| 1. |
- Andersson, Peter, 1981-, et al.
(författare)
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Coincidence spectroscopy for increased sensitivity in radionuclide monitoring
- 2022
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- The majority of the energy in a nuclear explosion is released in the immediate blast and the initial radiation accounts. The remaining fraction is released through radioactive decay of the explosion's fission products and neutron activation products over a longer time span. This allows for the detection of a nuclear explosion by detecting the presence of residual decay. Radionuclide monitoring stations for detection of radioactive emissions to the atmosphere is thereby an important tool in the verification of compliance with nuclear disarmament treaties. In particular, the globally spanning radionuclide station network of the International Monitoring System (IMS) has been implemented for verification of the Comprehensive Nuclear-Test-Ban Treaty.High Purity Germanium (HPGe) detectors are workhorses in radionuclide monitoring. The detection of characteristic gamma rays can be used to disclose the presence of signature nuclides produced innuclear weapon tests. A particular development that has potential to improve the sensitivity of radionuclide monitoring is the coincidence technique where decaying nuclides that emit several coincident gamma rays can be detected at much smaller activity concentrations than with conventional gamma spectroscopy.In this project, dedicated gamma-gamma coincidence detectors are being developed, utilizing electronically segmented HPGe detectors. These detectors are expected to be highly sensitive to low-activity samples of nuclides that present coincident emissions of gamma rays. In this paper we present the concept, define performance parameters, and explore the performance of such detectors to a subset of radionuclides of particular CTBT relevance. In addition, we discuss the path forward in developing a next generation gamma-gamma coincidence spectroscopy system of segmented HPGe.
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| 2. |
- Arvidsson, Eva, 1959-, et al.
(författare)
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Vägen framåt
- 2013
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Ingår i: Att välja rättvist. - Lund : Studentlitteratur AB. ; , s. 207-214
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Bokkapitel (övrigt vetenskapligt/konstnärligt)abstract
- Som vi visat har utvecklingen av metoder och strukturer för öppna prioriteringar i Sverige kommit långt. Många frågor återstår likväl. Under vårt arbete med denna bok har vi identifierat ett antal förbättringsområden och utmaningar som vi avslutningsvis vill lyfta fram. Det rör sig om vilka som ska delta i prioriteringarna, tydliggörande av värdegrunden, behov av bättre kunskap, baserad på både vetenskaplig metod och erfarenhet, och fortsatt utveckling av prioriteringsprocesser på olika nivåer och i olika sammanhang. Även om vi i Sverige skulle nå en god enighet kring principer och kriterier för prioriteringar så kommer vi alltid finna många olika sätt att praktiskt lösa specifika prioriteringsproblem.
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| 3. |
- Barra, Mathias, et al.
(författare)
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Do not despair about severity—yet
- 2020
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Ingår i: Journal of Medical Ethics. - : BMJ Publishing Group Ltd. - 0306-6800 .- 1473-4257. ; 46:8, s. 557-558
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- In a recent extended essay, philosopher Daniel Hausman goes a long way towards dismissing severity as a morally relevant attribute in the context of priority setting in healthcare. In this response, we argue that although Hausman certainly points to real problems with how severity is often interpreted and operationalised within the priority setting context, the conclusion that severity does not contain plausible ethical content is too hasty. Rather than abandonment, our proposal is to take severity seriously by carefully mapping the possibly multiple underlying accounts to well-established ethical theories, in a way that is both morally defensible and aligned with the term’s colloquial uses.
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| 4. |
- Branger, Erik, 1988-, et al.
(författare)
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Plutonium Production under Uranium Constraint
- 2023
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Ingår i: Science and Global Security. - : Routledge. - 0892-9882 .- 1547-7800. ; 31:3, s. 115-136
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Tidskriftsartikel (refereegranskat)abstract
- Production rates of fissile materials are often used to independently assess the number of nuclear warheads a state may possess. One key constraint of a plutonium-based nuclear weapons program is the availability of natural uranium, where a shortage of uranium will constrain plutonium production in the fuel cycle. Recycling of the reprocessed uranium can be used to mitigate such a shortage. Furthermore, since military reactors operate in short cycles to ensure that the plutonium is weapon-grade, it may be possible to operate them using slightly depleted uranium, provided that there are sufficient reactivity margins. Using slightly depleted or recycled uranium, the plutonium production can increase by a factor 2–5 as compared to a once-through scenario, for the same input of natural uranium. For future assessments of a state’s plutonium production, a uranium constraint should only be considered if there is clear evidence that no nuclear fuel cycle involving uranium recycling is implemented, or if evidence exists that the recycling is insufficient to mitigate the constraint.
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| 5. |
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| 6. |
- Grape, Sophie, 1982-, et al.
(författare)
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Development of a PhD course in verification of nuclear test explosions under AMC
- 2022
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- Under the AMC, a range of activities covering education, research and outreach are foreseen. One of them concerns education and the build-up of competence related to disarmament, and for that reason collaborative efforts have been ongoing during 2021 and 2022 to develop a PhD-level course in verification of nuclear test explosions, and to offer it during September-October 2022. The course has developed by Uppsala University and the Swedish Defence Reserach Agency (FOI) and corresponds to 7.5 credits. It is a cross-disciplinary course that spans over several disciplines. It introduces the participants to treaties and verification regimes governing nuclear weapons and it explains identification, calculation and analysis of signatures from nuclear weapon explosions. Furthermore, effort has been made to let the participants actively work with data collection, aggregation, analysis and with the interpretation and evaluation of data. The course includes also both a laboratory exercise on detection of radionuclides, and a project work in which the participants analyze a test explosion scenario and summarize their findings and conclusions in a manner very similar to how this is done in reality.This poster will describe the details of the course and its content. Since the course is planned to be offered just before this conference, we also hope to provide some information on its execution, as well as feedback from the participants.
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| 7. |
- Grape, Sophie, 1982-, et al.
(författare)
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Non-proliferation and safeguards activities within the Alva Myrdal Centre for nuclear disarmament
- 2022
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Ingår i: Proceedings of the Symposium on International Safeguards: Reflecting on the Past and Anticipating the Future.
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- In 2020, the Swedish government announced the intent to start up a national competence centre on nuclear disarmament in Sweden. The goal was to highlight the importance of nuclear disarmament issues, and to promote research, teaching and policy support on topics relevant to nuclear disarmament. During the spring semester 2021, the Alva Myrdal Centre (AMC) on nuclear disarmament was established at Uppsala University. The AMC combines competences from different disciplines such as peace and conflict research, applied nuclear physics, and international law, and organises the work into six different working groups. One of the working groups is focusing on technical aspects, while the remaining five working groups are focusing on policy aspects. The technical working group is led by the Division of Applied Nuclear Physics at Uppsala University, where research on nuclear safeguards has been performed for over 30 years, and where competence in addition exists on a number of applied physics applications ranging from nuclear reactions, nuclear power and detection of radionuclides.
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| 8. |
- Grape, Sophie, 1982-, et al.
(författare)
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Retrieving information about the Ågesta reactor in Sweden
- 2023
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Ingår i: AMC Annual conference 2023, 14-15 June, 2023.
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Konferensbidrag (populärvet., debatt m.m.)abstract
- The “Swedish line” was an ambitious program in the 1950s-1960s aiming to make Sweden self-sufficient with respect to nuclear technology. The plan was to combine civil power production with military plutonium production, should Sweden decide to develop nuclear weapons. The program included, among other things, domestic uranium mining, domestic uranium fuel production, operation of heavy-water reactors and a plutonium laboratory. The Ågesta nuclear power plant just outside Stockholm was part of the program. The reactor, also known as R3/Adam, was in operation in 1964-1974. The reactor was an underground, heavy-water cooled and heavy-water moderated pressurized reactor, providing district heat and a modest amount of electricity to the near-by suburb Farsta. After being closed down, the heavy water was sold to Canada while the fuel and some other equipment were removed. Large parts of the facility were preserved for several decades, but is now undergoing decommissioning, a process which is planned to be finalised in 2025. Within this project we are investigating how to locate and reconstruct historic information on the operation of the Ågesta reactor. Of particular interest is the nuclear fuel and its irradiation history in the reactor. There are many reasons for this: i) information and knowledge management about the operation of a nuclear facility under the “Swedish line”, ii) for assessments regarding to the produced plutonium qualities and quantities and iii) for nuclear safeguards verification of Ågesta fuel before encapsulation and final storage. For operating reactors, information about the fuel and its irradiation in the reactor is typically kept with the operator and follows the fuel as it undergoes transport and spent fuel management. In this case, the information is not straightforward to access, as the information has been distributed among multiple actors, and because custody of various parts of the information has changed over time. In this poster we will describe efforts to retrieve the detailed technical information, results thereof, and the plans for using it to support research related to the topics mentioned above.
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| 9. |
- Grape, Sophie, 1982-
(författare)
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Simulating submarine reactor fuel in light of the AUKUS deal
- 2023
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Ingår i: ESARDA Bulletin - The International Journal of Nuclear Safeguards and Non-proliferation. - Ispra, Italy. - 1977-5296. ; 65, s. 34-43
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Tidskriftsartikel (refereegranskat)abstract
- This work investigates fuel properties of submarine reactor fuel from a non-proliferation and safeguards perspective in light of the deal involving Australia, the United Kingdom and United States known as AUKUS. This study investigates the isotopic composition of the spent fuel at the end of intended reactor life. The fuel in the proposed AUKUS submarine is modelled after a Virginia Class fast attack submarine, discussed as an option for Australia.The vast majority of civil experience with plutonium production is with fuel starting at low enrichments for shorter burnups. The AUKUS fuel at the start of irradiation campaign is assumed to contain uranium enriched to between 93% and 97,3%. It is burned at high power for about 33 years before retirement. Because the fuel is mostly uranium-235 initially, there are very few thermal captures leading to production of plutonium-239. In the submarine, the majority of non-fissile captures lead to the production of uranium-236 with other capture chains that do not lead to the production of weapons grade plutonium or weapons usable uranium.This study concludes that the final isotopic composition of the AUKUS spent fuel is no longer VHEU, but a low grade of HEU diluted largely by uranium-236 instead of uranium-238. Several kilograms of plutonium are produced but it is composed of several different plutonium isotopes with a large fraction of plutonium-238. There is little likelihood that spent AUKUS fuel will be reprocessed by any of the countries involved. But if it were reprocessed, the resulting uranium and plutonium will have very unusual isotope compositions. Resulting materials would be subject to safeguards but would not, in fact, be well-suited as fissile material for weapons purposes.
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| 10. |
- Grape, Sophie, 1982-, et al.
(författare)
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State-of-the-Art Report : Prepared by Working Group 4: Technical nuclear non-proliferation and safeguards under the Alva Myrdal Centre for nuclear disarmament
- 2022
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- The Alva Myrdal Centre for nuclear disarmament (AMC) was established in 2021. AMC consists of six working Groups, and one of them - Working Group 4 - is called Technical nuclear non-proliferation and safeguards. This is the State-of-the-Art Report of that working group. The objective with the report is to provide an overview of the technical fields relevant to the working group and to highlight where research and activities within the working group may contribute to global nuclear disarmament. The report gives a brief explanation of actors in the field, introduces nuclear materials and assay techniques, and then continues to elaborate on challenges and needs associated with nuclear measurements and assessments in the fields of non-proliferation, nuclear safeguards and nuclear disarmament. A section is also devoted to the management of nuclear weapons materials after disarmament. Lastly, the report contains a section on interdisciplinary research and development in nuclear disarmament, and information about technical education and training in the non-proliferation and disarmament field.
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