Richard Garfield Simms

US Patent:

42530938, Feb 24, 1981

Filed:

May 15, 1979

Appl. No.:

6/039426

Inventors:

Edward W. Johanson - New Lenox IL
Richard Simms - Westmont IL

Assignee:

The United States of America as represented by the United States
Department of Energy - Washington DC

International Classification:

G08B 2100
G01P 1300
G21C 1702

US Classification:

340606

Abstract:

A scram signal generating circuit for nuclear reactor installations monitors a flow signal representing the flow rate of the liquid sodium coolant which is circulated through the reactor, and initiates reactor shutdown for a rapid variation in the flow signal, indicative of fuel motion. The scram signal generating circuit includes a long-term drift compensation circuit which processes the flow signal and generates an output signal representing the flow rate of the coolant. The output signal remains substantially unchanged for small variations in the flow signal, attributable to long term drift in the flow rate, but a rapid change in the flow signal, indicative of a fast flow variation, causes a corresponding change in the output signal. A comparator circuit compares the output signal with a reference signal, representing a given percentage of the steady state flow rate of the coolant, and generates a scram signal to initiate reactor shutdown when the output signal equals the reference signal.