GB1017992A - Improvements relating to electric safety systems for nuclear reactors - Google Patents

Abstract

1,017,992. Controlling reactors. ENGLISH ELECTRIC CO. Ltd. May 2, 1962 [May 5, 1961], No. 16371/61. Heading G6C. [Also in Division G1] Two groups of relays AA, AB, AC and ZA, ZB, ZC (Fig. 1) having pairs of contacts connected in parallel branches 11a of three D.G. lines 11 are tested by a circuit comprising indicating means which are inductively coupled to said branches, each of the relays being actuated by a transducer (not shown) through an amplifier 10 in response to changes in e.g. pressure or temperature, within a nuclear reactor. Operation of any pair of relays in each group renders lines 11 open-circuit to effect operation of further relays (not shown) controlling the reactor. Each of branches 11a may be inductively coupled to one of six cathode-ray oscilloscopes 31-36 (Fig. 2) by a current transformer 21, each transformer being connected to the corresponding oscilloscope by a separate element in a seven-element switch 22. A separate switch is provided for each relay, and one element 22a thereof when moved to a position 3 connects the amplifier 10 of the relay, e.g. relay AA, to a D.C. source 24 through a potential divider 23 whilst lines 11 are energized with an alternating current by an oscillator 20 through a transformer 28, the output of the oscillator being also connected to the X-plates of the oscilloscopes through a phase-shifter 27, whereby operation of each pair of contacts, e.g. contacts AA-1, AA-2, in the relay undergoing the test is indicated simultaneously by the six oscilloscopes. Alternatively, each branch 11a may be inductively coupled to a moving-coil meter 41 (Fig. 3, not shown) by a pair of saturable reactors 40 in a known manner.