scholarly journals Patchy snapshots of nuclear chain reactions

2020 ◽  
Author(s):  
Eric Dumonteil ◽  
Rian Bahran ◽  
Theresa Cutler ◽  
Benjamin Dechenaux ◽  
Travis Grove ◽  
...  
Keyword(s):  
Chain Reactions ◽  
Nuclear Chain

scholarly journals Patchy nuclear chain reactions

2021 ◽  
Vol 4 (1) ◽  
Author(s):  
Eric Dumonteil ◽  
Rian Bahran ◽  
Theresa Cutler ◽  
Benjamin Dechenaux ◽  
Travis Grove ◽  
...  
Keyword(s):  
Nuclear Reactor ◽  
Reactor Core ◽  
Rensselaer Polytechnic Institute ◽  
Operating Conditions ◽  
Chain Reactions ◽  
Branching Random Walks ◽  
Stochastic Fluctuations ◽  
Nuclear Chain ◽  
Reactor Operating ◽  
Experimental Findings

AbstractStochastic fluctuations of the neutron population within a nuclear reactor are typically prevented by operating the core at a sufficient power, since a deterministic (i.e., exactly predictable) behavior of the neutron population is required by automatic safety systems to detect unwanted power excursions. In order to characterize the reactor operating conditions at which the fluctuations vanish, an experiment was designed and took place in 2017 at the Rensselaer Polytechnic Institute Reactor Critical Facility. This experiment however revealed persisting fluctuations and striking patchy spatial patterns in neutron spatial distributions. Here we report these experimental findings, interpret them by a stochastic modeling based on branching random walks, and extend them using a “numerical twin” of the reactor core. Consequences on nuclear safety will be discussed.

scholarly journals Yakov Borissovich Zel'Dovich, 8 March 1914 - 2 December 1987

1994 ◽  
Vol 40 ◽  
pp. 429-441 ◽  
Keyword(s):  
General Theory ◽  
Nuclear Physics ◽  
New Technology ◽  
Elementary Particles ◽  
Chemical Physics ◽  
Theory Of Relativity ◽  
General Theory Of Relativity ◽  
Chain Reactions ◽  
Princeton University ◽  
Nuclear Chain

Yakov Borissovich Zel'Dovich was an exceedingly bright star in the firmament of Soviet and world physics and astrophysics. To these fields can be added physical chemistry or, as is sometimes said, chemical physics. More specifically, mention may be made of researches in catalysis, phase transitions, hydrodynamics, combustion and detonation theory, nuclear chain reactions, nuclear physics, the theory of elementary particles and, finally, the general theory of relativity and cosmology. To mark Ya.B.’s 70th birthday, two volumes of his selected works were published under the titles: Vol. 1 Chemical Physics and Hydrodynamics (1) and Vol. II Particles, Nuclei and the Universe (2). These volumes contain a complete list of Ya.B.’s works. As far as I know, both volumes are to be published in English in 1989 by Princeton University Press. The second volume concludes with an autobiographical afterword dated 3 March 1984. Unfortunately, Ya.B. died less than four years later and, although he continued to work with his former energy, these volumes (1,2) can and will provide the basis for this obituary. Access to all Ya.B.’s existing works in English translation, accompanied by expert and often highly detailed commentaries by leading specialists, together with a long editorial article of 56 pages introducing (1), provide abundant detail and references to many of Ya.B.’s articles. Ya.B.’s life can to a first approximation be divided into four periods: 1914-30, childhood and schooldays; 1931-47, the Institute of Chemical Physics, mainly work on physicochemical problems; 1947-63, work on the creation of a new technology, nuclear physics and the theory of elementary particles; 1964-87, mainly astronomy, with emphasis on the application of the general theory of relativity and on cosmology. This chronology, taken from (1,2), will also be used here.

Phenotyping and Genotyping of Coagulation Factor V Leiden

1996 ◽  
Vol 75 (02) ◽  
pp. 267-269 ◽  
Author(s):  
H Engel ◽  
L Zwang ◽  
H H D M van Vliet ◽  
J J Michiles ◽  
J Stibbe ◽  
...  
Keyword(s):  
Factor V Leiden ◽  
Coagulation Factor ◽  
Diagnostic Value ◽  
Resistance Test ◽  
Amplification Refractory Mutation System ◽  
Factor V ◽  
Chain Reactions ◽  
Apc Resistance ◽  
Specificity And Sensitivity ◽  
Coagulation Factor V

SummaryThe currently used activated Protein C resistance test demonstrated to be of limited diagnostic value for the detection of the mutant Factor V Leiden. Moreover, this assay is not useful for patients under anticoagulant therapy. A modification of the APC resistance test, applying Factor V deficient plasma is described which demonstrates a specificity and sensitivity of 1.0. The superiority of the modified APC resistance test over the existing APC resistance test was verified by genotyping.For that purpose, the Amplification Refractory Mutation System (ARMS) was applied to the detection of the G to A mutation at position 1691 in the gene encoding coagulation Factor V. The mutation at that position could be easily detected by using each of two allele-specific oligonucleotide primers concomitantly with one common primer in two separate polymerase chain reactions, thereby amplifying a fragment of 186 base-pairs of the Factor V gene.

Present-day theory of chain reactions

1966 ◽  
Vol 88 (4) ◽  
pp. 769-781 ◽  
Author(s):  
V.N. Kondrat'ev
Keyword(s):  
Chain Reactions
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