Presented by Brad Clawson

Fernald SEC Petition Review
 

Status Report and Action Items 


Following the Work Group Meeting
 

Held on August 11, 2011
 

Presented by Brad Clawson
 

Presented to the Advisory Board on Radiation and W

Full Board Meeting Held in Richland, Washing

August 23-25, 2011
 
Work Group Review: Overvie

•	 April 19, 2006: SEC Petition qualified 

–	 “All employees who worked in all facilities at the Feed 

Production Center (FMPC) in Fernald, Ohio, from Jan through Dec 31, 1989” 

•	 Nov 3, 2006: NIOSH Evaluation Report issued 

–	 “NIOSH found no part of the class under evaluation for whic

estimate radiation doses with sufficient accuracy.” 

•	 Nov 10, 2006: SC&A Site Profile Review •	 July 2, 2007: SC&A SEC PER Review •	 August 2007 

- August 2011: Eleven Work Group meetin

•	 May 24, 2011, ABRWH Meeting: SC&A presents detailed 

of SEC issues (as of April 2011) 
Work Group SEC Issues
 

1.	 Coworker Model for Uranium Internal Exposures – ope2.	 Validation of the HIS-20 database – closed* 3.	 Recycled Uranium (RU) – open 

4.	 Use of radon breath data for reconstructing doses from 

of Ra-226 and Th-230 – closed* 

5.	 Review of radon emissions from the K-65 silos and ass

exposures - moved to site profile discussions 

6.	 Reconstruction of internal exposures from inhalation of 

6A: DWE Data (1953 – 1967) – closed* 6B: Chest Counts (1968 – 1989) - open 

(* recommended by SC&A)
 
Open Issue (#1): Co-worker Model for Uranium

Internal Exposures
 

Description of Issue – Concerns regarding the completeness and adequacy of the ubioassay data available for dose reconstruction and supportinFernald internal dosimetry co-worker model (OTIB -0078, datNovember 6, 2007) 

Status of Issue –
 

Resolved except for matters related to the applicability of the Resolved except for matters related to the applicability of the model to Fernald construction workers
 Open action Items:
 NIOSH to perform an analysis of construction worker (CW) vsuranium bioassay data for TIB-0078 and deliver a report
 

August 11, 2011 WG meeting - NIOSH indicated analysis and report in internal review 

SC&A to review the report when it becomes available 
white paper (March 31, 2011) and NIOSH position paper on RU defaults 

Open Issue (#3): Recycled Uranium (R

Description of Issue: Concern that default concentrations of Pu-239, Npisotopes associated with RU at Fernald may not be bounding for some cactivities, buildings, and time periods. Status of issue: Numerous white papers have been exchanged where Nits technical basis in support of its default values and SC&A provides the believes that the default values may not bounding for all workers and timAugust 2011 Work Group Meeting: SC&A response to NIOSH review of 

white paper (March 31, 2011) and NIOSH position paper on RU defaults 2011) 

SC&A Observations – NIOSH review of second SC&A RU white pap

•	 NIOSH acknowledges processes that resulted in concentration of R

above levels in feed materials (e.g., MgF2 ‘dolomite’ problem) 

•	 NIOSH acknowledges limitations and uncertainties in the data from 

balance reports (basis for NIOSH default values) 

•	 Arithmetic mean concentrations for the 19 subgroup processes in DOE 

Report (DOE 2000) are not bounding; data highly variable and uncerta

•	 Propose upper 95th percentile of lognormal distributions for all but high

subgroup (1973–1989) 
Issue #3: Recycled Uranium - contin

August 11, 2011 Work Group Meeting
 

New NIOSH Position on Default Values (August 5, 2011): 

1953 -1960: Proposes no RU constituent intakes 1961-1972: Proposes ‘original’ defaults 

Pu-239 (100 ppb U) Np-237 (3500 ppb U) Tc-99 (9000 ppb U) 

1973-1989: Proposes increased default values (value, basis) 

Factor of 4 for Pu-239 (100 ppb U 

- 400 ppb U) (Subgroup 8; M

Factor of 3 for Np-237 (3500 ppb U 

- 11,000 ppb U) (Subgroup 

Residues)
 Factor of 2 for Tc-99 (9000 ppb U 

- 20,000 ppb U) (Subgroup 6

products) Based principally on MgF2 concentration in metal reduction (Plancontinuous worker exposures 
Issue #3: Recycled Uranium - contin

SC&A observations - NIOSH position on RU defaul

•	 NIOSH correlates increased worker exposure potential wit

receipts of 

Plutonium 

Out 

Of 

Specification (POOS) feed m

beginning in 1973 (worst was in 1980 – Paducah tower as

–	 Prior to 1973, NIOSH proposes original (lower) defaults – However, POOS feeds down-blended (Plants 1, 4, 8) before 

sent to the Refinery (Plants 2 and 3) and subsequent processsent to the Refinery (Plants 2 and 3) and subsequent processsteps 

–	 Therefore, concentrated constituents in MgF2 (metals produc

step) were mostly from down-blended materials 

–	 Because MgF2 data in DOE 2000 report were from 1982-198

cannot assess extent of MgF2 concentration prior to POOS r

•	 If MgF2 constituent concentrations are not correlated with POOS 

higher defaults could be applicable prior to 1973 (bounding one-all approach) 
- :

Issue #3: Recycled Uranium - conclu

SC&A position on new proposed NIOSH default values 

1953-1960: •	 This period can be bounded (site profile); However, SC&A believes 

of zero is neither appropriate nor claimant favorable 

1961-1972: •	 This period can be bounded (site profile); questions remain as to w

should be (original vs. new higher values) 

• Impact of MgF2 concentration with low feed levels
 

1973-1989
: •	 Proposed higher defaults; probably bounding for the highest contin

subgroup of workers (Plant 5 metal workers and associated millwri

•	 Initial POOS feed concentrations (subgroup 10A) could have impac

and down-blenders; also indirect exposures (bystander effect) (SEC 1985; 1986-1989 – good HP/IH program) 

•	 Small subset but cannot identify based on work records •	 Likely intermittent exposure but not yet quantified 

NIOSH Action Item: quantify down-blending intervals; assess impacSC&A action item: review NIOSH assessment 
Open Issue (#6B) Reconstruction of internal exp

from the inhalation of Th-232
 

Description of issue 6B: Use of chest counts to reconstruct Th

exposures (1968 -1989) 

•	 No DWE data after MIVRML introduced in 1968 – therefore comple

dependent on integrity of chest count data thereafter 

•	 SC&A believes that uncertainties in data sets are not adequately qStatus of issue: White papers exchanged; issue first discussed in d

April 19, 2011, Work Group meeting 

April 19, 2011, Work Group meeting: 

•	 NIOSH action item: post for review newly acquired documents on MIVRM

•	 Documents posted and new white paper provided (May 6, 2011) 

•	 SC&A action items: 

•	 Review the new calibration documents in the context of our June 2010 white pa

adequacy) 

•	 Provide a formal response to NIOSH concerning the issue of whether thorium w

underrepresented in the coworker model (data completeness) 

•	 New responses provided ( August 2011: data adequacy; data completeness) 
Issue #6B: Use of chest counts to reconstr

Th-232 exposures (1968-1989), continued 

August 11, 2011, Work Group meeting: Discussions of new NIOSH white pape

responses on data adequacy and completeness 

SC&A Concerns - Data Adequacy 

1968–1978: Reported in milligrams (mg) thorium (period of thorium processing) 

•	 Questionable calibration method (screening vs. quantitative) •	 Questionable calibration source used to derive MDL- contaminated with R•	 Questionable method to evaluate age of source and transform Ac-228/Pb

mg Th-232 – No raw data, just mg thorium reported 

• Examples indicate Ac-228 used – very sensitive to age of source 

•	 Uncertainty in age of source(s) at time(s) of intake (factor of about 2 for a 

using Pb-212; orders of magnitude if Ac-228 used) 

•	 Uncertainties in the resident time in the lung (progeny in-growth and trans

2.5 or more) 

•	 MDL of 6 mg not supported by reference or data (only 3 % of results > 6 m

in MDL and from ‘noise’ in values < MDL 

•	 Inconsistencies between mg Th-232 and nCi Pb-212 for period of overlap 

mg Th-232 correspond to negative Pb-212 results (SC&A white paper – J

•	 Data for individual workers inconsistent with biokinetic processes (SC&A M

April 6, 2011) 

•	 Large variability and uncertainty in mg Th-232 data and lack of knowle

derivation may preclude ability to bound intakes 1968 - 1978 (SEC iss
o . n > t percent e; uncerta nt es rom no se n v

Issue #6B: Use of chest counts to reconstr

Th-232 exposures (1968-1989), continued 

SC&A concerns - Data Adequacy, concluded 

1979–1988: Reported in nCi Thorium (based on Pb-212 and Ac-

stewardship) 

•	 Large impact of measurement variability (nCi Pb-212 and nCi Ac

derived result (cited example - factor of about 2) 

•	 Uncertainties in the resident time in the lung (progeny in-growth/• Uncertainties in the REMAB phantom (up to a factor of 3, pre-19

• MDL f 0 25 Ci 84 h il i i f ‘ i ’ i 

MDL of 0.25 nCi > 84th percentile; uncertainties from ‘noise’ in vthe MDL 

•	 Equilibrium factor (EF) of 0.42 for Pb-212 measurements based 

system (no translocation out of lung) 

•	 Experimental data indicate EF could be lower 

•	 Raw data are available - nCi thorium data may be adequate to 

intakes (site profile) 

• NIOSH coworker model uses a GSD of 3 (based on biokinetic m

•	 Does not appear to address measurement uncertainties •	 Possibly adequate when applied to a distribution of results for multip

year, but not quantified 
Issue #6B Use of chest counts to reconstruc

exposures post-1968, continued 

SC&A Concerns - Data Completeness (assuming data adequate for co

model) 

SC&A tasking – formal response (February and April 2011 Work Group 

•	 Are thorium workers adequately represented in the data set? 

•	 Only one reference identifies thorium workers with a specific production year (19

•	 If not, do chemical operators provide a reasonable surrogate for thorium wo

a coworker model? 

•	 Is sampling frequency correlated with lung burden? (sampling directed at m

exposed workers) 

SC&A response (thorium operational period – mg thorium data) Finding #1 •	 Thorium worker results generally higher than chemical operators at most pe•	 Thorium worker 95th percentiles are higher in all but 4 years when compare

all workers or chemical operator 95th percentiles 

•	 Non-parametric 95% confidence intervals for the 95th percentiles: only 197

significant differences between the thorium subgroup, the chemical operatoworkers 

•	 No evidence that chemical operator group provides definitive upper bound f

worker exposure 
Issue #6B Use of chest counts to reconstruc

exposures post-1968, concluded
 

Finding #2 •	 Less than 3% of the in-vivo records for mg Th are at or above the assumed 

•	 This, combined with uncertainties regarding the accuracy and veracity of the MD

the model into question 

•	 Nonetheless, thorium workers appear to be well represented among the in-

above the MDL 

•	 Workers comprise 7% of the total but over 20% of those with positive results • Samples comprise 13% of the total but nearly 33% of the positive results 

Finding #3 •	 No positive linear correlation between thorium monitoring frequency and ma

results 

•	 Uranium monitoring results showed much better linear correlation between 

frequency and the relative magnitude of results 

•	 Suggests that the in-vivo program may have been targeting higher risk work

uranium activities 

NIOSH action item: Formal response to SC&A responses before next meeting SC&A to review NIOSH response 
an ystan ers may ave een expose to su group concen

Summary
 

Issues remain to be dispositioned with NIOSH and •	 Work Group deferring action on recycled uranium for 1973 throu

pending further assessment 

–	 NIOSH to locate historical information regarding the time required f

blending 

–	 From this it may be possible to estimate periods during which down

( d b d ) h b d b 10A (and bystanders) may have been exposed to subgroup 10A concendetermine whether the new higher defaults are bounding 

– SC&A to review NIOSH’s quantitative analysis when it becomes av

•	 Work Group deferring action on thorium chest count data (1968-

pending further assessment 

–	 NIOSH to provide formal responses to SC&A on the August 2011 d

adequacy and completeness reports 

–	 SC&A to review NIOSH’s response when it becomes available 
Questions?