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At least 919 records · Page 51
All sourcesNASA NTRSDOE OSTI
DOE OSTI2017

Water Sealing With NOH{sub 2}O on the Fukushima Site - 17477

The Fukushima Daiichi nuclear site is still recovering from the natural disaster of March 11, 2011. Much of the recent recovery work has been focused on mitigating ground water intrusion into the radioactively contaminated basements of the reactor and turbine buildings of units 1 - 4. Other recovery efforts involve potentially sealing the vent lines in the primary containment vessels of units 1 - 3 to maintain a flooded vessel for core cooling and shielding. This paper details preliminary test results of a proprietary grout - NOH{sub 2}O{sup TM} - in sealing/plugging those vent lines to allow flooding of the primary containment vessel. Several partial and full-scale tests were conducted on primary containment vessel vent line mock-ups between March and October 2015 to ascertain the effectiveness of NOH{sub 2}O in sealing vent lines that have flowing water, which is problematic for conventional cement-based grouts that require relatively protracted set times. In contrast, NOH{sub 2}O can be used with a proprietary accelerant to provide instant set. The other key advantage of NOH{sub 2}O is its ability to penetrate even the smallest of cracks and porous soils, following and moving with the water flow and creating a continuous, impermeable barrier. It is also extremely flexible once set, conforming to its enclosure as upstream water head increases. Finally, the material's extremely high radiation resistance and longevity make it an ideal candidate for a permanent solution in high rad environments. (authors)

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗
DOE OSTI2015

Use of the underwater collimated spectrometric system for survey of storage ponds of research VVR-2 and or reactors - 15118

Spent nuclear fuel removal activities in the National Research Centre 'Kurchatov Institute' were resumed in 2004. During the last two years, removal was performed of the spent nuclear fuel from the VVR-2 and OR reactor installations, whose storage facilities are located within the Gas Plant complex. The Gas Plant complex is the experimental base of the Institute of Nuclear Reactors, which is part of the 'Kurchatov Institute'. The complex features four storage facilities for spent nuclear fuel, one in a dedicated building for storage of spent nuclear fuel and solid rad-waste and three in the reactor building. They are sub-surface vessels filled with water (the volume of water in each is about 6 m{sup 3}), closed with top shielding slabs. Some spent fuel assemblies and fuel elements stored are resized, deformed, or have defective claddings. In the course of works on removal from ponds of the spent nuclear fuel, its fragments could get to water. The bottoms of ponds storage are covered with a deposit. The bottom of ponds and water are possible to be pollution by fission products. The survey objective was to find uranium-containing materials (elements of irradiated nuclear fuel) at the bottom of the ponds and evaluation of surface activity of fission products. To solve this problem was used the underwater collimated spectrometric system on the basis of a semiconductor detector CdZnTe (volume of a crystal of 20 mm{sup 3}) and a multichannel analyzer InSpector 2000. The detector with the collimator is placed in the waterproof case on which the video camera fastens. The principle of detection of uranium-containing materials is based on the identification of the characteristic peaks in the spectra of uranium radiation measurements in the energy range 95 - 115 keV. The results of the most representative measurements at the bottom of reactor ponds are given. The received results are discussed; comparison of results between in-site pond measurements and gamma spectrometric and radiochemical analysis of the water in the lab is carried out. The received results will be used for scheduling on pond cleaning. (authors)

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗
DOE OSTI2015

On the influence of the power plant operational history on the inventory and the uncertainties of radionuclides relevant for the final disposal of PWR spent fuel - 15149

A mandatory requisite for official granting safe final disposal approval of SNF is the comprehensive specification and declaration of the nuclear inventory in SNF by the NPP-operators. The whole radiochemical characterization of each spent fuel assembly hides many difficulties such as very high radiation burden, destruction method, the inhomogeneous burn-up of fuel assembly, very high cost. Thus, non-destructive characterization is usually applied on industrial scale. In this case only several nuclides can be measured, and the rest is calculated using simulations and typical irradiation history. Like any other German rad-waste acceptance requirements all these declarations will have to be checked and verified by an independent inspector. In this verification process not only values of radionuclide (RN) activities are important, but also their uncertainties. The simple simulation using burn-up calculations based on typical and generic reactor operational parameters do not answer the question about possible uncertainties observed in real reactor operations. At the same time, the details of irradiation history are often unknown, which complicates the assessment of declared RN inventories. Therefore, the development of dedicated generic proof tools, which can be applied to different types of waste, often of unknown origin and history is worth a serious consideration. Here, we have compiled a set of burn-up calculations considering the operational history of 339 published or anonymized real PWR fuel assemblies. This gives us the possibility to calculate the realistic variation or spectrum of RN inventories. These histories were used as a basis for 'SRP analysis', to provide information about the range of the values of the associated secondary reactor parameters (SRP's), i.e. initial enrichment (IE), specific power (SP), irradiation time (IT), downtime (DT), boric acid concentration (BA), moderator and fuel density (MD and FD) and temperatures (MT and MT) used as input parameters for the simulation models. Then, burn-up calculation codes provide the anticipated results for the entire nuclear inventory such as characteristic activity values and the corresponding minimum and maximum limits as a function of the fuel burn-up. These results are being validated with the experimental data from various publications and the online database - SFCOMPO and subsequently transferred and summarized into our own database. Ultimately, this database will provide the basis of proof tools for the operator independent verification of the declared nuclear inventories for the quality and safety assessment of a radioactive waste compound and bounding values for certain RN as a function of burn-up. The RN inventory can hence be verified without taking credit of the whole of the operational history of the SNF. (authors)

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗
DOE OSTI2015

EDF industrial strategy for the management of radioactive waste - 15204

In France, EDF is in charge of electronuclear power operation since the sixties and consequently has to manage radioactive waste. Radioactive waste management is based on the control of each industrial step, taking into account the classification by activity level and radioactive half life. The main steps are to limit waste quantities at the generation stage, sort out non-rad and recoverable items from the waste, recycle, treat and package the radioactive waste as soon as it is generated, limit the use of interim storage, prepare and achieve as soon as reasonably practicable conditioning and disposal. EDF aims to empower operators in charge of NPP operating and of decommissioning and to centralize interfaces with the stakeholders in order to pool management routes and to guarantee the consistency of our industrial policy. The French regulatory framework for the management of radioactive waste and material is set by the French 2006 planning Act, in line with the European Directive. The legal framework structures interactions between EDF and the regulatory bodies (Nuclear Safety Authority, General Directorate for Energy and Climate), the French National Radioactive Waste Management Agency (ANDRA) and other waste producer (mainly AREVA Company and CEA). Regarding short lived waste, management routes are in current operation for the large majority of this waste generated both by power plants in service and during decommissioning. EDF is working on new management route for metallic materials knowing the future evolution of deposits is the field of large refit and decommissioning activities. Regarding long lived waste, disposal development represents a major stake for EDF. EDF contributes to design studies of the geological disposal center and collaborates with ANDRA for the acceptance of future national waste disposal. (authors)

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗
DOE OSTI2015

The completion of the construction and commissioning of the liquid radwaste treatment plant at ChNPP - 15685

Since a beginning of ChNPP operation, and after a tragedy in 1986, a few thousands m{sup 3} of LRW have been collected in a storage tanks. In 2004 ChNPP started the new project on creation of LRW treatment plant (LRWTP) financed from EBRD fund. But it was stopped in 2008 because of financial and contract problems. In 2010, FSUE RADON jointly with Ukrainian partners has won a tender on completion of LRWTP, in particular I and C system. The purpose of LRTP is to process liquid rad-wastes from SSE 'Chernobyl NPP' site and those liquids stored in the LRWS and SLRWS tanks as well as the would-be wastes after ChNPP Power Units 1, 2 and 3 decommissioning. The LRTP design lifetime - 20 years. (authors)

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗
DOE OSTI2016

Waste Management Processing Projects in the PRC - 16551

EnergySolutions continues to provide waste treatment solutions in the Peoples Republic of China (PRC). In 2015 ES had completed installation of systems at two different Nuclear power sites (Haiyang, an AP-1000{sup TM} site and Yangjiang, a CPR1000 site). This paper discusses progress on these two projects, and provides new information regarding the operation of the systems. The Yangjiang project became operational in the fall of 2015 while the Haiyang project will be done is nearly done with commissioning and is waiting for reactor operations. Haiyang Project: In the Shandong Province on China's northeast coast, EnergySolutions, as part of a consortium with China Power Investment (CPI) and Yuanda Environmental Protection Engineering Company (a PRC state-owned company), has designed and constructed the site's Site Rad Waste Treatment Facility (SRTF). The SRTF provides solid waste processing services for up to 8 AP-1000s{sup TM}. The SRTF performs the following functions: 1. Five year storage for HICs containing spent resin and filters from the nuclear power plants' waste liquid systems (WLS); 2. Sorting and Compaction System for solid waste generated from Nuclear Power Plant (NPP) operations. This system implements: a) Real time radiography to screen 200 liter waste drums for prohibited items, b) Pre-compaction, c) High Resolution Gamma Spectrophotometry (HRGS) for waste characterization, d) Supercompaction, e) Solidification of compacted drums inside overpack drums which are filled with 60 MPa compressive strength grout, and f) Automatic drum lidding which crimps the drum lid to the drum body. 3. Laundry services for NPP anti-contamination clothing. 4. At the nuclear islands, EnergySolutions is providing mobile liquid waste processing systems that utilize EnergySolutions Advanced Liquid Processing System ALPS{sup TM}/Advanced Injection Method System AIM{sup TM} processing systems to supplement the NPP's WLS system when radionuclide concentrations exceed release criteria. The spent resins and filters from the nuclear power plants are placed in EnergySolutions supplied HICs, dewatered using EnergySolutions Self Engaging Dewatering System (SEDS{sup TM}), and then placed in EnergySolutions 8-120B Type B cask for the transport of the HIC between the NPP and the SRTF and, ultimately, to a disposal site once it is ready for operations Yangjiang Project: EnergySolutions is providing liquid waste treatment system (TEU) and solid waste treatment system (TES) for Yangjiang units 3 and 4 for the China Nuclear Power Engineering Company (CNPEC). The Yangjiang site is located approximately 300 kilometers west of Hong Kong. The TEU system processes floor drain, chemical drain, and process drain tanks liquids to achieve a release concentration less than 37 Bq/l. The TES system receives spent resin and filters into HIC containers which are dewatered and subsequently transported to the Yangjiang sites QT building where they are stored for a period of up to 5 years or until a disposal site are available. TEU (Liquid waste treatment) consists of the following unit operations: - ALPS{sup TM}/AIM{sup TM} system, which includes two separate 8 vessel water treatment systems that consist of granular activated carbon (GAC), cation, anion ion and mixed bed media ion exchange (IX) columns; and: - A reverse osmosis system for final polishing, - TES (solid waste system), - SEDS (Self Engaging Dewatering System), - Shielding for the loading and storage of HICs, - Shielded transport container for the transfer of HIC to the QT building for storage, - Shielded transfer bell for the transport of spent filters from the NPP operating area to HIC. (authors)

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗
DOE OSTI2017

Radiation hardened successive-approximation ADC with error detection circuits - 238

For several decades, radiation-hardened-by-design (RHBD) techniques have been developed to meet the design requirements of irradiating environment in nuclear power plants. Improvements on the circuit side for radiation sensors in performance, chip size, and radiation hardening ability have been adopted in current plant systems; however, next generation reactors and/or preparation for severe events in existing reactors require advanced circuit structures that can provide relatively long viability in harsh conditions. In order to maintain performances of electronics in high radiating environments, we propose to develop a small-area, low resource-overhead data-converter architecture that is immune to radiation impact events, an architecture that includes three kinds of novel radiation-hardened (rad-hard) designs for each analog and digital circuit in an ADC structure: a) error detectable tri-state buffer for flip flop against DSET, b) error detection storage in flip flop against SEU, and c) analog algorithm for the analog parts of an SAR ADC. The novel ADC architecture including the three RHBD techniques was implemented in a standard 180 nm CMOS technology with a 1.8 V supply voltage. Simulation results show that the techniques can successfully recognize errors induced by radiation impact events. The static power consumption was 123 {mu}W with the sampling rate 36 MS/s and resolution of 8 bits. The performances could be highly advanced under fine-tune designs. (authors)

22 GENERAL STUDIES OF NUCLEAR REACTORS↗
DOE OSTI2014

Total Integrated Dose to Spent Fuel Pool Level Instrument Probes and Refueling Floor Personnel Dose Rates Meeting NRC Order EA-12-051 for a Typical Boiling Water Reactor - Paper 22

In reviewing the events after the March 11, 2011 Fukushima accident, the Nuclear Regulatory Commission (NRC) issued Order EA-12-051, Reference 1, requiring new reliable spent fuel pool (SFP) instrumentation for pool level determination under beyond design basis event conditions. In 2013, URS prepared a calculation for a typical Boiling Water Reactor to determine the Total Integrated Dose (TID) potentially to be imparted to radiation sensitive underwater probes (one primary and one backup) planned for meeting this Order. Additionally, URS calculated the radiological dose rates to an individual standing on the refueling floor for various SFP fill levels. NEI 12-02, Reference 2, defines the levels at which SFP condition identification is necessary as the following: Level 1 - level that is adequate to support operation of the normal fuel pool cooling system. Level 1 represents the higher of the following two points: - The level at which reliable suction loss occurs due to uncovering of the coolant inlet pipe, weir or vacuum breaker (depending on the design), or - The level at which the water height, assuming saturated conditions, above the centerline of the cooling pump suction provides the required net positive suction head specified by the pump manufacturer or engineering analysis. Level 2 - level that is adequate to provide substantial radiation shielding for a person standing on the spent fuel pool operating deck. Level 2 is based on either of the following: - 10 feet (+/- 1 foot) above the highest point of any fuel rack seated in the spent fuel pools, or - A designated level that provides adequate radiation shielding to maintain personnel radiological dose levels within acceptable limits while performing local operations in the vicinity of the pool. This level shall be based on either plant-specific or appropriate generic shielding calculations, considering the emergency conditions that may apply at the time and the scope of necessary local operations, including installation of portable SFP instrument channel components. Level 3 - level where fuel remains covered and actions to implement make-up water addition should no longer be deferred. Level 3 corresponds nominally (i.e. +/- 1 foot) to the highest point of any fuel rack seated in the spent fuel pool. The URS calculation did not define these levels or determine instrumentation setpoints. However, it determined refueling floor dose rates that could be used as a tool to determine the appropriate water depths for these levels. In determining the TID for the SFP probes and the radiological dose rates to the individual, the following radioactive sources were considered: 1. Spent Nuclear Fuel (SNF) stored in the spent fuel storage racks, 2. Local Power Range Monitors (LPRMs) stored above the top of the racks on hangers on the SFP walls 3. Radioactive material laden filters stored on platforms on top of the racks, and 4. Control Rod Blades (CRBs) stored above the top of the racks on hangers on the SFP walls. The TID for the SFP probes includes both the dose from normal operation (pool full of water) for the remaining plant life (an assumed 40 years, conservatively including an allowance for lifetime extension SFP loading) and, consistent with the NEI 12-02 guidelines, Reference 2, the assumed drop in elevation of the pool water level to the top of the spent fuel racks for a 6 hour period. The acceptable TID for the radiation-sensitive probe as defined by the manufacturer was 2x10{sup 9} rad. The individual on the pool deck was assumed to be standing on the edge of the pool with an unobstructed view of its contents, as a worst case scenario. Dose rates to this individual determined from direct shine from the same 4 sources were determined for SFP water levels varying from 1 ft above the SNF racks to 21 ft above the racks in one foot increments. (authors)

11 NUCLEAR FUEL CYCLE AND FUEL MATERIALS↗
DOE OSTI2024

Soft error-mitigating semiconductor design system and associated methods

A soft error-mitigating semiconductor design system and associated methods that tailor circuit design steps to mitigate corruption of data in storage elements (e.g., flip flops) due to Single Events Effects (SEEs). Required storage elements are automatically mapped to triplicated redundant nodes controlled by a voting element that enforces majority-voting logic for fault-free output (i.e., Triple Modular Redundancy (TMR)). Storage elements are also optimally positioned for placement in keeping with SEE-tolerant spacing constraints. Additionally, clock delay insertion (employing either a single global clock or clock triplication) in the TMR specification may introduce useful skew that protects against glitch propagation through the designed device. The resultant layout generated from the TMR configuration may relax constraints imposed on register transfer level (RTL) engineers to make rad-hard designs, as automation introduces TMR storage registers, memory element spacing, and clock delay/triplication with minimal designer input.

Miryala, Sandeep↗
DOE OSTI2026

Design and Testing of the Endcap Concentrator ASICs for the CMS High-Granularity Calorimeter Upgrade

A major upgrade of the High-Granularity Calorimeter (HGCAL) in the CMS detector is planned for Long-Shutdown 3 (LS3), currently expected to start in 2026. This upgrade will contain over 6 million channels and the electronics will be required to be low power and to withstand a radiation environment with a High-Energy Hadron flux of 3x10**6 particles per square centimeter per second. The solution to this significant challenge is the two Endcap Concentrator (ECON) ASICs, ECON-T and ECON-D, working in tandem with the HGCROC front-end ASIC. The two ECON ASICs provide critical on-detector data reduction for both the 40 MHz trigger path (ECON-T) and 750 kHz data acquisition path (ECON-D) of the HGCAL. The ASICs are fabricated in 65nm CMOS. They are rad-tolerant to 600 Mrad with low power consumption (<2.5 mW/channel). This presentation will be a comprehensive description of each ECON design, including the infrastructure that they share as well as the elements that make each unique. The presentation will also include functionality and radiation tests for both ASICs, and the first high statistics characterization results from the full production of 75k ECON-D and ECON-T ASICs.

Hoff, James R. [Fermilab] (ORCID:0000000163514592)↗
DOE OSTI2023

Ballistic Ejection of Microdroplets from Overpacked Interfacial Assemblies

Spontaneous emulsification, resulting from the assembly and accumulation of surfactants at liquid–liquid interfaces, is an interfacial instability where microdroplets are generated and diffusively spread from the interface until complete emulsification. Here, it is shown that an external magnetic field can modulate the assembly of paramagnetic nanoparticle surfactants (NPSs) at liquid–liquid interfaces to trigger an oversaturation in the areal density of the NPSs at the interface, as evidenced by a marked reduction in the interfacial tension, γ, and corroborated with a magnetostatic continuum theory. Despite the significant reduction in γ, the presence of the magnetic field does not cause stable interfaces to become unstable. Upon rapid removal of the field, however, an explosive ejection of a plume of microdroplets from the surface occurs, a dynamical interfacial instability which is termed explosive emulsification. Further, this explosive event rapidly reduces the areal density of the NPSs to its pre-field level, stabilizing the interface. The ability to externally suppress or trigger the explosive emulsification and controlled generation of tens of thousands of microdroplets, uncovers an efficient energy storage and release process, that has potential applications for controlled and directed delivery of chemicals and remotely controlled soft microrobots, taking advantage of the ferromagnetic nature of the microdroplets.

36 MATERIALS SCIENCE↗
DOE OSTI2026

Stabilization of Miscible Aqueous Phases via Diffusion‐Controlled Multifunctional Nanoparticle‐Ligand Complexation

Liquid‐in‐liquid structuring by harnessing miscible aqueous domains can be achieved by inducing thermodynamically defined phase separation using aqueous solutions of incompatible solutes, where immiscibility is dictated by the concentrations of the solutes. For instance, in aqueous two‐phase systems (ATPSs), the interfacial tension between the two different aqueous solutions is so small that it stabilizes the phase‐separated domains, but not their shape, thus falling short of designing tunable, robust structures. Here, we introduce a diffusion‐controlled strategy that enables liquid‐in‐liquid compartmentalization absent a thermodynamically defined interface or bulk liquid‐liquid phase separation using a barrier formed in situ at the initial contact boundary of an aqueous dispersion of multifunctional nanoparticles and a solution of multifunctional ligands in pure water or a water/alcohol mixture. The nanoparticles and ligands are entropically driven to disperse uniformly but interact at the initial contact boundary more rapidly than bulk mixing, forming a layer that establishes a barrier akin to a semi‐permeable membrane and allows the formation of tubular compartments. A wealth of opportunities is enabled by the proposed technique, where examples in separations, soft electronic devices, and ultralight porous electromagnetic shielding materials are shown.

cryogels↗
DOE OSTI2021

Codelivery of Paclitaxel and Parthenolide in Discoidal Bicelles for a Synergistic Anticancer Effect: Structure Matters

Nanotechnology has long been used to improve the tumor targeting of chemotherapeutics. The structure of these nanocarriers greatly affects their efficacy and toxicity. Herein, structurally stable nanodiscoidal phospholipid bicelles, which are capable of encapsulating anticancer drugs, paclitaxel (PTX) and parthenolide (PTL), are designed. This nanodiscoidal bicelle structure is shown previously to exhibit longer blood circulation, deeper tumor penetration, and increased tumor cell uptake compared with spherical particles of similar compositions. Structural characterization and loading capacity of the PTX‐ and PTL‐ loaded nanodiscs are conducted along with an investigation into the cytotoxicity of the bicelles based on the drug‐to‐lipid ratios of both drugs loaded separately and in combination. A significant synergistic effect between both loaded drugs is also observed in A549 lung cancer and drug‐resistant MDA‐MB‐231 cell lines. An in vivo study using mice bearing subcutaneous A549 tumors shows a long circulation time of the intravenously injected DiR‐loaded bicelles and significant antitumor efficacy of the PTX‐ and PTL‐loaded bicelles. This efficacious self‐assembled nanoparticle system displays great potential as a nanoplatform to codeliver multiple therapeutics or diagnostics for improving cancer therapy.

Rad, Armin Tahmasbi↗
DOE OSTI2026

RCSB protein data Bank: Next‐generation advanced search for exploration of experimental structures and computed structure models

Abstract The Protein Data Bank (PDB), established in 1971, is the primary global, open‐access archive for experimentally determined 3D macromolecular structures (proteins, RNA, DNA). The research‐focused RCSB.org web‐portal provides access to these data alongside more than one million machine‐learning‐predicted structure models, greatly expanding the available structural landscape. Rapid growth of both experimental and computational structures has increased the need for powerful yet accessible search tools that serve a broad and diverse scientific community. Herein, we describe a redesigned RCSB Protein Data Bank RCSB.org Advanced Search capability that supports intuitive discovery of 3D structures through a unified interface. This interface integrates annotation‐, sequence‐, and 3D structure‐based searches, embeds an interactive 3D viewer, and incorporates curated biological knowledge, such as catalytic site definitions from Mechanism and Catalytic Site Atlas and ligand‐guided structural motifs, for constructing geometry‐driven queries. A new Chemical Search tool allows definition of chemical queries via an integrated drawing tool or standard identifiers, seamlessly combining them with annotation filters. By allowing query definition directly within spatial and chemical contexts, these search interfaces reduce the need for detailed knowledge of residue numbering, chain identifiers, or external cheminformatics software. This capability enables efficient exploration of structures, chemical diversity, and structure–function relationships across all life domains. The redesigned interfaces can be accessed directly at rcsb.org/search/advanced for Advanced Search and rcsb.org/search/chemical for Chemical Search.

Rose, Yana [Research Collaboratory for Structural ↗