Recent Upgrades at the Safety and Tritium Applied Research Facility (original) (raw)
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Fusion Engineering and Design, 2016
Over the past five years, the fusion energy group at Lawrence Livermore National Laboratory (LLNL) has made significant progress in the area of safety and tritium research for Inertial Fusion Energy (IFE). Focus has been driven towards the minimization of inventories, accident safety, development of safety guidelines and licensing considerations. Recent technology developments in tritium processing and target fill have had a major impact on reduction of tritium inventories in the facility. A safety advantage of inertial fusion energy using indirect-drive targets is that the structural materials surrounding the fusion reactions can be protected from target emissions by a low-pressure chamber fill gas, therefore eliminating plasma-material erosion as a source of activated dust production. An important inherent safety advantage of IFE when compared to other magnetic fusion energy (MFE) concepts that have been proposed to-date (including ITER), is that loss of plasma control events with the potential to damage the first wall, such as disruptions, are non-conceivable, therefore eliminating a number of potential accident initiators and radioactive in-vessel source term generation. In this paper, we present an overview of the safety assessments performed to-date, comparing results to the US DOE Fusion Safety Standards guidelines and the recent lessons-learnt from ITER safety and licensing activities, and summarize our most recent thoughts on safety and tritium considerations for future nuclear fusion facilities.
Recent accomplishments of the fusion safety program at the Idaho National Laboratory
Fusion Engineering and Design, 2018
The Idaho National Laboratory (INL) Fusion Safety Program (FSP) is the Office of Fusion Energy Sciences' (FES) lead laboratory for Magnetic Fusion Energy (MFE) Safety. Our mission is to assist the US and international fusion communities in developing the inherent safety and environmental potential of fusion power by: 1) Developing fusion licensing data and analysis tools, 2) Participating in national and international collaborations and design studies, and 3) Assisting the US and international fusion community in licensing activities and guidance in operational safety. To achieve our mission, the FSP maintains core competencies in the several areas, two of which are: fusion safety code development and tritium retention and permeation in fusion plasma facing component (PFC) and blanket materials. This article details recent accomplishments of our program in these areas and future directions for fusion safety research and development at INL.
Preliminary Occupational Radiation Exposure evaluation related to NET/ITER tritium systems
Journal of Fusion Energy, 1993
This paper presents the criteria adopted to evaluate Occupational Radiation Exposure (ORE) during normal operation and maintenance of NET/ITER and some results concerning the fuel cycle systems located in the tokamak and tritium buildings. Prompt radiation, activity concentration, and intake situations as well as number of workers, number of events, and exposure time are considered. Many systems and components, whose location in the plant can affect radiological protection during maintenance and/or surveillance, are identified together with the operations needed for each activity. Accidental conditions and equipment failures have been considered in the special maintenance activity when they are due to events with a high probability of occurrence so that such events might be expected during the life of the plant. Some results are reported showing the ORE figures with reference to the main activities. The total man-Sv/y for the systems and activities considered is about 0.5. Such a result, even if very preliminary and incomplete, means that ORE for the tritium systems of a machine like NET/ITER is not negligible and has to be continuously controlled during the design phase.
Fusion Engineering and Design, 1992
The first JET tritium experiment was performed with no radiological incidents, minimal radiation exposure to JET personnel and controlled aerial discharges of tritium to the environment well within daily release limits derived from the discharge Authorisation. Most of the radiological protection measures are fundamental design features of the machine and its buildings. These have been in place for many years as JET is intended for protracted tritium operations. They all performed well and confirmed not only their basic design but also minor areas where enhancements had been thought necessary. Special additional equipment was necessary to perform this limited experiment and they were all designed and operated to the same criteria of safety and radiological protection, taking into account the extent of the experimental programme. The range of radiologieal protection measures implemented and their performance are described in the paper.
Tritium Environmental Risk in Future Fusion Reactors
Safety, Environmental Impact, and Economic Prospects of Nuclear Fusion, 1990
The rationales for the environmental tritium program carried out in the frame of the technology fusion and safety program of the EC are exposed in part one of the report.
Tritium aspects of the fusion nuclear science facility
Fusion Engineering and Design, 2017
h i g h l i g h t s • We estimate tritium losses from the FNSF using a TMAP model. • Permeation losses are minimized without permeation barriers in a DCLL blanket. • An efficient tritium extraction system is designed. • Parameter uncertainties are shown to profoundly effect predicted tritium loss rates.
Trends in fusion reactor safety research
Fusion Engineering and Design, 1991
Fusion has the potential to be an attractive energy source. From the safety ar,6 environmental perspective, fusion must avoid concerns about catastrophic accidents and ,b unsolvable waste disposal. In addition, fusion must achieve an acceptable level of risk from operational accidents that result in public exposure and economic loss. Finally, fusion reactors must control rouiine radioactive effluent, particularly tritium. Major progress in achieving this potential rests on development of low-activation materials or alternative fuels. The safety and performance of various material choices and fuels for commercial fusion reactors can be investigated relatively inexpensively through reactor design studies. These studies bring together experts in a wide range of backgrounds and force the group to either agree on a reactor design or identify areas for further study. Fusion reactors will be complex w-_th distributed radioactive inventories. The next generation of experiments will be critical in demonstrating that acceptable levels of safe operation can be achieved. These machines will use materials which are available today and for which a large database exists (e.g. for 316 stainless steel). Researchers have developed a good understanding of the risks associated with operation of these devices. Specifically, consequences from coolant system failures, loss of vacuum events, tritium releases, and liquid metal reactions have been studied. Recent studies go beyond next step designs and investigate commercial reactor concerns including tritium release and liquid metal reactions.
Fusion Science and Technology, 2010
A concise overview is given on materials applied in fusion technology. The influence of plasma operation on the behaviour of reactor components and diagnostic systems is discussed with emphasis on effects caused by fast particles reaching the reactor wall. Issues related to primary and induced radioactivity are reviewed: tritium inventory and transmutation. Tritium breeding in the reactor blanket, separation of hydrogen isotopes and safety aspects in handling radioactively contaminated components are also included.
Fusion Engineering and Design, 2002
Tritium and deuterium are expected to be the fuel for the first fusion power reactors. Being radioactive, tritium is a health, safety and environment concern. Room air tritium clean systems can be used to handle tritium that has been lost to the room from primary or secondary containment. Such a system called the Experimental Tritium Cleanup (ETC) systems is installed at the Tritium Systems Test Assembly (TSTA) at Los Alamos National Laboratory. The ETC consists of (1) two compressors which draw air from the room, (2) a catalyst bed for conversion of tritium to tritiated water, and (3) molecular sieve beds for collection of the water. The exhaust from this system can be returned to the room or vented to the stack. As part of the US Á/Japan fusion collaboration, on two separate occasions, tritium was released into the 3000 m 3 TSTA test cell, and the ETC was used to handle these releases. Each release consisted of about one Curie of tritium. Tritium concentrations in the room were monitored at numerous locations. Also recorded were the HT and HTO concentrations at the inlet and outlet of the catalyst bed. Tritium surface concentrations in the test cell were measured before and at a series of times after the releases. Surfaces included normal test cell equipment as well as idealized test specimens. The results showed that the tritium became well-mixed in the test cell after about 45 min. When the ETC was turned on, the tritium in the TSTA test cell decreased exponentially as was expected. The test cell air tritium concentration was reduced to below one DAC (derived air concentration) in about 260 min. For the catalyst bed, at startup when the bed was at ambient temperature, there was little conversion of tritium to HTO. However, once the bed warmed to about 420 K, all of the tritium that entered the bed was converted to HTO. Immediately after the experiment, surfaces in the room initially showed moderately elevated tritium concentrations. However, with normal ventilation, these concentrations soon returned to routine levels. The data collected and reported here should be useful for planning for the operation of existing and future tritium facilities. # (R.S. Willms).