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Title: Monitoring system for a liquid-cooled nuclear fission reactor. [PWR]

Abstract

The invention provides improved means for detecting the water levels in various regions of a water-cooled nuclear power reactor, viz., in the downcomer, in the core, in the inlet and outlet plenums, at the head, and elsewhere; and also for detecting the density of the water in these regions. The invention utilizes a plurality of exterior gamma radiation detectors and a collimator technique operable to sense separate regions of the reactor vessel to give respectively, unique signals for these regions, whereby comparative analysis of these signals can be used to advise of the presence and density of cooling water in the vessel.

Inventors:
Publication Date:
Research Org.:
Argonne National Lab., IL (USA)
OSTI Identifier:
5801537
Application Number:
ON: DE85011638
Assignee:
Dept. of Energy EDB-85-094010
DOE Contract Number:
W-31-109-ENG-38
Resource Type:
Patent
Country of Publication:
United States
Language:
English
Subject:
21 SPECIFIC NUCLEAR REACTORS AND ASSOCIATED PLANTS; 46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND TECHNOLOGY; LEVEL INDICATORS; RADIATION DETECTORS; PRIMARY COOLANT CIRCUITS; PWR TYPE REACTORS; GAMMA RADIATION; REACTOR INTERNALS; COOLING SYSTEMS; ELECTROMAGNETIC RADIATION; ENERGY SYSTEMS; IONIZING RADIATIONS; MEASURING INSTRUMENTS; RADIATIONS; REACTOR COMPONENTS; REACTOR COOLING SYSTEMS; REACTORS; WATER COOLED REACTORS; WATER MODERATED REACTORS; 210200* - Power Reactors, Nonbreeding, Light-Water Moderated, Nonboiling Water Cooled; 440101 - Radiation Instrumentation- General Detectors or Monitors & Radiometric Instruments

Citation Formats

DeVolpi, A. Monitoring system for a liquid-cooled nuclear fission reactor. [PWR]. United States: N. p., 1984. Web.
DeVolpi, A. Monitoring system for a liquid-cooled nuclear fission reactor. [PWR]. United States.
DeVolpi, A. Fri . "Monitoring system for a liquid-cooled nuclear fission reactor. [PWR]". United States. doi:.
@article{osti_5801537,
title = {Monitoring system for a liquid-cooled nuclear fission reactor. [PWR]},
author = {DeVolpi, A.},
abstractNote = {The invention provides improved means for detecting the water levels in various regions of a water-cooled nuclear power reactor, viz., in the downcomer, in the core, in the inlet and outlet plenums, at the head, and elsewhere; and also for detecting the density of the water in these regions. The invention utilizes a plurality of exterior gamma radiation detectors and a collimator technique operable to sense separate regions of the reactor vessel to give respectively, unique signals for these regions, whereby comparative analysis of these signals can be used to advise of the presence and density of cooling water in the vessel.},
doi = {},
journal = {},
number = ,
volume = ,
place = {United States},
year = {Fri Jul 20 00:00:00 EDT 1984},
month = {Fri Jul 20 00:00:00 EDT 1984}
}
  • This patent describes a fission reactor having a pressure vessel, a core in the pressure vessel, means for generating fission reaction heat in the core, and means including a coolant circulating under pressure through the reactor vessel and core for transmitting the heat to outside of the reactor for external conversion to useful work. An improved monitoring means is described for determining the level of the coolant at various regions in the reactor vessel, comprising the combination of gamma radiation detectors; means for positioning the radiation detectors adjacent the reactor vessel on the exterior side thereof. The radiation detectors aremore » vertically spaced apart over the reactor vessel and the detectors are arranged in at least two sets, wherein each set of detectors is oriented radially to span different radially adjacent regions in the reactor to the exclusion primarily of the other sets; means for collimating each of the detectors to admit gamma radiation energy only along a limited substantially straight beam path; and means for detecting changes in the signals of the respective detectors and for apprising the corresponding changes in the level and density of the water proximate thereto.« less
  • A monitoring system for detecting changes in the liquid levels in various regions of a water-cooled nuclear power reactor, viz., in the downcomer, in the core, in the inlet and outlet plenums, at the head, and elsewhere; and also for detecting changes in the density of the liquid in these regions. A plurality of gamma radiation detectors are used, arranged vertically along the outside of the reactor vessel, and collimator means for each detector limits the gamma-radiation it receives as emitting from only isolated regions of the vessel. Excess neutrons produced by the fission reaction will be captured by themore » water coolant, by the steel reactor walls, or by the fuel or control structures in the vessel. Neutron capture by steel generates gamma radiation having an energy level of the order of 5-12 MeV, whereas neutron capture by water provides an energy level of approximately 2.2 MeV, and neutron capture by the fission fuel or its cladding provides an energy level of 1 MeV or less. The intensity of neutron capture thus changes significantly at any water-metal interface. Comparative analysis of adjacent gamma detectors senses changes from the normal condition with liquid coolant present to advise of changes in the presence and/or density of the coolant at these specific regions. The gamma detectors can also sense fission-product gas accumulation at the reactor head to advise of a failure of fuel-pin cladding.« less