LANL: ADVANCED MODELING, SIMULATION TECH USED IN LIGHT-WATER REACTOR RESEARCH

FROM:  LOS ALAMOS NATIONAL LABORATORY
Los Alamos Boosts Light-Water Reactor Research with Advanced Modeling and Simulation Technology
Simulated nuclear reactor project benefits from funding extension

LOS ALAMOS, N.M., March 2, 2015, 2014—Hard on the heels of a five-year funding renewal, modeling and simulation (M&S) technology developed at Los Alamos National Laboratory as part of the Consortium for the Advanced Simulation of Light Water Reactors (CASL) will now be deployed to industry and academia under a new inter-institutional agreement for intellectual property.

“This agreement streamlines access to the reactor simulation research tools,” said Kathleen McDonald, software business development executive for the Laboratory, “and with a single contact through UT-Battelle, we have a more transparent release process, the culmination of a lengthy effort on the part of all the code authors,” she said.

CASL is a US Department of Energy “Energy Innovation Hub” established in 2010 to develop advanced M&S capabilities that serve as a virtual version of existing, operating nuclear reactors. As announced by DOE in January, the hub would receive up to $121.5 million over five years, subject to congressional appropriations. Over the next five years, CASL researchers will focus on extending the M&S technology built during its first phase to include additional nuclear reactor designs, including boiling water reactors and pressurized water reactor-based small modular reactors.

CASL’s Virtual Environment for Reactor Applications (VERA) – essentially a “virtual” reactor – has currently been deployed for testing to CASL’s industrial partners. Created with CASL Funding, VERA consists of CASL Physics Codes and the software that couples CASL Physics Codes to create the computer models to predict and simulate light water reactor (LWR) nuclear power plant operations. VERA is being validated with data from a variety of sources, including operating pressurized water reactors such as the Watts Bar Unit 1 Nuclear Plant in Tennessee, operated by the Tennessee Valley Authority (TVA)

As one of the original founding CASL partners, Los Alamos will continue to play an important role in Phase 2 of CASL.  Specifically, Los Alamos has leadership roles in three technical focus areas: Thermal Hydraulics Methods (THM), Fuel, Materials and Chemistry (FMC) and Validation and Modeling Applications (VMA).

Thermal-Hydraulics applications range from fluid-structure interaction to boiling multiphase flows. The Los Alamos-led THM team is targeting a number of industry-defined CASL “challenge problems” related to corrosion, fretting and departure from nucleate boiling.

The Fuel, Materials and Chemistry (FMC) Focus Area aims to develop improved materials performance models for fuel and cladding, and integrate those models via constitutive relations and behavioral models into VERA.  In particular, Los Alamos will bring to bear experience in structure-property relations, mechanical deformation and chemical kinetics to address several key aspects of nuclear fuel performance.

The Validation and Modeling Applications (VMA) Focus Area applies the products developed by CASL to address essential industry issues for achieving the CASL objectives of power uprates, lifetime extension, and fuel burn up limit increases, while ensuring the fuel performance and safety limits are met.

Los Alamos will continue to provide functions that are essential for achieving credible, science-based predictive modeling and simulation capabilities, including verification, validation, calibration through data assimilation, sensitivity analysis, discretization error analysis and control, and uncertainty quantification.

The new IIA agreement makes one of the Los Alamos-developed software tools, MAMBA, available for research, subject to agreements through the consortium partners. In addition, the Hydra-TH application is provided under an open-source license in VERA for advanced, scalable single and multiphase computational fluid dynamics simulations.

CASL, which is led by and headquartered at Oak Ridge National Laboratory (ORNL), has created hundreds of technical reports and publications and wide engagement with nuclear reactor technology vendors, utilities, and the advanced computing industry.

Doug Kothe, CASL Director at ORNL, notes that “CASL has benefitted tremendously from the innovative technical contributions and leadership provided by Los Alamos technical staff and is fortunate to have these contributions continuing as CASL moves into its second five-years of execution.”

LARGEST EVER NEUTRON BEAM CREATED AT LOS ALAMOS

FROM LOS ALAMOS NATIONAL LABORATORY

Trident Target caption: Tom Hurry of Plasma Physics adjusts the target positioner and particle beam diagnostics prior to an experiment at Trident.

World Record Neutron Beam at Los Alamos National Laboratory
New Method Has Potential to Advance Materials Measurement
LOS ALAMOS, NEW MEXICO, July 10, 2012— Using a one-of-a-kind laser system at Los Alamos National Laboratory, scientists have created the largest neutron beam ever made by a short-pulse laser, breaking a world record. Neutron beams are usually made with particle accelerators or nuclear reactors and are commonly used in a wide variety of scientific research, particularly in advanced materials science.

Using the TRIDENT laser, a unique and powerful 200 trillion-watt short-pulse laser, scientists from Los Alamos, the Technical University of Darmstadt, Germany, and Sandia National Laboratories focus high-intensity light on an ultra-thin plastic sheet infused with an isotope of hydrogen called deuterium.

The laser light — 200 quintillion watts per square centimeter, equivalent to focusing all of the light coming from the sun to the earth (120,000 terawatts) onto the tip of a pencil — interacts with the plastic sheet, creating a plasma, an electrically charged gas. A quintillion is a one with 18 zeros after it.

The plasma then accelerates large numbers of deuterons — the nucleus of the deuterium atom — into a sealed beryllium target, converting the deuterons into a neutron beam. Using a unique property of plasmas called relativistic transparency, the deuterons are accelerated in just one millimeter rather than the many meters required by standard accelerator technologies.

"So far only at TRIDENT has this new plasma acceleration mechanism been successfully implemented," said Markus Roth from the Technical University of Darmstadt, who serves as the 2012 Rosen Scholar at Los Alamos. "This result is the world’s record for short-pulse laser generated neutron flux, four quintillion neutrons per square centimeter for an object one centimeter from the source. In this generation scheme, the neutrons are emitted along the direction of the initial laser beam and can reach very high energies, in excess of 50 million electron volts."

According to Roth, the new record is five times larger than the previous record and required less than a quarter of the laser energy.

"Neutrons are a unique probe with many scientific applications," said Frank Merrill of LANL’s neutron science and technology group. "Neutrons are used to study fundamental properties of the universe, advanced materials, and have potential applications such as active interrogation of cargo containers, monitoring for clandestine nuclear explosives at border crossings, and as a test bed for fusion-relevant neutron diagnostics, the initial impetus for this study."

This record neutron beam has the speed and energy range that makes it an ideal candidate for radiography and a wide variety of high-energy-density physics studies.

"An object placed one centimeter behind the source would be exposed to more than 40 neutrons per square micrometer (one millionth of a meter) in less than a nanosecond (one billionth of a second) making it an impressive probe for radiography applications," said Merrill.

"Also, for the first time, in these experiments a neutron image driven by a short-pulse laser was realized and showed excellent agreement with numerical calculations," said Roth. Using short-pulse lasers for the production of neutrons can open the field of neutron research to universities, and a broader research community in general.

This project combined the expertise of LANL‘s Los Alamos Neutron Science Center (LANSCE) neutron science group with Physics division’s plasma physicists, TRIDENT laser scientists, and scientists developing neutron detection diagnostics to be fielded at the National Ignition Facility. Scientists from Sandia provided neutron yield and nuclear activation measurements.