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Title: Description and performance characteristics for the neutron Coincidence Collar for the verification of reactor fuel assemblies

Abstract

An active neutron interrogation method has been developed for the measurement of /sup 235/U content in fresh fuel assemblies. The neutron Coincidence Collar uses neutron interrogation with an AmLi neutron source and coincidence counting the induced fission reaction neutrons from the /sup 235/U. This manual describes the system components, operation, and performance characteristics. Applications of the Coincidence Collar to PWR and BWR types of reactor fuel assemblies are described.

Authors:
Publication Date:
Research Org.:
Los Alamos National Lab., NM (USA)
OSTI Identifier:
6038728
Report Number(s):
LA-8939-MS; ISPO-142
ON: DE82001881; TRN: 82-000302
DOE Contract Number:
W-7405-ENG-36
Resource Type:
Technical Report
Country of Publication:
United States
Language:
English
Subject:
98 NUCLEAR DISARMAMENT, SAFEGUARDS, AND PHYSICAL PROTECTION; 37 INORGANIC, ORGANIC, PHYSICAL AND ANALYTICAL CHEMISTRY; FUEL ASSEMBLIES; NUCLEAR REACTION ANALYSIS; URANIUM 235; BWR TYPE REACTORS; COINCIDENCE METHODS; NEUTRON BEAMS; PWR TYPE REACTORS; ACTINIDE ISOTOPES; ACTINIDE NUCLEI; ALPHA DECAY RADIOISOTOPES; BEAMS; CHEMICAL ANALYSIS; COUNTING TECHNIQUES; EVEN-ODD NUCLEI; HEAVY NUCLEI; ISOMERIC TRANSITION ISOTOPES; ISOTOPES; MINUTES LIVING RADIOISOTOPES; NUCLEI; NUCLEON BEAMS; PARTICLE BEAMS; RADIOISOTOPES; REACTORS; URANIUM ISOTOPES; WATER COOLED REACTORS; WATER MODERATED REACTORS; YEARS LIVING RADIOISOTOPES; 055001* - Nuclear Fuels- Safeguards, Inspection, & Accountability- Technical Aspects; 400103 - Radiometric & Radiochemical Procedures- (-1987)

Citation Formats

Menlove, H.O. Description and performance characteristics for the neutron Coincidence Collar for the verification of reactor fuel assemblies. United States: N. p., 1981. Web. doi:10.2172/6038728.
Menlove, H.O. Description and performance characteristics for the neutron Coincidence Collar for the verification of reactor fuel assemblies. United States. doi:10.2172/6038728.
Menlove, H.O. Sat . "Description and performance characteristics for the neutron Coincidence Collar for the verification of reactor fuel assemblies". United States. doi:10.2172/6038728. https://www.osti.gov/servlets/purl/6038728.
@article{osti_6038728,
title = {Description and performance characteristics for the neutron Coincidence Collar for the verification of reactor fuel assemblies},
author = {Menlove, H.O.},
abstractNote = {An active neutron interrogation method has been developed for the measurement of /sup 235/U content in fresh fuel assemblies. The neutron Coincidence Collar uses neutron interrogation with an AmLi neutron source and coincidence counting the induced fission reaction neutrons from the /sup 235/U. This manual describes the system components, operation, and performance characteristics. Applications of the Coincidence Collar to PWR and BWR types of reactor fuel assemblies are described.},
doi = {10.2172/6038728},
journal = {},
number = ,
volume = ,
place = {United States},
year = {Sat Aug 01 00:00:00 EDT 1981},
month = {Sat Aug 01 00:00:00 EDT 1981}
}

Technical Report:

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  • An active neutron interrogation technique has been developed for the measurement of the /sup 235/U content in fresh fuel assemblies. The method employs an AmLi neutron source to induce fission reactions in the fuel assembly and coincidence counting of the resulting fission reaction neutrons. When no interrogation source is present, the passive neutron coincidence rate gives a measure of the /sup 238/U by the spontaneous fission reactions. The system can be applied to the fissile content determination in fresh fuel assemblies for accountability, criticality control, and safeguards purposes. Field tests have been performed by International Atomic Energy Agency (IAEA) staffmore » using the Coincidence Collar to verify the /sup 235/U content in light-water-reactor fuel assemblies. The results gave an accuracy of 1 to 2% in the active mode (/sup 235/U) and 2 to 3% in the passive mode (/sup 238/U) under field conditions.« less
  • The neutron-coincidence collar has been evaluated for the measurement of pressurized-water reactor (PWR) fuel assemblies at the Fabrica de Elementos Combustiveis plant in Resende, Brazil. This evaluation was part of the cooperative-bilateral-safeguards technical-exchange program between the United States and Brazil. The neutron collar measures the STVU content per unit length of full fuel assemblies using neutron interrogation and coincidence counting. The STYU content is measured in the passive mode without the AmLi neutron-interrogation source. The extended evaluation took place over a period of 6 months with both scanning and single-zone measurements. The results of the tests gave a coincidence-response standardmore » deviation of 0.7% (sigma = 1.49% for mass) for the active case and 2.5% for the passive case in 1000-s measurement times. The length measurement in the scanning mode was accurate to 0.77%. The accuracies of different calibration methods were evaluated and compared.« less
  • The passive neutron Coincidence Collar, which was developed for the verification of plutonium content in fast reactor fuel subassemblies, has been field tested using Prototype Fast Reactor fuel. For passive applications, the system measures the /sup 240/Pu-effective mass from the spontaneous fission rate, and in addition, a self-interrogation technique is used to determine the fissile content in the subassembly. Both the passive and active modes were evaluated at the Windscale Works in the United Kingdom. The results of the tests gave a standard deviation 0.75% for the passive count and 3 to 7% for the active measurement for a 1000-smore » counting time. The unit will be used in the future for the verification of plutonium in fresh fuel assemblies.« less
  • The neutron-coincidence collar is used for the verification of the uranium content in light-water reactor fuel assemblies. An AmLi neutron source is used to give an active interrogation of the fuel assembly to measure the /sup 235/U content, and the /sup 238/U content is verified from a passive neutron-coincidence measurement. This report gives the collar calibration data of pressurized-water reactor and boiling-water reactor fuel assemblies. Calibration curves and correction factors are presented for neutron absorbers (burnable poisons) and different fuel assembly sizes. The data were collected at Exxon Nuclear, Franco-Belge de Fabrication de Combustibles, ASEA-Atom, and other nuclear fuel fabricationmore » facilities.« less
  • The neutron coincidence counter has been field tested and evaluated for the measurement of boiling-water-reactor (BWR) fuel assemblies at the ASEA-ATOM Fuel Fabrication Facility. The system measures the /sup 235/U content per unit length of full fuel assemblies using neutron interrogation and coincidence counting. The /sup 238/U content is measured in the passive mode without the AmLi neutron interrogatioin source. The field tests included both standard production movable fuel rods to investigate enrichment and absorber variations. Results gave a response standard deviation of 0.9% for the active case and 2.1% for the passive case in 1000-s measurement times. 10 figures,more » 2 tables.« less