Varied applications of a new maximum-likelihood code with complete covariance capability. [FERRET, for data adjustment]

Conference · Sun Jan 01 04:00:00 EST 1978

OSTI ID:6428376

Schmittroth, F.

Applications of a new data-adjustment code are given. The method is based on a maximum-likelihood extension of generalized least-squares methods that allow complete covariance descriptions for the input data and the final adjusted data evaluations. The maximum-likelihood approach is used with a generalized log-normal distribution that provides a way to treat problems with large uncertainties and that circumvents the problem of negative values that can occur for physically positive quantities. The computer code, FERRET, is written to enable the user to apply it to a large variety of problems by modifying only the input subroutine. The following applications are discussed: A 75-group a priori damage function is adjusted by as much as a factor of two by use of 14 integral measurements in different reactor spectra. Reactor spectra and dosimeter cross sections are simultaneously adjusted on the basis of both integral measurements and experimental proton-recoil spectra. The simultaneous use of measured reaction rates, measured worths, microscopic measurements, and theoretical models are used to evaluate dosimeter and fission-product cross sections. Applications in the data reduction of neutron cross section measurements and in the evaluation of reactor after-heat are also considered. 6 figures.

• Research Organization: Hanford Engineering Development Lab., Richland, WA (USA)
• DOE Contract Number: EY-76-C-14-2170
• OSTI ID: 6428376
• Report Number(s): HEDL-SA-1616-FP; CONF-780858-9
• Country of Publication: United States
• Language: English

Related Subjects

22 GENERAL STUDIES OF NUCLEAR REACTORS
220100 -- Nuclear Reactor Technology-- Theory & Calculation
651100* -- Nuclear Physics-- Experimental Techniques-- (1980-)
73 NUCLEAR PHYSICS AND RADIATION PHYSICS
BARYON REACTIONS
BARYONS
CAPTURE
CHARGED-PARTICLE REACTIONS
COMPUTER CALCULATIONS
CROSS SECTIONS
DAMAGING NEUTRON FLUENCE
DATA PROCESSING
DEUTERON REACTIONS
DIRECT REACTIONS
DOSIMETRY
ELECTROMAGNETIC RADIATION
ELEMENTARY PARTICLES
ENERGY RANGE
FAST NEUTRONS
FERMIONS
GAMMA RADIATION
HADRON REACTIONS
HADRONS
IONIZING RADIATIONS
KEV RANGE
KINETICS
LITHIUM 7 TARGET
MAXIMUM-LIKELIHOOD FIT
NEUTRON DOSIMETRY
NEUTRON FLUENCE
NEUTRON FLUX
NEUTRON REACTIONS
NEUTRONS
NUCLEAR REACTIONS
NUCLEON REACTIONS
NUCLEONS
NUMERICAL SOLUTION
PROCESSING
RADIATION FLUX
RADIATIONS
REACTOR KINETICS
SCANDIUM 45 TARGET
SILVER 109 TARGET
SPECTRA UNFOLDING
TARGETS