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Radiation Leukemogenesis at Low Dose Rates

The major goals of this program were to study the efficacy of low dose rate radiation exposures for the induction of acute myeloid leukemia (AML) and to characterize the leukemias that are caused by radiation exposures at low dose rate. An irradiator facility was designed and constructed that allows large numbers of mice to be irradiated at low dose rates for protracted periods (up to their life span). To the best of our knowledge this facility is unique in the US and it was subsequently used to study radioprotectors being developed for radiological defense (PLoS One. 7(3), e33044, 2012) and is currently being used to study the role of genetic background in susceptibility to radiation-induced lung cancer. One result of the irradiation was expected; low dose rate exposures are ineffective in inducing AML. However, another result was completely unexpected; the irradiated mice had a very high incidence of hepatocellular carcinoma (HCC), approximately 50%. It was unexpected because acute exposures are ineffective in increasing HCC incidence above background. This is a potential important finding for setting exposure limits because it supports the concept of an 'inverse dose rate effect' for some tumor types. That is, for the development of some tumor types low dose rate exposures carry greater risks than acute exposures.

61 RADIATION PROTECTION AND DOSIMETRY↗

2018 Annual Site Environmental Report Summary

We are committed to act as stewards of our environment to achieve our mission in accordance with all applicable environmental requirements. We set continual improvement objectives and targets, measure and document our progress, and share our results with our workforce, sponsors, and public. We reduce our environmental risk through legacy cleanup, pollution prevention, and long-term sustainability programs.

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗

2019 ASER Supplemental Tables Chapters 7 and 8

This pdf contains the data tables that will be posted on the LANL external website as a supplement to the Los Alamos National Laboratory 2019 Annual Site Environmental Report for Chapters 7 and 8.

54 ENVIRONMENTAL SCIENCES↗

B332 & B151 ACL Events

In September 2019, two Unexpected Radiological Event (HP-FO-601) reports were submitted to document the exceedance of a worker's default Administrative Control Level (ACL) of 100 mrem/y. One involved work in B332; the second in B151. B332 event: The worker was new to B332 and had completed qualification as an Associate Fissile Material Handler (FMH) in April of 2019. The worker received 61 mrem in June and an additional 100 mrem in July. The worker was on a monthly TLD exchange cycle. B151 event: A PLS radiochemist received ~20 mrem for the 1st quarter of the year and ~120 mrem for the 2nd quarter of the year. The worker was on a quarterly TLD exchange cycle.

61 RADIATION PROTECTION AND DOSIMETRY↗

Radiological Impact of 2021 Operations at the Savannah River Site

This report presents the environmental dose assessment methods and the estimated potential doses to the public from 2021 Savannah River Site (SRS) air and liquid radioactive releases. Also documented are potential doses from special-case exposure scenarios, such as the consumption of wildlife or goat milk.

54 ENVIRONMENTAL SCIENCES↗

Soil, Foodstuffs, and Biota Program [Slides]

We use several environmental monitoring tools to assess ecosystem health and in part, risk to human health. Generally, the concentrations of chemicals we observe are below background and screening levels. All of our monitoring data are available in Intellus, and our analyses and results are reported in the Annual Site Environmental Report. Our program is only one of several monitoring programs at LANL, others include air, surface water, ground water, canyon sediments. We strive to improve the program by incorporating new monitoring techniques, monitoring new locations, monitoring new chemicals of interest, and by using robust statistical analyses.

54 ENVIRONMENTAL SCIENCES↗

Calculation of Groundwater Pathway Radiological Dose for the Hanford Site Composite Analysis Base Case

The purpose of this environmental calculation file (ECF) is to present the results of the exposure route-specific and total radiological dose assessments for the groundwater exposure pathway as a part of the updated Hanford Site Composite Analysis (CA). The purpose of these radiological dose assessments is to provide an estimate of the cumulative radiological impacts from all screened sources of ionizing radiation and exposure routes that could potentially contribute to the projected dose to a hypothetical member of the public from both existing or future disposal facilities and other sources including past-practice discharge sites.

61 RADIATION PROTECTION AND DOSIMETRY↗

RCT Module 2.09: Environmental Monitoring [Slides]

Environmental monitoring plays a large role in the field of radiological control. It is used to estimate human population doses, determine the impact a site has on the environment, monitor for unplanned releases as well as quantifying planned releases, and gives us useful data in determining pathway data. This course will prepare the student with the skills necessary for RCT qualification.

54 ENVIRONMENTAL SCIENCES↗

FRMAC Laboratory Analysis Manual Volume 1, Revision 0

This manual is written for personnel who respond to a nuclear/radiological incident and will be called upon to provide support to ensure that samples receive appropriate laboratory analyses. Overall, this manual provides general guidance and some specific diagrams and forms. However, it is understood that site- and incident-specific operational decisions and procedures may need to be modified at the time of the incident. This manual is intended to provide guidance for laboratory analysis personnel without limiting FRMAC’s ability to integrate the work with other partners and stakeholders. Some of the titles of management positions with the FRMAC have been changed in order to comply with the structure of the Incident Command System (ICS) under the National Incident Management System (NIMS).

61 RADIATION PROTECTION AND DOSIMETRY↗

Fitting the RESRAD External Dose Rate Coefficients Model to the FGR 15 Data

FGR15 (Bellamy et al. 2025) lists external dose rate coefficients for radionuclides in soil, water and air. It has five tables of coefficients for contaminated soil; one for radionuclides on the surface of the soil and one each for radionuclides in soil layers of 1 cm, 5 cm, 15 cm and infinite thickness. Each table contains 7512 coefficients, quantifying the external dose rate from each of the 1252 ICRP107 radionuclides, to each of the six reference persons of different ages.

54 ENVIRONMENTAL SCIENCES↗

Approach and Issues Relating to Shield Material Design to Protect Astronauts from Space Radiation

One major obstacle to human space exploration is the possible limitations imposed by the adverse effects of long-term exposure to the space environment. Even before human spaceflight began, the potentially brief exposure of astronauts to the very intense random solar energetic particle (SEP) events was of great concern. A new challenge appears in deep space exploration from exposure to the low-intensity heavy-ion flux of the galactic cosmic rays (GCR) since the missions are of long duration and the accumulated exposures can be high. Since aluminum (traditionally used in spacecraft to avoid potential radiation risks) leads to prohibitively expensive mission launch costs, alternative materials need to be explored. An overview of the materials related issues and their impact on human space exploration will be given.

Wilson, J. W.↗

Estimation of neutron and other radiation exposure components in low earth orbit

The interaction of high-energy space radiation with spacecraft materials generates a host of secondary particles, some, such as neutrons, are more biologically damaging and penetrating than the original primary particles. Before committing astronauts to long term exposure in such high radiation environments, a quantitative understanding of the exposure and estimates of the associated risks are required. Energetic neutrons are traditionally difficult to measure due to their neutral charge. Measurement methods have been limited by mass and weight requirements in space to nuclear emulsion, activation foils, a limited number of Bonner spheres, and TEPCs. Such measurements have had limited success in quantifying the neutron component relative to the charged components. We will show that a combination of computational models and experimental measurements can be used as a quantitative tool to evaluate the radiation environment within the Shuttle, including neutrons. Comparisons with space measurements are made with special emphasis on neutron sensitive and insensitive devices. c2001 Elsevier Science Ltd. All rights reserved.

STS-57 Shuttle Project↗

Dose-Dependent Analysis of Acute Medical Effects of Mixed Neutron-Gamma Radiation from Selected Severe Uranium-235 or Plutonium-239 Criticality Accidents in USSR, United States and Argentina

Eight of the most severe cases of acute radiation disease (ARS) known to have occurred in man (as the result of criticality accidents) had survival times less than 120 hours (herein defined as “early death”). These accidents were analyzed and are discussed with respect to the specific accident scenarios and the resulting accident specific, mixed neutron-gamma radiation clinical dose distributions. Our analysis concludes that the cardiovascular system appears to be the most critical organ system failure for causing “early death”, following approximate total body, mixed gamma-neutron irradiations doses greater than 40–50 Gy. The clinical data also suggests that there is definite chest dose dependence in the resulting survival times for these eight workers, who unfortunately suffered profound radiation injury and unusual clinical effects from such high dose radiation exposures. In addition “toxemic syndrome” is correlated with the irradiation of large volumes of soft tissues. Doses to the hands or legs greater than 80 –100 Gy or radiation lung injury also play significant, but secondary, roles for causing “early death”, in accidents delivering chest doses greater than 50 Gy.

61 RADIATION PROTECTION AND DOSIMETRY↗