Advisory Board on Radiation and Worker Health

Naperville, IL

March 23, 2017
Work Group Members

 Josie Beach, Chair

 Brad Clawson

 John Poston

 Loretta Valerio

 Jim Lockey
Site Profile Activities to date

 ABRWH agreed dose reconstruction feasible, determination noticed in 

Federal Register on April 21, 2016.

 SEC process concluded November 19, 2015; remaining site profile issues 

combined with original TBD issues in final TBD Issues Matrix. 

 NIOSH addressed these TBD issues in January 2017 revision of KCP site 

profile (ORAUT-TKBS-0031 Rev. 01).

 SC&A reviewed revision and found conformance with matrix actions and 

work group commitments made previously.

 Work group met on March 2, 2017 and closed all remaining issues.
SEC Issues transferred to Site Profile Matrix

 SEC 2, Worker Location, Job Category, and Coworker Model. Because of 

varied historic operations and a lack of specific worker job locations and 

job categories, application of coworker and a generalized TBD could result 

in incorrect dose assignments. 

 Resolution: Revised TBD provides guidance for different categories of 

workers for depleted uranium, and for different categories of workers and 

time periods for other radionuclide intakes. Attachment B provides 

external coworker assignment guidelines. 
SEC Issues transferred to Site Profile Matrix

 SEC 3, Chronic vs. Acute Intakes, Uranium coworker model may not be 

applicable to most workers.

 Resolution: When estimating intakes, dose reconstructors should 

assume exposures to uranium dust were chronic. A chronic exposure 

pattern best approximates the true exposure conditions for most 

workers with a potential for intakes. In addition, a chronic exposure 

pattern approximates a series of acute intakes, which makes it 

appropriate when there is no specific information for a given 

individual.

 SEC 10, Non-penetrating Dose – for some periods details of nonpenetrating exposure (especially 1959-1962) are lacking. 

 Resolution: Revised TBD addresses concerns with the use of recorded dose 

units.
 Natural Uranium Operations (1950-1955) – applies Battelle TBD- 6000 methodology as bounding for inhalation and ingestion 

intakes, with accompanying information and guidance for these 

operations.

 Post Operations Period (1955-1959) – uses maximum gross- alpha measured air sample (49 pCi/m3) to determine internal 

exposure at KCP after natural uranium operations ceased in 1955 

until start of KCP urinalysis program in 1959. 

 Tritium Water Operations (1959-1975) – Bounding scenario uses 

400 ml bottle of tritiated water spilled over a work year and 

absorbed by a worker (6.66 mrem/year dose applied to all 

workers). 

NIOSH added the following operations and 

exposure bounding methods to the TBD
NIOSH added the following operations and 

exposure bounding methods to the TBD cont.

 Magnesium Thorium Alloy Operations (1961-1963, 1970-1977) - engineering control limit of 3 × 10-11 μCi/mL alpha applied as a constant 

distribution to estimate an exposure rate for identified Mg-Th workers. 

TBD-6000 applied to determine air concentrations for classes of workers 

that had less exposure potential or spent less time in the Mg-Th machining 

areas (e.g., Department 20 or the Model Shop) than the machine 

operators.

 Post Operations Period (1972-1984) - bounded using the maximum 

measured surface contamination survey data during DU and D&D 

operations and ORAUT-OTIB-0070.

 Organically Bound Tritium Operations (hi-lo switch plates, 1963-1968) – bounded using the 95th percentile contamination transferred to skin and 

absorbed; 1.77 mrem/year dose applied to all workers. 
NIOSH added the following operations and 

exposure bounding methods to the TBD cont.

 Decommissioning and decontamination (1984-1986) – bounded assuming 

alpha inhalation rate of 6.76 pCi/day and an ingestion intake rate of 0.135 

pCi/day, based on “the air sample control level of 1 × 10-12 μCi/mL, a 

breathing rate 1.2 m3/hr, and a period of 2,000 hr/yr.” (reflects Rockwell 

report indicating no personnel exposures occurred).

 Rad Waste Handling - for operations associated with routine rad waste 

handling, rad-area maintenance, housekeeping and decontamination, 

bounding doses assigned to all unmonitored personnel performing this 

work using DU coworker model (applying exposure category 2 (i.e., workers 

with occasional exposure). 
Remaining Findings from Nov. 2013 Site 

Profile review 

 SP1: AMAD - activities at KCP involved handling substantial quantities of 

UO2 powder. Site profile recommended using default option AMAD of 5 

μm, which was questioned by SC&A. Revised TBD includes additional 

guidance with detailed specifications for uranium oxide during operational 

period in question, satisfying original concern. 

 SP3: Bioassay Data – bioassay data appeared to be incomplete. Resolved 

by revised coworker data and validation and verification performed. 

 SP5: Admin Codes – approach used to categorize workers may result in 

misassignment of dose. Job titles and categories are now included in 

revised TBD to facilitate assignment. 
Remaining Findings from Nov. 2013 Site 

Profile review cont.

 SP13: Mg-Th Alloy operations – Inhalation and ingestion intake 

rates by job category and time periods questioned. Revised TBD now 

provides information on this issue, and inhalation and ingestion 

intake rates by job category and time periods. 

 SP20: Photon Calibration – correction factor for exposures to 

photon radiation, especially exposure to skin and shallow organs, 

was found to be needed. Revised TBD provides coworker shallow 

dose parameters, and recommends use of complete list of dose 

conversion factors in OCAS-IG-001, Revision 3, External Dose 

Reconstruction Implementation Guideline, instead of abbreviated list 

in previous TBD. 
NIOSH will carry one commitment forward 

 The TBD indicates no Mg-Th operations at KCP from 1963-1970. The Work 

Group remains concerned that while there is no evidence of continued MgTh operations, there is also no clear operational documentation regarding 

the cessation of those operations for that period of time. Therefore, 

NIOSH agrees to carry a commitment forward for “the period from 1963-

1970 [which will] remain an issue for continued follow-up to ensure 

operations were in fact suspended.”