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Title: Nuclear reactor with internal thimble-type delayed neutron detection system

Abstract

This invention teaches improved apparatus for the method of detecting a breach in cladded fuel used in a nuclear reactor. The detector apparatus is located in the primary heat exchanger which conveys part of the reactor coolant past at least three separate delayed-neutron detectors mounted in this heat exchanger. The detectors are spaced apart such 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 delay 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 formore » 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];  [3]
  1. (Lemont, IL)
  2. (Downers Grove, IL)
  3. (Wheaton, IL)
Issue Date:
Research Org.:
Argonne National Laboratory (ANL), Argonne, IL
OSTI Identifier:
867442
Patent Number(s):
4938917
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:
nuclear; reactor; internal; thimble-type; delayed; neutron; detection; teaches; improved; apparatus; method; detecting; breach; cladded; fuel; detector; located; primary; heat; exchanger; conveys; coolant; past; separate; delayed-neutron; detectors; mounted; spaced; apart; flow; time; core; differences; activity; function; delay; reaction; carrying; emitter; passes; respective; broken; components; including; isotopic; holdup; required; move; transit; times; loop; 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; daughter isotope; neutron detection; detector apparatus; time required; transit time; time delay; reactor coolant; heat exchange; nuclear reactor; heat exchanger; spaced apart; coolant flow; neutron detector; improved apparatus; primary heat; delay time; reactor operation; transit times; normal reactor; components including; third time; parameter values; delayed neutron; cladded fuel; neutron detectors; flow time; detectors mounted; teaches improved; neutron activity; separate component; /376/

Citation Formats

Gross, Kenny C., Poloncsik, John, and Lambert, John D. B. Nuclear reactor with internal thimble-type delayed neutron detection system. United States: N. p., 1990. Web.
Gross, Kenny C., Poloncsik, John, & Lambert, John D. B. Nuclear reactor with internal thimble-type delayed neutron detection system. United States.
Gross, Kenny C., Poloncsik, John, and Lambert, John D. B. Mon . "Nuclear reactor with internal thimble-type delayed neutron detection system". United States. https://www.osti.gov/servlets/purl/867442.
@article{osti_867442,
title = {Nuclear reactor with internal thimble-type delayed neutron detection system},
author = {Gross, Kenny C. and Poloncsik, John and Lambert, John D. B.},
abstractNote = {This invention teaches improved apparatus for the method of detecting a breach in cladded fuel used in a nuclear reactor. The detector apparatus is located in the primary heat exchanger which conveys part of the reactor coolant past at least three separate delayed-neutron detectors mounted in this heat exchanger. The detectors are spaced apart such 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 delay 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 = {1990},
month = {1}
}

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