, F W = 0.02 (NCRP 1996, p. 70), and the irrigation 
deposition velocity F ir = 0.002 m/d (NCRP 1996, Table 5.1). The definitions of the other 
symbols in Eq. I-1 are not needed for the development here, but may be found in the NCRP 
report (NCRP 1996, Section 8.2). Plugging in the NCRP and project values yields a value for 
the adjustment factor for garden and shoreline activities as follows. 
sh F W + U F 
U F  ir so
s 
=
F 
adj 
U F sh F W + U F 
s ir so 
(2.0)( h/y 0)( m/d 07.0 )+ (h/y 3387)( m/d 002.0 ) 
Eq. I-2 
= 
(2.0 )( h/y 2000 )( m/d 07.0 )+ (h/y 500)( m/d 002.0 )
= 23.0
Consumption of drinking water 
The screening factor for drinking water is a simple multiple of the usage factor for consumption 
of drinking water (NCRP 1996, Equation 8.13). Therefore, the adjustment factor is simply the 
ratio of project-generated to generic usage factors. The project-generated best estimate of the 
usage factor is 752.85 L/y (Section 4.1.1), while the generic value is 800 L/y (NCRP 1996, 
Table 7.1). Thus, almost no adjustment is indicated for drinking water. The adjustment factor 
for drinking water is 752.85 / 800 = 0.94. 
Consumption of fish 
The screening factor for fish consumption is a simple multiple of the usage factor for 
consumption of locally raised fish (NCRP 1996, Equation 8.14). Therefore, the adjustment 
factor is simply the ratio of project-generated to generic usage factors. The project-generated 

Consumption of vegetables 
The screening factor for vegetable consumption is a simple multiple of the usage factor for 
consumption of locally grown vegetables (NCRP 1996, Equations 8.15 and 8.16). Therefore, the 
adjustment factor is simply the ratio of project-generated to generic usage factors. The project-
generated best estimate of the usage factor (including leafy and root vegetables, fruit, and grain) 
is 39 kg/y (Section 4.1.1), while the generic value is 200 kg/y (NCRP 1996, Table 7.1). The 
adjustment factor for vegetable consumption is 39 / 200 = 0.20. 
Consumption of milk 
The screening factor for milk consumption is a simple multiple of the usage factor for 
consumption of locally produced milk (NCRP 1996, Equations 8.15 and 8.17). Therefore, the 
adjustment factor is simply the ratio of project-generated to generic usage factors. The project-
generated best estimate of the usage factor is 4.14 kg/y (Section 4.1.1), while the generic value is 
300 L/y or 300 kg/y (with the density of milk approximately equal to that of water, 1 kg/L) 
(NCRP 1996, Table 7.1). The adjustment factor for milk consumption is 4.14 / 300 = 0.014. 
Consumption of meat 
The screening factor for meat consumption is a simple multiple of the usage factor for 
consumption of locally produced meat (NCRP 1996, Equations 8.15 and 8.18). Therefore, the 
adjustment factor is simply the ratio of project-generated to generic usage factors. The project-
generated best estimate of the usage factor (including beef, poultry, and eggs) is 10.41 kg/y 
(Section 4.1.1), while the generic value is 100 kg/y (NCRP 1996, Table 7.1). The adjustment 
factor for meat consumption is 10.41 / 100 = 0.10. 
Inadvertent ingestion of soil 
The screening factor for soil ingestion is a simple multiple of the usage factor for ingestion of 
soil (NCRP 1996, Equations 8.6a and 8.6c). Therefore, the adjustment factor is simply the ratio 
of two usage factors. The best estimate of the usage factor from project documentation is 
50 mg/d (Section 4.1.1), while the NCRPs generic value is 0.365 kg/y (NCRP 1996, Table 7.1). 
Although the projects best estimate is actually a generic value based on a recommendation by 
the EPA, it has been found appropriate to characterize the soil ingestion rate for the projects 
biosphere dose conversion factor calculations (CRWMS M&O 2001b, Section 6.5). The 
adjustment factor for soil ingestion is (50 mg/d)(1 kg/106 mg)(365 d/y) / 0.365 kg/y = 0.05. 
CORRECTING THE GROUND-EXPOSURE COMPONENT FOR Np-236a 
As noted in Assumption 5.8, the value of the freshwater screening factor for Np-236a from the 
NCRP report is erroneously high. Scoping calculations using the value 1.4  10-2 
(Sv/y) / (Bq/m3) failed to screen out Np-236a although only miniscule activities appeared in the 
waste form. Evidently, the error can be traced to an erroneously high effective dose factor for 

ground irradiation: 1.19  10-6 (Sv/y) / (Bq/m3). The source cited by the NCRP report (Kocher 
1983, Table 3) gives a value of 4.35  10-5 (Sv/y) / (Bq/m3) / (365.25 d/y) / (1002 cm2/m2) = 
1.19  10-11 (Sv/d)/(Bq/m2), which is a factor of 105 lower than the value given in the NCRP 
report (1996, Table A.1). 
The dose coefficient from contaminated ground influences the freshwater screening factor by 
two avenues: the dose contributions from direct exposure to garden soil and to shoreline deposits 
(NCRP 1996, Equations 8.11 and 8.12). The two contributions are combined into a single value 
for garden soil and shoreline deposits (G&S) (NCRP 1996, p. 138). Because the dose coefficient 
is a simple multiplier for each radionuclide, the corrected value for the G&S component is a 
factor of 105 less than the value provided in the NCRP report (1996, Table C.1): 1.4  10-2 / 105 
= 1.4  10-7 (Sv/y) / (Bq/m3). 
Table I-2. Calculation of Groundwater Screening Factors 
Nuclide 
Garden & 
Shoreline Water Fish Vegetable Milk Meat Soil 
AdjustedTotal 
Ac-225 8.8E-10 3.0E-08 2.8E-09 1.5E-08 1.2E-11 2.2E-11 3.7E-11 3.1E-08 
Ac-227 1.1E-06 1.8E-06 6.7E-07 2.3E-06 1.2E-08 6.0E-09 1.0E-06 2.5E-06 
Ac-228 3.9E-10 3.4E-10 3.6E-12 4.1E-11 4.3E-12 5.9E-13 3.5E-12 4.2E-10 
Ag-108 3.7E-15 0.0E+00 0.0E+00 0.0E+00 0.0E+00 0.0E+00 0.0E+00 8.5E-16 
Ag-108m 1.3E-06 1.6E-09 4.1E-10 2.1E-09 4.5E-09 5.7E-10 1.2E-09 3.0E-07 
Ag-109m 5.2E-16 0.0E+00 0.0E+00 0.0E+00 0.0E+00 0.0E+00 0.0E+00 1.2E-16 
Ag-110 1.1E-15 0.0E+00 0.0E+00 0.0E+00 0.0E+00 0.0E+00 0.0E+00 2.5E-16 
Ag-110m 8.5E-08 2.3E-09 5.2E-10 2.6E-09 5.6E-09 6.9E-10 6.8E-11 2.2E-08 
Am-241 2.4E-07 4.6E-07 3.5E-07 5.6E-07 4.3E-10 2.7E-09 3.6E-07 6.3E-07 
Am-242 1.6E-11 3.0E-10 5.7E-12 7.3E-11 4.8E-14 1.2E-13 6.1E-12 3.0E-10 
Am-242m 1.7E-07 4.4E-07 3.3E-07 5.4E-07 4.1E-10 2.6E-09 3.6E-07 5.9E-07 
Am-243 7.1E-07 4.6E-07 3.4E-07 5.6E-07 4.3E-10 2.7E-09 3.6E-07 7.3E-07 
Ar-39 0.0E+00 0.0E+00 0.0E+00 0.0E+00 0.0E+00 0.0E+00 0.0E+00 0.0E+00 
At-217 9.2E-18 1.1E-15 1.8E-18 8.5E-21 1.6E-23 9.0E-35 8.2E-21 1.0E-15 
Ba-133 1.6E-07 7.6E-10 7.5E-11 9.8E-10 1.7E-10 1.7E-11 2.8E-10 3.8E-08 
Ba-137m 1.4E-13 0.0E+00 0.0E+00 0.0E+00 0.0E+00 0.0E+00 0.0E+00 3.2E-14 
Bi-210 5.5E-14 1.6E-09 1.2E-10 5.4E-09 7.9E-10 1.9E-09 1.0E-10 2.8E-09 
Bi-211 1.0E-14 0.0E+00 0.0E+00 0.0E+00 0.0E+00 0.0E+00 0.0E+00 2.3E-15 
Bi-212 6.7E-12 1.3E-10 6.5E-14 4.6E-20 1.5E-26 0.0E+00 8.9E-16 1.2E-10 
Bi-213 7.8E-13 9.2E-11 1.5E-13 7.2E-16 1.4E-18 7.6E-30 6.9E-16 8.7E-11 
Bi-214 2.4E-12 3.1E-11 5.7E-12 1.7E-12 1.9E-13 2.5E-13 7.2E-13 3.0E-11 
Bk-249 6.8E-09 1.5E-09 8.6E-10 1.8E-09 1.4E-12 4.2E-12 1.1E-09 3.4E-09 
C-14 0.0E+00 4.5E-10 5.6E-07 0.0E+00 0.0E+00 0.0E+00 0.0E+00 1.4E-08 
Ca-41 1.7E-11 2.1E-10 5.3E-09 2.5E-09 1.9E-09 3.1E-10 1.7E-10 8.9E-10 
Ca-45 4.5E-18 6.8E-10 1.4E-08 9.4E-10 9.3E-10 1.5E-10 1.3E-11 1.2E-09 
Cd-109 5.5E-11 1.8E-09 8.3E-09 3.4E-09 1.6E-09 1.9E-10 9.7E-11 2.6E-09 
Cd-113 0.0E+00 2.0E-08 9.9E-08 2.3E-07 3.6E-08 4.5E-09 1.6E-08 6.9E-08 
Cd-113m 0.0E+00 1.9E-08 9.3E-08 1.3E-07 2.5E-08 3.2E-09 7.8E-09 4.7E-08 
Ce-139 3.1E-08 2.9E-10 1.8E-10 3.2E-10 3.4E-12 5.6E-13 4.8E-12 7.5E-09 
Ce-142 0.0E+00 0.0E+00 0.0E+00 0.0E+00 0.0E+00 0.0E+00 0.0E+00 0.0E+00 

Table I-2. Calculation of Groundwater Screening Factors (continued) 
Nuclide 
Garden & 
Shoreline Water Fish Vegetable Milk Meat Soil 
AdjustedTotal 
Ce-144 1.9E-08 6.6E-09 4.4E-09 7.5E-09 7.9E-11 1.3E-11 2.2E-10 1.2E-08 
Cf-249 2.9E-06 5.6E-07 3.5E-07 6.8E-07 5.2E-10 3.9E-09 4.3E-07 1.4E-06 
Cf-250 3.0E-09 2.6E-07 1.6E-07 3.1E-07 2.2E-10 1.7E-09 1.0E-07 3.2E-07 
Cf-251 1.1E-06 5.7E-07 3.6E-07 7.0E-07 5.3E-10 4.0E-09 4.4E-07 9.6E-07 
Cf-252 7.5E-10 1.4E-07 8.4E-08 1.6E-07 1.2E-10 8.7E-10 1.5E-08 1.7E-07 
Cl-36 3.9E-15 6.7E-10 1.7E-08 2.8E-07 6.8E-07 3.4E-07 5.3E-10 1.0E-07 
Cm-242 2.2E-10 1.8E-08 1.2E-08 2.1E-08 1.5E-11 3.9E-11 1.8E-09 2.2E-08 
Cm-243 9.0E-07 3.2E-07 2.4E-07 3.9E-07 2.9E-10 7.3E-10 1.8E-07 6.0E-07 
Cm-244 4.2E-09 2.6E-07 1.9E-07 3.1E-07 2.3E-10 5.8E-10 1.3E-07 3.2E-07 
Cm-245 7.2E-07 4.7E-07 3.6E-07 5.8E-07 4.4E-10 1.1E-09 3.8E-07 7.5E-07 
Cm-246 6.1E-09 4.7E-07 3.5E-07 5.7E-07 4.4E-10 1.1E-09 3.7E-07 5.8E-07 
Cm-247 3.1E-06 4.3E-07 3.3E-07 5.3E-07 4.0E-10 1.0E-09 3.4E-07 1.2E-06 
Cm-248 5.0E-09 1.7E-06 1.3E-06 2.1E-06 1.6E-09 4.0E-09 1.4E-06 2.1E-06 
Co-58 8.9E-09 7.9E-10 4.1E-09 8.1E-10 5.9E-10 2.1E-09 6.7E-12 3.3E-09 
Co-60 5.2E-07 5.7E-09 4.2E-08 9.3E-09 7.7E-09 2.9E-08 1.2E-09 1.3E-07 
Cs-134 1.5E-07 1.6E-08 7.5E-07 2.6E-08 7.2E-08 9.1E-08 1.4E-09 8.3E-08 
Cs-135 0.0E+00 1.5E-09 7.7E-08 8.3E-09 1.4E-08 1.8E-08 1.2E-09 7.0E-09 
Cs-137 3.5E-07 1.1E-08 5.4E-07 4.6E-08 8.5E-08 1.1E-07 6.2E-09 1.3E-07 
Eu-150 9.9E-07 1.4E-09 1.7E-09 1.7E-09 3.7E-11 3.1E-10 8.2E-10 2.3E-07 
Eu-152 4.9E-07 1.5E-09 1.9E-09 1.9E-09 4.0E-11 3.4E-10 6.3E-10 1.1E-07 
Eu-154 4.1E-07 2.4E-09 3.0E-09 2.9E-09 6.2E-11 5.2E-10 7.6E-10 9.7E-08 
Eu-155 1.5E-08 4.0E-10 4.9E-10 4.8E-10 1.0E-11 8.6E-11 8.1E-11 3.9E-09 
Fe-55 2.6E-10 1.2E-10 5.9E-10 1.4E-10 1.5E-11 3.8E-10 1.4E-11 2.5E-10 
Fr-221 2.3E-13 1.1E-11 1.4E-14 7.6E-17 1.3E-19 7.0E-31 7.3E-17 1.0E-11 
Fr-223 2.7E-12 8.0E-10 2.9E-11 7.3E-11 2.8E-11 5.2E-12 1.9E-13 7.7E-10 
Gd-152 0.0E+00 2.1E-08 1.6E-08 2.6E-08 5.8E-10 4.9E-09 1.7E-08 2.7E-08 
Gd-153 3.9E-09 3.1E-10 2.1E-10 3.6E-10 7.6E-12 6.3E-11 9.0E-12 1.3E-09 
H-3 0.0E+00 1.4E-11 3.4E-13 0.0E+00 0.0E+00 0.0E+00 0.0E+00 1.3E-11 
Ho-166m 1.4E-06 1.8E-09 5.3E-07 2.2E-09 4.9E-11 4.1E-10 1.4E-09 3.4E-07 
I-129 1.8E-09 9.9E-08 9.9E-08 1.6E-07 4.6E-07 4.6E-07 7.8E-08 1.8E-07 
In-113m 2.4E-11 1.5E-11 8.5E-12 5.0E-18 1.5E-22 1.3E-43 1.5E-16 2.0E-11 
K-40 1.1E-08 4.0E-09 1.0E-06 3.0E-08 5.4E-08 3.9E-08 3.2E-09 4.1E-08 
Kr-85 0.0E+00 0.0E+00 0.0E+00 0.0E+00 0.0E+00 0.0E+00 0.0E+00 0.0E+00 
La-138 9.6E-07 1.2E-09 9.2E-10 1.5E-09 3.4E-11 2.9E-10 9.6E-10 2.2E-07 
Mn-54 3.3E-07 5.7E-10 6.5E-09 8.2E-10 1.1E-10 9.0E-11 2.1E-11 7.7E-08 
Mo-93 8.9E-10 1.9E-10 4.7E-11 6.4E-10 2.3E-10 2.9E-11 2.0E-10 5.3E-10 
Nb-91 0.0E+00 0.0E+00 0.0E+00 0.0E+00 0.0E+00 0.0E+00 0.0E+00 0.0E+00 
Nb-93m 4.6E-10 1.5E-10 1.1E-09 2.0E-10 1.3E-13 5.1E-15 6.4E-11 3.2E-10 
Nb-94 1.4E-06 1.7E-09 1.3E-08 2.4E-09 1.6E-12 6.1E-14 1.4E-09 3.2E-07 
Nb-95 3.5E-09 5.9E-10 2.4E-09 5.1E-10 3.8E-13 1.3E-14 2.5E-12 1.5E-09 
Nb-95m 3.9E-10 6.6E-10 5.3E-10 1.8E-10 1.4E-13 2.6E-15 5.4E-13 7.6E-10 
Nd-144 0.0E+00 0.0E+00 0.0E+00 0.0E+00 0.0E+00 0.0E+00 0.0E+00 0.0E+00 
Ni-59 3.5E-10 5.2E-11 1.3E-10 1.2E-10 9.6E-10 6.0E-11 4.1E-11 1.8E-10 
Ni-63 0.0E+00 1.5E-10 3.8E-10 3.2E-10 2.6E-09 1.6E-10 1.1E-10 2.7E-10 

Table I-2. Calculation of Groundwater Screening Factors (continued) 
Nuclide 
Garden & 
Shoreline Water Fish Vegetable Milk Meat Soil 
AdjustedTotal 
Np-235 2.4E-10 6.8E-11 4.7E-11 8.0E-11 2.7E-13 6.9E-12 3.2E-12 1.4E-10 
Np-236a 1.4E-07 1.9E-07 1.4E-07 3.0E-07 9.2E-10 2.2E-08 1.6E-07 2.8E-07 
Np-237 2.2E-07 5.1E-07 3.8E-07 8.3E-07 2.4E-09 5.9E-08 4.0E-07 7.3E-07 
Np-238 1.5E-10 1.0E-09 4.9E-11 1.5E-10 4.7E-13 2.6E-12 1.9E-11 1.0E-09 
Np-239 5.7E-11 9.0E-10 4.9E-11 1.2E-10 4.8E-13 2.8E-12 3.5E-13 8.8E-10 
Pa-231 5.9E-07 1.1E-06 2.8E-07 1.6E-06 5.8E-09 1.4E-09 1.4E-06 1.6E-06 
Pa-233 7.9E-10 1.1E-09 1.3E-10 8.5E-10 1.6E-12 3.6E-13 3.4E-12 1.4E-09 
Pa-234 7.2E-11 4.2E-10 9.7E-13 9.2E-13 5.0E-16 6.1E-18 1.5E-14 4.1E-10 
Pa-234m 1.5E-15 1.6E-15 3.7E-18 3.5E-18 1.8E-21 2.0E-27 5.6E-20 1.8E-15 
Pb-209 0.0E+00 3.8E-11 1.3E-12 3.1E-15 1.2E-17 6.6E-29 6.9E-16 3.6E-11 
Pb-210 1.7E-08 6.4E-07 4.8E-06 8.2E-07 8.9E-08 6.7E-08 4.2E-07 9.1E-07 
Pb-211 1.9E-12 7.4E-11 4.6E-13 2.9E-25 5.1E-37 0.0E+00 3.9E-16 7.0E-11 
Pb-212 1.6E-10 6.5E-09 7.0E-10 5.4E-11 3.3E-12 9.4E-16 3.6E-13 6.2E-09 
Pb-214 9.7E-12 9.3E-11 2.9E-12 2.3E-12 2.6E-13 3.3E-13 9.7E-13 9.0E-11 
Pd-107 0.0E+00 4.7E-11 1.2E-11 1.5E-10 3.1E-12 1.6E-12 3.7E-11 7.7E-11 
Pm-145 1.5E-07 1.2E-10 8.9E-11 1.5E-10 3.2E-12 2.7E-11 5.7E-11 3.5E-08 
Pm-146 1.8E-08 9.2E-10 6.8E-10 1.1E-09 2.3E-11 2.0E-10 2.0E-10 5.3E-09 
Pm-147 4.8E-12 3.2E-10 2.3E-10 3.8E-10 7.9E-12 6.6E-11 3.5E-11 3.9E-10 
Po-210 1.5E-12 1.7E-07 3.5E-07 1.9E-07 2.7E-08 8.2E-08 2.8E-09 2.1E-07 
Po-211 6.0E-17 0.0E+00 0.0E+00 0.0E+00 0.0E+00 0.0E+00 0.0E+00 1.4E-17 
Po-212 0.0E+00 0.0E+00 0.0E+00 0.0E+00 0.0E+00 0.0E+00 0.0E+00 0.0E+00 
Po-213 1.9E-24 1.4E-20 4.6E-22 1.1E-24 4.1E-27 2.4E-38 2.5E-25 1.3E-20 
Po-214 2.0E-22 0.0E+00 0.0E+00 0.0E+00 0.0E+00 0.0E+00 0.0E+00 4.6E-23 
Po-215 1.5E-18 6.1E-17 3.8E-19 2.4E-31 4.2E-43 0.0E+00 3.2E-22 5.8E-17 
Po-216 6.4E-16 2.6E-14 2.8E-15 2.1E-16 1.3E-17 3.7E-21 1.4E-18 2.5E-14 
Po-218 1.1E-12 1.1E-11 2.8E-13 2.6E-13 2.9E-14 3.7E-14 1.1E-13 1.1E-11 
Pr-144 4.6E-13 1.2E-11 1.2E-14 3.5E-39 0.0E+00 0.0E+00 5.7E-17 1.1E-11 
Pr-144m 2.5E-13 6.9E-12 6.8E-15 1.5E-39 0.0E+00 0.0E+00 2.4E-17 6.5E-12 
Pt-193 3.8E-10 3.6E-11 3.1E-11 1.1E-10 2.2E-12 1.1E-12 2.3E-11 1.5E-10 
Pu-236 6.6E-08 1.5E-07 1.1E-07 1.8E-07 2.4E-10 1.6E-09 2.3E-08 2.0E-07 
Pu-238 6.4E-09 4.1E-07 3.1E-07 5.0E-07 1.9E-10 4.7E-09 2.9E-07 5.1E-07 
Pu-239 3.2E-09 4.5E-07 3.4E-07 5.5E-07 2.1E-10 5.2E-09 3.5E-07 5.6E-07 
Pu-240 6.9E-09 4.5E-07 3.4E-07 5.5E-07 2.1E-10 5.2E-09 3.5E-07 5.6E-07 
Pu-241 3.7E-09 8.6E-09 6.4E-09 1.1E-08 4.5E-12 9.9E-11 9.1E-09 1.2E-08 
Pu-242 5.7E-09 4.3E-07 3.2E-07 5.2E-07 2.0E-10 5.0E-09 3.4E-07 5.3E-07 
Pu-243 7.5E-12 6.5E-11 3.3E-13 8.7E-14 3.3E-17 1.9E-16 2.9E-14 6.3E-11 
Ra-223 1.2E-09 1.0E-07 3.5E-08 5.5E-08 2.2E-08 4.1E-09 1.4E-10 1.1E-07 
Ra-224 1.3E-09 5.9E-08 8.0E-09 1.3E-08 5.2E-09 5.1E-10 2.9E-11 5.9E-08 
Ra-225 1.3E-09 5.7E-08 2.3E-08 4.6E-08 1.4E-08 2.8E-09 1.5E-10 6.4E-08 
Ra-226 3.4E-06 1.8E-07 2.2E-07 3.9E-07 9.7E-08 2.9E-08 3.5E-07 1.1E-06 
Ra-228 2.9E-06 2.2E-07 2.7E-07 3.3E-07 9.9E-08 2.5E-08 7.6E-08 9.5E-07 
Rb-87 0.0E+00 1.0E-09 5.2E-08 5.6E-09 1.5E-08 1.1E-08 8.1E-10 4.7E-09 
Rh-102 2.8E-08 2.2E-09 1.6E-08 2.8E-09 4.6E-10 4.7E-10 2.7E-10 9.5E-09 
Rh-106 9.6E-16 0.0E+00 0.0E+00 0.0E+00 0.0E+00 0.0E+00 0.0E+00 2.2E-16 

Table I-2. Calculation of Groundwater Screening Factors (continued) 
Nuclide 
Garden & 
Shoreline Water Fish Vegetable Milk Meat Soil 
AdjustedTotal 
Rn-219 3.4E-15 1.3E-13 8.4E-16 5.3E-28 9.4E-40 0.0E+00 7.2E-19 1.2E-13 
Rn-220 2.4E-13 9.5E-12 1.0E-12 7.9E-14 4.8E-15 1.4E-18 5.3E-16 9.0E-12 
Rn-222 2.0E-09 7.5E-11 8.3E-13 3.7E-10 3.9E-11 5.0E-11 2.0E-10 6.2E-10 
Ru-106 1.0E-09 8.0E-09 1.8E-09 9.5E-09 6.5E-11 1.6E-09 3.5E-10 9.9E-09 
Sb-125 6.2E-09 7.4E-10 1.8E-09 9.9E-10 4.3E-11 1.2E-10 1.1E-10 2.4E-09 
Sb-126 4.5E-10 2.6E-09 1.9E-09 1.4E-09 5.8E-11 1.1E-10 3.8E-12 2.9E-09 
Sb-126m 3.4E-13 9.5E-12 2.0E-13 2.2E-13 8.3E-15 1.6E-14 6.1E-16 9.1E-12 
Se-79 0.0E+00 1.2E-09 6.2E-09 4.1E-09 8.3E-09 2.1E-08 9.7E-10 4.4E-09 
Sm-145 3.8E-08 2.4E-10 1.4E-10 2.8E-10 5.9E-12 4.9E-11 1.3E-11 9.0E-09 
Sm-146 0.0E+00 2.8E-08 1.7E-08 3.4E-08 7.7E-10 6.4E-09 2.2E-08 3.5E-08 
Sm-147 0.0E+00 2.5E-08 1.6E-08 3.1E-08 7.0E-10 5.9E-09 2.0E-08 3.2E-08 
Sm-148 0.0E+00 0.0E+00 0.0E+00 0.0E+00 0.0E+00 0.0E+00 0.0E+00 0.0E+00 
Sm-149 0.0E+00 0.0E+00 0.0E+00 0.0E+00 0.0E+00 0.0E+00 0.0E+00 0.0E+00 
Sm-151 3.9E-11 1.1E-10 6.7E-11 1.3E-10 3.0E-12 2.5E-11 7.6E-11 1.5E-10 
Sn-113 4.0E-08 8.7E-10 5.2E-08 1.0E-09 3.4E-10 8.3E-10 1.2E-11 1.2E-08 
Sn-119m 2.2E-10 4.2E-10 2.8E-08 6.0E-10 1.8E-10 4.4E-10 1.4E-11 1.3E-09 
Sn-121 0.0E+00 2.4E-10 6.4E-10 1.2E-11 4.2E-12 5.1E-13 3.2E-14 2.4E-10 
Sn-121m 3.2E-09 4.8E-10 3.6E-08 3.8E-09 4.4E-10 1.0E-09 4.4E-10 2.9E-09 
Sn-123 1.1E-10 2.6E-09 1.6E-07 3.2E-09 1.0E-09 2.5E-09 4.0E-11 7.2E-09 
Sn-126 2.2E-07 5.3E-09 3.9E-07 4.0E-08 4.8E-09 1.2E-08 4.4E-09 7.4E-08 
Sr-90 0.0E+00 2.5E-08 3.7E-08 1.5E-07 9.3E-08 1.2E-07 1.6E-08 6.8E-08 
Tb-160 9.7E-08 1.8E-09 8.0E-10 1.8E-09 4.0E-11 3.2E-10 1.6E-11 2.4E-08 
Tc-98 1.2E-07 1.5E-09 7.3E-10 1.6E-07 3.0E-08 7.5E-10 1.2E-09 6.2E-08 
Tc-99 5.2E-14 5.3E-10 2.7E-10 5.7E-08 1.1E-08 2.7E-10 4.2E-10 1.2E-08 
Te-123m 2.5E-09 9.6E-10 7.7E-09 1.1E-09 1.9E-10 6.5E-10 1.4E-11 2.0E-09 
Te-125m 1.6E-10 7.2E-10 4.8E-09 7.2E-10 1.3E-10 4.4E-10 5.0E-12 1.0E-09 
Te-127 2.6E-13 1.4E-10 1.8E-11 8.5E-13 7.4E-14 3.8E-17 6.9E-15 1.3E-10 
Te-127m 1.6E-10 1.8E-09 1.4E-08 2.0E-09 3.6E-10 1.2E-09 2.6E-11 2.6E-09 
Th-227 4.7E-09 1.0E-08 9.8E-09 4.5E-08 1.1E-08 2.2E-09 2.5E-10 2.0E-08 
Th-228 2.5E-07 5.3E-08 1.3E-07 1.1E-07 1.2E-08 1.7E-09 9.6E-09 1.3E-07 
Th-229 1.5E-06 3.8E-07 9.6E-07 5.5E-07 1.4E-08 7.0E-09 3.7E-07 8.5E-07 
Th-230 2.9E-08 6.2E-08 1.5E-07 7.7E-08 2.8E-10 7.8E-10 5.1E-08 8.7E-08 
Th-231 2.6E-11 3.5E-10 3.0E-11 1.6E-11 2.8E-14 5.6E-15 1.7E-13 3.4E-10 
Th-232 6.9E-06 2.9E-07 7.4E-07 5.2E-07 1.9E-08 7.8E-09 4.1E-07 2.0E-06 
Th-234 3.7E-10 4.2E-09 4.7E-09 3.3E-09 6.2E-12 2.7E-11 1.2E-11 4.8E-09 
Tl-206 4.4E-17 0.0E+00 0.0E+00 0.0E+00 0.0E+00 0.0E+00 0.0E+00 1.0E-17 
Tl-207 9.2E-16 0.0E+00 0.0E+00 0.0E+00 0.0E+00 0.0E+00 0.0E+00 2.1E-16 
Tl-208 8.1E-13 0.0E+00 0.0E+00 0.0E+00 0.0E+00 0.0E+00 0.0E+00 1.9E-13 
Tl-209 4.0E-13 4.4E-13 1.5E-14 3.5E-17 1.3E-19 7.5E-31 7.8E-18 5.1E-13 
Tm-171 7.0E-10 1.3E-10 7.9E-11 1.5E-10 3.3E-12 2.7E-11 1.1E-11 3.2E-10 
U-232 1.9E-06 1.0E-07 2.6E-08 1.6E-07 2.3E-08 1.0E-08 1.5E-07 5.7E-07 
U-233 2.4E-09 2.3E-08 5.8E-09 2.9E-08 4.3E-09 2.1E-09 1.9E-08 2.9E-08 
U-234 6.8E-10 2.3E-08 5.6E-09 2.8E-08 4.2E-09 2.1E-09 1.8E-08 2.9E-08 
U-235 3.1E-07 2.2E-08 5.5E-09 2.7E-08 4.0E-09 2.0E-09 1.8E-08 9.9E-08 

Table I-2. Calculation of Groundwater Screening Factors (continued) 
Nuclide 
Garden & 
Shoreline Water Fish Vegetable Milk Meat Soil 
AdjustedTotal 
U-236 6.1E-10 2.1E-08 5.3E-09 2.6E-08 4.0E-09 2.0E-09 1.7E-08 2.6E-08 
U-237 1.4E-10 9.2E-10 4.2E-11 3.4E-10 5.5E-11 1.7E-11 7.5E-13 9.7E-10 
U-238 1.0E-07 2.1E-08 5.2E-09 2.7E-08 3.8E-09 1.9E-09 2.0E-08 5.0E-08 
Y-90 0.0E+00 3.1E-09 1.9E-10 4.9E-10 1.2E-11 2.7E-11 1.0E-12 3.0E-09 
Y-91 2.4E-10 3.0E-09 1.5E-09 2.9E-09 6.4E-11 5.0E-10 2.1E-11 3.5E-09 
Zn-65 1.7E-08 3.0E-09 6.6E-08 4.3E-09 1.2E-08 3.1E-08 8.6E-11 1.2E-08 
Zr-93 4.0E-10 2.4E-10 1.8E-09 3.1E-10 7.5E-14 2.9E-14 2.5E-10 4.4E-10 
Zr-95 6.7E-08 9.7E-10 4.9E-09 1.1E-09 2.9E-13 8.6E-14 1.2E-11 1.7E-08 
NOTE: The adjusted total screening factor in (Sv / y) / (Bq / m3) is the sum of the products of the components (from 
NCRP 1996, Table C.1; or Assumption 5.10) and the adjustment factors in Table I-1 above. Multiplication 
and summation operators in Microsoft Excel were used for the computations. 

SCREENING FACTORS FOR THE ERUPTIVE SCENARIO 
(6 pages) 
DEVELOPMENT OF ERUPTIVE SCREENING FACTORS 
As stated in Assumption 5.2, adjusted air screening factors from NCRP (1996) are used as 
screening factors in the screening analysis. The following sections develop adjustment factors 
(Table I-1) for each component represented in the NCRP report (NCRP 1996, Table B.1). The 
adjusted total screening factor (Table II-1) is the sum of the products of the components and their 
adjustment factors. Table II-1 provides a complete list of the radionuclides considered in the 
screening calculation along with the corresponding eruptive screening factors. 
Inhalation 
The screening factor for inhalation is a simple multiple of the usage factor for inhalation (NCRP 
1996, Equation 8.2). Therefore, the adjustment factor is simply the ratio of project-generated to 
generic usage factors. The best estimate of the project-generated usage factor is given by the 
product of the inhalation exposure time 6073.5 h/y (Section 4.1.1) and the chronic breathing rate 
23 m3/d (Section 4.1.1): 6073.5 h/y  (23 m3/d) / (24 h/d) = 5820 m3/y. The generic value is 
8000 m3/y (NCRP 1996, Table 7.1). The adjustment factor for inhalation is 5820 / 8000 = 0.73. 
The appropriateness of the relative weight assigned to the inhalation pathway by the screening 
factors developed in this attachment is addressed in Assumption 5.2. 
External exposure to the ash plume 
External exposure to the ash plume is not considered in the development of biosphere dose 
conversion factors (CRWMS M&O 2001a, Table 10, Section 6.3.2), so it is not considered in 
this screening analysis. In effect, the adjustment factor for external exposure to the ash plume is 
zero. 
External exposure to the contaminated ground surface 
The screening factor for ground exposure is a simple multiple of the usage factor for ground 
exposure (NCRP 1996, Equation 8.2). Therefore, the adjustment factor is simply the ratio of 
project-generated to NCRP usage factors. The best estimate of the project-generated usage 
factor is 3387 h/y (Section 4.1.1), while the NCRP value is 8000 h/y (NCRP 1996, Table 7.1). 
The adjustment factor for external exposure to contaminated ground is 3387 / 8000 = 0.42. 
Consumption of terrestrial food and soil 
The screening factors for consumption of vegetables, milk, meat, and soil are simple multiples of 
the corresponding usage factors (NCRP 1996, Equation 8.5 through 8.6c). Therefore, the 
adjustment factors are simply the ratios of project-generated to NCRP generic usage factors. The 

CORRECTING THE GROUND-EXPOSURE COMPONENT FOR Np-236a 
As noted in Assumption 5.2, the value of the air screening factor for Np-236a from the NCRP 
report is erroneously high. The error can be traced to an erroneously high effective dose factor 
for ground irradiation: 1.19  10-6 (Sv/y) / (Bq/m3). The source cited by the NCRP report 
(Kocher 1983, Table 3) gives a value of 4.35  10-5 (Sv/y) / (Bq/m3) / (365.25 d/y) / (1002 
cm2/m2) = 1.19  10-11 (Sv/d)/(Bq/m2), which is a factor of 105 lower than the value given in the 
NCRP report. Because the dose coefficient is a simple multiplier for each radionuclide (NCRP 
1996, Equation 8.2), the corrected value for the ground exposure component is a factor of 105 
less than the value provided in the NCRP report (1996, Table B.1): 3.8  103 / 105 = 3.8  10-2 
(Sv/y) / (Bq/m3). 
Table II-1. Calculation of Igneous Eruptive Screening Factors 
Nuclide Inhalation 
Ground 
Surface Vegetable Milk Meat Soil 
AdjustedTotal 
Ac-225 1.7E-02 8.6E-05 7.5E-03 5.4E-06 9.6E-06 1.8E-05 1.4E-02 
Ac-227 8.6E+00 6.7E-02 1.1E+00 6.0E-03 2.9E-03 5.0E-01 6.6E+00 
Ac-228 4.0E-04 2.1E-05 2.0E-05 2.1E-06 3.0E-07 1.8E-06 3.0E-04 
Ag-108 0.0E+00 1.0E-09 0.0E+00 0.0E+00 0.0E+00 0.0E+00 4.2E-10 
Ag-108m 5.7E-04 3.5E-01 1.0E-03 2.2E-03 2.7E-04 6.0E-04 1.5E-01 
Ag-109m 0.0E+00 1.5E-10 0.0E+00 0.0E+00 0.0E+00 0.0E+00 6.3E-11 
Ag-110 0.0E+00 3.1E-10 0.0E+00 0.0E+00 0.0E+00 0.0E+00 1.3E-10 
Ag-110m 1.7E-04 2.4E-02 1.3E-03 2.6E-03 3.2E-04 3.4E-05 1.1E-02 
Am-241 5.7E-01 6.8E-03 2.8E-01 2.0E-04 1.3E-03 1.8E-01 4.8E-01 
Am-242 9.6E-05 4.4E-07 3.7E-05 2.3E-08 5.9E-08 3.0E-06 7.8E-05 
Am-242m 5.4E-01 5.2E-03 2.7E-01 2.0E-04 1.2E-03 1.8E-01 4.6E-01 
Am-243 5.6E-01 6.0E-02 2.8E-01 2.0E-04 1.3E-03 1.8E-01 5.0E-01 
Ar-39 0.0E+00 0.0E+00 0.0E+00 0.0E+00 0.0E+00 0.0E+00 0.0E+00 
At-217 3.2E-10 2.6E-12 4.3E-15 3.1E-18 1.6E-29 4.1E-15 2.3E-10 
Ba-133 1.5E-05 4.5E-02 4.9E-04 7.8E-05 7.8E-06 1.4E-04 1.9E-02 
Ba-137m 0.0E+00 3.8E-08 0.0E+00 0.0E+00 0.0E+00 0.0E+00 1.6E-08 
Bi-210 4.1E-04 1.5E-09 2.7E-03 3.8E-04 9.4E-04 5.2E-05 9.4E-04 
Bi-211 0.0E+00 2.8E-09 0.0E+00 0.0E+00 0.0E+00 0.0E+00 1.2E-09 
Bi-212 3.4E-05 1.9E-06 2.3E-14 6.4E-22 0.0E+00 4.4E-10 2.6E-05 
Bi-213 2.7E-05 2.2E-07 3.6E-10 2.6E-13 1.4E-24 3.5E-10 2.0E-05 
Bi-214 9.6E-06 6.7E-07 8.6E-07 9.4E-08 1.2E-07 3.6E-07 7.5E-06 
Bk-249 1.6E-03 1.9E-04 9.2E-04 6.6E-07 2.0E-06 5.4E-04 1.5E-03 
C-14 4.5E-06 0.0E+00 1.3E-04 6.3E-05 7.2E-05 3.4E-08 3.7E-05 
Ca-41 2.3E-06 4.7E-06 1.3E-03 9.3E-04 1.6E-04 8.4E-05 3.0E-04 
Ca-45 1.4E-05 1.2E-12 4.7E-04 4.4E-04 7.2E-05 6.6E-06 1.2E-04 

Nuclide Inhalation 
Ground 
Surface Vegetable Milk Meat Soil 
AdjustedTotal 
Cd-109 1.3E-04 1.5E-04 1.7E-03 7.4E-04 9.2E-05 4.8E-05 5.2E-04 
Cd-113 1.9E-03 0.0E+00 1.2E-01 1.8E-02 2.2E-03 7.8E-03 2.6E-02 
Cd-113m 1.7E-03 0.0E+00 6.3E-02 1.2E-02 1.5E-03 3.9E-03 1.4E-02 
Ce-139 2.0E-05 8.6E-04 1.6E-04 1.6E-06 2.6E-07 2.4E-06 4.1E-04 
Ce-142 0.0E+00 0.0E+00 0.0E+00 0.0E+00 0.0E+00 0.0E+00 0.0E+00 
Ce-144 8.1E-04 5.2E-04 3.8E-03 3.7E-05 6.1E-06 1.1E-04 1.6E-03 
Cf-249 6.9E-01 8.0E-02 3.4E-01 2.5E-04 1.9E-03 2.1E-01 6.2E-01 
Cf-250 3.6E-01 8.4E-05 1.5E-01 1.1E-04 8.0E-04 5.2E-02 3.0E-01 
Cf-251 7.0E-01 3.1E-02 3.5E-01 2.5E-04 1.9E-03 2.2E-01 6.1E-01 
Cf-252 3.2E-01 2.1E-05 8.2E-02 5.4E-05 4.1E-04 7.7E-03 2.5E-01 
Cl-36 4.7E-05 1.1E-08 1.4E-01 3.4E-01 1.7E-01 2.6E-04 5.0E-02 
Cm-242 2.8E-02 6.3E-06 1.0E-02 6.9E-06 1.8E-05 8.9E-04 2.2E-02 
Cm-243 4.0E-01 2.5E-02 2.0E-01 1.4E-04 3.4E-04 9.2E-02 3.5E-01 
Cm-244 3.2E-01 1.2E-04 1.6E-01 1.1E-04 2.7E-04 6.3E-02 2.7E-01 
Cm-245 5.8E-01 2.0E-02 2.9E-01 2.1E-04 5.3E-04 1.9E-01 5.0E-01 
Cm-246 5.8E-01 1.7E-04 2.9E-01 2.1E-04 5.2E-04 1.9E-01 4.9E-01 
Cm-247 5.3E-01 8.6E-02 2.6E-01 1.9E-04 4.8E-04 1.7E-01 4.8E-01 
Cm-248 2.1E+00 1.4E-04 1.1E+00 7.7E-04 1.9E-03 6.8E-01 1.8E+00 
Co-58 2.3E-05 2.5E-03 4.1E-04 2.8E-04 1.0E-03 3.3E-06 1.3E-03 
Co-60 4.5E-04 1.4E-01 4.7E-03 3.7E-03 1.4E-02 6.0E-04 6.2E-02 
Cs-134 9.9E-05 4.2E-02 1.3E-02 3.4E-02 4.3E-02 6.8E-04 2.5E-02 
Cs-135 9.8E-06 0.0E+00 4.2E-03 6.9E-03 8.6E-03 6.0E-04 1.8E-03 
Cs-137 6.8E-05 9.9E-02 2.3E-02 4.1E-02 5.1E-02 3.1E-03 5.2E-02 
Eu-150 5.8E-04 2.8E-01 8.4E-04 1.8E-05 1.5E-04 4.1E-04 1.2E-01 
Eu-152 3.7E-04 1.4E-01 9.3E-04 1.9E-05 1.6E-04 3.2E-04 5.9E-02 
Eu-154 4.7E-04 1.1E-01 1.4E-03 2.9E-05 2.4E-04 3.8E-04 4.7E-02 
Eu-155 6.1E-05 4.3E-03 2.4E-04 4.8E-06 4.0E-05 4.0E-05 1.9E-03 
Fe-55 5.1E-06 7.3E-06 7.2E-05 7.2E-06 1.8E-04 6.9E-06 4.0E-05 
Fr-221 2.1E-06 2.7E-08 3.8E-11 2.7E-14 1.4E-25 3.6E-11 1.5E-06 
Fr-223 1.5E-05 2.0E-07 3.6E-05 1.3E-05 2.4E-06 9.5E-08 1.9E-05 
Gd-152 3.0E-01 0.0E+00 1.3E-02 2.8E-04 2.3E-03 8.3E-03 2.2E-01 
Gd-153 3.3E-05 1.1E-03 1.8E-04 3.6E-06 2.9E-05 4.5E-06 5.3E-04 
H-3 1.4E-07 0.0E+00 5.8E-07 8.6E-07 2.9E-07 1.1E-10 2.6E-07 
Ho-166m 1.1E-03 3.8E-01 1.1E-03 2.3E-05 1.9E-04 6.8E-04 1.6E-01 
I-129 6.2E-04 5.1E-03 8.0E-02 2.2E-01 2.2E-01 3.9E-02 4.6E-02 
In-113m 7.8E-08 6.6E-07 2.5E-12 8.7E-18 7.1E-39 7.5E-11 3.3E-07 
K-40 2.7E-05 3.2E-02 1.5E-02 2.7E-02 1.9E-02 1.6E-03 1.9E-02 
Kr-85 0.0E+00 0.0E+00 0.0E+00 0.0E+00 0.0E+00 0.0E+00 0.0E+00 
La-138 2.3E-03 2.7E-01 7.6E-04 1.6E-05 1.3E-04 4.8E-04 1.2E-01 
Mn-54 1.4E-05 9.2E-03 4.1E-04 5.2E-05 4.3E-05 1.0E-05 4.0E-03 
Mo-93 6.1E-05 1.5E-03 3.2E-04 1.1E-04 1.4E-05 1.0E-04 7.5E-04 
Nb-91 0.0E+00 0.0E+00 0.0E+00 0.0E+00 0.0E+00 0.0E+00 0.0E+00 
Nb-93m 6.3E-05 1.3E-04 1.0E-04 6.4E-08 2.4E-09 3.2E-05 1.2E-04 

Nuclide Inhalation 
Ground 
Surface Vegetable Milk Meat Soil 
AdjustedTotal 
Nb-94 8.6E-04 3.8E-01 1.2E-03 7.7E-07 2.9E-08 6.8E-04 1.6E-01 
Nb-95 1.3E-05 9.6E-04 2.6E-04 1.8E-07 6.1E-09 1.2E-06 4.6E-04 
Nb-95m 6.0E-06 1.1E-04 9.2E-05 6.0E-08 1.1E-09 2.7E-07 6.9E-05 
Nd-144 0.0E+00 0.0E+00 0.0E+00 0.0E+00 0.0E+00 0.0E+00 0.0E+00 
Ni-59 5.8E-06 9.8E-05 5.9E-05 4.7E-04 2.9E-05 2.0E-05 6.8E-05 
Ni-63 1.4E-05 0.0E+00 1.6E-04 1.3E-03 8.0E-05 5.3E-05 7.1E-05 
Np-235 6.2E-06 6.6E-05 4.0E-05 1.3E-07 3.2E-06 1.6E-06 4.1E-05 
Np-236a 2.2E-01 3.8E-02 1.5E-01 4.4E-04 1.0E-02 7.9E-02 2.1E-01 
Np-237 6.2E-01 6.1E-02 4.1E-01 1.1E-03 2.8E-02 2.0E-01 5.7E-01 
Np-238 4.6E-05 4.1E-05 7.4E-05 1.8E-07 9.7E-07 9.6E-06 6.6E-05 
Np-239 5.8E-06 1.6E-05 6.1E-05 1.8E-07 1.0E-06 1.7E-07 2.3E-05 
Pa-231 1.4E+00 4.3E-02 8.2E-01 2.8E-03 6.8E-04 7.0E-01 1.2E+00 
Pa-233 2.2E-05 2.2E-04 4.3E-04 7.5E-07 1.7E-07 1.7E-06 1.9E-04 
Pa-234 1.6E-06 2.0E-05 4.6E-07 8.3E-11 3.0E-12 7.5E-09 9.7E-06 
Pa-234m 6.1E-12 4.0E-10 1.7E-12 2.9E-16 2.9E-22 2.8E-14 1.7E-10 
Pb-209 1.8E-07 0.0E+00 1.5E-09 1.1E-12 5.8E-24 3.4E-10 1.3E-07 
Pb-210 1.6E-02 4.6E-04 4.1E-01 4.3E-02 3.2E-02 2.1E-01 1.1E-01 
Pb-211 1.6E-05 9.5E-08 1.5E-19 1.7E-32 0.0E+00 2.0E-10 1.2E-05 
Pb-212 2.9E-04 2.2E-05 2.7E-05 6.8E-07 1.8E-10 1.8E-07 2.3E-04 
Pb-214 1.6E-05 1.1E-06 1.2E-06 1.3E-07 1.6E-07 4.9E-07 1.2E-05 
Pd-107 2.8E-05 0.0E+00 7.7E-05 1.5E-06 7.5E-07 1.8E-05 3.7E-05 
Pm-145 5.9E-05 4.2E-03 7.3E-05 1.5E-06 1.3E-05 2.8E-05 1.8E-03 
Pm-146 3.0E-04 5.0E-02 5.5E-04 1.1E-05 9.2E-05 1.0E-04 2.1E-02 
Pm-147 8.2E-05 1.3E-07 1.9E-04 3.8E-06 3.1E-05 1.8E-05 1.0E-04 
Po-210 1.4E-02 4.2E-08 9.4E-02 1.3E-02 3.8E-02 1.4E-03 3.3E-02 
Po-211 0.0E+00 1.7E-12 0.0E+00 0.0E+00 0.0E+00 0.0E+00 7.1E-13 
Po-212 0.0E+00 0.0E+00 0.0E+00 0.0E+00 0.0E+00 0.0E+00 0.0E+00 
Po-213 6.3E-17 5.4E-20 5.5E-19 4.0E-22 2.1E-33 1.2E-19 4.6E-17 
Po-214 0.0E+00 5.7E-18 0.0E+00 0.0E+00 0.0E+00 0.0E+00 2.4E-18 
Po-215 1.3E-11 7.8E-14 1.2E-25 1.4E-38 0.0E+00 1.6E-16 9.5E-12 
Po-216 1.1E-09 8.7E-11 1.1E-10 2.7E-12 7.2E-16 7.1E-13 8.6E-10 
Po-218 1.6E-06 1.2E-07 1.3E-07 1.4E-08 1.8E-08 5.5E-08 1.2E-06 
Pr-144 6.8E-08 1.3E-08 1.7E-33 0.0E+00 0.0E+00 2.8E-11 5.5E-08 
Pr-144m 1.8E-08 7.1E-09 7.3E-34 0.0E+00 0.0E+00 1.2E-11 1.6E-08 
Pt-193 3.1E-07 1.1E-04 5.3E-05 1.1E-06 5.4E-07 1.2E-05 5.8E-05 
Pu-236 2.4E-01 8.9E-03 9.0E-02 1.2E-04 7.7E-04 1.2E-02 2.0E-01 
Pu-238 5.0E-01 1.8E-04 2.5E-01 8.9E-05 2.2E-03 1.4E-01 4.2E-01 
Pu-239 5.5E-01 8.8E-05 2.7E-01 9.9E-05 2.5E-03 1.8E-01 4.6E-01 
Pu-240 5.5E-01 1.9E-04 2.7E-01 9.9E-05 2.5E-03 1.8E-01 4.6E-01 
Pu-241 1.0E-02 1.0E-04 5.3E-03 2.1E-06 4.7E-05 4.5E-03 8.6E-03 
Pu-242 5.2E-01 1.6E-04 2.6E-01 9.4E-05 2.3E-03 1.7E-01 4.4E-01 
Pu-243 3.2E-07 2.1E-07 4.3E-08 1.6E-11 9.6E-11 1.5E-08 3.3E-07 
Ra-223 1.7E-02 1.3E-04 2.8E-02 1.0E-02 1.8E-03 7.1E-05 1.8E-02 

Nuclide Inhalation 
Ground 
Surface Vegetable Milk Meat Soil 
AdjustedTotal 
Ra-224 6.6E-03 1.8E-04 6.6E-03 2.1E-03 2.1E-04 1.4E-05 6.3E-03 
Ra-225 1.7E-02 1.4E-04 2.3E-02 6.3E-03 1.3E-03 7.7E-05 1.7E-02 
Ra-226 1.7E-02 3.8E-01 1.9E-01 4.6E-02 1.4E-02 1.8E-01 2.2E-01 
Ra-228 9.3E-03 1.5E-01 1.7E-01 4.7E-02 1.2E-02 3.8E-02 1.1E-01 
Rb-87 6.7E-06 0.0E+00 2.8E-03 7.2E-03 5.4E-03 4.1E-04 1.2E-03 
Rh-102 2.4E-04 7.8E-02 1.4E-03 2.2E-04 2.2E-04 1.3E-04 3.3E-02 
Rh-106 0.0E+00 2.7E-09 0.0E+00 0.0E+00 0.0E+00 0.0E+00 1.1E-09 
Rn-219 2.9E-08 1.7E-10 2.7E-22 3.1E-35 0.0E+00 3.6E-13 2.1E-08 
Rn-220 4.2E-07 3.2E-08 3.9E-08 9.9E-10 2.7E-13 2.6E-10 3.3E-07 
Rn-222 1.9E-06 2.2E-04 1.9E-04 1.9E-05 2.5E-05 1.0E-04 1.4E-04 
Ru-106 1.0E-03 2.8E-03 4.8E-03 3.1E-05 7.7E-04 1.7E-04 3.0E-03 
Sb-125 2.7E-05 1.6E-02 4.9E-04 2.1E-05 5.6E-05 5.3E-05 6.8E-03 
Sb-126 2.7E-05 1.3E-03 7.2E-04 2.6E-05 5.0E-05 1.9E-06 7.2E-04 
Sb-126m 6.0E-08 9.5E-07 1.1E-07 3.9E-09 7.4E-09 3.1E-10 4.7E-07 
Se-79 1.5E-05 0.0E+00 2.0E-03 4.0E-03 1.0E-02 4.9E-04 1.5E-03 
Sm-145 1.9E-05 1.0E-03 1.4E-04 2.8E-06 2.3E-05 6.3E-06 4.6E-04 
Sm-146 1.1E-01 0.0E+00 1.7E-02 3.7E-04 3.1E-03 1.1E-02 8.5E-02 
Sm-147 9.9E-02 0.0E+00 1.6E-02 3.3E-04 2.8E-03 9.9E-03 7.6E-02 
Sm-148 0.0E+00 0.0E+00 0.0E+00 0.0E+00 0.0E+00 0.0E+00 0.0E+00 
Sm-149 0.0E+00 0.0E+00 0.0E+00 0.0E+00 0.0E+00 0.0E+00 0.0E+00 
Sm-151 4.0E-05 1.1E-06 6.7E-05 1.4E-06 1.2E-05 3.8E-05 4.6E-05 
Sn-113 2.4E-05 1.2E-03 5.2E-04 1.6E-04 3.9E-04 6.1E-06 6.7E-04 
Sn-119m 1.4E-05 6.1E-05 3.0E-04 8.4E-05 2.1E-04 7.2E-06 1.2E-04 
Sn-121 1.2E-06 0.0E+00 6.2E-06 1.3E-06 1.5E-07 1.6E-08 2.2E-06 
Sn-121m 2.5E-05 8.9E-04 1.9E-03 2.2E-04 4.9E-04 2.2E-04 8.4E-04 
Sn-123 7.4E-05 3.0E-05 1.6E-03 4.9E-04 1.2E-03 2.0E-05 5.1E-04 
Sn-126 2.2E-04 4.9E-01 2.0E-02 2.3E-03 5.9E-03 2.2E-03 2.1E-01 
Sr-90 2.8E-03 0.0E+00 7.3E-02 4.6E-02 5.8E-02 8.0E-03 2.3E-02 
Tb-160 5.1E-05 2.7E-03 9.2E-04 1.9E-05 1.5E-04 7.8E-06 1.4E-03 
Tc-98 5.1E-05 3.5E-01 7.8E-02 1.5E-02 3.8E-04 5.8E-04 1.6E-01 
Tc-99 1.9E-05 1.5E-07 2.8E-02 5.5E-03 1.4E-04 2.1E-04 5.7E-03 
Te-123m 2.0E-05 6.9E-04 5.4E-04 9.0E-05 3.0E-04 6.8E-06 4.4E-04 
Te-125m 1.5E-05 4.5E-05 3.6E-04 6.2E-05 2.0E-04 2.5E-06 1.2E-04 
Te-127 6.8E-07 7.1E-08 4.3E-07 1.4E-08 6.9E-12 3.4E-09 6.1E-07 
Te-127m 4.5E-05 4.5E-05 1.0E-03 1.7E-04 5.7E-04 1.3E-05 3.1E-04 
Th-227 3.5E-02 2.9E-04 2.3E-02 5.7E-03 1.1E-03 1.3E-04 3.0E-02 
Th-228 7.0E-01 3.4E-02 5.6E-02 6.0E-03 8.3E-04 4.8E-03 5.4E-01 
Th-229 2.8E+00 8.5E-02 2.8E-01 6.8E-03 3.4E-03 1.9E-01 2.1E+00 
Th-230 4.3E-01 2.6E-03 3.8E-02 1.3E-04 3.7E-04 2.5E-02 3.2E-01 
Th-231 2.0E-06 7.2E-07 8.2E-06 8.6E-09 1.7E-09 8.4E-08 3.4E-06 
Th-232 1.8E+00 3.6E-01 2.6E-01 9.7E-03 3.8E-03 2.1E-01 1.5E+00 
Th-234 8.2E-05 2.4E-05 1.6E-03 2.9E-06 1.3E-05 6.1E-06 3.9E-04 
Tl-206 0.0E+00 1.2E-11 0.0E+00 0.0E+00 0.0E+00 0.0E+00 5.0E-12 

Nuclide Inhalation 
Ground 
Surface Vegetable Milk Meat Soil 
AdjustedTotal 
Tl-207 0.0E+00 2.5E-10 0.0E+00 0.0E+00 0.0E+00 0.0E+00 1.1E-10 
Tl-208 0.0E+00 2.3E-07 0.0E+00 0.0E+00 0.0E+00 0.0E+00 9.7E-08 
Tl-209 1.9E-09 1.1E-07 1.7E-11 1.3E-14 6.6E-26 3.9E-12 4.8E-08 
Tm-171 1.2E-05 1.9E-05 7.7E-05 1.5E-06 1.3E-05 5.4E-06 3.4E-05 
U-232 1.4E+00 2.6E-01 8.2E-02 1.1E-02 4.7E-03 7.3E-02 1.2E+00 
U-233 2.9E-01 2.3E-04 1.4E-02 2.0E-03 1.0E-03 9.3E-03 2.2E-01 
U-234 2.9E-01 1.9E-04 1.4E-02 2.0E-03 9.9E-04 8.9E-03 2.2E-01 
U-235 2.6E-01 4.6E-02 1.4E-02 1.9E-03 9.6E-04 9.1E-03 2.1E-01 
U-236 2.7E-01 1.7E-04 1.3E-02 1.9E-03 9.4E-04 8.4E-03 2.0E-01 
U-237 8.7E-06 3.9E-05 1.7E-04 2.4E-05 7.3E-06 3.7E-07 5.8E-05 
U-238 2.6E-01 6.7E-03 1.4E-02 1.8E-03 9.2E-04 9.8E-03 2.0E-01 
Y-90 2.1E-05 0.0E+00 2.4E-04 4.5E-06 1.0E-05 5.0E-07 6.4E-05 
Y-91 1.1E-04 6.7E-06 1.5E-03 3.0E-05 2.3E-04 1.0E-05 4.1E-04 
Zn-65 4.2E-05 4.8E-03 2.2E-03 5.9E-03 1.4E-02 4.3E-05 4.0E-03 
Zr-93 3.4E-04 1.1E-04 1.6E-04 3.6E-08 1.3E-08 1.2E-04 3.3E-04 
Zr-95 5.1E-05 3.4E-03 5.6E-04 1.4E-07 4.0E-08 6.0E-06 1.6E-03 
NOTE: The adjusted total screening factor in (Sv / y) / (Bq / m3) is the sum of the products of the components (from 
NCRP 1996, Table B.1; or Assumption 5.10) and the adjustment factors in Table I-1 above. Multiplication 
and summation operators in Microsoft Excel were used for the computations. 

EVALUATION OF DOSE COEFFICIENTS FROM NCRP (1996) 
(15 pages) 
EVALUATION OF NCRP DOSE COEFFICIENTS FOR GROUND IRRADIATION 
The error in the Np-236a dose coefficient raises the possibility that there may be other errors in 
the inputs used in the NCRP report (1996). Also, there are methodological differences in the 
way dose coefficients were computed in the original source (Kocher 1983) and in the source that 
provides the most recent federal guidance available at the time of this analysis on external dose 
coefficients (Eckerman & Ryman 1993). To increase confidence in the ground irradiation dose 
coefficients from the NCRP report, Table III-1 provides the basis for a comparison of the dose 
coefficients for irradiation by contaminated ground from NCRP (1996) to the comparable values 
provided by Eckerman and Ryman (1993). The ratios of dose coefficients (Table III-1, fifth 
column) are mostly near 1, which indicates a favorable comparison. Cases where the ratio is 
greater than two or less than one-half are discussed in the following paragraphs. 
Wherever the NCRP dose coefficient is equal to zero the ratio is undefined. Where Eckerman 
and Rymans coefficient is also zero, the comparison is favorable. Generally, where the NCRP 
coefficient is zero and Eckerman and Rymans coefficient is not zero, it may be seen that 
Eckerman and Rymans coefficient is less than 10-13, which is small by comparison to typical 
values, so that precise agreement is not important; therefore, the comparison is favorable. The 
only exception to this rule is for Y-90. NCRP (1996) did not carry over the nonzero coefficient 
from Kocher (1983). Yttrium-90 has such a short half-life (Table 2) that it is not directly 
included in the groundwater screening (Assumption 5.9), so there is no direct impact. Yttrium90 
is the decay product of Sr-90, so it is included indirectly in the groundwater screening. 
Because Sr-90 is screened in anyway (Section 7), there is no impact on the results of the 
screening analysis. 
There are large differences in dose coefficients between the NCRP report and the latest federal 
guidance for two radionuclides: Ca-45 and Cl-36. The values that appear in NCRP (1996, Table 
A.1) do not agree with those listed in the original source (Kocher 1983). The differences appear 
to be due to an error of omission on the part of NCRP, in which they removed the skin-dose 
contribution without indicating that they had done so. The Ca-45 dose coefficient given by 
Kocher is 6.35  10-14 (Sv/y)/(Bq/cm2) / (365 d/y) / (1002 cm2/m2) = 1.74  10-20 (Sv/d)/(Bq/m2), 
which is slightly greater than the value given by NCRP and reproduced here in Table III-1. 
Thus, the NCRP report provides a Ca-45 dose coefficient that differs little from the original 
source, but there remains an extremely large difference between the NCRP report and Eckerman 
and Rymans work. The reason for the large difference is unknown, but the Ca-45 dose 
coefficient is less than 10-14, which is very small compared to typical values, so that precise 
agreement is not important. Therefore, the dose coefficient for Ca-45 is judged acceptable. 
The Cl-36 dose coefficient given by Kocher (1983) is 2.23  10-6 (Sv/y)/(Bq/cm2) / (365 
d/y) / (1002 cm2/m2) = 6.11  10-13 (Sv/d)/(Bq/m2), which is about a factor of 105 greater than the 

value given by NCRP and reproduced in Table III-1. Chlorine-36 is not a gamma emitter 
(Parrington et al. 1996), so it is not expected to be a significant contributor to dose from 
exposure to direct irradiation from contaminated ground. Indeed, the contributions to the 
unadjusted screening factors from terrestrial food consumption are at least eight orders of 
magnitude greater than the ground irradiation contributions (NCRP 1996, Tables B.1 and C.1). 
Therefore, no correction is made for the questionable Cl-36 dose coefficient for ground 
irradiation. 
For Cd-109, Pm-147, Pt-193, Sn-119m, Tl-206, and Y-91 there are differences of more than a 
factor of two between the NCRP report and the latest federal guidance. Of these, all but Pt-193 
have a half-lives less than 10 y (Table 2), so they are not used in the groundwater screening. For 
the eruptive screening, the short-lived radionuclides are included as contributors to the screening 
factors for the parent radionuclides, so their particular screening factors are not important. The 
Pt-193 dose coefficient given by Kocher (1983) is 1.69  10-7 (Sv/y)/(Bq/cm2) / (365 d/y) / (1002 
cm2/m2) = 4.63  10-14 (Sv/d)/(Bq/m2), which is slightly larger than the value given by NCRP 
and reproduced in Table III-1. The Pt-193 dose coefficient from NCRP is judged acceptable 
because it is in reasonable agreement with Kocher (1983) and is less than 10-13, which is small 
compared to typical values, so that precise agreement is not important. 
Table III-1. Comparison of Ground Irradiation Dose Coefficients from Two Sources 
Nuclide 
Ac-225 
Ac-227 
Ac-228 
Ag-108 
Ag-108m 
Ag-109m 
Ag-110 
Ag-110m 
Am-241 
Am-242 
Am-242m 
Am-243 
Ar-39 
At-217 
Ba-133 
Ba-137m 
Bi-210 
Bi-211 
Bi-212 
Bi-213 
Bi-214 
Bk-249 
C-14 
Dose Coefficient for Exposure to Contaminated Ground 
FGR-12a 
(Sv/s)/(Bq/m2) 
FGR-12 
(Sv/d)/(Bq/m2) 
NCRP-123b 
(Sv/d)/(Bq/m2) 
Ratio FGR-12 : 
NCRP-123 
(dimensionless)c 
1.58E-17 1.37E-12e 1.20E-12 1.14E+00 
1.57E-19 1.36E-14 1.60E-14 8.48E-01 
9.28E-16 8.02E-11 6.70E-11 1.20E+00 
1.99E-17 1.72E-12 1.30E-12 1.32E+00 
1.60E-15 1.38E-10 1.20E-10 1.15E+00 
9.71E-18 8.39E-13 6.60E-13 1.27E+00 
3.82E-17 3.30E-12 2.30E-12 1.43E+00 
2.65E-15 2.29E-10 2.00E-10 1.14E+00 
2.75E-17 2.38E-12 2.20E-12 1.08E+00 
1.57E-17 1.36E-12 1.30E-12 1.04E+00 
3.02E-18 2.61E-13 2.00E-13 1.30E+00 
5.35E-17 4.62E-12 4.90E-12 9.43E-01 
3.38E-19 2.92E-14 0.00E+00 Undefinedc 
3.03E-19 2.62E-14 1.80E-14 1.45E+00 
3.97E-16 3.43E-11 3.10E-11 1.11E+00 
5.86E-16 5.06E-11 4.50E-11 1.13E+00 
1.05E-18 9.07E-14 0.00E+00 Undefined 
4.58E-17 3.96E-12 3.80E-12 1.04E+00 
1.79E-16 1.55E-11 1.30E-11 1.19E+00 
1.32E-16 1.14E-11 1.10E-11 1.04E+00 
1.41E-15 1.22E-10 1.00E-10 1.22E+00 
6.85E-21 5.92E-16 0.00E+00 Undefined 
1.61E-20 1.39E-15 0.00E+00 Undefined 

Nuclide 
Ca-41 
Ca-45 
Cd-109 
Cd-113 
Cd-113m 
Ce-139 
Ce-142 
Ce-144 
Cf-249 
Cf-250 
Cf-251 
Cf-252 
Cl-36 
Cm-242 
Cm-243 
Cm-244 
Cm-245 
Cm-246 
Cm-247 
Cm-248 
Co-58 
Co-60 
Cs-134 
Cs-135 
Cs-137 
Eu-150 
Eu-152 
Eu-154 
Eu-155 
Fe-55 
Fr-221 
Fr-223 
Gd-152 
Gd-153 
H-3 
Ho-166m 
I-129 
In-113m 
K-40 
Kr-85 
La-138 
Mn-54 
Dose Coefficient for Exposure to Contaminated Ground 
FGR-12a 
(Sv/s)/(Bq/m2) 
FGR-12 
(Sv/d)/(Bq/m2) 
NCRP-123b 
(Sv/d)/(Bq/m2) 
Ratio FGR-12 : 
NCRP-123 
(dimensionless)c 
0.00E+00 0.00E+00 1.50E-15 0.00E+00 
4.61E-20 3.98E-15 1.60E-20 2.49E+05d 
2.25E-17 1.94E-12 7.00E-13 2.78E+00d 
6.99E-20 6.04E-15 0.00E+00 Undefined 
2.63E-19 2.27E-14 0.00E+00 Undefined 
1.56E-16 1.35E-11 1.30E-11 1.04E+00 
Not listed Not listed Not listed Undefined 
2.03E-17 1.75E-12 1.60E-12 1.10E+00 
3.28E-16 2.83E-11 2.60E-11 1.09E+00 
7.37E-19 6.37E-14 5.10E-14 1.25E+00 
1.22E-16 1.05E-11 1.00E-11 1.05E+00 
7.22E-19 6.24E-14 4.70E-14 1.33E+00 
6.73E-19 5.81E-14 3.40E-18 1.71E+04d 
9.56E-19 8.26E-14 6.90E-14 1.20E+00 
1.25E-16 1.08E-11 1.10E-11 9.82E-01 
8.78E-19 7.59E-14 6.10E-14 1.24E+00 
8.70E-17 7.52E-12 6.30E-12 1.19E+00 
7.85E-19 6.78E-14 5.40E-14 1.26E+00 
3.10E-16 2.68E-11 2.50E-11 1.07E+00 
6.00E-19 5.18E-14 4.40E-14 1.18E+00 
9.50E-16 8.21E-11 7.30E-11 1.12E+00 
2.35E-15 2.03E-10 1.70E-10 1.19E+00 
1.52E-15 1.31E-10 1.20E-10 1.09E+00 
3.33E-20 2.88E-15 0.00E+00 Undefined 
2.85E-19 2.46E-14 0.00E+00 Undefined 
1.46E-15 1.26E-10 1.15E-10 1.10E+00 
1.10E-15 9.50E-11 8.20E-11 1.16E+00 
1.19E-15 1.03E-10 9.00E-11 1.14E+00 
5.90E-17 5.10E-12 5.30E-12 9.62E-01 
0.00E+00 0.00E+00 1.60E-14 0.00E+00c 
2.98E-17 2.57E-12 2.50E-12 1.03E+00 
5.65E-17 4.88E-12 4.40E-12 1.11E+00 
0.00E+00 0.00E+00 0.00E+00 Undefined 
1.06E-16 9.16E-12 9.40E-12 9.74E-01 
0.00E+00 0.00E+00 0.00E+00 Undefined 
1.70E-15 1.47E-10 1.20E-10 1.22E+00 
2.58E-17 2.23E-12 1.60E-12 1.39E+00 
2.54E-16 2.19E-11 2.00E-11 1.10E+00 
1.46E-16 1.26E-11 1.00E-11 1.26E+00 
2.64E-18 2.28E-13 1.70E-13 1.34E+00 
1.16E-15 1.00E-10 8.44E-11 1.19E+00 
8.12E-16 7.02E-11 6.20E-11 1.13E+00 

Nuclide 
Mo-93 
Nb-91 
Nb-93m 
Nb-94 
Nb-95 
Nb-95m 
Nd-144 
Ni-59 
Ni-63 
Np-235 
Np-236a 
Np-237 
Np-238 
Np-239 
Pa-231 
Pa-233 
Pa-234 
Pa-234m 
Pb-209 
Pb-210 
Pb-211 
Pb-212 
Pb-214 
Pd-107 
Pm-145 
Pm-146 
Pm-147 
Po-210 
Po-211 
Po-212 
Po-213 
Po-214 
Po-215 
Po-216 
Po-218 
Pr-144 
Pr-144m 
Pt-193 
Pu-236 
Pu-238 
Pu-239 
Pu-240 
Dose Coefficient for Exposure to Contaminated Ground 
FGR-12a 
(Sv/s)/(Bq/m2) 
FGR-12 
(Sv/d)/(Bq/m2) 
NCRP-123b 
(Sv/d)/(Bq/m2) 
Ratio FGR-12 : 
NCRP-123 
(dimensionless)c 
5.34E-18 4.61E-13 4.30E-13 1.07E+00 
Not listed Not listed Not listed Undefined 
9.39E-19 8.11E-14 7.60E-14 1.07E+00 
1.53E-15 1.32E-10 1.20E-10 1.10E+00 
7.48E-16 6.46E-11 5.70E-11 1.13E+00 
6.26E-17 5.41E-12 5.10E-12 1.06E+00 
Not listed Not listed Not listed Undefined 
0.00E+00 0.00E+00 3.10E-14 0.00E+00c 
0.00E+00 0.00E+00 0.00E+00 Undefined 
3.65E-18 3.15E-13 3.50E-13 9.01E-01 
1.20E-16 1.04E-11 1.19E-11 8.71E-01 
2.87E-17 2.48E-12 2.40E-12 1.03E+00 
5.29E-16 4.57E-11 4.00E-11 1.14E+00 
1.63E-16 1.41E-11 1.40E-11 1.01E+00 
4.07E-17 3.52E-12 2.60E-12 1.35E+00 
1.95E-16 1.68E-11 1.70E-11 9.91E-01 
1.84E-15 1.59E-10 1.50E-10 1.06E+00 
1.53E-17 1.32E-12 8.40E-13 1.57E+00 
3.01E-19 2.60E-14 0.00E+00 Undefined 
2.48E-18 2.14E-13 2.20E-13 9.74E-01 
5.08E-17 4.39E-12 3.90E-12 1.13E+00 
1.43E-16 1.24E-11 1.20E-11 1.03E+00 
2.44E-16 2.11E-11 2.00E-11 1.05E+00 
0.00E+00 0.00E+00 0.00E+00 Undefined 
3.26E-17 2.82E-12 2.20E-12 1.28E+00 
7.41E-16 6.40E-11 5.70E-11 1.12E+00 
3.41E-20 2.95E-15 3.00E-16 9.82E+00d 
8.29E-21 7.16E-16 6.40E-16 1.12E+00 
7.61E-18 6.58E-13 5.80E-13 1.13E+00 
0.00E+00 0.00E+00 0.00E+00 Undefined 
0.00E+00 0.00E+00 2.30E-15 0.00E+00c 
8.13E-20 7.02E-15 6.20E-15 1.13E+00 
1.74E-19 1.50E-14 1.20E-14 1.25E+00 
1.65E-20 1.43E-15 1.10E-15 1.30E+00 
8.88E-21 7.67E-16 0.00E+00 Undefined 
3.78E-17 3.27E-12 2.20E-12 1.48E+00 
1.30E-17 1.12E-12 7.50E-13 1.50E+00 
1.19E-19 1.03E-14 4.10E-14 2.51E-01d 
9.81E-19 8.48E-14 7.30E-14 1.16E+00 
8.38E-19 7.24E-14 6.30E-14 1.15E+00 
3.67E-19 3.17E-14 2.80E-14 1.13E+00 
8.03E-19 6.94E-14 6.10E-14 1.14E+00 

Nuclide 
Pu-241 
Pu-242 
Pu-243 
Ra-223 
Ra-224 
Ra-225 
Ra-226 
Ra-228 
Rb-87 
Rh-102 
Rh-106 
Rn-219 
Rn-220 
Rn-222 
Ru-106 
Sb-125 
Sb-126 
Sb-126m 
Se-79 
Sm-145 
Sm-146 
Sm-147 
Sm-148 
Sm-149 
Sm-151 
Sn-113 
Sn-119m 
Sn-121 
Sn-121m 
Sn-123 
Sn-126 
Sr-90 
Tb-160 
Tc-98 
Tc-99 
Te-123m 
Te-125m 
Te-127 
Te-127m 
Th-227 
Th-228 
Th-229 
Dose Coefficient for Exposure to Contaminated Ground 
FGR-12a 
(Sv/s)/(Bq/m2) 
FGR-12 
(Sv/d)/(Bq/m2) 
NCRP-123b 
(Sv/d)/(Bq/m2) 
Ratio FGR-12 : 
NCRP-123 
(dimensionless)c 
1.93E-21 1.67E-16 0.00E+00 Undefined 
6.67E-19 5.76E-14 5.00E-14 1.15E+00 
2.41E-17 2.08E-12 2.10E-12 9.92E-01 
1.28E-16 1.11E-11 1.10E-11 1.01E+00 
9.57E-18 8.27E-13 8.10E-13 1.02E+00 
1.33E-17 1.15E-12 1.10E-12 1.04E+00 
6.44E-18 5.56E-13 5.60E-13 9.94E-01 
0.00E+00 0.00E+00 4.90E-20 0.00E+00c 
8.80E-20 7.60E-15 0.00E+00 Undefined 
2.08E-15 1.80E-10 1.59E-10 1.13E+00 
2.12E-16 1.83E-11 1.60E-11 1.14E+00 
5.49E-17 4.74E-12 4.60E-12 1.03E+00 
3.81E-19 3.29E-14 4.00E-14 8.23E-01 
3.95E-19 3.41E-14 3.00E-14 1.14E+00 
0.00E+00 0.00E+00 0.00E+00 Undefined 
4.25E-16 3.67E-11 3.30E-11 1.11E+00 
2.78E-15 2.40E-10 2.10E-10 1.14E+00 
1.52E-15 1.31E-10 1.20E-10 1.09E+00 
2.07E-20 1.79E-15 0.00E+00 Undefined 
6.84E-17 5.91E-12 5.15E-12 1.15E+00 
0.00E+00 0.00E+00 0.00E+00 Undefined 
0.00E+00 0.00E+00 0.00E+00 Undefined 
Not listed Not listed Not listed Not listed 
Not listed Not listed Not listed Not listed 
5.03E-21 4.35E-16 3.80E-16 1.14E+00 
2.13E-17 1.84E-12 1.10E-12 1.67E+00 
1.04E-17 8.99E-13 4.40E-13 2.04E+00d 
1.05E-19 9.07E-15 0.00E+00 Undefined 
4.89E-18 4.22E-13 3.35E-13 1.26E+00 
8.37E-18 7.23E-13 4.80E-13 1.51E+00 
5.47E-17 4.73E-12 4.60E-12 1.03E+00 
2.84E-19 2.45E-14 0.00E+00 Undefined 
1.08E-15 9.33E-11 7.80E-11 1.20E+00 
1.38E-15 1.19E-10 1.10E-10 1.08E+00 
7.80E-20 6.74E-15 4.60E-17 1.47E+02 
1.43E-16 1.24E-11 1.20E-11 1.03E+00 
3.61E-17 3.12E-12 1.60E-12 1.95E+00 
5.18E-18 4.48E-13 3.80E-13 1.18E+00 
1.13E-17 9.76E-13 5.00E-13 1.95E+00 
1.04E-16 8.99E-12 8.70E-12 1.03E+00 
2.35E-18 2.03E-13 2.00E-13 1.02E+00 
8.54E-17 7.38E-12 7.80E-12 9.46E-01 

Nuclide 
Th-230 
Th-231 
Th-232 
Th-234 
Tl-206 
Tl-207 
Tl-208 
Tl-209 
Tm-171 
U-232 
U-233 
U-234 
U-235 
U-236 
U-237 
U-238 
Y-90 
Y-91 
Zn-65 
Zr-93 
Zr-95 
Dose Coefficient for Exposure to Contaminated Ground 
FGR-12a 
(Sv/s)/(Bq/m2) 
FGR-12 
(Sv/d)/(Bq/m2) 
NCRP-123b 
(Sv/d)/(Bq/m2) 
Ratio FGR-12 : 
NCRP-123 
(dimensionless)c 
7.50E-19 6.48E-14 6.70E-14 9.67E-01 
1.85E-17 1.60E-12 1.40E-12 1.14E+00 
5.51E-19 4.76E-14 4.90E-14 9.72E-01 
8.32E-18 7.19E-13 7.50E-13 9.58E-01 
1.99E-18 1.72E-13 8.70E-15 1.98E+01d 
3.76E-18 3.25E-13 1.60E-13 2.03E+00 
2.98E-15 2.57E-10 2.20E-10 1.17E+00 
1.90E-15 1.64E-10 1.50E-10 1.09E+00 
6.41E-19 5.54E-14 5.90E-14 9.39E-01 
1.01E-18 8.73E-14 7.60E-14 1.15E+00 
7.16E-19 6.19E-14 3.70E-14 1.67E+00 
7.48E-19 6.46E-14 6.00E-14 1.08E+00 
1.48E-16 1.28E-11 1.30E-11 9.84E-01 
6.50E-19 5.62E-14 5.40E-14 1.04E+00 
1.33E-16 1.15E-11 1.20E-11 9.58E-01 
5.51E-19 4.76E-14 4.80E-14 9.92E-01 
5.32E-18 4.60E-13 0.00E+00 Undefined 
5.74E-18 4.96E-13 2.40E-13 2.07E+00d 
5.53E-16 4.78E-11 4.10E-11 1.17E+00 
0.00E+00 0.00E+00 0.00E+00 Undefined 
7.23E-16 6.25E-11 5.50E-11 1.14E+00 
a
NOTES: FGR-12 denotes Eckerman & Ryman 1993 (Table III.3). 
b 
NCRP-123 denotes NCRP 1996 (Table A.1). 
c 
Division by zero indicates that the NCRP value is zero. See the text for discussion. 
d 
Cases where the ratio is greater than 2 or less than 0.5 are discussed in the text. 
e 
The computations represented in this table were done using multiplication and 
division operations in Excel. 
EVALUATION OF NCRP DOSE COEFFICIENTS FOR INHALATION 
The errors in the dose coefficients for ground irradiation (Attachment I) raise the possibility that 
one or more of the inhalation dose coefficients from the NCRP report may be in error in (NCRP 
1996, Table A.1). Also, there are methodological differences in the way inhalation dose 
coefficients were computed in the NCRP report and in the source that provides the most recent 
federal guidance on internal dose coefficients (Eckerman et al. 1988). To increase confidence in 
the inhalation dose coefficients from the NCRP report, Table III-2 and Figure III-1 provide the 
basis for a comparison of the dose coefficients for inhalation of the chemical form that results in 
the highest dose coefficient from NCRP (1996) to the comparable values provided by Eckerman 
et al. (1988, Table 2.1). The ratios of dose coefficients for inhalation exposure from Eckerman et 
al. (1988) to those from NCRP (1996) are near 1 (no greater than about 2 and no less than about 
0.6), indicating a favorable comparison (Table III-2). 

Nuclide 
FGR-11a 
Inhalation DCF 
(Sv/Bq) 
NCRP-123b 
Inhalation DCF 
(Sv/Bq) 
Ratio FGR-11 to 
NCRP-123 
(dimensionless)c 
Ac-225 2.92E-06 2.18E-06 1.34E+00 
Ac-227 1.81E-03 1.08E-03 1.68E+00 
Ac-228 8.33E-08 5.01E-08 1.66E+00 
Ag-108m 7.66E-08 7.16E-08 1.07E+00 
Ag-110m 2.17E-08 2.07E-08 1.05E+00 
Am-241 1.20E-04 7.08E-05 1.69E+00 
Am-242 1.58E-08 1.20E-08 1.32E+00 
Am-242m 1.15E-04 6.71E-05 1.71E+00 
Am-243 1.19E-04 7.05E-05 1.69E+00 
Bi-210 5.29E-08 5.19E-08 1.02E+00 
Bi-212 5.83E-09 4.72E-09 1.24E+00 
Bi-213 4.63E-09 3.83E-09 1.21E+00 
Bi-214 1.78E-09 1.60E-09 1.11E+00 
Bk-249 3.75E-07 2.04E-07 1.84E+00 
C-14 5.64E-10 5.64E-10 1.00E+00 
Ca-41 3.64E-10 2.93E-10 1.24E+00 
Ca-45 1.79E-09 1.75E-09 1.02E+00 
Cd-109 3.09E-08 1.62E-08 1.91E+00 
Cd-113 4.51E-07 2.34E-07 1.93E+00 
Cd-113m 4.13E-07 2.14E-07 1.93E+00 
Ce-144 1.01E-07 1.01E-07 1.00E+00 
Cf-249 1.56E-04 8.59E-05 1.82E+00 
Cf-250 7.08E-05 4.52E-05 1.57E+00 
Cf-251 1.59E-04 8.72E-05 1.82E+00 
Cf-252 4.24E-05 3.95E-05 1.07E+00 
Cl-36 5.93E-09 5.93E-09 1.00E+00 
Cm-242 4.67E-06 3.54E-06 1.32E+00 
Cm-243 8.30E-05 4.97E-05 1.67E+00 
Cm-244 6.70E-05 4.04E-05 1.66E+00 
Cm-245 1.23E-04 7.27E-05 1.69E+00 
Cm-246 1.22E-04 7.23E-05 1.69E+00 
Cm-247 1.12E-04 6.64E-05 1.69E+00 
Cm-248 4.47E-04 2.64E-04 1.69E+00 
Co-58 2.94E-09 2.93E-09 1.00E+00 
Co-60 5.91E-08 5.62E-08 1.05E+00 
Cs-134 1.25E-08 1.24E-08 1.01E+00 
Cs-135 1.23E-09 1.23E-09 1.00E+00 
Cs-137 8.63E-09 8.56E-09 1.01E+00 
Eu-150 7.25E-08 7.25E-08 1.00E+00 
Eu-152 5.97E-08 4.62E-08 1.29E+00 
Eu-154 7.73E-08 5.84E-08 1.32E+00 
Eu-155 1.12E-08 7.60E-09 1.47E+00 

Nuclide 
FGR-11a 
Inhalation DCF 
(Sv/Bq) 
NCRP-123b 
Inhalation DCF 
(Sv/Bq) 
Ratio FGR-11 to 
NCRP-123 
(dimensionless)c 
Fe-55 7.26E-10 6.34E-10 1.15E+00 
Fr-223 1.68E-09 1.68E-09 1.00E+00 
Gd-152 6.58E-05 3.74E-05 1.76E+00 
Gd-153 6.43E-09 4.10E-09 1.57E+00 
H-3 1.73E-11 1.73E-11 1.00E+00 
Ho-166m 2.09E-07 1.36E-07 1.54E+00 
I-129 4.69E-08 7.81E-08 6.01E-01 
In-113m 1.11E-11 1.04E-11 1.07E+00 
K-40 3.34E-09 3.32E-09 1.01E+00 
La-138 3.70E-07 2.83E-07 1.31E+00 
Mn-54 1.81E-09 1.74E-09 1.04E+00 
Mo-93 7.68E-09 7.66E-09 1.00E+00 
Nb-93m 7.90E-09 7.90E-09 1.00E+00 
Nb-94 1.12E-07 1.07E-07 1.05E+00 
Nb-95 1.57E-09 1.60E-09 9.81E-01 
Nb-95m 6.59E-10 7.49E-10 8.80E-01 
Ni-59 7.31E-10 7.23E-10 1.01E+00 
Ni-63 1.70E-09 1.70E-09 1.00E+00 
Np-235 1.12E-09 7.79E-10 1.44E+00 
Np-236a 2.81E-05 2.81E-05 1.00E+00 
Np-237 1.46E-04 7.79E-05 1.87E+00 
Np-238 1.00E-08 5.72E-09 1.75E+00 
Np-239 6.78E-10 7.23E-10 9.38E-01 
Pa-231 3.47E-04 1.73E-04 2.01E+00 
Pa-233 2.58E-09 2.74E-09 9.42E-01 
Pa-234 2.20E-10 2.04E-10 1.08E+00 
Pb-209 2.56E-11 2.27E-11 1.13E+00 
Pb-210 3.67E-06 2.03E-06 1.81E+00 
Pb-211 2.35E-09 2.33E-09 1.01E+00 
Pb-212 4.56E-08 3.66E-08 1.25E+00 
Pb-214 2.11E-09 2.03E-09 1.04E+00 
Pd-107 3.45E-09 3.46E-09 9.97E-01 
Pm-145 8.23E-09 7.43E-09 1.11E+00 
Pm-146 3.96E-08 3.74E-08 1.06E+00 
Pm-147 1.06E-08 1.02E-08 1.04E+00 
Po-210 2.54E-06 1.70E-06 1.49E+00 
Pr-144 1.17E-11 1.19E-11 9.83E-01 
Pt-193 6.14E-11 3.84E-11 1.60E+00 
Pu-236 3.91E-05 2.99E-05 1.31E+00 
Pu-238 1.06E-04 6.26E-05 1.69E+00 
Pu-239 1.16E-04 6.87E-05 1.69E+00 
Pu-240 1.16E-04 6.87E-05 1.69E+00 
Pu-241 2.23E-06 1.29E-06 1.73E+00 

Nuclide 
FGR-11a 
Inhalation DCF 
(Sv/Bq) 
NCRP-123b 
Inhalation DCF 
(Sv/Bq) 
Ratio FGR-11 to 
NCRP-123 
(dimensionless)c 
Pu-242 1.11E-04 6.54E-05 1.70E+00 
Pu-243 4.44E-11 4.03E-11 1.10E+00 
Ra-223 2.12E-06 2.08E-06 1.02E+00 
Ra-224 8.53E-07 8.32E-07 1.03E+00 
Ra-225 2.10E-06 2.07E-06 1.01E+00 
Ra-226 2.32E-06 2.17E-06 1.07E+00 
Ra-228 1.29E-06 1.16E-06 1.11E+00 
Rb-87 8.74E-10 8.42E-10 1.04E+00 
Rh-102 3.24E-08 2.98E-08 1.09E+00 
Ru-106 1.29E-07 1.31E-07 9.85E-01 
Sb-125 3.30E-09 3.38E-09 9.76E-01 
Sb-126 3.17E-09 3.37E-09 9.41E-01 
Sb-126m 9.17E-12 1.00E-11 9.17E-01 
Se-79 2.66E-09 1.93E-09 1.38E+00 
Sm-146 2.23E-05 1.36E-05 1.64E+00 
Sm-147 2.02E-05 1.24E-05 1.63E+00 
Sm-151 8.10E-09 4.99E-09 1.62E+00 
Sn-113 2.88E-09 3.00E-09 9.60E-01 
Sn-119m 1.69E-09 1.74E-09 9.71E-01 
Sn-121 1.38E-10 1.51E-10 9.14E-01 
Sn-121m 3.11E-09 3.14E-09 9.90E-01 
Sn-123 8.79E-09 9.20E-09 9.55E-01 
Sn-126 2.69E-08 2.70E-08 9.96E-01 
Sr-90 3.51E-07 3.51E-07 1.00E+00 
Tb-160 6.75E-09 6.36E-09 1.06E+00 
Tc-98 6.18E-09 6.39E-09 9.67E-01 
Tc-99 2.25E-09 2.42E-09 9.30E-01 
Te-123m 2.86E-09 2.46E-09 1.16E+00 
Te-125m 1.97E-09 1.82E-09 1.08E+00 
Te-127 8.60E-11 8.55E-11 1.01E+00 
Te-127m 5.81E-09 5.63E-09 1.03E+00 
Th-227 4.37E-06 4.34E-06 1.01E+00 
Th-228 9.23E-05 8.77E-05 1.05E+00 
Th-229 5.80E-04 3.53E-04 1.64E+00 
Th-230 8.80E-05 5.33E-05 1.65E+00 
Th-231 2.37E-10 2.56E-10 9.26E-01 
Th-232 4.43E-04 2.21E-04 2.00E+00 
Th-234 9.47E-09 1.02E-08 9.28E-01 
Tm-171 2.47E-09 1.56E-09 1.58E+00 
U-232 1.78E-04 1.78E-04 1.00E+00 
U-233 3.66E-05 3.65E-05 1.00E+00 
U-234 3.58E-05 3.58E-05 1.00E+00 
U-235 3.32E-05 3.31E-05 1.00E+00 

Nuclide 
FGR-11a 
Inhalation DCF 
(Sv/Bq) 
NCRP-123b 
Inhalation DCF 
(Sv/Bq) 
Ratio FGR-11 to 
NCRP-123 
(dimensionless)c 
U-236 3.39E-05 3.39E-05 1.00E+00 
U-237 9.54E-10 1.09E-09 8.75E-01 
U-238 3.20E-05 3.19E-05 1.00E+00 
Y-90 2.28E-09 2.69E-09 8.48E-01 
Y-91 1.32E-08 1.37E-08 9.64E-01 
Zn-65 5.51E-09 5.27E-09 1.05E+00 
Zr-93 8.67E-08 4.31E-08 2.01E+00 
Zr-95 6.39E-09 6.35E-09 1.01E+00 
NOTES: aFGR-11 denotes Eckerman et al. 1988 (Table 2.1). 
bNCRP-123 denotes NCRP 1996 (Table A.1). 
cThe computations were done using multiplication and summation 
operations in Excel. 
NCRP (1996) Inhalation Dose Coefficient (Sv/Bq) 
1.0E-02 
1.0E-03 
1.0E-04 
1.0E-05 
1.0E-06 
1.0E-07 
1.0E-08 
1.0E-09 
1.0E-10 
1.0E-11 
1.0E-12 
1.0E-12 1.0E-11 1.0E-10 1.0E-09 1.0E-08 1.0E-07 1.0E-06 1.0E-05 1.0E-04 1.0E-03 1.0E-02 
Eckerman et al. (1988) Inhalation Dose Coefficient (Sv/Bq) 
Figure III-1. Graphical Comparison of Inhalation Dose Coefficients from Two Sources 

The errors in the dose coefficients for ground irradiation (Attachment I) raise the possibility that 
one or more of the ingestion dose coefficients from the NCRP report may be in error in (NCRP 
1996, Table A.1). Also, there are methodological differences in the way ingestion dose 
coefficients were computed in the NCRP report and in the source that provides the most recent 
federal guidance on internal dose coefficients (Eckerman et al. 1988). To increase confidence in 
the ingestion dose coefficients from the NCRP report, Table III-3 and Figure III-2 provide the 
basis for a comparison of the dose coefficients for ingestion of the chemical form that results in 
the highest dose coefficient from NCRP (1996) to the comparable values provided by Eckerman 
et al. (1988, Table 2.1). The ratios of the dose coefficients for ingestion exposure from 
Eckerman et al. (1988) to those from NCRP (1996) are near 1 (no greater than about 2.7 times 
and no less than about 0.6 times), indicating a favorable comparison (Table III-3). 
Table III-3. Comparison of Ingestion Dose Coefficients from Two Sources 
Nuclide 
FGR-11a 
Ingestion DCF 
(Sv/Bq) 
NCRP-123b 
Ingestion DCF 
(Sv/Bq) 
Ratio FGR-11 to 
NCRP-123 
(dimensionless)c 
Ac-225 3.00E-08 3.81E-08 7.87E-01 
Ac-227 3.80E-06 2.26E-06 1.68E+00 
Ac-228 5.85E-10 4.50E-10 1.30E+00 
Ag-108m 2.06E-09 2.05E-09 1.00E+00 
Ag-110m 2.92E-09 2.89E-09 1.01E+00 
Am-241 9.84E-07 5.79E-07 1.70E+00 
Am-242 3.81E-10 3.85E-10 9.90E-01 
Am-242m 9.50E-07 5.54E-07 1.71E+00 
Am-243 9.79E-07 5.75E-07 1.70E+00 
Ba-133 9.19E-10 9.50E-10 9.67E-01 
Bi-210 1.73E-09 1.93E-09 8.96E-01 
Bi-212 2.87E-10 2.21E-10 1.30E+00 
Bi-213 1.95E-10 1.75E-10 1.11E+00 
Bi-214 7.64E-11 1.07E-10 7.14E-01 
Bk-249 3.24E-09 1.89E-09 1.71E+00 
C-14 5.64E-10 5.64E-10 1.00E+00 
Ca-41 3.44E-10 2.67E-10 1.29E+00 
Ca-45 8.55E-10 8.56E-10 9.99E-01 
Cd-109 3.55E-09 2.22E-09 1.60E+00 
Cd-113 4.70E-08 2.47E-08 1.90E+00 
Cd-113m 4.35E-08 2.33E-08 1.87E+00 
Ce-139 3.09E-10 3.67E-10 8.42E-01 
Ce-144 5.68E-09 8.18E-09 6.94E-01 
Cf-249 1.28E-06 7.02E-07 1.82E+00 
Cf-250 5.76E-07 3.19E-07 1.81E+00 
Cf-251 1.31E-06 7.14E-07 1.83E+00 
Cf-252 2.93E-07 1.73E-07 1.69E+00 
Cl-36 8.18E-10 8.36E-10 9.78E-01 

Nuclide 
FGR-11a 
Ingestion DCF 
(Sv/Bq) 
NCRP-123b 
Ingestion DCF 
(Sv/Bq) 
Ratio FGR-11 to 
NCRP-123 
(dimensionless)c 
Cm-242 3.10E-08 2.31E-08 1.34E+00 
Cm-243 6.79E-07 4.03E-07 1.68E+00 
Cm-244 5.45E-07 3.25E-07 1.68E+00 
Cm-245 1.01E-06 5.94E-07 1.70E+00 
Cm-246 1.00E-06 5.90E-07 1.69E+00 
Cm-247 9.24E-07 5.43E-07 1.70E+00 
Cm-248 3.68E-06 2.17E-06 1.70E+00 
Co-58 9.68E-10 9.86E-10 9.82E-01 
Co-60 7.28E-09 7.09E-09 1.03E+00 
Cs-134 1.98E-08 1.95E-08 1.02E+00 
Cs-135 1.91E-09 1.92E-09 9.95E-01 
Cs-137 1.35E-08 1.35E-08 1.00E+00 
Eu-150 1.72E-09 1.72E-09 1.00E+00 
Eu-152 1.75E-09 1.92E-09 9.11E-01 
Eu-154 2.58E-09 2.99E-09 8.63E-01 
Eu-155 4.13E-10 5.03E-10 8.21E-01 
Fe-55 1.64E-10 1.52E-10 1.08E+00 
Fr-223 2.33E-09 2.34E-09 9.96E-01 
Gd-152 4.34E-08 2.63E-08 1.65E+00 
Gd-153 3.17E-10 3.94E-10 8.05E-01 
H-3 1.73E-11 1.73E-11 1.00E+00 
Ho-166m 2.18E-09 2.19E-09 9.95E-01 
I-129 7.46E-08 1.24E-07 6.02E-01 
In-113m 2.83E-11 2.28E-11 1.24E+00 
K-40 5.02E-09 5.09E-09 9.86E-01 
La-138 1.59E-09 1.53E-09 1.04E+00 
Mn-54 7.48E-10 7.09E-10 1.06E+00 
Mo-93 3.64E-10 2.36E-10 1.54E+00 
Nb-93m 1.41E-10 1.92E-10 7.34E-01 
Nb-94 1.93E-09 2.17E-09 8.89E-01 
Nb-95 6.95E-10 7.35E-10 9.46E-01 
Nb-95m 6.22E-10 8.30E-10 7.49E-01 
Ni-59 5.67E-11 6.51E-11 8.71E-01 
Ni-63 1.56E-10 1.88E-10 8.30E-01 
Np-235 6.56E-11 8.45E-11 7.76E-01 
Np-236a 2.34E-07 2.34E-07 1.00E+00 
Np-237 1.20E-06 6.38E-07 1.88E+00 
Np-238 1.08E-09 1.26E-09 8.57E-01 
Np-239 8.82E-10 1.13E-09 7.81E-01 
Pa-231 2.86E-06 1.42E-06 2.01E+00 
Pa-233 9.81E-10 1.33E-09 7.38E-01 
Pa-234 5.84E-10 5.57E-10 1.05E+00 
Pb-209 5.75E-11 5.31E-11 1.08E+00 

Nuclide 
FGR-11a 
Ingestion DCF 
(Sv/Bq) 
NCRP-123b 
Ingestion DCF 
(Sv/Bq) 
Ratio FGR-11 to 
NCRP-123 
(dimensionless)c 
Pb-210 1.45E-06 8.02E-07 1.81E+00 
Pb-211 1.42E-10 1.64E-10 8.66E-01 
Pb-212 1.23E-08 8.35E-09 1.47E+00 
Pb-214 1.69E-10 1.54E-10 1.10E+00 
Pd-107 4.04E-11 5.82E-11 6.94E-01 
Pm-145 1.28E-10 1.49E-10 8.59E-01 
Pm-146 9.91E-10 1.15E-09 8.62E-01 
Pm-147 2.83E-10 3.98E-10 7.11E-01 
Po-210 5.14E-07 2.14E-07 2.40E+00 
Pr-144 3.15E-11 4.93E-11 6.39E-01 
Pt-193 3.21E-11 4.49E-11 7.15E-01 
Pu-236 3.15E-07 1.89E-07 1.67E+00 
Pu-238 8.65E-07 5.10E-07 1.70E+00 
Pu-239 9.56E-07 5.62E-07 1.70E+00 
Pu-240 9.56E-07 5.62E-07 1.70E+00 
Pu-241 1.85E-08 1.07E-08 1.73E+00 
Pu-242 9.08E-07 5.33E-07 1.70E+00 
Pu-243 9.02E-11 8.71E-11 1.04E+00 
Ra-223 1.78E-07 1.29E-07 1.38E+00 
Ra-224 9.89E-08 7.41E-08 1.33E+00 
Ra-225 1.04E-07 7.09E-08 1.47E+00 
Ra-226 3.58E-07 2.25E-07 1.59E+00 
Ra-228 3.88E-07 2.76E-07 1.41E+00 
Rb-87 1.33E-09 1.29E-09 1.03E+00 
Rh-102 2.82E-09 2.73E-09 1.03E+00 
Ru-106 7.40E-09 1.00E-08 7.40E-01 
Sb-125 7.59E-10 9.30E-10 8.16E-01 
Sb-126 2.89E-09 3.23E-09 8.95E-01 
Sb-126m 2.54E-11 3.47E-11 7.32E-01 
Se-79 2.35E-09 1.55E-09 1.52E+00 
Sm-145 2.46E-10 3.04E-10 8.09E-01 
Sm-146 5.51E-08 3.46E-08 1.59E+00 
Sm-147 5.01E-08 3.15E-08 1.59E+00 
Sm-151 1.05E-10 1.35E-10 7.78E-01 
Sn-113 8.33E-10 1.09E-09 7.64E-01 
Sn-119m 3.76E-10 5.22E-10 7.20E-01 
Sn-121 2.44E-10 3.00E-10 8.13E-01 
Sn-121m 4.19E-10 6.01E-10 6.97E-01 
Sn-123 2.27E-09 3.25E-09 6.98E-01 
Sn-126 5.27E-09 6.55E-09 8.05E-01 
Sr-90 3.85E-08 3.10E-08 1.24E+00 
Tb-160 1.82E-09 2.26E-09 8.05E-01 
Tc-98 1.32E-09 1.83E-09 7.21E-01 

Nuclide 
FGR-11a 
Ingestion DCF 
(Sv/Bq) 
NCRP-123b 
Ingestion DCF 
(Sv/Bq) 
Ratio FGR-11 to 
NCRP-123 
(dimensionless)c 
Tc-99 3.95E-10 6.64E-10 5.95E-01 
Te-123m 1.53E-09 1.20E-09 1.28E+00 
Te-125m 9.92E-10 9.06E-10 1.09E+00 
Te-127 1.87E-10 1.84E-10 1.02E+00 
Te-127m 2.23E-09 2.28E-09 9.78E-01 
Th-227 1.03E-08 1.27E-08 8.11E-01 
Th-228 1.07E-07 6.55E-08 1.63E+00 
Th-229 9.54E-07 4.80E-07 1.99E+00 
Th-230 1.48E-07 7.75E-08 1.91E+00 
Th-231 3.65E-10 4.40E-10 8.30E-01 
Th-232 7.38E-07 3.69E-07 2.00E+00 
Th-234 3.69E-09 5.30E-09 6.96E-01 
Tm-171 1.16E-10 1.64E-10 7.07E-01 
U-232 3.54E-07 1.31E-07 2.70E+00 
U-233 7.81E-08 2.88E-08 2.71E+00 
U-234 7.66E-08 2.82E-08 2.72E+00 
U-235 7.19E-08 2.73E-08 2.63E+00 
U-236 7.26E-08 2.67E-08 2.72E+00 
U-237 8.57E-10 1.15E-09 7.45E-01 
U-238 6.88E-08 2.58E-08 2.67E+00 
Y-90 2.91E-09 3.93E-09 7.40E-01 
Y-91 2.57E-09 3.71E-09 6.93E-01 
Zn-65 3.90E-09 3.72E-09 1.05E+00 
Zr-93 4.48E-10 3.03E-10 1.48E+00 
Zr-95 1.02E-09 1.21E-09 8.43E-01 
NOTES: aFGR-11 denotes Eckerman et al. 1988 (Table 2.1). 
bNCRP-123 denotes NCRP 1996 (Table A.1). 
cThe computations were done using multiplication and summation 
operations in Excel. 

1.0E-05
1.0E-06
1.0E-07
1.0E-08
1.0E-09
1.0E-10
1.0E-11
NCRP (1996) Ingestion Dose Coefficient (Sv/Bq) 
1.0E-11 1.0E-10 1.0E-09 1.0E-08 1.0E-07 1.0E-06 1.0E-05
Eckerman et al. (1988) Ingestion Dose Coefficient (Sv/Bq) 
Figure III-2. Graphical Comparison of Ingestion Dose Coefficients from Two Sources 

CORRECTION OF Se-79 ACTIVITIES 
(1 page) 
The first section below derives a generic correction factor for an activity calculation that was 
originally performed with an erroneous half-life or decay constant. The second section applies 
the generic correction factor to the present screening analysis to compute correction factors for 
Se-79 activity during the regulatory period and at 1 million years. 
DERIVATION OF THE CORRECTION FACTOR 
Assuming the number of nuclei, N 0, is correct in the activity calculations at time zero, the old 
(incorrect) and new (corrected) activities are given by 
A 
old(t ) = lold N 0 exp(-l t )
old 
2 ln 2 ln 
= N 0 exp(-t ) 
t 
old 
t old 
and 
A (t ) = lnew N 0 exp(-l t )
new new 
2 ln 2 ln 
= N 0 exp(-t ), 
tt
new new 
where and lold and lnew are the old and new decay constants, told and tnew are the old and new 
half-lives, and t is the decay time. The correction factor is 
new
( 
A
t F ) = 
A (t ) 
old(t ) 
t 11
old 
= )( 2 exp[(ln -) t ]. 
t 
new t old t new 
APPLICATION TO Se-79 IN THE PRESENT ANALYSIS 
For Se-79 in the present analysis, told is 330,000 y and tnew is 1.1  106 y (Assumption 5.3). At 
t = 0, which corresponds approximately to reactor discharge, waste emplacement, or repository 
closure, application of the correction factor yields 0.33  106 / 1.1  106 = 0.30. At 10,000 y, the 
correction factor is still about 0.30 because the exponential term has only grown to about 1.01 
(so that a precise definition of t = 0 is unimportant). Thus, the correction reduces the Se-79 
activity throughout the regulatory period by a factor of about 0.3. At 1 million years, the 
exponential term will have grown to about 4.4, so that the correction factor is about 1.3. 

ATTACHMENT V. 
CONTENTS OF ATTACHMENT VI 
(1 page) 
Figure V-1 provides a directory listing of the files contained in Attachment VI, which is a 
compact disk. The filenames indicate the waste form type (BWR, etc.), representativeness 
(Av = average, Max = outlying), and the time period (100-10k = the 10,000-y regulatory period, 
20k = 20,000 y only, and 20k-1M = 20,000 y through 1 million y). Except for the Screening 
Summary file, which is an output summary, the first two worksheets in each workbook file 
provide the inputs, while the remaining worksheets provide the outputs. The screening summary 
provides a summary of results by waste form. 
Figure V-1. Contents of Attachment VI