DISCLAIMER; This is a working document provided by the Centers for Disease Control and Prevention (CDC) 

technical support contractor, SC&A, for use in discussions with the National Institute for Occupational Safety and 

Health (NIOSH) and the Advisory Board on Radiation and Worker Health (ABRWH), including its Working Groups 

or Subcommittees. Documents produced by SC&A, such as memorandum, white paper, draft or working documents 

are not final NIOSH or ABRWH products or positions, unless specifically marked as such. This document prepared 

by SC&A represents its preliminary evaluation on technical issues.

NOTICE: This document has been reviewed to identify and redact any information that is protected by the 

Privacy Act 5 USC §552a and has been cleared for distribution. 

MEMORANDUM 

TO: Savannah River Site Work Group 

FROM: SC&A, Inc.

DATE: January 11, 2018 

SUBJECT: Missing or Incomplete Radiological Source Terms

At the November 14, 2017, Savannah River Site (SRS) Work Group meeting, SC&A noted in its 

presentation (under the slide, “Other concerns (yet to be reviewed in detail),” SC&A 2017), a 

finding that some SRS workers were enrolled in incorrect routine bioassay programs prior to 

1999. In its presentation, SC&A noted that “unrecognized Am-241 sources were not included in 

Radiation Work Permit (RWP) preparation” and that some workers were unmonitored for 

americium (Am). We also noted that a site-wide formal radiological hazard characterization 

process was established on March 10, 1999. SC&A provided the Work Group and NIOSH the 

three primary Site Research Database (SRDB) references for this finding: SRDB Ref. IDs 

167760, 167754, and 167753. The Work Group subsequently asked that SC&A detail its concern 

“such that the work group and NIOSH can review for potential impact on monitoring methods” 

(Taulbee 2017). SC&A provides its review in this memorandum in the chronological order of the 

SRDB document references that are the basis of this concern.

SRDB Ref. ID 167760 (Findley, November 7, 1997 (Rev. 3), “Understanding Urine Bioassay 

Sampling”) 

This note (it is not clear what form of Westinghouse Savannah River Company [WSRC] 

guidance this represented) underscored that “being on a routine sampling program does not 

automatically cover the bioassay sampling requirement specified on the RWP.” Findley goes on 

to state that: 

section 5.2.4. of 5Q1.1, 504 “Radiological Work Permit” used to require that the 

radiological control supervisor identify the RWP bioassay requirements so that 

they were consistent with 5Q1.1, 506 “In Vivo and In Vitro Bioassay Scheduling 

and Administration”. This link was eliminated because routine sampling 

programs may not be appropriate for work involving non-routine mixes or

concentrations of radioactive material. [Findley 1997, PDF page 9]

The implication from this note is that improper cross-referencing in WSRC procedures may have 

led radiological control supervisors to apply routine facility bioassay requirements for RWPs that 

entailed radiological source terms different from those of routine work. 
Memo – SRS Source Terms 2 SC&A – January 11, 2018 

NOTICE: This document has been reviewed to identify and redact any information that is protected by the 

Privacy Act 5 USC §552a and has been cleared for distribution. 

SRDB Ref. ID 167753 (WSRC interoffice memorandum, ESH-HPT-98-0453, August 13, 

1998, “Specification of Bioassay Requirements on Radiological Work Permits (U)”) 

This memorandum was written “In response to a concern over prescribing the correct urine 

bioassay sampling program[s] on radiological work permits.” It notes that WSRC staff “are 

working in tandem on a pilot program to establish guidelines in determining the radionuclide(s) 

of concern for urine samples in the Burial Ground” (WSRC 1998, page 1). In addition to noting 

the same concerns as in Findley 1997 (SRDB Ref. ID 167760), WSRC also adds that: 

Additionally, certain facilities such as the Savannah River Technology Center 

(SRTC) and the solid waste disposal facilities handle a wide array of radioactive 

materials, some of which may not be encountered in the typical radiological work 

environment by workers in those areas. For facilities such as 221-FB-Line, where 

the source term is well defined and not subject to change, this is not a concern 

unless there is a major change in the facility mission. To ensure that the proper 

radionuclide(s) is identified for the RWP urine sampling program it may be 

necessary to perform a thorough characterization of the work environment. It is 

important also that this characterization be performed on a routine basis to stay 

current on the source term present. [WSRC 1998, page 2]

This memorandum goes on to note that a review by the Facility Evaluation Board of SRS solid 

waste management facilities identified concerns over how radionuclides were identified for 

urinalysis on RWPs. Specifically, curium was identified as a principal waste constituent but was 

not specified on RWPs for solid waste management workers. While a follow-up investigation 

resolved the concern (due to the physical inaccessibility of curium as a potential exposure source 

and the co-presence of plutonium), WSRC identified the underlying concern as one of “how the 

Radiological Control organizations determine which radionuclide(s) of concern are identified on 

the RWP and how these determinations are made” [WSRC 1998, pages 2–3] 

WSRC indicated that “To resolve this concern, guidelines that will aid the Radiological Control 

organizations in prescribing RWP urine bioassay sampling will be developed for each facility.” 

Further, a “pilot program for the development of RWP urine bioassay sampling guidance will be 

conducted in the Burial Ground.” 

The implication of all of the above is to raise questions and concerns over how facility source 

term characterizations at SRS had been performed before WSRC realized that they may be 

inadequate or incomplete. What are the ramifications to dose reconstruction with sufficient 

accuracy if RWP job-specific bioassays neglected to include relevant radionuclides, particularly 

for certain facilities where complex, mixed, or unusual radioactive sources existed, e.g., SRTC, 

solid waste, burial grounds, tank farms, and decontamination and decommissioning projects? 

Also, this issue may have transcended RWP job-specific bioassays and implicated routine 

pre-schedule bioassays for radionuclides that were not recognized at the time due to program or 

facility changes that took place (given the apparent lack of a procedural means for systematic 

facility source term characterization).
Memo – SRS Source Terms 3 SC&A – January 11, 2018 

NOTICE: This document has been reviewed to identify and redact any information that is protected by the 

Privacy Act 5 USC §552a and has been cleared for distribution. 

SRDB Ref. ID 167725 (Memorandum from T.R. LaBone to C.R. Morgan, August 25, 1998, 

“Missed Dose from Curium Intakes by Solid Waste Workers”) 

This memorandum contends that missed dose from curium intakes by solid waste workers is not 

a concern because such monitoring is not required, in the first place, by 10 CFR 835.402c(1), as 

such exposures are not “likely” to occur based on “professional judgement.” More specifically, 

this memorandum contends that including a worker on routine bioassay (presumably both prescheduled and job-specific) for a particular radionuclide is only necessary if there is a probability 

of greater than 1% chance of “having one or more intakes in a year that deliver more than 100 

mrem CEDE” (page 2). In terms of any “missed dose” for routine bioassays not collected, this 

memorandum makes the following conclusion: 

Assigning missed doses for “tardy” routine urine samples would result in the 

assignment of significant internal doses to workers who are not being exposed to 

radioactive materials – a clearly undesirable situation. 

The same logic can be applied to a routine urine sample that is collected a year 

late or not at all. In both cases there is no associated missed dose because the 

sample was not required to be collected in the first place, i.e., the sample is not 

required to assess the dose to the worker. [LaBone 1998, page 3]

The implication of the memorandum and WSRC’s response is unclear. The author seems to be 

suggesting that there is no need to be concerned about missing radionuclides for bioassay 

purposes because any such routine monitoring is not required for dose assessment under 10 CFR 

Part 835 regulations, in any case. This position seems to be at odds with other WSRC 

documentation and will need further follow-up. 

SRDB Ref. ID 167754 (Memorandum from W.E. Farrell and W.M. Findley to M.D. 

Matheny, March 10, 1999, “Specifications of Urine Bioassay Requirements on Radiological 

Work Permits – (U)”) 

This WSRC interoffice memorandum establishes a formal “methodology for determining 

workplace radionuclides of concern when determining RWP bioassay requirements” (page 1). 

This directive includes the following discussion: 

Historically, bioassay requirements were identified by the Radiological Control 

Operations (RCO) organization through facility process knowledge (i.e., safety 

analysis documentation), procedural guidance and professional judgement. The 

methodology discussed in this memorandum was used by Health Physics 

Technology (HPT) to update and/or reverify facility specific radionuclides of 

concern for bioassay program compliance. The routine urine bioassay program is 

based on the premise that monitoring must be performed a posteriori (after the 

fact) to verify that radioactive materials are not being internally deposited in 

workers. 

... 
Memo – SRS Source Terms 4 SC&A – January 11, 2018 

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Privacy Act 5 USC §552a and has been cleared for distribution. 

When a urine sample is submitted, it is imperative that the correct analysis be 

requested. This requires that the radiological source term be well know and 

characterized. [Farrell and Findley 1999, pages 1–2]

The methodology provided by this memorandum is a detailed facility-by-facility baselining of 

relevant radiological source terms based on review of “existing waste certification or process 

stream analysis data,” coupled with alternative means such as isotopic workplace air and 

contamination sampling. The basis for including target radionuclides were those isotopes with 

“dose fractions greater than 10%” based on respective Annual Limit on Intake Values, which is 

indicative of “which isotopes contribute the majority of internal dose to an individual for a 

specific source term” (page 2). 

The implications of this directive are clear: If WSRC instituted such a policy in March 1999 

requiring the RCOs to base bioassay monitoring on actual, updated workplace characterization 

versus expert judgement or longstanding facility knowledge, how incomplete were bioassays 

(including RWPs) prior to this date with regard to appropriately targeted radionuclides? How 

does this impact dose reconstruction with sufficient accuracy if workers were incorrectly 

enrolled in bioassay programs, with potential exposure to key radiological sources not evaluated? 

What is the significance of an apparent lack of ongoing facility source term characterization to 

adequate internal dose monitoring during the 1990s with the advent and growth of new activities 

and programs involving new and complex radiological sources, e.g., decontamination and 

decommissioning (D&D), solid waste management, environmental cleanup, SRTC?

SRDB Ref. ID 167676 (Memorandum from C.R. Morgan to M.D. Matheny, November 2, 

1999, “Response to the Compilation of PAAA Internal Dosimetry Issues (U)”) 

This memorandum details WSRC’s review of the 31 general deficiencies cited by the U.S. 

Department of Energy’s (DOE’s) Office of Enforcement and Investigation as part of its “120-day 

suspension of PAAA enforcement actions for issues associated with contractor Internal Dose 

Evaluation Programs (IDEPs)” (page 1). This review highlights whether the issue applies to 

SRS and if so, what corrective actions were taken. 

For Issue B.8, “Workers enrolled in incorrect routine bioassay program,” WSRC identified this 

as an SRS issue and indicated the following: 

Both the workers who require routine bioassay and the correct radionuclides for 

analysis are determined by RWPs under which they work. Earlier this year, it was 

determined that in some areas site workers were potentially exposed to 

americium, but that radionuclide was not recognized as an issue when preparing 

RWPs for those areas. As a result, radiological hazards are now more formally 

documented and both a periodic review and a method for re-evaluation is defined 

(see also items A.8 and B.14). An RCO self-assessment completed 4/30/99 

determined that formally documented source terms are being properly used to 

designate bioassay requirement on RWPs. [Morgan 1999, page 6]
Memo – SRS Source Terms 5 SC&A – January 11, 2018 

NOTICE: This document has been reviewed to identify and redact any information that is protected by the 

Privacy Act 5 USC §552a and has been cleared for distribution. 

The implication here is that improper worker enrollment, which had been identified by DOE 

enforcement reviews across DOE sites, had been found to be an issue at SRS, requiring action to 

implement a formal, ongoing facility characterization program that did not exist before. If key 

radionuclides such as americium had been missed, what other sources were not reflected on 

RWPs over time and what are the ramifications for dose reconstruction with sufficient accuracy

for those workers potentially affected? 

Thomas LaBone Interview (written response to questions), October 6, 2017

Mr. LaBone responds to the following question (18): 

To what extent did this deficient RWP source term review process [as detailed in 

SRDB Ref ID 167676 above] extend to job-specific RWPs and in the larger sense, 

how much broader was this issue (improper bioassay enrollment) in terms of 

other radionuclide source terms on a site-wide basis in prior years (e.g., 1989–

1999)? Did WSRC review prior RWPs to ascertain status on this question, or to 

address potential missed dose from americium and other radionuclides due to 

inadequate enrollment reviews?

Response (partial):

I think that when SRS moved from the production phase to the D&D phase in the 

1990’s there were changes in the source terms that were not fully anticipated 

because of the change in mission. This, combined with a change in the way we 

specified routine bioassay programs was most likely the cause of the problem with 

the routine program you cited with Am-241. I think ESH-RPS-2005-00054 has a 

good discussion of this issue. However, we did not have this problem for special 

samples where we always required specification of the source term by analysis of 

the contamination that triggered collection of the sample. [LaBone 2017]

SC&A reviewed ESH-RPS-2005-00054 (SRDB Ref. ID 167846; Hadlock et. al. 2005) and found 

it to be essentially a “lessons learned” review, dated March 11, 2005, of experience gained with 

the WSRC source term characterization program originally implemented 6 years earlier in 1999. 

Key conclusions included that it was “not necessary to perform an a priori determination of the 

radionuclides of interest for every task and worker within a Facility” (page 8), and that there 

remained a need for “professional judgement” in the characterization process. There was also a 

need identified for radionuclides identified for monitoring through the characterization process to 

be validated, where possible, through the “isotopic analysis of air samples within the facility.” 

The implication of what was provided in this interview was to substantiate that the disparities 

with source term identification had its roots in the rapidly changing nature of SRS’ mission, with 

new or more complex source terms not being fully anticipated as the site moved from a primary 

production mission to one that included D&D, as well as how routine bioassay programs were 

implemented.
Memo – SRS Source Terms 6 SC&A – January 11, 2018 

NOTICE: This document has been reviewed to identify and redact any information that is protected by the 

Privacy Act 5 USC §552a and has been cleared for distribution. 

Conclusion

SC&A believes that based on the foregoing WSRC documentation for 1998–1999, there was a 

clear deficiency recognized that may have impacted the proper bioassay enrollment of workers 

under RWPs prior to the implementation of a new site-wide formal policy, “Specifications of 

Urine Bioassay Requirements on Radiological Work Permits,” issued on March 10, 1999. Lack 

of proper specification of radionuclides of significance for internal dosimetry may have led to 

unmonitored exposures for which dose reconstruction with sufficient accuracy may not be 

feasible. This concern should be investigated further to ascertain its significance, scope, and 

implications for dose reconstruction. 

References

Farrell and Findley 1999. Memorandum from W.E. Farrell and W.M. Findley to M.D. Matheny, 

“Specification of Urine Bioassay Requirements on Radiological Work Permits – (U),” ESHHPT-99-0051, Westinghouse Savannah River Company. March 10, 1999. [SRDB Ref. ID 

167754] 

Findley 1997. Guidance document from W.M. Findley, “Understanding Urine Bioassay 

Sampling,” Revision 3, Westinghouse Savannah River Company. November 7, 1997. [SRDB 

Ref. ID 167760] 

Hadlock et al. 2005. Memorandum from Dennis Hadlock, S. John Moxley, and R. Dean Thames 

to Theodore Padezanin, III, “Field Protocols for Determining Radionuclides of Interest in a 

Facility Radiobioassay Program (U),” ESH-RPS-2005-00054, Westinghouse Savannah River 

Company. March 11, 2005. [SRDB Ref. ID 167846] 

LaBone 1998. Memorandum from T.R. LaBone to C.R. Morgan, “Missed Dose from Curium 

Intakes by Solid Waste Workers,” ESH-HPT-980459, Westinghouse Savannah River Company. 

August 25, 1998. [SRDB Ref. ID 167725] 

LaBone 2017. Thomas LaBone Interview (written response to questions), October 6, 2017, 

forwarded by NIOSH via email on October 24, 2017. 

Morgan 1999. Memorandum from C.R. Morgan to M.D. Matheny, “Response to the Compilation 

of PAAA Internal Dosimetry Issues (U),” ESH-HPT-99-0226, Westinghouse Savannah River 

Company. November 2, 1999. [SRDB Ref. ID 167676] 

SC&A 2017. Presentation by Joe Fitzgerald, SC&A, at the Savannah River Site Work Group 

Meeting, “Summary of SC&A’s Concerns with SRS Subcontractor Bioassay Data 

Completeness.” November 14, 2017. 

Taulbee 2017. Email from Tim Taulbee, NIOSH, to Savannah River Site Work Group and 

others, “Open Issues regarding Subcontractor Bioassay Monitoring, Rev. 1,” Draft action items 

for review. November 17, 2017. 
Memo – SRS Source Terms 7 SC&A – January 11, 2018 

NOTICE: This document has been reviewed to identify and redact any information that is protected by the 

Privacy Act 5 USC §552a and has been cleared for distribution. 

WSRC 1998. WSRC interoffice memorandum, “Specification of Bioassay Requirements on 

Radiological Work Permits (U),” ESH-HPT-98-0453, Westinghouse Savannah River Company. 

August 13, 1998. [SRDB Ref. ID 167753]