Monitoring system for a liquid-cooled nuclear fission reactor

Patent · Thu Jan 01 04:00:00 EST 1987

OSTI ID:866171

DeVolpi, Alexander ^[1]

---

1. Bolingbrook, IL

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 the 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.

• Research Organization: Argonne National Laboratory (ANL), Argonne, IL
• DOE Contract Number: W-31109-ENG-38
• Assignee: United States of America as represented by United States (Washington, DC)
• Patent Number(s): US 4649015
• OSTI ID: 866171
• Country of Publication: United States
• Language: English

Related Subjects

/376/976/
5-12
accumulation
adjacent
advise
analysis
approximately
arranged
capture
captured
changes
cladding
collimator
comparative
comparative analysis
condition
control
coolant
cooled nuclear
core
density
detecting
detecting changes
detector
detectors
downcomer
emitting
energy
energy level
excess
failure
fission
fission reactor
fission-product
fuel
fuel-pin
gamma
gamma detector
gamma radiation
gamma-radiation
gas
generates
head
inlet
intensity
interface
isolated
level
levels
limits
liquid
liquid coolant
liquid level
liquid levels
liquid-cooled
means
metal interface
mev
monitoring
neutron
neutron capture
neutrons
neutrons produced
normal
normal condition
nuclear
nuclear fission
nuclear power
outlet
outlet plenum
outside
plenums
plurality
power
power reactor
presence
produced
product gas
provides
radiation
radiation detector
radiation detectors
reaction
reactor
reactor head
reactor vessel
reactor wall
reactor walls
receives
regions
sense
senses
significantly
specific
steel
structures
various
vertically
vessel
viz
walls
water
water coolant
water-cooled
water-cooled nuclear
water-metal