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Title: Apparatus for and method of monitoring for breached fuel elements

Abstract

This invention teaches improved apparatus for the method of detecting a breach in cladded fuel used in a nuclear reactor. The detector apparatus uses a separate bypass loop for conveying part of the reactor coolant away from the core, and at least three separate delayed-neutron detectors mounted proximate this detector loop. The detectors are spaced apart so that the coolant flow time from the core to each detector is different, and these differences are known. The delayed-neutron activity at the detectors is a function of the dealy time after the reaction in the fuel until the coolant carrying the delayed-neutron emitter passes the respective detector. This time delay is broken down into separate components including an isotopic holdup time required for the emitter to move through the fuel from the reaction to the coolant at the breach, and two transit times required for the emitter now in the coolant to flow from the breach to the detector loop and then via the loop to the detector. At least two of these time components are determined during calibrated operation of the reactor. Thereafter during normal reactor operation, repeated comparisons are made by the method of regression approximation of the third timemore » component for the best-fit line correlating measured delayed-neutron activity against activity that is approximated according to specific equations. The equations use these time-delay components and known parameter values of the fuel and of the part and emitting daughter isotopes.« less

Inventors:
 [1];  [2]
  1. (Lemont, IL)
  2. (Woodbridge, IL)
Issue Date:
Research Org.:
Argonne National Laboratory (ANL), Argonne, IL
OSTI Identifier:
864786
Patent Number(s):
4415524
Assignee:
United States of America as represented by United States (Washington, DC) ANL
DOE Contract Number:  
W-31109-ENG-38
Resource Type:
Patent
Country of Publication:
United States
Language:
English
Subject:
apparatus; method; monitoring; breached; fuel; elements; teaches; improved; detecting; breach; cladded; nuclear; reactor; detector; separate; bypass; loop; conveying; coolant; core; delayed-neutron; detectors; mounted; proximate; spaced; apart; flow; time; differences; activity; function; dealy; reaction; carrying; emitter; passes; respective; delay; broken; components; including; isotopic; holdup; required; move; transit; times; via; determined; calibrated; operation; thereafter; normal; repeated; comparisons; regression; approximation; third; component; best-fit; line; correlating; measured; approximated; according; specific; equations; time-delay; parameter; values; emitting; daughter; isotopes; separate components; breached fuel; daughter isotope; detector apparatus; time required; transit time; time delay; reactor coolant; fuel elements; fuel element; nuclear reactor; spaced apart; coolant flow; neutron detector; improved apparatus; reactor operation; transit times; normal reactor; components including; third time; parameter values; cladded fuel; neutron detectors; flow time; detectors mounted; teaches improved; neutron activity; separate component; bypass loop; /376/976/

Citation Formats

Gross, Kenny C., and Strain, Robert V. Apparatus for and method of monitoring for breached fuel elements. United States: N. p., 1983. Web.
Gross, Kenny C., & Strain, Robert V. Apparatus for and method of monitoring for breached fuel elements. United States.
Gross, Kenny C., and Strain, Robert V. Sat . "Apparatus for and method of monitoring for breached fuel elements". United States. https://www.osti.gov/servlets/purl/864786.
@article{osti_864786,
title = {Apparatus for and method of monitoring for breached fuel elements},
author = {Gross, Kenny C. and Strain, Robert V.},
abstractNote = {This invention teaches improved apparatus for the method of detecting a breach in cladded fuel used in a nuclear reactor. The detector apparatus uses a separate bypass loop for conveying part of the reactor coolant away from the core, and at least three separate delayed-neutron detectors mounted proximate this detector loop. The detectors are spaced apart so that the coolant flow time from the core to each detector is different, and these differences are known. The delayed-neutron activity at the detectors is a function of the dealy time after the reaction in the fuel until the coolant carrying the delayed-neutron emitter passes the respective detector. This time delay is broken down into separate components including an isotopic holdup time required for the emitter to move through the fuel from the reaction to the coolant at the breach, and two transit times required for the emitter now in the coolant to flow from the breach to the detector loop and then via the loop to the detector. At least two of these time components are determined during calibrated operation of the reactor. Thereafter during normal reactor operation, repeated comparisons are made by the method of regression approximation of the third time component for the best-fit line correlating measured delayed-neutron activity against activity that is approximated according to specific equations. The equations use these time-delay components and known parameter values of the fuel and of the part and emitting daughter isotopes.},
doi = {},
journal = {},
number = ,
volume = ,
place = {United States},
year = {1983},
month = {1}
}

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