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At least 19 records
All sourcesNASA NTRSDOE OSTI
DOE OSTI2014

Task 6 - Subtask 1: PNNL Visit by JAEA Researchers to Evaluate the Feasibility of the FLESCOT Code for the Future JAEA Use for the Fukushima Surface Water Environmental Assessment

Four Japan Atomic Energy Agency (JAEA) researchers visited Pacific Northwest National Laboratory (PNNL) for seven working days and have evaluated the suitability and adaptability of FLESCOT to a JAEA’s supercomputer system to effectively simulate cesium behavior in dam reservoirs, river mouths, and coastal areas in Fukushima contaminated by the Fukushima Daiichi nuclear accident. PNNL showed the following to JAEA visitors during the seven-working day period: FLESCOT source code; User’s manual; FLESCOT description – Program structure – Algorism – Solver – Boundary condition handling – Data definition – Input and output methods – How to run. During the visit, JAEA had access to FLESCOT to run with an input data set to evaluate the capacity and feasibility of adapting it to a JAEA super computer with massive parallel processors. As a part of this evaluation, PNNL ran FLESCOT for sample cases of the contaminant migration simulation to further describe FLESCOT in action. JAEA and PNNL researchers also evaluated time spent for each subroutine of FLESCOT, and the JAEA researcher implemented some initial parallelization schemes to FLESCOT. Based on this code evaluation, JAEA and PNNL determined that FLESCOT is: applicable to Fukushima lakes/dam reservoirs, river mouth areas, and coastal water; and feasible to implement parallelization for the JAEA supercomputer. In addition, PNNL and JAEA researchers discussed molecular modeling approaches on cesium adsorption mechanisms to enhance the JAEA molecular modeling activities. PNNL and JAEA also discussed specific collaboration of molecular and computational modeling activities.

54 ENVIRONMENTAL SCIENCES↗
DOE OSTI2015

Current status of R and D activities and future plan and role of JAEA's two generic URLs - 15356

The Japan Atomic Energy Agency (JAEA) has promoted R and D on geological disposal technology contribute to the implementation and safety regulation for high-level radioactive waste(HLW) disposal. JAEA launched two purpose-built generic URL projects to cover the diversity of geological environments in Japan, in accordance with 'Long-Term Program for Development and Utilization of Nuclear Energy' published in 1994 by the Japan Atomic Energy Commission. One is the Mizunami URL Project started in 1996. The Mizunami URL Project is a comprehensive geo-scientific research project investigating the deep underground environment within crystalline rock at Mizunami City in Gifu Prefecture, central Japan. The other one is the Horonobe URL Project started in 2001. The Horonobe URL Project consists of two major research areas, geo-scientific studies and R and D on geological disposal technology in the sedimentary rock environment at Horonobe Town in Hokkaido Prefecture, northern Japan. Both of the URL projects have been planned to proceed in three overlapping phases, 'Phase I: Surface-based investigation', 'Phase II: Construction' and 'Phase III: Operation', with a total duration of about 20 years. Currently, the construction of research galleries in both of the Mizunami and the Horonobe URLs has been completed to 500 m and 350 m depths, respectively. R and D activities in Phase III are being conducted at both URLs. According to the latest five-year plan, announced in September 2014, JAEA will promote R and D activities in Phase III including study of the effects of long-term evolution of the geological environment on geological characteristics such as groundwater flow and chemistry for reducing the uncertainty inherent in the evaluation of the long-term stability of the geological environment. This has been a very critical issue for HLW geological disposal in Japan after the Great East Japan Earthquake in 2011. Furthermore, JAEA will contribute to international cooperation especially with countries having a similar geological environment such as those in the Circum-Pacific area, development of human resources and communication amongst stakeholders through the generic URL projects. (authors)

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

Calculations in Support of JAEA ZEUS Experiments

A comparison of Los Alamos National Laboratory’s model for measuring Pb void reactivity with the JAEA. Comparison: •Stacking of HEU/Pbslightly off based on different “unit stack”composition.•LANL model has no “top plate”•LANL model does not have•Small difference in Pb/Al plates: 1.212 (JAEA) cm vs 1.2cm (LANL).•Material uncertainties•Composition of Pb is the largest uncertainty. Other issues could be in composition of upper reflector, lower reflector and corner and side reflectors

73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗
DOE OSTI2016

DOE and JAEA Field Trial of the Single Chip Shift Register (SCSR)

Los Alamos National Laboratories (LANL) has recently developed a new data acquisition system for multiplicity analysis of neutron detector pulse streams. This new technology, the Single Chip Shift Register (SCSR), places the entire data acquisition system along with the communications hardware onto a single chip. This greatly simplifies the instrument and reduces the size. The SCSR is designed to be mounted into the neutron detector head alongside the instrument amplifiers. The user’s computer connects via USB directly to the neutron detector eliminating the external data acquisition electronics entirely. JAEA, through the INSEP program, asked LANL to demonstrate the functionality of the SCSR in Tokai using the JAEA Epithermal Neutron Multiplicity Counter, ENMC. In late September of 2015 LANL traveled to Tokai to install, demonstrate and uninstall the SCSR in the ENMC. This report documents the results of that field trial.

97 MATHEMATICS AND COMPUTING↗
DOE OSTI2013

Waste handling and storage in the decontamination pilot projects of JAEA for environments of Fukushima

After the Fukushima Daiichi nuclear accident, Japan Atomic Energy Agency (JAEA) was chosen by the national government to conduct decontamination pilot projects at selected sites in Fukushima prefecture. Despite tight boundary conditions in terms of timescale and resources, the projects served their primary purpose to develop a knowledge base to support more effective planning and implementation of stepwise regional remediation of the evacuated zone. A range of established, modified and newly developed techniques were tested under realistic field conditions and their performance characteristics were determined. The results of the project can be summarized in terms of site characterization, cleanup and waste management. A range of options were investigated to reduce the volumes of waste produced and to ensure that decontamination water could be cleaned to the extent that it could be discharged to normal drainage. Resultant solid wastes were packaged in standard flexible containers, labelled and stored at the remediation site (temporary storage until central interim storage becomes available). The designs of such temporary storage facilities were tailored to available sites, but all designs included measures to ensure mechanical stability (e.g., filling void spaces between containers with sand, graded cover with soil) and prevent releases to groundwater (impermeable base and cap, gravity flow drainage including radiation monitors and catch tanks). Storage site monitoring was also needed to check that storage structures would not be perturbed by external events that could include typhoons, heavy snowfalls, freeze/thaw cycles and earthquakes. (authors)

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗
DOE OSTI2013

Task 3: PNNL Visit by JAEA Researchers to Participate in TODAM Code Applications to Fukushima Rivers and to Evaluate the Feasibility of Adaptation of FLESCOT Code to Simulate Radionuclide Transport in the Pacific Ocean Coastal Water Around Fukushima

Four JAEA researchers visited PNNL for two weeks in February, 2013 to learn the PNNL-developed, unsteady, one-dimensional, river model, TODAM and the PNNL-developed, time-dependent, three dimensional, coastal water model, FLESCOT. These codes predict sediment and contaminant concentrations by accounting sediment-radionuclide interactions, e.g., adsorption/desorption and transport-deposition-resuspension of sediment-sorbed radionuclides.

Coastal Water Model↗
DOE OSTI2016

HTTR-GT/H2 test plant - design study on helium gas turbine for the heat utilization system connected to JAEA's HTTR - 18674

In JAEA (Japan Atomic Energy Agency), the program of verification of combined system with helium gas turbine power generation and hydrogen production using nuclear heat which becomes the first in the world, is proceeding. From 2014 to 2015 Japanese Fiscal Year, the design study of the heat utilization system which is arranged in cascade to the heat supply system to supply the hydrogen production system and helium gas turbine system which are installed in the secondary helium-cooling system of High Temperature Engineering Test Reactor (HTTR) was performed and measure technologies of the system have been verified. MHI participated in the design study work of main equipment of this system. This paper reports the result of the design study of a helium gas turbine among those results. Self-sustaining condition (a power generation output is attained) is required for the gas turbine system in three modes of operation such as a) gas turbine individual operation, b) gas turbine + hydrogen production system combined operation, and c) hydrogen production system load loss and gas turbine independent shift operation]. By adopting a multi-stage centrifugal type impeller as a gas turbine and a compressor as a result of design study, it confirmed that all the mode-of-operation self-sustaining can be attained, and can attain a maximum of approx. 1 MWe power generation output on condition of the turbine inlet temperature of 560 deg. C, the turbine flow of 9.8 kg/sec, the compressor inlet temperature of 30 deg. C, and the compression ratio 1.3. (authors)

21 SPECIFIC NUCLEAR REACTORS AND ASSOCIATED PLANTS↗
DOE OSTI2014

Report: Update of chemical analysis results for the Japan Atomic Energy Agency (JAEA) collaboration study sample (CRM 124-3)

Additional measurement data for collected by the Actinide Analytical Chemistry group at Los Alamos National Laboratory is provided in this report. Initial data was provided in April 2014 (LA-UR-14-22300) on the same sample material. That earlier document also contained procedure references for all the utilized techniques including those used to generate the data in this document. The Measurement Protocol table below summarizes the characterization that was planned for this sample material.

07 ISOTOPE AND RADIATION SOURCES↗
DOE OSTI2017

Uncertainty propagation for the coulometric measurement of the plutonium concentration in CRM126 solution provided by JAEA

This GUM WorkbenchTM propagation of uncertainty is for the coulometric measurement of the plutonium concentration in a Pu standard material (C126) supplied as individual aliquots that were prepared by mass. The C126 solution had been prepared and as aliquoted as standard material. Samples are aliquoted into glass vials and heated to dryness for distribution as dried nitrate. The individual plutonium aliquots were not separated chemically or otherwise purified prior to measurement by coulometry in the F/H Laboratory. Hydrogen peroxide was used for valence adjustment.

11 NUCLEAR FUEL CYCLE AND FUEL MATERIALS↗
DOE OSTI2013

Current status of research and development program for characterizing fuel debris at Fukushima Daiichi NPS by JAEA

Japan Government and TEPCO submitted a research road map for decommissioning Fukushima Daiichi Nuclear Power Plant. Two projects about debris are in progress: 'Assessment of simulated fuel debris characteristics' and 'Development of technologies for the processing of fuel debris'. The major results concerning the first project are the following 4 points. First, it was suggested that typical phase of oxide of fuel debris is (U,Zr)O{sub 2} and that of metal is Fe{sub 2}(Zr,U) by thermodynamic calculation. Secondly, important properties of fuel debris for developing defueling tools were identified as shape, size, density, hardness, elastic modulus, fracture toughness, thermal conductivity, specific heat (heat capacity), and melting point. Thirdly, the influence of seawater salt and B{sub 4}C/SUS to characteristics of debris was found, such as deposition of magnesium oxide crystal on the surface of fuel debris. The Influence of Pu to thermal properties of fuel debris was found, such as the increase of melting point. Concerning the second project, the major results are the following. First, a draft of the whole image of scenarios was developed. Secondly, the alkaline resolution method using Na{sub 2}O{sub 2} is most likely to be applied as a part of analysis technologies. Thirdly, it was shown that a part of fuel debris rich in U might be soluble in nitric acid. Fourthly, it was shown that all pyrochemical processes examined have potential to be applied for treating fuel debris. The results of the projects will contribute to the decommissioning program.

11 NUCLEAR FUEL CYCLE AND FUEL MATERIALS↗
DOE OSTI2013

Research and development on waste management for the Fukushima Daiichi NPS by JAEA

Technologies for waste management of Fukushima Daiichi Nuclear Power Station (F1NPS) have been investigated. It is expected that the amount of wastes will be considerable. It is considered that F1NPS wastes were contaminated with radionuclides contained in spent fuel and with activation products, therefore the number of nuclides which needs to be considered in evaluating disposal safety is high. As a result, it is possible that the technologies selected will be different from those of the current wastes from nuclear reactors and fuel cycle facilities. The secondary waste from the accumulated water treatment, contaminated rubble and trees were analyzed, and the data obtained was provided for inventory evaluation. Demand on analytical data is strong, and sampling at the site and analysis have been continued. Storage safety of the secondary waste, especially for zeolite and sludge is under investigation. Investigation on conditioning and disposal was initiated, for survey on existing disposal concept assuming that both inventory and waste classification are uncertain. Different from usual methodology, these research and development activities should be conducted side-by-side.

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗
DOE OSTI2012

Presentation to JAEA Visitors, July 24, 2012 [Slides]

There are 7 Reasons for characterizing spent fuel nuclide concentrations: (1) Provide IAEA with the capability to independently verify the mass of plutonium at any site that has spent fuel; (2) Shipper/receiver difference; (3) Determination of the input accountability mass of an electrochemical (pyro-chemical) processing facility; (4) Continuity of knowledge at spent fuel storage site; (5) Optimal reloads through knowledge of true actinide content; (6) Burnup credit for fuel transport and storage; and (7) Provide confidence to the public that the shipment of spent fuel around the world is being undertaken in a rigorous manner, assuring that material is not diverted during shipment. Types of fuel of interest are: Fast Reactor Fuel, Normal burnup low enriched uranium (LEU), Mixed oxide (MOX), Low burnup LEU, and Research reactor. MCNPX calculates the slowing down and the energy spread for a given time. The principles are: (1) Neutrons slow down in LSDS; (2) Slow neutrons capture preferentially on a fission resonance; (3) Fission emits high-energy neutrons; (4) High-energy neutrons detected in threshold detector (that is not sensitive to slow neutrons) (e.g., 238 U, 232 Th); and (5) The detection time is characteristic of the slow neutron energy. Following each PSR pulse, the entire signal is digitized in 2 nanosecond intervals, and subsequently analyzed Analysis involves applying a digital filter to extract fission pulses in a background of initial oscillations and noise throughout. Some of the noise is not random. Depending on the threshold setting and filter parameters, both the normalization and the trend change. Original PNNL LSDS design required a 1-meter radius cylindrical LSDS. Much higher efficiency would allow us to use a (1.2m) LSDS (this is the LANL LSDS size), or a less intense source, or a combination of both. We still estimate 10 16 total neutrons from the source to obtain 2-3% precision in 239 Pu and 235 U assay.

11 NUCLEAR FUEL CYCLE AND FUEL MATERIALS↗