Page 1 of 16 

This is a working document prepared by NIOSH’s Division of Compensation Analysis and Support (DCAS) or its contractor for 

use in discussions with the ABRWH or its Working Groups or Subcommittees. Draft, preliminary, interim, and White Paper 

documents are not final NIOSH or ABRWH (or their technical support and review contractors) positions unless specifically 

marked as such. This document represents preliminary positions taken on technical issues prepared by NIOSH or its contractor.

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

has been cleared for distribution. 5 United States Code (U.S.C.) § 552a.

To: LANL Work Group

From: LaVon Rutherford

Subject: Weight of Evidence Supports NIOSH’s Ability to Bound LANL TA-53 Doses

for 1996–2005

Date: August 15, 2023

After designating a Los Alamos National Laboratory (LANL) Special Exposure Cohort 

(SEC) class for 1976 through 1995, the Advisory Board on Radiation and Worker 

Health’s LANL Work Group questioned the National Institute for Occupational Safety 

and Health (NIOSH)’s ability to bound doses from exotic radionuclides1 for the period 

from 1996 through 2005 [NIOSH 2019]. One area of focus in Work Group discussions of 

exotic radionuclide exposures was the Los Alamos Neutron Science Center (LANSCE) 

in Technical Area-53 (TA-53), which included an accelerator and various experimental 

facilities. With respect to LANSCE, exotic radionuclides included activation and 

spallation products produced (directly or indirectly) by the proton beam of the 

accelerator. For the purpose of this NIOSH assessment of LANSCE operations, work 

activities are identified as routine work and non-routine work.

1 The term “exotics” includes everything other than U-234/235/238, Pu-238/239, tritium, Am-241, and Cs137. This term includes Sr-90, Th-232, Cm-244, Ac-227, Pa-231, Np-237, and others.

“Routine work” is work not performed under the requirements of a specific radiological

work permit (RWP). Worker categories that performed routine work included guards and 

custodians [ORAUT 2022a, PDF p. 8]. NIOSH and the LANL Work Group consider 

“routine work monitoring” to include monitoring for plutonium, uranium, and tritium. The 

ORAU Team demonstrated in ORAUT-RPRT-0101, Bounding Intakes of Exotic 

Radionuclides at Los Alamos National Laboratory [ORAUT 2022a] and ORAUT-RPRT0103, Review of Potential Exposure to Exotic Radionuclides Using Radiological Work 

Permit Data at Los Alamos National Laboratory [ORAUT 2022b] that LANL Health 

Physics personnel monitored work areas for air and surface contamination adequately 

to demonstrate that workers performing such routine work were unlikely to have 

received intakes resulting in greater than 100 mrem/year committed effective dose 

(CED). LANL designed their radiological control program to comply with 10 Code of 

Federal Regulations (C.F.R.) Part 835 [DOE 1993] but with an intended outcome that 
Page 2 of 16 

This is a working document prepared by NIOSH’s Division of Compensation Analysis and Support (DCAS) or its contractor for 

use in discussions with the ABRWH or its Working Groups or Subcommittees. Draft, preliminary, interim, and White Paper 

documents are not final NIOSH or ABRWH (or their technical support and review contractors) positions unless specifically 

marked as such. This document represents preliminary positions taken on technical issues prepared by NIOSH or its contractor.

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

has been cleared for distribution. 5 United States Code (U.S.C.) § 552a.

unmonitored individuals (including workers performing routine work) would be unlikely to 

receive doses greater than 100 mrem/year. NIOSH maintains that, by complying with 10 

C.F.R. Part 835 [DOE 1993], LANL monitored all workers with a potential to receive a

CED in excess of 100 mrem/year.

“Non-routine work” is work performed under the requirements of an RWP and is often 

performed in posted radiological areas. The ORAU Team demonstrated in ORAUTRPRT-0103 that LANL Health Physics personnel monitored RWP work in an effort to 

maintain worker radiation doses under 100 mrem/year. Workers performing non-routine 

work who were suspected of having the potential for radiation intakes were 

subsequently monitored by nasal smears or whole body count bioassay. 

The data and information included in ORAUT-RPRT-0101 and ORAUT-RPRT-0103

addressed LANL Work Group questions regarding personnel exposures to exotic 

radionuclides. As a follow-up to those reports, NIOSH completed a LANL site visit that 

included a tour of LANSCE in TA-53. On that site visit, NIOSH collected additional data 

and information specific to Work Group questions regarding the possibility of a LANSCE

worker gaining access to the accelerator beam area during beam operation or the 

potential for intakes from isotope production. This information is included in the 

discussion in the following sections.

LANL’s use of access control systems, surveys, adherence to RWP requirements, and 

monitoring practices support NIOSH’s position that LANL worked to maintain TA-53 

personnel doses at or below 100 mrem/year while performing routine work and that TA53 personnel doses for workers performing non-routine work can be bounded using 

whole body count bioassay data. 

Access Control Systems

Potential exposure to exotic radionuclides from spallation sources would most likely 

have occurred during beam operation and within a few minutes after the beam dropped. 

For the 1996–2005 period, LANL staff tightly controlled entry into the LANSCE beam 

line area when the beam was in operation. Access control systems engineered for 

LANSCE accelerator operations were robust and were used to prevent inadvertent 

access to radiological areas during beam operations. Beginning as early as 1991 [DOE 

1991; Sturrock et al. 1996], one of LANL’s access controls included the Radiation 

Security System (RSS). The RSS automatically terminated beam delivery in response 

to pre-defined abnormal conditions [Gallegos 1996]. The RSS contained beam-loss 

interlocks, beam-current interlocks, and area-radiation interlocks [Macek 1996, PDF pp. 

7–9]. Beginning January 1996 [Gallegos 1996], additional access controls to areas with 

potential radiation hazards from an accelerator beam included the Personnel Access 

Control System (PACS) and Experimental Personnel Access Control System (EPACS). 

These access control systems and interlocks are described in greater detail in BeamLimiting and Radiation-Limiting Interlocks [Macek 1996].
Page 3 of 16 

This is a working document prepared by NIOSH’s Division of Compensation Analysis and Support (DCAS) or its contractor for 

use in discussions with the ABRWH or its Working Groups or Subcommittees. Draft, preliminary, interim, and White Paper 

documents are not final NIOSH or ABRWH (or their technical support and review contractors) positions unless specifically 

marked as such. This document represents preliminary positions taken on technical issues prepared by NIOSH or its contractor.

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

has been cleared for distribution. 5 United States Code (U.S.C.) § 552a.

In general terms, the PACS operation involved a two-key control system. The two-key 

system provided redundant access control to the accelerator beam area, which 

prevented personnel from accessing the area when the beam was active but permitted 

access when the beam was not active.

In addition to PACS, LANSCE also used another access-control system known as 

EPACS to ensure that LANL staff did not enter a high-radiation testing area while the 

beam shutter was open to an experiment flight path. EPACS was an experimental-area 

PACS system for secondary beam-line flight paths in which the experimental scientists, 

with support from Radiological Control Technicians (RCTs), controlled entry and exit

through a radiation interlock system [LANL 2002a, PDF p. 90; LANL 1995–1999, PDF 

pp. 47–56]. 

Access to Beam Channel Before and After Operation

Available documentation shows that LANL Health Physics staff ensured that all 

personnel were clear of beam areas prior to beam operations. LANSCE Radiation 

Security System (RSS), received in 1996, and Section 5.16 of the 1999 LANSCE 

Accelerator Operations Manual documented the procedure for entering a beam area

(referred to as a sweep) before and after beam operations [Gallegos 1996; LANL 1995–

1999, PDF pp. 47–56]. 

Sweep Before Beam Operation

LANL Health Physics and TA-53 personnel ensured that staff were not present in the beam 

area prior to starting beam operation. Personnel conducting the sweep verified that all entry 

doors were closed and latched. Once all checks were validated, the PACS entry door was 

locked, and approval was given to start the beam. Any breach of the PACS caused the 

beam operation to immediately shut down [Sturrock et al. 1996; LANL 1995–1999, PDF pp. 

47–56]. 

Sweep After Beam Operation

After beam shutdown, LANL procedure required Health Physics staff to conduct a 

sweep of the beam area, monitoring for residual activation radioactivity, before allowing 

personnel to access the area [LANL 1995–1999, PDF pp. 47–56]. Health Physics staff 

would only release PACS keys once they had ensured the following: beam stops were 

in place, residual activation was being monitored, appropriate radiological postings were 

in place, and entry could be conducted safely following RWP requirements. 

Access Controls to High/Very High Radiation Areas

Per 10 C.F.R. Part 835, a High Radiation Area is designated as any area accessible to 

individuals in which radiation levels could result in an individual receiving a deep dose

equivalent in excess of 0.1 rem (0.001 sievert) in 1 hour at 30 centimeters from the radiation 

source or from any surface that the radiation penetrates [DOE 1993, PDF p. 37]. A Very 
Page 4 of 16 

This is a working document prepared by NIOSH’s Division of Compensation Analysis and Support (DCAS) or its contractor for 

use in discussions with the ABRWH or its Working Groups or Subcommittees. Draft, preliminary, interim, and White Paper 

documents are not final NIOSH or ABRWH (or their technical support and review contractors) positions unless specifically 

marked as such. This document represents preliminary positions taken on technical issues prepared by NIOSH or its contractor.

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

has been cleared for distribution. 5 United States Code (U.S.C.) § 552a.

High Radiation Area is designated as any area accessible to individuals in which radiation 

levels could result in an individual receiving an absorbed dose in excess of 500 rads (5 

grays) in one hour at 1 meter from the radiation source or from any surface that the radiation 

penetrates [DOE 1993, PDF p. 37].

For any work in areas designated as high radiation areas, Health Physics personnel would 

monitor the work from start to finish. LANL required RCTs to perform weekly inspections of 

the physical access controls used to prevent unauthorized entries into high and very high

radiation areas [LANL 1999a, PDF p. 10; LANL 2002b, PDF p. 8; LANL 2005, PDF pp. 7, 

30]. Table 1 shows the areas that required the inspections, including LANSCE and the 

Isotope Production Facility.

Table 1: High Radiation Access Areasa

Location Description

Sector B Roll-up Door 1 lock

Sector E Elevator & upper beam channel door

Sector F Upper beam channel door

Sector G Door midway down stairwell

Sector H Elevator & upper beam channel door

TOFI Time-of-flight isochronous (TOFI) spectrometer deionization 

cave door

TOFI Time-of-flight isochronous (TOFI) spectrometer filter banks, 2 

locks

South Hot Cell Door 1 lock

Hot Cell Upper Door 1 lock

A-6 2 locks

A East Door

Isotope Production 2 doors

Isotope Production 

Stringer 1 lock

LANSCE-7 Boneyard 2 locks

High Resolution 

Spectrometer Beam stop entrance door

Land Disposal-2 Pit 1 lock

1L Service Area Target pump alcove, 1 lock

LANSCE-12 

Boneyard 1 lock

a Source: [LANL 2005, PDF p. 30]

Diagrams of LANSCE and some of the associated locations mentioned in Table 1 are 

provided in Figures 1 and 2 below. Attachment One provides an aerial photograph, to help 

visualize the vast area covered by access controls, as well as an Isotope Production Facility 

Hot Cell diagram.
Page 5 of 16 

This is a working document prepared by NIOSH’s Division of Compensation Analysis and Support (DCAS) or its contractor for 

use in discussions with the ABRWH or its Working Groups or Subcommittees. Draft, preliminary, interim, and White Paper 

documents are not final NIOSH or ABRWH (or their technical support and review contractors) positions unless specifically 

marked as such. This document represents preliminary positions taken on technical issues prepared by NIOSH or its contractor.

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

has been cleared for distribution. 5 United States Code (U.S.C.) § 552a.

Figure 1 shows a diagram of LANSCE in the most recent Isotope Production Facility 

configuration, from the front to the experimental areas.

Figure 1: LANSCE diagram, beginning 2003 [LANL 2010, PDF p. 10]

Figure 2 shows the older Isotope Production Facility configuration in Area A.

Figure 2: LANSCE diagram, 1990s [Coulson et al., no date, PDF p. 12] 
Page 6 of 16 

This is a working document prepared by NIOSH’s Division of Compensation Analysis and Support (DCAS) or its contractor for 

use in discussions with the ABRWH or its Working Groups or Subcommittees. Draft, preliminary, interim, and White Paper 

documents are not final NIOSH or ABRWH (or their technical support and review contractors) positions unless specifically 

marked as such. This document represents preliminary positions taken on technical issues prepared by NIOSH or its contractor.

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

has been cleared for distribution. 5 United States Code (U.S.C.) § 552a.

Surveys of Contamination Area Boundaries

LANL required Health Physics personnel to collect smear surveys in areas bordering all 

established, accessible contamination areas at TA-53 on a weekly basis. The 

Wednesday night shift completed the survey during beam operations, and the day shift 

completed the survey during maintenance periods [LANL 1999a, PDF p. 10; LANL 

2002b, PDF p. 8; LANL 2005, PDF p. 7]. These areas included the A-6 Contamination 

Area, 1L Service Area (above 1L Target), and the Switchyard Valve Gallery [LANL 

2005, PDF pp. 7–8]. 

LANL required Health Physics personnel to conduct smear surveys on all primary and

secondary beam line areas, Meson Physics Facility (MPF)-3 (Area A), and other areas

specified in HSR-1/TA-53 Routine Monitoring Instructions on a quarterly basis [LANL 

2005]. When beam operations prevented access to these areas, personnel collected 

smears during the next quarter that they were due [LANL 2005, PDF p. 11].

Entry Controlled by RWP

LANL did not allow employees to perform work in beam line areas unless it followed

RWP stipulations. LANL Health Physics staff and the person requesting the work jointly 

determined RWP requirements, including any additional dosimetry and monitoring in 

accordance with LANL’s As Low As Reasonably Achievable (ALARA) requirements 

[LANL 1995–1999, PDF pp. 12, 18]. LANL’s Radiation Protection Program integrated 

ALARA into radiological design and control [LANL 1995–1999, PDF p. 18]. 

LANL staff also followed RWP requirements for other work performed in locations

throughout LANSCE; this included areas controlled by PACS or EPACS, including 

experimental stations, the Blue Room, Building 7 (Weapons Neutron Research), and 

the Isotope Production Facility. NIOSH has access to a portion of RWPs written for TA53 during the period from 1996 through 2004, as shown in Table 2. The available RWP

documentation demonstrates that LANL Health Physics personnel appropriately 

monitored work performed under RWPs [ORAUT 2022b]. In cases where contamination 

incidents did occur, radiological data available with the RWPs show that LANL Health 

Physics personnel followed up with appropriate monitoring, as required by LANL 

radiation monitoring procedures. 
Page 7 of 16 

This is a working document prepared by NIOSH’s Division of Compensation Analysis and Support (DCAS) or its contractor for 

use in discussions with the ABRWH or its Working Groups or Subcommittees. Draft, preliminary, interim, and White Paper 

documents are not final NIOSH or ABRWH (or their technical support and review contractors) positions unless specifically 

marked as such. This document represents preliminary positions taken on technical issues prepared by NIOSH or its contractor.

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

has been cleared for distribution. 5 United States Code (U.S.C.) § 552a.

Table 2: Available TA-53 RWPs

Year Source

1996-1999 LANL 1995–1999

1998 LANL 1998a

1999a LANL 1999b

1999 LANL 1999c

2000 LANL 2000

2001 LANL 2001a

2002b LANL 2002c,d,e,f,g,h,i,j,k,l

2003c LANL 2003

2004d LANL 2004

a LANL [1999b, PDF pp. 536, 584, 603, 1108, 2305] shows examples of RWP worksheets and logbook 

printouts used completely or partially for sweeps of the beam line and experimental area.

b LANL [2002f, PDF pp. 19–20] and LANL [2002j, PDF p. 9] show examples of RWP worksheets used 

completely or partially for sweeps of the beam line and experimental area.

c LANL [2003, PDF p. 22] shows an example of RWPs used completely or partially for sweeps of the 

beam line and experimental area.

d LANL [2004, PDF p. 323] shows an example of an RWP Worksheet used for a sweep of an

experimental area.

Portal Monitoring

TA-53 Health Physics personnel used portal monitors as an additional means of

identifying worker contamination. Portal monitor locations included: 

• MPF-3 M, A-1; 

• MPF-3 M, A-East; 

• MPF-7, Blue Room Hallway; 

• MPF-7, IL Service Area; 

• MPF-8, Proton Storage Ring; 

• MPF-30, ER-2 (2); and

• MPF-3P, Proton Radiography Facility. 

NIOSH has obtained some of the source check logs for TA-53 portal monitors [LANL 

1997–1999; LANL 2001–2003].

LANL required workers to self-monitor upon exiting areas with potential contamination 

and housed with a portal monitor. Attachment A from the 1994 LANL Radiological 

Control Manual [LANL 1994, PDF p. 2] states: 

1. Personnel exiting Contamination Areas, High Contamination Areas, Airborne 

Radioactivity Areas, and Radiological Buffer Areas or Controlled Areas 

established for contamination control shall frisk for contamination as required 
Page 8 of 16 

This is a working document prepared by NIOSH’s Division of Compensation Analysis and Support (DCAS) or its contractor for 

use in discussions with the ABRWH or its Working Groups or Subcommittees. Draft, preliminary, interim, and White Paper 

documents are not final NIOSH or ABRWH (or their technical support and review contractors) positions unless specifically 

marked as such. This document represents preliminary positions taken on technical issues prepared by NIOSH or its contractor.

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

has been cleared for distribution. 5 United States Code (U.S.C.) § 552a.

by Article 338. This does not apply to personnel exiting areas containing only 

radionuclides, such as tritium, that cannot be detected using hand-held or 

automatic frisking equipment.

2. Monitoring for contamination should be performed using frisking equipment 

that under laboratory conditions can detect total contamination of at least the 

values specified in Table 2-2. Use of automatic monitoring units that meet the 

above requirements is encouraged.

3. Personnel found with detectable contamination on their skin, personal clothing, 

or company-issued clothing other than noble gases or natural background 

radioactivity should be promptly decontaminated as described in Article 541.

In regard to monitoring for personnel contamination, the 1994 LANL Radiological 

Control Manual states [LANL 1994, PDF p. 3]:

1. Personnel shall perform a whole-body frisk [survey themselves] under 

the following conditions:

a. Immediately upon entry into an uncontaminated area after leaving 

existing Contamination Areas, High Contamination Areas, and 

Airborne Radioactivity Areas

b. As directed by the radiological work permit, the ESH-1 RCT, or the 

area exit posting

2. In addition to the above, personnel exiting a Controlled Area or 

Radiological Buffer Area containing Contamination, High Contamination, 

or Airborne Radioactivity Areas should, at a minimum, perform a hand 

and foot frisk. The frisk is optional if the Controlled Area or Radiological 

Buffer Area exit is immediately adjacent to the location where the existing 

worker has already performed a whole-body frisk.

3. Where frisking cannot be performed at the exit from Contamination 

Areas, High Contamination Areas, or Airborne Radioactivity Areas due to 

high background radiation levels, personnel shall perform the following:

a. Remove all protective equipment and clothing at the exit. 

b. Proceed directly to the nearest designated monitoring station.

c. Conduct whole-body-frisk. 
Page 9 of 16 

This is a working document prepared by NIOSH’s Division of Compensation Analysis and Support (DCAS) or its contractor for 

use in discussions with the ABRWH or its Working Groups or Subcommittees. Draft, preliminary, interim, and White Paper 

documents are not final NIOSH or ABRWH (or their technical support and review contractors) positions unless specifically 

marked as such. This document represents preliminary positions taken on technical issues prepared by NIOSH or its contractor.

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

has been cleared for distribution. 5 United States Code (U.S.C.) § 552a.

4. Personnel frisking shall be performed after removal of protective clothing 

and before washing or showering.

The 1994 LANL Radiological Control Manual states, as action number 5, that personnel 

should respond to a personnel contamination monitor alarm with the following actions

[LANL 1994, p. 5]:

a. Remain in the immediate area.

b. Notify ESH-1 personnel and line supervision.

c. Take actions that may be available to minimize cross-contamination, 

such as putting a glove on a contaminated hand.

LANL Health Physics personnel were required to collect weekly large-area swipes on 

walkways leading from contamination areas to personnel contamination monitors to 

ensure that walkways leading up to the portal monitors were free of removable 

contamination [LANL 2005, PDF p. 8].

Gate Monitoring

Since at least 1987 [LANL 1988, PDF pp. 9–10], LANL used a gate (exit) monitor to 

check vehicles and associated equipment for contamination when leaving the TA-53 

area. The requirements for an alarm were the presence of a vehicle over the road 

detector and the detection of radiation at some level above background [LANL 1998b, 

PDF p. 3]. The gate monitor alarm system was based on monitoring beta/gamma dose 

rate and gamma-emitting radionuclides.

The gate monitor was source checked nightly by Health Physics personnel [LANL 

1999a, PDF p. 6–7; LANL 2001b, PDF pp. 6, 13, 20, 35; LANL 1999d, pp. 2, 6, 22, 27;

LANL 2005, PDF p. 5; LANL 2004–2006]. The LANL procedure Operation and 

Maintenance of the TA-53 Front Gate Radiation Monitor details the process used for 

responding to gate alarms [LANL1998b].

Department of Energy (DOE) REMS Database Review

NIOSH obtained a copy of the DOE Radiation Exposure Monitoring System (REMS) for 

LANL [LANL 2023]. NIOSH extracted records of LANL workers reported to have 

exceeded 100 mrem CED in any one year for the period 1996 through 2005 into a 

separate dataset [ORAUT 2023]. NIOSH found that none of the workers had worked in 

the LANSCE facility or TA-53 for the period 1996 through 2005, while a majority of the 

workers had worked in TA-55.
Page 10 of 16 

This is a working document prepared by NIOSH’s Division of Compensation Analysis and Support (DCAS) or its contractor for 

use in discussions with the ABRWH or its Working Groups or Subcommittees. Draft, preliminary, interim, and White Paper 

documents are not final NIOSH or ABRWH (or their technical support and review contractors) positions unless specifically 

marked as such. This document represents preliminary positions taken on technical issues prepared by NIOSH or its contractor.

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

has been cleared for distribution. 5 United States Code (U.S.C.) § 552a.

Dose Estimation from Intakes of Exotic Radionuclides at LANSCE

NIOSH acknowledges that while LANL used the access control and other protections 

mentioned in this memo, it is possible that some workers were exposed to exotic 

radionuclides. NIOSH reviewed the Department of Energy (DOE)’s Occurrence 

Reporting and Processing System and incident reports for 1996 through 2005 and 

found no violations that were reportable to DOE related to the PACS or EPACS 

systems. 

As stated in ORAUT-RPRT-0101, workers performing routine work in TA-53 were 

unlikely to have received intakes resulting in doses greater than 100 mrem/year CED. 

NIOSH is developing a proof-of-concept method to bound doses for routine TA-53 

workers who received whole body counts; this method will be described in ORAUTRPRT-0107, Dose Estimation from Intakes of Exotic Radionuclides at LANSCE, 1996–

2005. The method estimates the dose to LANSCE workers from intakes of all 

radionuclides to which they were potentially exposed based on Co-60 body burdens 

measured with the LANL whole body counter. To accomplish this, dose conversion 

factors (DCF) are used along with the relative amounts of radionuclides in targets and 

structural materials to help identify radionuclides in each target organ that are 

dosimetrically significant. This information is used to derive an effective DCF for the 

radionuclide mixtures relative to the Co-60 in each target, and ultimately select a 

reference target for use in bounding doses. Targets used during the 1996–2005 period

included the 1L tungsten target and targets at A6 (isotope production through 1998), the 

new Isotope Production Facility (2003–2005), and the Weapons Neutron Research 

facilities [Fuehne, no date PDF p. 10; LANL 1999e, PDF pp. 17–20; Kelley 2004, PDF 

p. 16; LANL 2022]. LANL has reported that the 1L Target provides the most 

conservative estimate on the radionuclide inventory and is used [LANL 2022] in the 

proof-of-concept model. 

Summary

This memo shows: 

1) LANL strictly controlled access to the beam line and hot area. Personnel did not gain 

access while the beam was operating. LANL Health Physics personnel monitored 

areas adjacent to the beam areas during beam operation. LANL Health Physics 

personnel, entering under RWP directives, were the first group to re-enter the beam 

area after shutdown. 

2) All work performed in beam areas, during and after beam operation, was controlled 

by RWP directives and radiological monitoring. 

3) LANL required workers to self-monitor for potential contamination upon exiting 

posted contamination areas. LANL personnel investigated all alarms. Vehicles 

leaving TA-53 were monitored for contamination using gate detectors.
Page 11 of 16 

This is a working document prepared by NIOSH’s Division of Compensation Analysis and Support (DCAS) or its contractor for 

use in discussions with the ABRWH or its Working Groups or Subcommittees. Draft, preliminary, interim, and White Paper 

documents are not final NIOSH or ABRWH (or their technical support and review contractors) positions unless specifically 

marked as such. This document represents preliminary positions taken on technical issues prepared by NIOSH or its contractor.

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

has been cleared for distribution. 5 United States Code (U.S.C.) § 552a.

4) Data obtained from DOE in the REMS database show no workers in TA-53 received 

over 100 mrem CED in any year from 1996 through 2005.

5) For workers who performed routine work in TA-53 and who were monitored by whole

body counting, doses can be bounded using the method NIOSH will describe in 

Dose Estimation from Intakes of Exotic Radionuclides at LANSCE, 1996–2005.

Based on the conclusions of ORAUT-RPRT-0101 and ORAUT-RPRT-0103, and the 

fact that LANL maintained adequate administrative and engineering controls discussed 

in this memorandum, the weight of evidence supports NIOSH’s ability to bound radiation 

doses at 100 mrem/year with sufficient accuracy for unmonitored LANL TA-53 workers

from 1996 through 2005.
Page 12 of 16 

This is a working document prepared by NIOSH’s Division of Compensation Analysis and Support (DCAS) or its contractor for 

use in discussions with the ABRWH or its Working Groups or Subcommittees. Draft, preliminary, interim, and White Paper 

documents are not final NIOSH or ABRWH (or their technical support and review contractors) positions unless specifically 

marked as such. This document represents preliminary positions taken on technical issues prepared by NIOSH or its contractor.

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

has been cleared for distribution. 5 United States Code (U.S.C.) § 552a.

References

Coulson AJ, Elwyn, Freeman WS [no date]. Accelerator health physics characterization 

report of DOE Laboratories. Draft. Batavia, IL: Fermi National Accelerator Laboratory. 

[SRDB Ref ID: 109575]

DOE [1991]. Occurrence report SC-ALO-LA-LANL-ACCCOMPLEX-1991-1024 

degraded radiation security system electronic module TA-53 RSS/MPF-7. Final. 

Washington DC: U.S. Department of Energy. SC-ALO-LA-LANL-ACCCOMPLEX-1991-

1024, October 11. [SRDB Ref ID: 189906]

DOE [1993]. Occupational radiation protection. Final Rule. Fed Regist 58(238):65458. 

[SRDB Ref ID: 165855]

Fuehne DP [no date]. Operations report for Rad-NESHAP compliance project 2001–

2005. Los Alamos National Laboratory, Los Alamos, NM: University of California. LAUR-07-0523. [SRDB Ref ID: 102452]

Gallegos FR [1996]. LANSCE radiation security system (RSS). In: Health Physics 

Society 1997 midyear topical meeting held in San Jose, CA. Los Alamos National 

Laboratory, Los Alamos, NM: University of California. LA-UR-96-3568. [SRDB Ref ID: 

192685] 

Kelley KC [2004]. Gadolinium-148 and other spallation production cross section 

measurements for accelerator target facilities. Dissertation. Atlanta, GA: Georgia 

Institute of Technology. March. [SRDB Ref ID: 196439]

LANL [1988]. Accelerator health protection quarterly progress report for the fourth 

quarter 1987. Los Alamos National Laboratory, Los Alamos, NM: University of 

California. [SRDB Ref ID: 45487] 

LANL [1994]. Radiological standards and conduct of radiological work LANL radiological 

control manual. Chapter 2 and 3 excerpts. Los Alamos National Laboratory, Los 

Alamos, NM: University of California. December 23. [SRDB Ref ID: 196580] 

LANL [1995–1999]. RWPs and documentation associated with LANL experiments 

(1995–1999). Los Alamos National Laboratory, Los Alamos, NM: University of 

California. [SRDB Ref ID: 176083]

LANL [1997–1999]. Portal monitor source check logs PSR (January 1997– March 

1999). Los Alamos National Laboratory, Los Alamos, NM: University of California. 

[SRDB Ref ID: 181214]

LANL [1998a]. RWPs TA-53 CY1998 (January–June 1998). Los Alamos National 

Laboratory, Los Alamos, NM: University of California. [SRDB Ref ID: 181133]
Page 13 of 16 

This is a working document prepared by NIOSH’s Division of Compensation Analysis and Support (DCAS) or its contractor for 

use in discussions with the ABRWH or its Working Groups or Subcommittees. Draft, preliminary, interim, and White Paper 

documents are not final NIOSH or ABRWH (or their technical support and review contractors) positions unless specifically 

marked as such. This document represents preliminary positions taken on technical issues prepared by NIOSH or its contractor.

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

has been cleared for distribution. 5 United States Code (U.S.C.) § 552a.

LANL [1998b]. Operation and maintenance of the TA-53 front gate radiation monitor 

procedure LANL 1998. Los Alamos, NM: University of California. ESH-1/TA-53-DP-304-

R0, May. [SRDB Ref ID: 196693] 

LANL [1999a]. Radiation monitoring instructions procedure LANL 1999. Los Alamos, 

NM: University of California. ESH-1/TA-53-RMI-26-R5, February. [SRDB Ref ID: 

196697]

LANL [1999b]. RWPs TA-53 (1999). Los Alamos National Laboratory, Los Alamos, NM: 

University of California. [SRDB Ref ID: 178775]

LANL [1999c]. Radiological incident reports TA-53 building 7 (1999). Los Alamos 

National Laboratory, Los Alamos, NM: University of California. [SRDB Ref ID: 17857]

LANL [1999d]. Logbook printouts and attendance lists TA-53 (November 1999). Los 

Alamos National Laboratory, Los Alamos, NM: University of California. [SRDB Ref ID: 

181163]

LANL [1999e]. LANSCE activity report 1995–1998. Los Alamos National Laboratory, 

Los Alamos, NM: University of California. LA-13547-SR, February. [SRDB Ref ID: 

195294]

LANL [2000]. RWPs LANSCE (2000). Los Alamos National Laboratory, Los Alamos, 

NM: University of California. [SRDB Ref ID: 178800]

LANL [2001a]. Sample of LANSCE RWPs TA-53 (2001). Los Alamos National 

Laboratory, Los Alamos, NM: University of California. [SRDB Ref ID: 176869]

LANL [2001b]. Worksheets logbook notes and shift attendance list TA-53 (2001). Los 

Alamos National Laboratory, Los Alamos, NM: University of California. [SRDB Ref ID: 

178799]

LANL [2001–2003]. Portal monitor source check logs TA-53 (2001-2003). Los Alamos 

National Laboratory, Los Alamos, NM: University of California. [SRDB Ref ID: 181200]

LANL [2002a]. Laboratory implementation requirement occupational radiation protection 

requirements. Original issue: December 22, 2000. Los Alamos National Laboratory, Los 

Alamos, NM: University of California. February 14. [SRDB Ref ID: 195583]

LANL [2002b]. Radiation monitoring instructions procedure. Draft. Los Alamos National 

Laboratory, Los Alamos, NM: University of California. ESH-1/TA-53-RMI-26-R7, 

February. [SRDB Ref ID: 196698]

LANL [2002c]. Surveys and RWPs at TA-53 (2002). Los Alamos National Laboratory, 

Los Alamos, NM: University of California. [SRDB Ref ID: 176867]
Page 14 of 16 

This is a working document prepared by NIOSH’s Division of Compensation Analysis and Support (DCAS) or its contractor for 

use in discussions with the ABRWH or its Working Groups or Subcommittees. Draft, preliminary, interim, and White Paper 

documents are not final NIOSH or ABRWH (or their technical support and review contractors) positions unless specifically 

marked as such. This document represents preliminary positions taken on technical issues prepared by NIOSH or its contractor.

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

has been cleared for distribution. 5 United States Code (U.S.C.) § 552a.

LANL [2002d]. RWPs and smear surveys TA-53 (2002). Los Alamos National 

Laboratory, Los Alamos, NM: University of California. [SRDB Ref ID: 178793]

LANL [2002e]. Radiation surveys, radioactive material tags, RWPs 2002-031-01 and 

2002-039-01 TA-53 buildings 3 and 8 (April–May 2002). Los Alamos National 

Laboratory, Los Alamos, NM: University of California. [SRDB Ref ID: 180954]

LANL [2002f]. RWPs TA-53 2002 part A (March–May 2002). Los Alamos National 

Laboratory, Los Alamos, NM: University of California. [SRDB Ref ID: 181126]

LANL [2002g]. RWPs TA-53 CY2002 part B (May 2002). Los Alamos National 

Laboratory, Los Alamos, NM: University of California. [SRDB Ref ID: 181127]

LANL [2002h]. RWPs TA-53 CY2002 part C (June–July 2002). Los Alamos National 

Laboratory, Los Alamos, NM: University of California. [SRDB Ref ID: 181128]

LANL [2002i]. RWPs TA-53 CY2002 part D (July–November 2002). Los Alamos 

National Laboratory, Los Alamos, NM: University of California. [SRDB Ref ID: 181129]

LANL [2002j]. RWPs TA-53 CY2002 part E (August–September 2002). Los Alamos 

National Laboratory, Los Alamos, NM: University of California. [SRDB Ref ID: 181130]

LANL [2002k]. RWPs TA-53 CY2002 part F (September–October 2002]. Los Alamos 

National Laboratory, Los Alamos, NM: University of California. [SRDB Ref ID: 181131]

LANL [2002l]. RWPs TA-53 CY2002 part G (November 2002). Los Alamos National 

Laboratory, Los Alamos, NM: University of California. [SRDB Ref ID: 181132]

LANL [2003]. RWPs direct, smear, LAS surveys and external radiation TA-53 (2003). 

Los Alamos National Laboratory, Los Alamos, NM: University of California. [SRDB Ref 

ID: 178809]

LANL [2004]. RWPs TA-53 building 7 (2004). Los Alamos National Laboratory, Los 

Alamos, NM: University of California. [SRDB Ref ID: 178705]

LANL [2004–2006]. TA-53 front gate radiation monitor source check log 2004–2006. 

Compilation of source check logs. Los Alamos National Laboratory, Los Alamos, NM: 

University of California. [SRDB Ref ID: 196699]

LANL [2005]. HSR-1/TA-53 routine monitoring instructions. Los Alamos National 

Laboratory, Los Alamos, NM: University of California. HSR-1/TA-53-RMI-26-R10, 

February 28. [SRDB Ref ID: 181156]

LANL [2010]. Actinide research quarterly fourth quarter 2009 and first quarter 2010. 

Accelerator radioisotopes save lives: Part II. Actinide Research Quarterly, 4th Quarter 

2009/1st Quarter 2010. Los Alamos National Laboratory, Los Alamos, NM: University of 

California. [SRDB Ref ID: 120805] 
Page 15 of 16 

This is a working document prepared by NIOSH’s Division of Compensation Analysis and Support (DCAS) or its contractor for 

use in discussions with the ABRWH or its Working Groups or Subcommittees. Draft, preliminary, interim, and White Paper 

documents are not final NIOSH or ABRWH (or their technical support and review contractors) positions unless specifically 

marked as such. This document represents preliminary positions taken on technical issues prepared by NIOSH or its contractor.

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

has been cleared for distribution. 5 United States Code (U.S.C.) § 552a.

LANL [2022]. LANL response to EEOICPA NIOSH ORAU data request LANL FY22-005 

(item #2). Letter to JL Jung with attachments. Los Alamos National Laboratory, Los 

Alamos, NM: U.S. Department of Energy, National Nuclear Security Administration. July 

13. [SRDB Ref ID: 193216]

LANL [2023]. LANL REMS database. Database. Los Alamos National Laboratory, Los 

Alamos, NM: Triad National Security. June 13. [SRDB Ref ID: 197952] 

Macek RJ [1996]. Beam-limiting and radiation-limiting interlocks. In: Radiation 

Protection held in Vienna, Austria, April 1996. Los Alamos National Laboratory, Los 

Alamos, NM: University of California. LA-UR-96-443, April. [SRDB Ref ID: 195746]

NIOSH [2019]. U.S. Department of Health and Human Services Centers for Disease 

Control National Institute for Occupational Safety and Health Advisory Board on 

Radiation and Worker Health Los Alamos National Laboratory (LANL) work group 

Thursday, July 25, 2019. Transcript. Washington, DC: U.S. Department of Health and 

Human Services, Centers for Disease Control, National Institute for Occupational Safety 

and Health, Advisory Board on Radiation and Worker Health. July 25. [SRDB Ref ID: 

184933]

O’Neill M [2020]. News media report - DOE investigates small fire Oct. 4 at Los Alamos 

Neutron Science Center October 12, 2020. The Los Alamos Reporter. October 12. 

[SRDB Ref ID: 197951]

ORAUT [2022a]. Bounding intakes of exotic radionuclides at Los Alamos National

Laboratory. Oak Ridge, TN: Oak Ridge Associated Universities Team. ORAUT-RPRT0101 Rev. 00, March 1. [SRDB Ref ID: 191729]

ORAUT [2022b]. Review of potential exposure to exotic radionuclides using radiological 

work permit data at Los Alamos National Laboratory. Oak Ridge, TN: Oak Ridge 

Associated Universities Team. ORAUT-RPRT-0103 Rev. 00, August 15. [SRDB Ref ID: 

193468] 

ORAUT [2023]. Workers with over 100 mrem CED in a year at LANL 1996–2005. 

Spreadsheet. Oak Ridge, TN: Oak Ridge Associated Universities Team. June 23. 

[SRDB Ref ID: 198633]

Sturrock JC, Gallegos FR, Hall MJ [1996]. LANSCE personnel access control system 

(PACS). In: Health Physics Society 1997 midyear topical meeting held in San Jose, CA. Los 

Alamos National Laboratory, Los Alamos, NM: University of California. LA-UR-96-3552, 

December 26. [SRDB Ref ID: 195747] 
Page 16 of 16 

This is a working document prepared by NIOSH’s Division of Compensation Analysis and Support (DCAS) or its contractor for 

use in discussions with the ABRWH or its Working Groups or Subcommittees. Draft, preliminary, interim, and White Paper 

documents are not final NIOSH or ABRWH (or their technical support and review contractors) positions unless specifically 

marked as such. This document represents preliminary positions taken on technical issues prepared by NIOSH or its contractor.

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

has been cleared for distribution. 5 United States Code (U.S.C.) § 552a.

Attachment One: LANSCE Images

Figure A-1 shows an aerial view of LANSCE from the front where the beam is started.

Figure A-1: Aerial view of TA-53 with LANSCE [O’Neill 2020]

Figure A-2 shows a diagram of hot cells located in the LANSCE Isotope Production Facility.

Figure A-2: Diagram of hot cells in the Isotope Production Facility [LANL 2010, PDF p. 9]