Ambient office  = 100 nanosieverts per hour

Ambient outside = 120 nanosieverts per hour

Soil exposed to rain water = 119 nanosieverts per hour

Heirloom tomato from Central Market = 125 nanosieverts per hour

Tap water = 104 nanosieverts per hour

Filtered water = 90 nanosieverts per hour

Dover sole – Caught in USA = 82 nanosieverts per hour

     The Trump administration has bragged about the development and deployment of new more powerful and accurate nuclear weapons to expand the U.S. arsenal. Now the Senate Appropriation Committee wants the U.S. Department of Energy (DoE) to carry out an investigation into technical problems that are plaguing U.S. nuclear weapons programs. The mandate of the Committee to order such an investigation by the DoE is part of the appropriation process that dealt with the allocation of about forty nine billion dollars for an Energy and Water spending bill that was approved by the Committee on September 12th of this year.
     The Committee is worried that recent problems with nuclear weapons development and production may have wider implications beyond the U.S. weapons programs. The Senators on the Committee are committed to delving into the details of the problems. A Congressional aide who is familiar with the problems in the weapons programs said that those problems will increase the nuclear weapons budget by hundreds of millions of dollars.
    The report that accompanied the spending bill said, “The Committee is concerned that a recent technical challenge demonstrates a lack of systems engineering and highlights a lack of coordination and leadership focus, which in turn jeopardizes successful program execution.”
    The report does not specify any particular weapons programs or give any details of the nature of the problems. Nuclear weapons experts say that the problems probably involve two new versions of existing weapons. One new weapon is a nuclear bomb called the B61-12. The other is a new version of submarine-launched warhead named the W-88.
     In both of these weapons programs, the use of commercially manufactured electrical components resulted in months of delay. This has been publicly admitted by the U.S. government. The House Armed Services Subcommittee on Strategic Forces intends to hold a hearing on September 25th to discuss problems with both of these weapons programs.
     The Senate Committee report contained suggestions that the delays in these nuclear weapons programs could indicated a fundamental problem with Congressional oversight of the military. They are worried that there could be a domino effect that would influence other nuclear initiatives. These concerns include keeping nuclear weapons and materials out of the hands of terrorists, updating the nuclear engines on U.S. warships and modernizing government nuclear facilities.
     The Committee says that the investigation of the nuclear weapons programs must identify causes and possible solutions. It must “ensure the extent of condition is not more widespread than currently reported.” The report says that the DoE organizations who are responsible for nuclear weapons “need to ensure any technical challenges or production issues, particularly in the electronic components, are discovered quickly and mitigated to minimize impacts” on the programs under review as well as other priorities of the departments.
     Nuclear weapons experts say that increasing cost overrun and scheduling delays are a serious and continuing problem for the National Nuclear Security Administration. This is the department of the DoE that is responsible for the management of the U.S. nuclear weapons program. The problems being uncovered also highlights how dependent secret Pentagon projects are on off-the-shelf commercial components.
    Stephen Young is a nuclear arms specialist with the Union of Concerned Scientists. He said, “It is astounding that these two programs, which together were estimated to cost roughly $12 billion before this new problem was discovered, are being delayed because a commercially produced electronic component does not meet specifications. The good news is, because of how robust the U.S. deterrent is, this will not materially affect American security. But it is still a troubling sign for an agency that has so much work on its plate.”
     The B61 nuclear bomb is the oldest nuclear weapon in the U.S. nuclear arsenal. It was originally deployed in 1968. There are now four configurations in deployment. The new B61-12 version is intended to replace all four. The first production version of the new B61-12 was scheduled to be deployed as early this month in a report issued by the DoE in 2018. Last May, congressional testimony by U.S. officials and interviews with officials revealed that both the B61-12 and W-88 program were behind scheduled and would be delayed.
     During a Senate Armed Services Subcommittee on Strategic Forces hearing in May, a Republican Senator asked the head of the National Nuclear Security Administration whether or not the new B61-12 would be ready for widespread deployment in 2023 as had been planned. The response was that it would be delayed until at least 2025.

Ambient office  = 128 nanosieverts per hour

Ambient outside = 105 nanosieverts per hour

Soil exposed to rain water = 100 nanosieverts per hour

Avocado from Central Market = 119 nanosieverts per hour

Tap water = 115 nanosieverts per hour

Filtered water = 93 nanosieverts per hour

Part 2 of 2 Parts (Please read Part 1)
   Computer models of flow processes in nuclear power reactors can only accomplish so much in illuminating such processes. In order to find out how accurately computational models match the reality they are simulating; it is necessary to compare the results of the simulations with data from actual experiments on real reactors. This process is referred to as validation.
    It can be quite expensive and time consuming to collect experimental data for all the different configurations that are possible in an advanced nuclear reactor. The goal of using computers to model and simulate processes inside nuclear reactors is to be able to improve understanding of such systems without the need for a great deal of experimental data.
     Shemon said, “We still can’t fully trust our computational models without experimental data, but we can make use of whatever limited experimental data are available. So, what we have is an iterative process in which designers use our software to do the preliminary analysis, allowing them to narrow down design choices or make improvements to their systems, and validate their final design with more targeted tests.”
      Good models not only match experimental data but also add to known data and give the researchers more confidence in their predictions based on the computational models. This is especially important when working with very different reactor designs and fuel types and fuel assemblies. Many different possible new reactor designs have been proposed ranging from sodium-cooled fast reactors to reactors cooled by gas or molten salts. Advanced computational modeling is understood to be the best path that researchers have to assess and compare the capabilities of the different designs.
     Usually, it is necessary for computer algorithms to swap information about the rate of heat generation, the range of temperatures and the stresses of the structure of reactors because the neutronic, thermal and structural phenomena all have an influence on each other. Argonne’s computer modeling program has two major goals. The first goal is to develop an understanding of the basic physics of reactors cores, thermal hydraulics, structural mechanics, and fuels and materials modeling tools. The second goal is to create multiphysical analysis capabilities that are capable of capturing the interdependence among all of these fields.
     Even in cases where it is not possible for researches to directly validate their models, developing more accurate models that are closer to first principles is a valuable pursuit. Some higher-fidelity models allow researchers to develop a better understanding of quantities for which they had only previously been able to obtain average values. Shemon said, “Previous low-order codes were accurate, but they were, in a sense, blurry. These new high-fidelity codes give us the ability to be much more precise in terms of energy, space and time.”
     One important way that high-fidelity model can improve the design and operation of a reactor is by the reduction of uncertainty in the temperature margins or tolerances that are required for safe and efficient reactor operation. In one example, the researchers run models in what are called the best-case scenarios. In these scenarios, fuel elements and their cladding are assumed to be manufactured exactly to their design specifications. Then they run worst-case scenarios where these components vary from their ideal specification. This allows the researchers to take into account uncertainties about tolerances. Ultimately, the ideal and the bad cases are compared which sheds light on how to evaluate safety margins.
     Shemon believes that there is a broader and more overarching objective in this and other projects being carried out at Argonne. She said, “We’re trying to enable safer, faster, more economical design through modeling and simulation. Everything we do is geared toward that.”

Ambient office  = 121 nanosieverts per hour

Ambient outside = 181 nanosieverts per hour

Soil exposed to rain water = 181 nanosieverts per hour

Bannana from Central Market = 137 nanosieverts per hour

Tap water = 99 nanosieverts per hour

Filtered water = 88 nanosieverts per hour

Part 1 of 2 Parts
        Designing a new type of nuclear reactor is a very complicated undertaking. Years of development and billions of dollars are required. In addition, many different configurations have been proposed for the next generation of commercial power reactors that researchers hope will be safe, economical and efficient. Due to the high cost of actually constructing working models of all the different designs being considered, researchers are employing high performance computers to model and test reactor designs.
    Researchers at the U.S. Department of Energy’s Argonne National Laboratory are running a variety of special programs on the supercomputers that make up the Argonne Leadership Computing Facility (ALCF) which is a DoE Office of Science User Facility. Here researchers from around the world can utilized resources that are only available at a few sites. Emily Shemon is an Argonne nuclear engineer. She said, “We have a good understanding of the laws underpinning reactor physics and thermal hydraulics, so modeling and simulation tools give us the ability to analyze potential reactor designs virtually.”  
      The purpose of the nuclear modeling and simulation activities at Argonne and other such facilities in the DoE’s national laboratory complex is to overcome some of the hurdles faced by the nuclear industry as it considers the design, licensing and deployment of next-generation nuclear power reactors. Shemon says, “The purpose of the labs’ modeling efforts is to fill in the knowledge gaps for industry. They may be able to use our codes and models to inform their design decisions if we can do some of the legwork.”
    One major research project at Argonne deals with the modeling of turbulent flows in sodium-cooled fast reactors (SCFRs). SCFRs have attracted researchers for decades because of their promise of greater fuel efficiency and less production of waste than the currently popular and wide-spread light water-cooled nuclear power reactors. One very promising capability of SCFRs is the built-in passive safety features which prevent meltdowns even in cases where all the operational systems of the reactor have failed.
    In SCFRs, as liquid sodium is circulated around fuel elements in the core of the reactor, heat is carried away from the fuel. Warmer sodium rises and cooler sodium sinks which results in a circulation pattern like the old lava lamps and preventing the build up of heat at any one point.
     Very powerful computers are needed to simulate the complex movement of the whorls and eddies of hot and cold liquid sodium in a nuclear reactor core. The computer models are also used to assess the effect of the three-dimensional layout of the reactor and the fuel assemblies on the movement of heat and the flow of the liquid sodium. Alexandr Obabko is an Argonne nuclear engineer. He said, “We try to model turbulence directly, as close to the needed resolution as possible, using supercomputers. We need supercomputers because there are a lot of vortices to model, and because they all contribute to the process of mixing.”
    In order to successfully model the mixing and turbulence in a nuclear reactor, Obabko and his team use a computation coding system called Nek5000 to solve problems involving computation fluid dynamics. Nek5000 is a set of general-purpose fluid mechanics computer modeling tools. It can be used to model vascular flows, aerodynamics, hydrodynamics and the behavior of air flow in internal combustion engines and, of course, liquid sodium in SCFRs.
     There are other computer algorithms which model fluid dynamics but Nek5000 has some advantages over them. Primarily, it cuts the time and cost required for such simulation. Paul Fischer is a computational scientist at Argonne who created Nek5000. He said, “By the time most other codes get to 80 percent of the solution, we’re at 90 percent, and that can make a big difference in terms of computing expense.”
Please read Part 2

Ambient office  = 148 nanosieverts per hour

Ambient outside = 111 nanosieverts per hour

Soil exposed to rain water = 105 nanosieverts per hour

Garlic root from Central Market = 153 nanosieverts per hour

Tap water = 111 nanosieverts per hour

Filtered water = 95 nanosieverts per hour