MOOSE NTP modeling: current status, needs and challenges
Presentation given at Georgia Tech
33 ADVANCED PROPULSION SYSTEMS↗
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Analysis of the Phenix end-of-life natural convection test with SAS4A/SASSYS-1
From a reduced power and flow condition, the 2009 Phenix Natural Convection Test mimics a protected loss-of-heat sink event. The measured transient response of the Phenix reactor to such an event provides an important data set for validating safety analysis codes. A model of the Phenix reactor and primary coolant system was developed using the reactor safety analysis code system SAS4A/SASSYS-1. While the overall global response of the reactor was predicted reasonably well, there were some non-negligible discrepancies in the temperature predictions during the transient and work continues to improve the model. Some modeling issues have been identified, and will be addressed as improvements to the model continue. (authors)
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Overall results of and lessons learned from the IAEA CRP on sodium natural circulation test performed during the Phenix end-of-life experiments
In 2007, the International Atomic Energy Agency (IAEA) launched the Coordinated Research Project (CRP) 'Control Rod Withdrawal and Sodium Natural Circulation Tests Performed during the Phenix End-of-Life Experiments'. The overall purpose of the CRP, performed within the framework of the IAEA programme in support of innovative fast reactor technology development and deployment, is to improve the Member States' analytical capabilities in the various fields of research and design of sodium-cooled fast reactors through data and codes verification and validation. In particular the CRP, taking advantage of the End-of-Life set of experiments performed before the final shut-down of the French prototype fast breeder power reactor Phenix, aims at improving fast reactor simulation methods and design capabilities in the field of temperature and power distribution evaluation, as well as of the analysis of sodium natural circulation phenomena. The paper presents the overall results of the CRP, including blind calculations and post-test and sensitivity analyses carried out by the CRP participants, as well as lessons learned and recommendations for further future implementations to resolve open issues. (authors)
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Of the final end state for decommissioning of reactors at SRS: collaboration between stakeholders, regulators, and the Federal Government - 15279
The Savannah River Site (SRS) is an 802 square-kilometer (310 square-miles) United States Department of Energy (US DOE) nuclear facility located along the Savannah River near Aiken, South Carolina. Nuclear weapons material production began in the early 1950's, utilizing five (5) production reactors. In the early 1990's all SRS production reactor operations were terminated. The first reactor closure end-state declaration was documented in a Comprehensive Environmental Response and Compensation and Liability Act (CERCLA) Early Action Record of Decision. The decision for the final closure of the 29,543 square-meter (318,000 square-feet) 105-P Reactor was determined to be in situ decommissioning (ISD). ISD is an acceptable and cost-effective alternative to off-site disposal for the reactor building, which will allow for consolidation of remedial action wastes generated from other cleanup activities within the P Area. ISD is considered protective by the regulators, U.S. Environmental Protection Agency (USEPA) and the South Carolina Department of Health and Environmental Control (SCDHEC), public and stakeholders as waste materials are stabilized / immobilized, and radioactivity is allowed to naturally decay, thus preventing future exposure to the environment. Stakeholder buy-in was critical in the up-front planning in order to achieve this monumental final decision. Numerous public meetings and workshops were held in two different states (covering a 321 kilometer (200-mile) radius) with stakeholder and SRS Citizens Advisory Board (CAB) participation. These meetings were conducted over an eight- month period as the end-state decision making progressed. Information provided to the public evolved from workshop to workshop as data became available and public input from the public meetings were gathered. ISD is being considered for the balance of the four (4) SRS reactors and other hardened facilities such as the chemical Separation Facilities (canyons). Closure of the SRS P Reactor Area was precedent setting and sets the stage for closure of other reactors and hardened facilities. The DOE, USEPA, and SCDHEC engaged in active, up-front, and timely involvement with the SRS. The SRS CAB, elected officials, and citizens of South Carolina and Georgia met to discuss the P reactor area closure and associated risks. Early public involvement gave SRS and the regulators assurance that the selected decision was valid and would not be overturned. Public input improved the process and ensured that the important decision on the final end-state of the reactor facilities was not made in isolation. ISD of P Reactor will provide adequate protection of human health and the environment and the lowest cost since short-term risk is minimized to remedial workers from exposure to contaminated equipment and facilities by leaving the reactor vessel in place allowing for radiological decay over time. (authors)
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Post-closure program streamlining at the Nevada national security site - 15290
More than 200 sites on the Nevada National Security Site (NNSS), Nevada Test and Training Range (NTTR), and Tonopah Test Range (TTR) have been closed in place. At these sites, contamination has been left in place, and protection of human health, safety, and the environment is ensured through the establishment of use restrictions (URs). Post-closure requirements were initially established in the Closure Report (CR) for each site and include a variety of inspection, monitoring, maintenance, and reporting commitments. Post-closure requirements and site controls (fences, monuments, soil covers, and postings) may vary depending on site location, accessibility, land use scenario, and the nature of contaminants left in place. Corrective Action Sites (CASs) on the NNSS, NTTR, and TTR have been identified for closure under the Federal Facility Agreement and Consent Order (FFACO), which was signed in 1996. Over 1,900 CASs have been closed under the framework of the FFACO, and more than 200 of those have URs. Many post-closure requirements have been modified over time. In addition, because the scope of the program has spanned almost 20 years, the post-closure requirements have varied due to changing strategies and expectations. Because of the number of sites closed over the course of the program, post-closure requirements are found in hundreds of closure documents, addendums, errata sheets, Records of Technical Change, inspection reports, permit modifications, and correspondence. Furthermore, resources such as personnel and funding necessary to conduct the post-closure program have diminished, while computer capabilities and configuration control principles have improved since closure activities under the FFACO began. Because of these factors, to effectively manage the post-closure program, ensure that all commitments are being met, and improve the ease of identifying the most current post-closure requirements for each UR, the current requirements for every use-restricted site under the purview of the U.S. Department of Energy, National Nuclear Security Administration Nevada Field Office will be consolidated into a single Post-Closure Plan. The Consolidated Post-Closure Plan will also outline a strategy and present possible criteria that may be used for future evaluation of post-closure requirements. Continual assessment of the post-closure program will ensure that the post-closure requirements for URs across the NNSS, NTTR, and TTR are consistently justifiable and sufficient to protect site workers, the public, and the environment while increasing efficiency. Future changes to post-closure requirements and justification for those changes will be recorded in revisions to the Consolidated Post-Closure Plan. This process will provide a comprehensive, consistent, and streamlined method for evaluation of post-closure requirements and implementation of changes. (authors)
54 ENVIRONMENTAL SCIENCES↗
WIPP - February 2014 operational events and the compliance re-certification application (CRA) 2014 - 15293
On Wednesday, February 5, 2014, an underground mine fire involving a salt haul truck occurred at the Waste Isolation Pilot Plant (WIPP). There were 86 workers in the mine when the fire occurred. All workers were evacuated. Nine days later, on Friday, February 14, 2014, there was an incident in the underground repository at WIPP which resulted in the release of americium and plutonium from one or more transuranic (TRU) waste containers into the environment. The release was detected by an underground continuous air monitor and then directed through high-efficiency particulate air (HEPA) filter banks located in the surface exhaust building. However, a measurable portion bypassed the HEPA filters via leakage through two ventilation system dampers and was discharged directly to the environment from an exhaust duct. No personnel were determined to have received external contamination; however, some individuals that were on site were identified through bioassay to have initially tested positive for low level amounts of internal contamination. Trace amounts of americium and plutonium were detected off-site.While significant to day-to-day operations, these events have no impact to the long-term performance of the repository. Because WIPP's re-certification is based solely on the post-closure performance of the repository (40 CFR 191, Subparts B and C), these recent events do not affect the long-term performance predictions or its technical and scientific basis. In this paper we will further explore the requirements for WIPP's re-certification, and the basis for our contention that the recent WIPP operational events do not impact long-term repository performance or have any implications on salt as a geologic disposal media, and that re-certification efforts should continue uninterrupted. (authors)
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Preliminary performance assessment for the Waste Management Area C at the Hanford site in southeast Washington - 15331
A performance assessment of Single-Shell Tank Waste Management Area C located at the U.S. Department of Energy's Hanford Site in southeastern Washington is being conducted to satisfy the requirements of the Hanford Federal Facility Agreement and Consent Order, as well as other Federal requirements and State-approved closure plans and permits. The Waste Management Area C performance assessment assesses the fate, transport, and impacts of radionuclides and hazardous chemicals within residual wastes left in tanks and ancillary equipment and facilities in their assumed closed configuration and the subsequent risks to humans into the far future. The part of the performance assessment focused on radiological impacts is being developed to meet the requirements for a closure authorization under U.S. Department of Energy Order 435.1 that include a waste incidental to reprocessing determination for residual wastes remaining in tanks, ancillary equipment, and facilities. An additional part of the performance assessment will evaluate human health and environmental impacts from hazardous chemical inventories in residual wastes remaining in Waste Management Area C tanks, ancillary equipment, and facilities needed to meet the requirements for permitted closure under the Resource Conservation and Recovery Act of 1976. Preliminary results of the performance assessment are evaluating the groundwater and air pathways to determine radiation exposure once radionuclides are released to the environment due to degradation of the engineered barriers. Per DOE Order 435.1, results of the preliminary analyses are being compared to the performance objectives during the 1,000-year post-closure period of compliance. Per the Order, performance assessment results are also being compared to the performance measures related to acute and chronic inadvertent intruder analyses and groundwater protection. (authors)
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Safety assessment for the radon-type surface disposal facility at Saakadze, Georgia - 15406
The Saakadze disposal facility is located about 40 km from Tbilisi and was planned and constructed during Soviet times as Radon-type surface facility to accommodate up to 600 m{sup 3} of low and intermediate level waste generated on the territory of Georgia. The disposal facility was operated from 1963 until its closure in 1995. The vast majority of waste in the Saakadze facility has been disposed of in two near surface concrete vaults with typical Radon-type dimensions, which cover layers already show significant structural damages. In order to assess the present safety of the site and provide the competent Georgian authorities with the necessary basis to take decisions in regard to the future of the repository, the European Commission launched and financially supported a project, which was assigned to a consortium of TUV-Nord ENSYS GmbH and DBE Technology GmbH. The safety assessment of Saakadze facility, which was an essential part of this project and which is the subject of this paper was carried out by DBE Technology GmbH. The Government of Georgia has been gradually increasing efforts to improve the regulatory processes and the legislation on nuclear and radiation safety, and, in particular, on safe management of radioactive waste and sealed radioactive sources. Currently, however, there are still areas where specific Georgian laws and regulations do not exist. Accordingly, in certain aspects IAEA recommendations and best practices were used as guidelines for the methodology of the safety assessment. In spite of the large uncertainties to be considered, especially in regard to the inventory, preliminary results of the safety assessment indicate that scenarios related to the groundwater pathway do not lead to radiological impacts that are above or near to limiting values. However, human intrusion scenarios might lead to dose rates for the critical group that are exceeding these values. This is mainly due to the fact that today there is no proper engineered cover on top of the concrete vaults. Based on the comparison of existing options and considering the results of the long-term safety assessment, it is recommended to backfill the remaining voids inside the concrete vaults and to construct an engineered cover to reduce the probability of human intrusion scenarios and to minimize their potential impact. (authors)
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Advanced dismantling techniques applied in an industrial project for the dismantling of highly activated equipment - 15446
Commissioned in 1958 on the CEA nuclear site of Marcoule (France) and shut down in 1997, the former UP1 plant was dedicated to reprocess the spent fuel from G1, G2 and G3 GCR reactors. Since 1998, a wide program for cleaning-up and dismantling the plant has been developed in order to dismantle the process equipment, eliminate any radiological risk in all buildings concerned and remove all the resulting waste. Major technical challenges are related to the wide range of complex components and equipment in the facilities such as chemical dissolvers, extractor batteries, evaporators, tanks; and to a high risk of exposure, due to the presence of fission products. To address these challenges, CEA led R and D programs to develop advanced tools for complex dismantling projects: immersive virtual reality, laser cutting techniques, special remote-controlled arms combining dexterity and high resistance to irradiation The purpose of this paper is to provide an overview of a practical implementation and to show first results of these advanced techniques on a real case: the dismantling of dissolver's equipment from the dissolution workshop of UP1 plant. ONET Technologies has been chosen by CEA to design, build and operate the overall dismantling and waste treatment system for this project. ONET Technologies designed two main subsystems to meet all the requirements for this project: first, the 'Remotely-Operated Handling and Cutting Unit' and second the 'Waste Extraction and Conditioning Unit' and the combining innovative technologies. During the design phase, the 'Immersive Virtual Reality' has been used to qualify the kinematics in the final environment and the preliminary dismantling scenario. Following a first R and D program of CEA regarding the laser cutting technique applied to nuclear decommissioning, ONET Technologies and CEA realized elementary inactive tests based on a 6 kW Nd-Yag laser source to qualify the cutting performance according to material and thickness. Main objective was to meet the safety criteria and to check the physical characteristics of waste resulting from the laser cutting operation. The Remotely-Operated Handling and Cutting Unit was equipped with a MAESTRO manipulator, resulting from ten years of research and development cooperation between CEA and Cybernetix. This manipulator, a 6 axis hydraulic manipulator-arm specifically designed to work in harsh environment, entered in its industrial phase. ONET Technologies was responsible for the overall system integration, confinement and performance. A comprehensive qualification program in real conditions has been driven during 2014. The dismantling scenario was tested with a mockup at a full scale of dissolver equipment and confirmed at this stage the expected level of performance and safety. (authors)
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Geo-polymer solidification technology approved by Czech / Slovak nuclear authority to immobilise NPP resins and sludge waste - 15555
This paper presents the features and performance record of the geo-polymer solidification technology, SIAL{sup R}, licensed for use by both the Slovakian (UJD SR) and Czech Nuclear (SUJB) regulators. An overview of its performance at Bohunice in Slovakia, where it has been used to successfully treat resins and sludge wasteforms will be provided along with references to other plants where it has been used. More recently, geo-polymers have been noted as an immobilization technology which shows potential for resins produced by treatment of radioactive contaminated water resulting from the clean-up of the Fukushima Daiichi Plant. The Nuclear Power Plant A-1 located in Jaslovske Bohunice was completed in 1972 and operated for 5 years until two accidents in 1976 and 1977. After the second accident in February 1977 (INES level 4) the Nuclear Power Plant was permanently shut down for decommissioning. Fuel assemblies and fuel cladding damaged in the accidents led to significant Sr-90, Cs-137 and transuranic contamination. As a consequence of the long-term corrosion of the barrier's material, highly contaminated sludge accumulated which could not be effectively immobilized using conventional methods such as cementation or bitumen treatment due to adverse physical-chemical properties and high specific activity of the waste (Cs-137). This challenge led to AMEC developing and licensing the geo-polymer, SIAL{sup R}. Today, this geo-polymer is one of the most proven and widely used for on-site solidification of radioactive materials such as sludge, resins, sorbents and organic liquids. There are numerous benefits to using this geo-polymer for waste immobilisation. It can be used at room temperature and can incorporate up to approximately four times as much waste (sludge, resin) as a Portland cement matrix equivalent depending on the waste being treated. In addition, it is characterized by excellent mechanical and physical properties, compared with the earlier generation techniques. This includes higher mechanical strength, lower leachability, low volatility, posing a low fire risk and excellent physical stability in the presence of frost and water (no distortion or cracking). Dedicated facilities to receive and encapsulate waste from different locations can be created but this geo-polymer can also provide efficient and practical on-site treatment of radioactive waste streams. This is achievable because the equipment used to encapsulate waste using SIAL{sup R} is also modular, flexible and versatile. At Bohunice, the facility for encapsulation was designed to occupy existing areas of the plant in close proximity to the tanks where the waste was being stored. This allowed for the removal of the waste using Remote Operated Vehicles (ROVs) and for the waste to be immediately treated on site without the need for transportation saving both time and resource. To achieve this, some of the rooms and areas of the building were assessed and modified to ensure that the waste package flow was suitable whilst ensuring that appropriate safety measures were in place such as adequate shielding to reduce or entirely eliminate dose uptake of workers. To date, SIAL{sup R} has been used to successfully immobilize approximately 500 tons of waste which includes sludge and resin from Bohunice, Slovakia and approximately 250 m{sup 3} of spent ion exchange resins from tanks on site at the Dukovany nuclear plant, Czech Republic. It now has a track record of over 15 years which includes on-going research and development. The International missions WANO and OSART evaluated the SIAL{sup R} matrix technology at NPP Dukovany as an example of good practice. (authors)
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Nevada National Security Site (NNSS) Environmental Remediation Using EPA's Model Evaluation Guidance to Move to Closure - 15588
The National Nuclear Security Administration Nevada Field Office (NNSA/NFO) has adapted the Environmental Protection Agency's guidance on environmental model evaluation as a framework for evaluating corrective action investigation models. Model evaluation is an important confidence building activity, which is needed to support closure of the Nevada National Security Site (NNSS) Corrective Action Units (CAUs) associated with underground nuclear testing. Through this process, site-investigation models of groundwater flow and contaminant transport are reviewed and compared to new site-specific data to determine if the results can be used to support regulatory decisions required for closure and to achieve NNSA/NFO site management objectives. The regulatory decisions include identifying and establishing CAU regulatory boundaries; identifying institutional controls, including use-restriction boundaries; and developing a long-term closure monitoring program. A successful case study from Frenchman Flat, Nevada is used to illustrate the model evaluation process. Groundwater flow and transport from two of the 10 underground nuclear tests in Frenchman Flat had the largest potential for contaminating groundwater, and were selected for evaluation. Wells were drilled, logged, hydraulically tested, sampled, and analyzed for radionuclides and the data was evaluated with respect to previous site conceptualization and numerical model results. The approach and results of this process as applied to the PIN STRIPE test and how it helped build confidence to close the Frenchman Flat CAU is described in this case study. (authors)
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RCRA closure at the Connecticut Yankee atomic power company Haddam neck plant - 15655
From 1968 through 1996 Connecticut Yankee Atomic Power Company (CYAPCO) operated the Haddam Neck Plant (HNP) at 362 Injun Hollow Road, East Hampton, Connecticut. In 1980 CYAPCO applied to be a permitted generator and storage facility for hazardous waste and was issued a Resource Conservation and Recovery Act (RCRA) Part A Treatment, Storage, and Disposal Facility Permit. During the operational period, the HNP produced more than 110 billion kilowatt-hours of energy. In 1996, CYAPCO decided to close and decommission the HNP. Decommissioning activities began in 1998 and were successfully completed in 2007 in accordance with Nuclear Regulatory Commission (NRC) regulations and the CYAPCO License Termination Plan. As part of the closure process for the HNP, closure of the RCRA permit under the RCRA Corrective Action Program (CAP) was required. From 2002 through 2007, under the RCRA CAP, CYAPCO completed investigations and remediation work to address environmental impacts resulting from chemical usage at the HNP. The RCRA CAP was conducted under the regulatory authority of the United States Environmental Protection Agency (USEPA) and the Connecticut Department of Energy and Environmental Protection (CTDEEP). In the fall of 2014, the RCRA closure process was completed, and CYAPCO, with concurrence from USEPA, was issued a Letter of Completion from the CTDEEP signifying completion of the RCRA closure process. The paper discusses the RCRA closure process completed at the HNP, including the investigation, remediation, groundwater monitoring, and closure activities completed to achieve closure of the HNP under the RCRA requirements. (authors)
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