Burn Up
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As clients may add backlog items midway through your progress, this line could increase due to scope creep. For example, in the burn up chart we highlighted earlier, the total work line moved up during the fifth iteration. This was likely due to the client adding some backlog items at that stage.
\"Burnout\" isn't a medical diagnosis. Some experts think that other conditions, such as depression, are behind burnout. Researchers point out that individual factors, such as personality traits and family life, influence who experiences job burnout.
If you answered yes to any of these questions, you might be experiencing job burnout. Consider talking to a doctor or a mental health provider because these symptoms can also be related to health conditions, such as depression.
To understand \"burnup,\" it helps to know more about the uranium that fuels a reactor. Before it is made into fuel, uranium is processed to increase the concentration of atoms that can split in a controlled chain reaction in the reactor. The atoms release energy as they split. This energy produces the heat that is turned into electricity. In general, the higher the concentration of those atoms, the longer the fuel can sustain a chain reaction. And the longer the fuel remains in the reactor, the higher the burnup.
In other words, burnup is a way to measure how much uranium is burned in the reactor. It is the amount of energy produced by the uranium. Burnup is expressed in gigawatt-days per metric ton of uranium (GWd/MTU). Average burnup, around 35 GWd/MTU two decades ago, is over 45 GWd/MTU today. Utilities now are able to get more power out of their fuel before replacing it. This means they can operate longer between refueling outages. It also means they use less fuel.
The burnup level affects the fuel's temperature, radioactivity and physical makeup. It is important to the NRC's review of spent fuel cask designs because each system has limits on temperature and radioactivity. How hot and how radioactive spent fuel is depends on burnup, as well as the fuel's initial makeup and conditions in the core. All these factors must be taken into account in designing and approving dry storage and transport systems for spent fuel.
Nuclear fuel is encased in metal cladding. In the reactor, this cladding reacts with cooling water. The reaction forms oxide on the outside (similar to rust) and releases hydrogen. These processes begin slowly, then start to accelerate as the fuel reaches burnup of 45 GWd/MTU. Anything higher has historically been considered high burnup. But in reality there is no sharp line between low and high burnup. It is a continuum. That means the difference between fuel burned to 45 GWd/MTU and 46 or 47 GWd/MTU can be very small.
When spent fuel is placed in a dry storage system and the water is removed, the temperature of the fuel temporarily increases and the makeup of the cladding can change. This change can be more pronounced in high burnup spent fuel, which prompted the NRC to evaluate whether the cladding can become less \"ductile,\" or less pliable, as it cools. To address the technical concern, the NRC and the U.S. Department of Energy sponsored research programs to evaluate the performance of high burnup spent fuel. This research showed that the cladding remains ductile and the dry storage systems and transportation packages can safely hold the fuel.
Based on these reviews, the NRC has certified systems for dry storage and transportation of high burnup spent fuel. Because low burnup spent fuel has been around longer and there is more of it, there are more systems for low than for high burnup spent fuel. However, as more data has become available on the performance of high burnup spent fuel, the NRC has certified dry storage and transportation systems for higher burnups for an initial term up to 20 years.
Operating experience since dry storage began in 1986 and short-term tests show that both low and high burnup spent fuel can be stored and transported safely. The NRC has sponsored testing at Oak Ridge National Laboratory on high burnup fuel under stresses greater than the loads expected during normal storage and transport. These tests have shown that high burnup fuel is very strong. However, the NRC wants to continue to obtain valuable information on high burnup spent fuel stored in the U.S., which is why users of dry storage systems will evaluate results from a demonstration program of an actual loaded dry storage system. These results will provide added confirmation of the safety of dry storage and transport of aged high burnup spent fuel.
The primary focus of research today is to get more data to support the continued safety of dry storage systems for high burnup spent fuel beyond the initial 20-year storage term. The research is designed to ensure that the existing data is accurate as the fuel gets older. Results are expected to confirm that the fuel will remain safe for transport even after extended storage.
The Department of Energy is sponsoring two research programs on high burnup spent fuel. The Research Cask Program, run jointly with the nuclear industry and with regulatory oversight by the NRC, is currently underway. In this study, high burnup spent fuel was loaded into a dry storage system fitted with instruments to provide temperature readings and allow sampling of the gas inside. These readings, combined with tests on the fuel assemblies and inspection of the cask's interior after years of dry storage, will provide more data. The results will enhance our understanding of what happens to high burnup spent fuel in a storage system as it cools over time.
The second study focuses on the characteristics, material properties, and performance of high burnup fuel rods with similar irradiation histories as those loaded in the research cask. These \"sister rods\" will be tested against the con ditions as measured in the research cask as well as against conditions modeled for other dry storage systems that have different thermal profiles and histories. All this work will help system designers, users and regulators better understand how to ensure high burnup spent fuel will remain safe in dry storage over the long term and during eventual transportation to a centralized storage or disposal facility.
The NRC also provides oversight before and during loading of dry storage systems to ensure the correct fuel will go into the right systems. Fuel with burnup higher than the NRC certificate allows cannot be loaded. It must remain in pool storage until a cask approved for higher burnup becomes available. The NRC also inspects loaded systems every few years.
A burn up chart is a visual diagram commonly used on Agile projects to help measure progress. Agile burn up charts allow project managers and teams to quickly see how their workload is progressing and whether project completion is on schedule.
A burn up chart is a graph that shows project progress over time. There are two main lines shown on the chart: one for the total project work planned, and the other for tracking the work completed to date.
Burn up charts are an essential part of the Agile methodology, as they keep track of what has been accomplished across each sprint. In this way, they are also useful for Scrum teams, as the Scrum master can review their burn up chart to analyse where improvements can be made, and cover these in daily meetings with the rest of the team.
First, a burn down chart starts with the total amount of work and then graphs the amount remaining over time. As time progresses, the amount of work to be done lessens, and the line decreases toward the right.
A burn up chart tracks the amount of work to be completed as one straight line across the top of the graph (unless a scope change occurs). A second line is then used to track work completed, starting at zero and increasing to the right as more tasks are finished.
A sprint burn up chart helps your Agile team monitor how efficient they are from one sprint to the next. It also helps everyone keep track of how much work is left and whether you can expect to complete the project on time based on your progress rate so far.
If your team was completing 20 SPs per sprint and now suddenly they only completed 10 SPs, your burn up chart will highlight that change. This makes it easier for you to spot differences and investigate them to see if a bottleneck or issue is slowing your team.
Plus, a burn up chart monitors your overall scope and how that impacts your project length. What does scope mean in project management It's essentially all of the requirements and objectives that a project needs to be a success. Your burn up chart is an easy way to show your client and other stakeholders how much longer the project should take if they want additional work added.
The reactivity of nuclear reactor fuels typically decreases as the fuel burnup proceeds. Essentially, the decrease in reactivity comes from a reduction in concentration of fissile nuclides and an increase in concentration of fission products that absorb neutrons. Burn-up credit, which is currently of wide interest in the field of nuclear criticality safety research, generally involves taking into account this reactivity decrease for criticality safety assessments and control of spent fuel by crediting burn up of fuel.
To provide information of more accurate safety analysis, Expert Group on Burn-up Credit Criticality Safety (EGBUC) was formed in 1991 and published several benchmark reports. The NEA's activities had examined burn-up credit as applied to criticality safety in the transportation, storage and treatment of spent fuel for a wide range of fuel types and reactors, including UOX and MOX fuels for PWR, BWR and VVER.
Getting rid of the smaller satellites in low orbits is simple. The heat from the friction of the air burns up the satellite as it falls toward Earth at thousands of miles per hour. Ta-da! No more satellite.
At each day you can see the amount of work completed and the total amount of work. The distance between the two lines is thus the amount of work remaining. When the two lines meet, the project will be complete. This is a powerful measure of how close you are to completion of the project, similar to a burn down chart. 59ce067264