A National Perspective: Establishing and Implementing a Characterization Program in the U.S. for Remote-Handled Transuranic Waste

Author(s):  
Roger Nelson ◽  
Alton D. Harris

The U.S. Department of Energy (DOE) is responsible for waste management from nuclear weapons production and operates the Waste Isolation Pilot Plant (WIPP) for permanent disposal of defense-generated transuranic waste (TRU), as authorized by Congress in 1979. Radioactive waste in the U.S. has historically been managed in one of two ways depending on its penetrating radiation dose rate. Waste with surface dose rates above 200 millirem/hour (0.002 sievert/hour) and waste that has been managed remotely (remote-handled). In 1992, Congress passed the WIPP Land Withdrawal Act, which created the regulatory framework under which DOE was to operate the facility, and authorized disposal of waste up to 1,000 rems/hour (10 Sievert/hour). Subsequently, DOE submitted applications to the Environmental Protection Agency (EPA), at the Federal level, for certification to operate WIPP, and to the New Mexico Environment Department (NMED), at the State level, for a hazardous waste permit. Both applications described the characterization methods that DOE proposed to use to ensure only compliant waste was shipped to WIPP. No distinction was employed in these methods concerning the surface dose rate from the waste. During the applications review, both regulatory agencies came to the conclusion in their approval that DOE had not demonstrated that remote-handled transuranic (RH-TRU) waste could be adequately characterized. Therefore, WIPP was only granted approval to begin waste disposal operations of waste with surface dose rates less than 200 millirem/hour (0.002 sievert/hour) — or contact-handled transuranic (CH-TRU) waste. Emplacement of CH-TRU waste in WIPP began March 26, 1999. However, WIPP was designed for disposal of both CH- and RH-TRU waste, with the RH-TRU waste in canisters emplaced in the walls of the underground disposal rooms and CH-TRU waste in containers in the associated open drifts. Therefore, as disposal rooms filled with CH-TRU waste, the space along the walls for RH-TRU waste disposal was lost. This made removal of the regulatory prohibition on RH-TRU waste a very high priority, and DOE immediately began an iterative process to change the two regulatory bases for RH-TRU waste disposal. These changes focused on how DOE could rely on CH-TRU characterization methods for adequate characterization of RH-TRU waste. On January 23, 2007, the first shipment of RH-TRU waste was finally received at WIPP. The revised EPA certification and NMED permit now both consider all waste characterization methods to be equally effective when applied to either CH- or RH-TRU waste, as DOE maintained in the original applications over 10 years ago.

Author(s):  
Scott D. Monroe

Abstract The Waste Isolation Pilot Plant (WIPP) is the United State’s (U.S.) first deep disposal facility for transuranic radioactive (TRU) waste generated as a result of defense activities. The U.S. Environmental Protection Agency (USEPA or “the Agency”) initially certified the WIPP in May 1998, and WIPP received the first shipment of TRU waste on March 26, 1999. Every five years thereafter, USEPA is required by law to recertify whether the WIPP continues to comply with the USEPA’s radioactive waste disposal regulations. USEPA is coordinating with the U.S. Department of Energy (USDOE), which operates the WIPP, to prepare for the first recertification in 2004. This process involves many interesting technical and policy issues.


Author(s):  
Amir Hamzah ◽  
Hery Adrial ◽  
Subiharto Subiharto

EVALUATION OF RADIATION DOSE RATE OF RSG-GAS REACTOR. The RSG-GAS reactor has been operated for 30 years. Since the nuclear reactor has been operated for a long time, aging process on its components may occur. One important parameter for maintaining the safety level of the RSG-GAS reactor is to maintain radiation exposure as low as possible, especially in the working area. The evaluation results should be able to demonstrate that the radiation exposure of the RSG-GAS is still safe for workers, communities and the surrounding environments. The purpose of this study is to evaluate radiation exposure in the working area to ensure that the operation of RSG-GAS is still safe for the next 10 years. The scope of this work is confirming the calculation results with the measured radiation dose in the RSG-GAS reactor working area. Measurement of radiation exposure is done by using the installed equipments at some points in the RSG-GAS working area and a portable radiation exposure measurement equipment. The calculations include performance of a modeling and analysis of dose rate distribution based on the composition and geometry data of RSG-GAS by using MCNP.  The analysis results show that the maximum dose rate at Level 0 m working area of RSG-GAS reactor is 3.0 mSv/h with a deviation of 6%, which is relatively close to the measurement value. The evaluation results show that the dose rate in RSG-GAS working area is below the limit value established by the Nuclear Energy Regulatory Agency of Indonesia (BAPETEN) of 10 mSv/h (for the average effective dose of 20 mSv/year). Therefore, it is concluded that the dose rate in RSG-GAS working area is safe for personnel..Kata kunci: dose rates, RSG-GAS, radiation safety, MCNP.


Author(s):  
Tomoharu Hashimoto ◽  
Masahiro Kondo ◽  
Ryuichi Tayama ◽  
Hideho Gamo

The Japanese government plans to conduct decontamination tasks in radioactively contaminated areas. For such a situation, we developed a system that evaluates radiation dose rates in a wide radioactively contaminated area by utilizing our radiation dose evaluation technology. This system can not only generate present maps of radiation dose rate in the air based on the dose rate measured at the surface of the contaminated areas, but can also quickly calculate the reduction effect of dose rate due to decontamination tasks by entering decontamination factors. The system can then formulate decontamination plans and make it possible to plan measures to reduce radiation exposure for workers and local residents. Radioactive nuclides that contribute to gamma-ray dose rate are mainly Cs-134 and Cs-137 in soil, on trees, buildings, and elsewhere. Shapes of such radiation sources are assumed to be 10m square or 100m square. If it is unsuitable that the radiation sources assume to squares, the radiation sources can assume to point. The relation between distance from the surface or point source and the radiation dose rate is calculated using MCNP5 code (A General Monte Carlo N-Particle Transport Code - Version 5), and approximated using four-parameter empirical formula proposed by Harima et al. In addition, the system can consider shielding such as soil, concrete, and iron. When setting such shielding, the skyshine dose rate is taken into account in dose rate calculation.


2016 ◽  
Author(s):  
Stefanie A. Fountain ◽  
Rudolph Bonaparte ◽  
John F. Beech ◽  
Leslie M. Griffin

Author(s):  
Edward A. Beimborn ◽  
Michael J. Greenwald ◽  
Xia Jin

Travelers can be classified into two groups: choice users and captive users. Choice users select transit or automobile service when they view one option as superior, whereas captive users have only one travel option. Surprisingly, little is known about captivity effects on mode split models. This research examines the way transit service factors such as accessibility and connectivity relate to mode captivity and mode choice. Data for this investigation come from the Portland, Oregon, 1994 Household Activity and Travel Diary Survey, the Regional Land Information System for the Portland area, the U.S. Environmental Protection Agency fuel economy database, and the U.S. Department of Energy. Individual trip data were segmented into transit captive, automobile captive, and choice users based on information about private vehicle availability, transit connectivity, and distance from a transit stop. Traditional transit mode split models are compared with models that segment users into choice and captive groups. It was found that traditional models underestimate the variation in mode choice for captive users, while overestimating the attractiveness of transit for choice users. These results indicate that better transit forecasts can result if accessibility and connectivity are used to help identify captive users. Additionally, among choice transit users, differences in travel times between automobile and transit modes do little to influence mode selection, while walk access to transit has more effect than previously thought.


2000 ◽  
Vol 663 ◽  
Author(s):  
M. K. Silva ◽  
V. M. Oversby

ABSTRACTThe Waste Isolation Pilot Plant (WIPP) is located at a depth of 655 m in bedded salt at a site about 40 km east of Carlsbad, New Mexico.The 1996 U. S. Department of Energy (DOE) application for certification by the U. S. Environmental Protection Agency (EPA) included results of a performance assessment (PA) for the planned repository.After the EPA certified the facility in May, 1998, emplacement of contact handled transuranic waste (CHTRU) began in March, 1999.The WIPP facility must undergo a recertification by EPA every 5 years to demonstrate compliance with disposal regulations.Performance assessment is expected to be a key part of the recertification process.The PA will include probabilistic calculations to predict the release of actinides to the accessible environment over a 10,000 year period using a variety of plausible scenarios.The 1996 PA used a model for Pu(IV) solubility based on Th data and the assumption of analogous behavior for all actinides in the (IV) oxidation state.That model did not allow for mobility between the various possible oxidation states of Pu.The possible effects of increases in solubility of Pu through complexation with organic ligands was also not included in the PA because it was argued by DOE that such complexation would be insignificant. Subsequent data from tests using actual TRU wastes show strong evidence that the importance of organic ligands and the potential for multiple oxidation states must be carefully considered in estimating the expected solution concentrations of Pu in WIPP brines.This paper reviews the present state of knowledge of the behavior of Pu-containing wastes in contact with brines similar to those expected to be important for the WIPP repository, recent advances in understanding of the nature of Pu-oxide phases, and analytical methods that have high sensitivity for Pu speciation. A conceptual model for Pu in TRU wastes is presented and a series of steps - including experiments and calculations - that could led to an improved basis for the PA calculations to be done during the WIPP recertification process is outlined.


2020 ◽  
Vol 287 (1937) ◽  
pp. 20201638
Author(s):  
Katherine E. Raines ◽  
Penelope R. Whitehorn ◽  
David Copplestone ◽  
Matthew C. Tinsley

The consequences for wildlife of living in radiologically contaminated environments are uncertain. Previous laboratory studies suggest insects are relatively radiation-resistant; however, some field studies from the Chernobyl Exclusion Zone report severe adverse effects at substantially lower radiation dose rates than expected. Here, we present the first laboratory investigation to study how environmentally relevant radiation exposure affects bumblebee life history, assessing the shape of the relationship between radiation exposure and fitness loss. Dose rates comparable to the Chernobyl Exclusion Zone (50–400 µGy h −1 ) impaired bumblebee reproduction and delayed colony growth but did not affect colony weight or longevity. Our best-fitting model for the effect of radiation dose rate on colony queen production had a strongly nonlinear concave relationship: exposure to only 100 µGy h −1 impaired reproduction by 30–45%, while further dose rate increases caused more modest additional reproductive impairment. Our data indicate that the practice of estimating effects of environmentally relevant low-dose rate exposure by extrapolating from high-dose rates may have considerably underestimated the effects of radiation. If our data can be generalized, they suggest insects suffer significant negative consequences at dose rates previously thought safe; we therefore advocate relevant revisions to the international framework for radiological protection of the environment.


2020 ◽  
Vol 8 (4) ◽  
pp. 31-40
Author(s):  
Reza Baghaei Lakeh ◽  
◽  
Christopher Salerno ◽  
Ega P. Herlim ◽  
Joseph Kiriakos ◽  
...  

The reject of the reverse osmosis water treatment process (aka brine, concentrate, ROC) is a mixture of salts that are dissolved in high salinity water. The ROC is classified as an industrial waste by the U.S. Environmental Protection Agency and can face regulatory limitations on disposal. State-of-the-art of ROC disposal includes deep-well injection, surface discharge to rivers, discharge to the ocean, and evaporation ponds. In this study, the feasibility of using Reverse Osmosis Concentrate as a low-cost Thermal Energy Storage (TES) medium is explored by a techno-economic analysis. The normalized cost of TES (cost per unit volume of stored thermal energy) is estimated through a series of cost analyses and is compared to the cost targets of the U.S. Department of Energy for low-cost thermal energy storage. It was shown that the normalized cost of TES using ROC salt content is in the range of $6.11 to $8.73 depending on ROC processing methods.


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