Apparatus for and method of monitoring for breached fuel elements

Patent · Tue Nov 15 04:00:00 EST 1983

OSTI ID:5347482

Gross, K C; Strain, R V

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 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 bestfit 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.

• Assignee: Dept. of Energy
• Patent Number(s): US 4415524
• OSTI ID: 5347482
• Country of Publication: United States
• Language: English

Related Subjects

22 GENERAL STUDIES OF NUCLEAR REACTORS
220300* -- Nuclear Reactor Technology-- Fuel Elements
BARYONS
CLADDING
COOLANTS
DELAYED NEUTRONS
DEPOSITION
DETECTION
ELEMENTARY PARTICLES
FERMIONS
FISSION NEUTRONS
FUEL ELEMENTS
HADRONS
MONITORING
NEUTRONS
NUCLEAR FACILITIES
NUCLEAR POWER PLANTS
NUCLEONS
POWER PLANTS
REACTOR COMPONENTS
SURFACE COATING
THERMAL POWER PLANTS