US3654607A - Signal sequencing system - Google Patents

Signal sequencing system Download PDF

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Publication number
US3654607A
US3654607A US798914A US3654607DA US3654607A US 3654607 A US3654607 A US 3654607A US 798914 A US798914 A US 798914A US 3654607D A US3654607D A US 3654607DA US 3654607 A US3654607 A US 3654607A
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Prior art keywords
bank
signals
signal
pulse signal
banks
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Andre Wavre
Dean Santis
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Westinghouse Electric Corp
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Westinghouse Electric Corp
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    • G—PHYSICS
    • G21—NUCLEAR PHYSICS; NUCLEAR ENGINEERING
    • G21C—NUCLEAR REACTORS
    • G21C7/00—Control of nuclear reaction
    • G21C7/36—Control circuits
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E30/00—Energy generation of nuclear origin
    • Y02E30/30—Nuclear fission reactors

Definitions

  • Such an apparatus could be the well known jack mechanism for mov- PP 798,914 ing the respective positions of a plurality of control rods operative with a reactor device.
  • a reversible control signal [52] us Cl. 340/168, 176/22 counter is provided which counts the cumulative number of 511 rm. cI. ..II04 42 steps take," by the M banks- Adjustable demding means [58] Field of Search 176/1933 235/92 PE 92 provide selected signals at predetermined counter states. The 340/147 184 214/18 selected signals are indicative of the incremental steps taken by the first and final group of elements during bank sequencing. Means are provided responsive to the selected signals to [56] References Cited provide sequential bank signals.
  • the disclosure includes FOREIGN PATENTS OR APPLICATIONS means for insuring that the last element moved prior to a change in sequencing direction is the first to be moved in the 226,843 9/1958 Australia ..204/l93.3 Opposite direction when a change of direction is desired Primary Examiner-Eugene G. Botz Attorney-A. T. Stratton, Z. L. Dermer and J. W. Wigert, Jr.
  • FIG.4A I02 2 BANK l BANK 2 STEPS
  • FIG.4B I02 2 BANK l BANK 2 STEPS
  • FIG.4B Pf
  • the present invention relates to a system for providing signals to sequence the position of, in either a forward or reverse direction, a plurality of banks of elements such as reactor control rods, composed of up to N elements per bank.
  • Sequentially inserting or withdrawing a plurality of elements is necessary in a nuclear reactor rod control system.
  • banks of control rods are sequentially inserted or withdrawn in accordance with the desired energy output of the nuclear reactor.
  • the output of the reactor is increased if control rods are positionally withdrawn from the reactor and decreased if the control rods are positionally inserted into the reactor.
  • control rods are arranged in a plurality of banks comprising a number of groups each of which contains one or more rods.
  • one bank of rods will be sequenced, that is, a first bank of rods will be incrementally withdrawn from the reactor, others will be withdrawn if more power is required. It is generally desirable to begin to withdraw other banks before the first bank has been withdrawn its maximum distance.
  • Each rod is moved incrementally by a well known jack mechanism.
  • a well known jack mechanism is disclosed in US. Pat. No. 3,158,766, by E. Frisch. Further, a brief description of the operation of such a jack mechanism is given in patent application Ser. No. 798,912 (Westinghouse Case No. 40,535).
  • each bank is composed of one or more rods or groups of rods
  • each of these rods or groups of rods are incrementally moved in the desired direction, one at a time.
  • the first rod or groups of rods will move first, then the second, then the third, and so forth, until the last rod or groups of rods have been moved that one increment.
  • the direction of the rods it is necessary that the last rod or groups of rods which have been moved prior to the change in direction, be the first to be moved in the opposite direction when the change of direction is called for. This is necessary in order to maintain proper alignment of the rods within the reactor and the desired control over the operation of the reactor.
  • Present nuclear reactors typically utilize two banks of rods and employ an electromechanical control bank sequencing unit.
  • present sequencing units consist of two reversible, three-decade electromechanical counters.
  • the first counter counts the steps taken by the first control bank and the second counter counts steps taken by the second control bank.
  • the first control bank is sequenced.
  • the second control bank is sequenced after the first control bank has taken N incremental steps, and the first control bank is halted after the second control bank has taken N steps.
  • the first control bank is sequenced in a reverse direction, i.e., so as to insert the rods, when the second bank is N steps from the maximum inserted point for the second bank, and the second control bank is halted when the first control bank is N, steps from the point of maximum inserted distance for the first control bank.
  • the purpose of the overlaps of the banks is to provide the desired control over the incremental change in radioactivity within the reactor.
  • a further object of the present invention is to provide an improved sequencing system which is more adaptable for any number of banks of elements or rods.
  • a further object of the present invention is to provide an improved sequencing unit which is operable to provide signals to banks of elements comprising from one to N elements or groups of elements per bank.
  • a single reversible signal counter is provided which is responsive to the cumulative number of position steps taken by the banks.
  • Cumulative step signals are provided by logic means responsive to first and final pulses associated with the first and final rod moved during each incremental step.
  • Adjustable signal decoders are provided which are responsive to predetermined counter state signals according to the points in which each of the banks is to begin and stop sequencing. The adjustable decoders provide signals at these points, which are then sent to a controlled switching circuit which provides sequential bank signals in accordance with the adjustable decoder signals and also in accordance with a signal provided by the logic means indicating the direction and previous directional history of the control rod movement. This signal is important to prevent misalignment among the rods and is provided at times in accordance with the teachings of the present invention.
  • Means are also provided for manually overriding the system and providing an output display indicating the current counter state.
  • FIG. 1 illustrates the relationship between the bank sequencing and power output in a nuclear reactor
  • FIG. 2 illustrates a bank sequencing system in accordance with the present invention
  • FIGS. 3A, 3B and 3C respectively show different rod positions for one bank of rods or groups of rods illustrating the sequential movement of the rods or groups of rods within each control bank.
  • FIGS. 4A and 4B illustrate the relationship between rods or groups of rods within two different banks of elements
  • FIG. 5 illustrates a functional diagram, expressed in Boolean algebra, the logic means shown in FIG. 2 for preventing misalignment between groups within banks;
  • FIG. 6 illustrates a schematic of the controlled switching means.
  • FIG. 1 the horizontal axis of the graph therein corresponds to the cumulative total number of steps taken by all of the M banks within the reactor. Thus, if bank one and bank two both take a step movement, the cumulative total is still only one step. The greater the number of steps taken, the greater the power output of the reactor.
  • the vertical direction indicates the number of steps taken by each bank. At the origin, the output of the nuclear reactor is zero or minimum.
  • bank one rods are withdrawn incrementally as shown. When bank one has traveled S number of steps, bank two begins to be withdrawn and the power output of the reactor will increase further.
  • S bank one sequencing is stopped. At counter state S bank three begins to be withdrawn, at S. bank two is halted, and at S bank four begins. For a system comprising M banks it can be seen that bank M will begin to be withdrawn at counter state an-a.
  • the reverse control rod movement sequence takes place.
  • state S the bank M is stopped.
  • Bank four is halted when counter state reaches S bank two begins to be inserted at 8,, bank three is halted at S bank one begins to be inserted at 8,, and bank two is halted at 8,.
  • FIG. 2 A system for providing the control rod movement sequencing illustrated in FIG. 1 is shown in FIG. 2.
  • Logic means 10 provides two output signals F and R to reversible counter 12, the F signal causing forward count by reversible counter 12, the direction corresponding to a withdrawal of control rods in a nuclear reactor rod control system, and the R signal causing a reverse count by the counter 12, corresponding to insertion of rods in a rod control system.
  • Logic means 10 determines when a bank steps by receiving two input pulses P and P These pulses are associated with movement of the first and final rods or groups of rods within each bank.
  • the P and P signals desirably, are the actual go signals for the first and final rods or groups of rods sequenced within each bank.
  • a system for providing these pulses is disclosed in the above-mentioned copending patent application Ser. No. 798,913, to Wavre (Westinghouse Case No. 40,536).
  • the forward and reverse signals F and R are given in response to a sequencing direction signal provided to the logic means 10 as shown. The timing of these pulses however, is determined in a manner which will be set forth in detail subsequently.
  • Each of a plurality of adjustable decoders 14 is responsive to a particular counter level or state. Each state is selected in accordance with the points at which each of the banks are to begin to be sequenced and halted.
  • a desirable adjustable decoder for providing the aforesaid function is a thumbwheel switch decoder well known in the digital decoding art, which is manually adjustable and which provides an output signal in response to the states of a binary coded decimal counter.
  • Signals S through S are sent to controlled switching means 16. Also inputted to control switching means 16 is a control signal C from logic means 10 and a strobe signal from logic means 10. The strobe signal and the control signal C act to gate signals S through as they are sent through the control switching means. Control signal C relates to the direction in which the banks are being sequenced and plays a very important part in the prevention of rod misalignment. Its function will also be described in more detail subsequently.
  • Controlled switching means 16 comprises a series of binary flip-flops, which when set and reset by the adjustable decoder signals S, through S when the proper strobe and control signal C are present, provide the various bank sequence signals for a plurality of M banks. Details of the aforesaid will be described subsequently.
  • a manual override 18 when actuated by a manual input signal 20, provides a signal to controlled switching means 16, permitting manual operation of the bank sequencing signals. At the same time controlled switching means 16 sends an inhibit signal to the logic means 10 to override its automatic functions.
  • a display unit 22 may provide a visual display of the signal count within the reversible counter 12. If the reversible counter 12 is, for example, a three-decade counter, then the display 22 would also be a three-decade display unit.
  • the output signals forward F and reverse R provided by logic means 10 to the reversible counting means 12, and the control signal C, which is either a binary 1 or a binary 0 are provided according to the following operation rules for logic means 10:
  • FIG. 3 illustrates in FIG. 3A a group of N rod elements all situated at step 102 of bank one, which is also step 102 of counter 12. If the rods in bank one are being inserted into a nuclear reactor, the counting direction of the counter 12 would be reverse. In going from level 102 to 101, first, the N th rod would drop an incremental step, then rod N-l, and so on through rod 1. The counter 12 is decreased one state only after rod 1 is stepped. Thus, the counter goes from state 102 to 101, only when all of the rods are in the position shown in FIG. 3B.
  • This rule is the corollary to Rule 1.
  • the rule prevents an incorrect count in the counter 12 where reverse direction is called for.
  • the controlled switching means 16 must know whether or not the sequencing direction is forward or reverse. If signal S is provided at the counter state 100, controlled switching means 16 will provide a bank two signal if the rods are being withdrawn, i.e., if the sequencing is in the forward direction, but will remove the bank two signal if the rods are being inserted, i.e., if the sequencing is in the reverse direction. Thus, it is imperative that the controlled switching means 16 be provided with information as to the history of the movement direction of the control rod system as well as the now desired movement direction. This is the function of control signal C provided by logic means 10.
  • operation rule 3a is no longer applicable, since misalignment could occur. This may best be illustrated by reference to FIGS. 4A and 4B.
  • FIG. 4A the number of movement steps taken by bank one of control rod elements are shown.
  • Operation rule 3b eliminate the possibility of such a misalignment by delaying the change from 1 to 0 of the control signal C to until after the next P pulse is received, when the last pulse signal received by logic means 10 prior to a change in direction was P It should be noted that this operation rule also covers the situation where the banks are sequenced in the forward direction, are then halted, and then reversed, as well as all other situations where misalignment could occur, when going from forward to reverse.
  • control signal C is changed from 0 to l a. Immediately if the last pulse signal received by logic means 10 was P b. After the next P pulse signal if the last pulse signal received by logic means 10 was P This last operation rule is the corollary to Rule 3. The rule prevents rod misalignment when the sequencing direction changes from reverse to forward.
  • Logic means 10 performs the functions prescribed by the aforesaid rules. Given these operation rules, one skilled in the art of logical digital design readily could, by utilizing suitable logic elements, such as AND, OR and NOT (inversion) gates, construct a logic means 10.
  • FIG. 5 illustrates one suitable configuration for logic means 10, expressed in Boolean algebraic terms, for carrying out the functions required by the aforesaid rules.
  • the logic circuit shown is an asynchronous sequential circuit, since it contains secondary internal signals F and F where:
  • F is defined in functional block 30 and F is defined in functional block 32,
  • DIR is indicative of a forward signal provided to logic means 10
  • f is a feedback signal from the output of function block 30 to the inputs of blocks 30, 32 and 42 after a time delay provided by the time delay 34,
  • f is a feedback signal from the output of function block 32 to the inputs of blocks 32, 38, 40 and 42 after a time delay 36,
  • a bar over a symbol or combination of symbols, or an apostrophe after a combination of symbols within brackets or parenthesis indicates negation, i.e., the absence of such a signal
  • Input signals P P after going through inhibit means'45, and control signal DIR are provided as shown to function blocks 30, 32 and to function block 42 which provides and defines output signal C. Additionally, signal DIR and P,- are provided to function block 38 which provides and defines the output signal F, and signal DIR and P are provided to function block 40 which provides and defines the output signal R.
  • Control signal C and the strobe signal are inputted to gate means 50 to provide forward and reverse signals from contacts 52 and 54 respectively. Since C is either a binary l or 0 signal, the forward signal will be provided when C is a binary l and the reverse signal when C is a binary 0, whenever a strobe pulse is provided.
  • Forward signal output 52 is connected to inputs of AND gates 56, 57, 58, 59, and 61.
  • Reverse signal output 54 is connected to inputs of AND gates 62, 63, 64, 65, 66 and 67.
  • Signal S is provided at inputs to AND gates 57 and 63, S to 56 and 62, S to 59 and 65, S to 58 and 64, S to 61 and 67 and S to 60 and 66.
  • the output from AND gates 62 and 56 are sent to set and reset inputs respectively of a first binary flip-flop 70.
  • the outputs from AND gates 57 and 64 are sent to the set input of a second binary flip-flop 72.
  • the outputs from AND gates 63 and 58 are sent to the reset input of flip-flop 72.
  • the outputs from AND gate 59 and 66 is sent to the set input of a third binary flip-ilop 74.
  • the outputs from AND gates and 60 are sent to the set input of flip-flop
  • the output from AND gates 65 and 60 are sent to the set input of flip-flop 74.
  • the output from AND gates 61 and 67 are sent to the set and reset inputs, respectively, of a fourth flip-flop 76.
  • flip-flop 70 When set, flip-flop 70 provides a bank one output signal, flip-flop 72 a bank two output signal, flip-flop 74 a bank three input signal, and flip-flop 76 a bank four output signal. A reset signal to any of the flip-flops will cause a bank output signal to be stopped.
  • FORWARD DIRECTION Adjustable Decoder Signal Flip-Flop Bank Signal S sets 72 Bank 2-ON S, resets 70 Bank l-OFF S, sets 74 Bank 3-ON S reses 72 Bank 2-OFF S, sets 76 Bank 4ON S resets 74 Bank 3-OFF REVERSE DIRECTION Adjustable Decoder Signal FlipFlop Bank Signal 5, sets 74 Bank 3-ON S resets 76 Bank 4OFF S sets 72 Bank 2-ON S resets 74 Bank 3-0FF S sets 70 Bank l-ON S, resets 72 Bank 2OFF 1.
  • apparatus for providing sequential bank signals corresponding to the banks to be sequenced comprising:
  • signal counter means responsive to cumulative incremental bank changes for counting the same
  • adjustable signal decoding means responsive to predetermined selected states of said signal counter means for providing selected state signals
  • first means responsive to the selected state signals for providing sequential bank signals.
  • Apparatus as in claim 1 including second means responsive to first and final pulse signals provided in accordance with the incremental movement of the first and final elements in each bank, respectively, during each incremental bank movement for providing cumulative incremental bank change signals wherein the last element moved prior to a change in sequencing direction is the first to be moved after the change in direction.
  • control signal is at least either a first or second binary digit.
  • control signal changes from a second binary digit to a first binary digit when a sequencing direction from forward to reverse is called for either immediately, when the change in direction is called for if the last pulse signal received by said second means was a final pulse signal or after the next first pulse signal, if the last pulse signal received by said second means was a first pulse signal.
  • Apparatus as in claim 8 for preventing erroneous counter states wherein said second binary signal is provided in response to each first pulse signal when reverse sequencing is called for and when the last pulse signal provided prior to the first ulse was a last pulse signal.
  • said adjustable signal decoding means provides a predetermined number of selected state signals in accordance with the plurality of M banks of elements.
  • Apparatus as in claim 2 including means for providing an output display of the current state of said reversible counter.
  • apparatus for providing signals to either incrementally withdraw or insert a plurality of banks of control rods within a nuclear reactor comprising:

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  • General Engineering & Computer Science (AREA)
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US798914A 1969-02-13 1969-02-13 Signal sequencing system Expired - Lifetime US3654607A (en)

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JP (1) JPS4819838B1 (fr)
BE (1) BE745780A (fr)
BR (1) BR7016753D0 (fr)
CH (1) CH538149A (fr)
DE (1) DE2005767A1 (fr)
ES (1) ES376206A1 (fr)
FR (1) FR2031408B1 (fr)
GB (1) GB1282224A (fr)
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Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4114138A (en) * 1976-08-23 1978-09-12 Bell Telephone Laboratories, Incorporated Selective calling circuit
US4239595A (en) * 1979-01-11 1980-12-16 Westinghouse Electric Corp. Data system for automatic flux mapping applications
US4551718A (en) * 1983-06-24 1985-11-05 Tetragenics, Inc. Method and apparatus for transmitting status information between remote locations
US5217678A (en) * 1991-07-22 1993-06-08 Hitachi, Ltd. Gang control-rod controlling system and reactor operation method
US5412291A (en) * 1992-10-30 1995-05-02 General Electric Company Reconfigurable appliance electronic control system with automatic model determination, internally restructurable control and flexible programmable test modes
CN114326493A (zh) * 2021-12-20 2022-04-12 广东核电合营有限公司 核电厂信号通道切换控制电路及控制装置

Family Cites Families (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE1244307B (de) * 1964-11-23 1967-07-13 Siemens Ag Verfahren und Anordnung zur Steuerung eines Kernreaktors

Cited By (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4114138A (en) * 1976-08-23 1978-09-12 Bell Telephone Laboratories, Incorporated Selective calling circuit
US4239595A (en) * 1979-01-11 1980-12-16 Westinghouse Electric Corp. Data system for automatic flux mapping applications
US4551718A (en) * 1983-06-24 1985-11-05 Tetragenics, Inc. Method and apparatus for transmitting status information between remote locations
US5217678A (en) * 1991-07-22 1993-06-08 Hitachi, Ltd. Gang control-rod controlling system and reactor operation method
US5412291A (en) * 1992-10-30 1995-05-02 General Electric Company Reconfigurable appliance electronic control system with automatic model determination, internally restructurable control and flexible programmable test modes
CN114326493A (zh) * 2021-12-20 2022-04-12 广东核电合营有限公司 核电厂信号通道切换控制电路及控制装置
CN114326493B (zh) * 2021-12-20 2024-06-07 广东核电合营有限公司 核电厂信号通道切换控制电路及控制装置

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GB1282224A (en) 1972-07-19
BE745780A (fr) 1970-07-16
DE2005767A1 (de) 1970-09-03
NL7002103A (fr) 1970-08-17
JPS4819838B1 (fr) 1973-06-16
FR2031408A1 (fr) 1970-11-20
FR2031408B1 (fr) 1973-07-13
CH538149A (de) 1973-06-15
ES376206A1 (es) 1975-06-16
SE348306B (fr) 1972-08-28
BR7016753D0 (pt) 1973-01-16

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