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Record W98676757 · doi:10.13182/nse07-a2711

Perturbation Theory Based on the Method of Cyclic Characteristics

2007· article· en· W98676757 on OpenAlex

Why this work is in the frame

A frame that forgets how it found something cannot be audited. These are the routes that admitted this work.

affAt least one author lists a Canadian institution in the pinned OpenAlex snapshot.
fundA Canadian funder is recorded on the work.
aboutThe title or abstract carries a Canadian signal from the geographic lexicon.

Bibliographic record

VenueNuclear Science and Engineering · 2007
Typearticle
Languageen
FieldEngineering
TopicNuclear reactor physics and engineering
Canadian institutionsPolytechnique Montréal
FundersNatural Sciences and Engineering Research Council of Canada
KeywordsEigenvalues and eigenvectorsNeutron transportEstimatorNeutron fluxNuclideMathematicsApplied mathematicsGeneralized functionPerturbation theory (quantum mechanics)Mathematical analysisNeutronPhysicsNuclear physicsQuantum mechanics

Abstract

fetched live from OpenAlex

Generalized perturbation theory (GPT) is a technique used for the estimation of small changes in performance functionals, such as linear reaction rate ratios, eigenvalues, power density, etc., affected by small variations in reactor core compositions. Here, a GPT algorithm is developed for the multigroup integral neutron transport problems in two-dimensional fuel assemblies with isotropic scattering. We then use the relationship between the generalized flux importance and generalized source importance functions to transform the generalized flux importance transport equations into the integrodifferential equations for the generalized adjoints. The resulting adjoint and generalized adjoint transport equations are then solved using the method of cyclic characteristics (MOCC). Because of the presence of negative adjoint sources, a coupled flux biasing/decontamination scheme is applied to make the generalized adjoint functions positive in such a way that it can be used for the multigroup rebalance technique. After convergence is reached, the decontamination procedure extracts from the generalized adjoints the component parallel to the adjoint function. Three types of biasing/decontamination schemes are investigated in the study. To demonstrate the efficiency of our solution algorithms, calculations are performed on 17 × 17 pressurized water reactor and 37-pin Canada deuterium uranium reactor (CANDU) lattices. Numerical comparisons of the generalized adjoint functions and GPT estimates using the MOCC and collision probability method are presented as well as sensitivity coefficients of nuclide densities.

Fetched live from OpenAlex and de-inverted. Abstracts are not stored in this database: the inverted indexes are 8.6 GB of the frame’s 9.3 GB of text, and the host has 13 GB free.

Full frame distilled prediction

Teacher imitation

Not calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.

metaresearch head score (Codex)0.001
metaresearch head score (Gemma)0.000
Version: codex-gemma-dda1882f352aValidation status: machine_predicted_unvalidated
Candidate categoriesnone
Consensus categoriesnone
DomainCandidate signal: none · Consensus signal: none
Study designCandidate signal: Simulation or modeling · Consensus signal: none
GenreCandidate signal: Empirical · Consensus signal: Empirical
Teacher disagreement score0.921
Threshold uncertainty score0.326

Codex and Gemma teacher scores by category

CategoryCodexGemma
Metaresearch0.0010.000
Meta-epidemiology (narrow)0.0000.000
Meta-epidemiology (broad)0.0000.000
Bibliometrics0.0000.000
Science and technology studies0.0000.000
Scholarly communication0.0000.000
Open science0.0000.000
Research integrity0.0000.000
Insufficient payload (model declined to judge)0.0000.000

Machine scores (provisional)

The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.

Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.

Opus teacher head0.007
GPT teacher head0.200
Teacher spread0.193 · how far apart the two teachers sit on this one work
Validation statusscore_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from it