GB827436A - Improvements in or relating to instrumentation for nuclear reactors - Google Patents

Abstract

827,436. Electric measuring systems. UNITED KINGDOM ATOMIC ENERGY AUTHORITY. March 26, 1959 [Jan. 7, 1958], No. 581/58. Class 40(1). [Also in Group XL (a)] Measuring equipment in a nuclear reactor comprises two elements each sensitive to corelated variables and means for producing an output signal proportional to the ratio of the magnitude of one variable to a function of the magnitude of the other variable. The volume of coolant flowing through the duct 11 into the reactor is measured by an anemometer 16 comprises a platinum wire on a soap-stone former. This is heated so that its resistance balances a resistance 17. In this way it is arranged to simulate the heating of a fuel element, the power derived for heating coming from an amplifier 19 the power output of which is represented across a secondary winding 21. The output from 21 is rectified at 23 and passed to an electronic switch 24. A voltage derived from a neutron flux meter 14 is applied to an electronic switch 26. These switches 24, 26 are closed periodically and the voltage reaching a comparator 28 is compared with a reference voltage K so that when these are equal a switch 30 is momentarily closed. When this switch 30 closes the voltage then reaching it from 26 is passed to an alarm 31 where it is compared with an alarm point signal and if in excess the alarm is operated. Operation of this alarm may shut down the reactor. To prevent false alarms subsidiary alarms such as no-volt alarms on the anemometer and the meter 14 and high- and low-volt alarms on the switches can be included which in turn isolate the alarm 31. Other variables which may be checked include failure of gas circulating through one or more ducts ; mean core temperature; heat transfer properties of the coolant and heat exchanger characteristics.