Criticality analyses of regions containing uranium in the earth history
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M. Ravnik
Abstract
Investigations of necessary conditions for a self-sustained chain reaction in the Earth inner regions hypothetically containing uranium is presented for the time interval from Earth formation to present time. It is determined that criticality was theoretically possible up to 2.5 Ga before present if uranium concentrated in pure form. In the early geological history (4 Ga before present) the self-sustained criticality could occur even if uranium was diluted up to 1: 20 by the average core material or 1: 60 by the average mantle material. If other metallic materials of similar density as uranium (e. g., Au, W) or similar atomic weight (e. g., Th) concentrated from the primordial mixture in equal proportion as uranium, criticality was not possible for any period in Earth history provided that the basic material contained no light nuclides (H, C). Criticality in the Earth inner regions could have established only if uranium concentrated from the basic material more effectively than elements of similar density or atomic number.
Kurzfassung
Untersuchungen der notwendigen Bedingungen für eine selbst-erhaltende Kettenreaktion in Uran-haltigen Regionen im Erdinnern werden vorgestellt für den Zeitraum von der Entstehung der Erde bis heute. Es wurde festgestellt, dass Kritikalität theoretisch möglich war bis 2, 5 Ga vor heute, wenn Uran in reiner Form vorliegt. In der frühen geologischen Geschichte (4 Ga vor heute) konnte die selbst-erhaltende Kettenreaktion sogar dann auftreten, wenn Uran bis zu 1: 20 verdünnt durch das durchschnittliche Erdkernmaterial vorlag oder 1: 60 durch das durchschnittliche Erdmantelmaterial. Wenn andere metallische Materialien ähnlicher Dichte wie Uran (z. B. Au, W) oder mit ähnlichem Atomgewicht (z. B. Th) aus dem primordialen Gemisch in gleichen Anteilen konzentriert vorlagen wie Uran, so war Kritikalität zu keiner Zeit der Erdgeschichte möglich, vorausgesetzt das Grundmaterial enthielt keine leichten Nuklide (H, C). Kritikalität konnte nur entstehen, wenn sich Uran aus dem Grundmaterial effektiver anreicherte als Elemente ähnlicher Dichte oder Atomzahl.
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Articles in the same Issue
- Contents/Inhalt
- Contents
- Summaries/Kurzfassungen
- Summaries/Kurzfassungen
- Editorial
- 70 Volumes Kerntechnik
- Technical Contributions/Fachbeiträge
- Uncertainty and sensitivity analysis of void and power reactivity coefficients in an RBMK-1500 reactor core
- Theoretical studies on thermal stratification in a side heated cavity
- Measurement of the neutron fluence on the spallation source at Dubna
- Neutron reflection and leakage models for one-dimensional reactor computations
- Reactivity worth of the control rods at the ET-RR-2 reactor core
- Neutronic conceptual design of the ETRR-2 cold neutron source
- Criticality analyses of regions containing uranium in the earth history
- Semi-statistical mechanical fuel rod design
- Brennstabauslegung und Brennstabmodellierung – Teil 2
- The chemical separation of Eka-Hg from CERN W targets in view of recent relativistic calculations
- Letter to the Editor
- Comments on the question of the discovery of element 112 as early as 1971
Articles in the same Issue
- Contents/Inhalt
- Contents
- Summaries/Kurzfassungen
- Summaries/Kurzfassungen
- Editorial
- 70 Volumes Kerntechnik
- Technical Contributions/Fachbeiträge
- Uncertainty and sensitivity analysis of void and power reactivity coefficients in an RBMK-1500 reactor core
- Theoretical studies on thermal stratification in a side heated cavity
- Measurement of the neutron fluence on the spallation source at Dubna
- Neutron reflection and leakage models for one-dimensional reactor computations
- Reactivity worth of the control rods at the ET-RR-2 reactor core
- Neutronic conceptual design of the ETRR-2 cold neutron source
- Criticality analyses of regions containing uranium in the earth history
- Semi-statistical mechanical fuel rod design
- Brennstabauslegung und Brennstabmodellierung – Teil 2
- The chemical separation of Eka-Hg from CERN W targets in view of recent relativistic calculations
- Letter to the Editor
- Comments on the question of the discovery of element 112 as early as 1971
