Reactivity control system

Information shall be provided which demonstrates that the reactivity control mechanisms and their drive system can fulfil their designated safety functions during all foreseeable operating conditions. Only the technical safety functions (such as insertion capability) shall be addressed the reactivity aspects shall be treated in the section on nuclear design, paras A.513 and A.S14 the incorporation of the protection and power regulating systems into the instrumentation is treated in Chapter A.8 (Instrumentation and Control). [Pg.36]

Basic information shall be provided on the design of reactivity control mechanisms and drive systems, including the materials, redundancy and diversity aspects, the anticipated performance characteristics (such as drive speed and insertion time), fail-safe feamres, etc. [Pg.36]

An analysis shall be provided which shows that the reactivity control system will function properly under all operational states of the reactor and that it will maintain its reactor shutdown capability under all foreseeable accident conditions, including failures of the control system itself [Pg.36]

CORE AND REACTOR SYSTEM 3.1. Core and Reactivity Control System... [Pg.160]

The 4S employs a reactivity control system with an annular reflector in place of the control rods and driving mechanisms which traditionally require frequent maintenance service. Reactivity is controlled only by the vertical movement of the annular reflector during plant startup, shutdown and power generation, thus eliminating the necessity for complicated control rod operations. Although this reactivity control method using a reflector has been studied in some projects using this method for the core bum-up phase is a new approach. [Pg.160]

Thus, the inherent core safety against partial movement of the reactivity control system is assured for the 4S core. [Pg.166]

Additionally, the reactivity control system(s) shall be designed, fabricated, and operated such that during insertion of reactivity the reactor thermal power will not exceed acceptable values. [Pg.377]

MaIfunct i ons. The protect i on system sha11 be des i gned to ensure that specified acceptable design limits are not exceeded for any single malfunction of the reactivity control systems. [Pg.16]

Cr.l2 Suppression of reactor power oscillations III Protection and Reactivity Control Systems Cr.29 Protection against anticipated operational occurrences... [Pg.307]

Cr.20 Protection system functions III Protection and Reactivity Control Systems Cr.21 Protection system reliability and testability Cr.22 Protection system independence Cr.23 Protection system failure modes... [Pg.310]

Reactivity Control Systems Protection System Reliability and Testability 21... [Pg.343]

Consideration of the possibility of systematic, nonrandom, concurrent failures of redundant elements in the design of protection systems and reactivity control systems. (See Criteria 22, 24, 26, and 29.)... [Pg.345]

Criterion 20 - Protection system functions. The protection system shall be designed (1) to initiate automatically the operation of appropriate systems including the reactivity control systems, to assure that specified acceptable fuel design limits are not exceeded as a result of anticipated operational occurrences and (2) to sense accident conditions and to initiate the operation of systems and components important to safety. [Pg.348]

Criterion 27 - Combined reactivity control systems capability. The reactivity control systems shall be designed to have a combined capability, in conjtmction with poison addition by the emergency core cooling system, of reliably controlling reactivity changes to assure that under postulated accident conditions and with appropriate margin for stuck rods the capability to cool the core is maintained. [Pg.349]

Criterion 28 - Reactivity limits. The reactivity control systems shall be designed with appropriate limits on the potential amount and rate of reactivity increase to assure that the effects of postulated reactivity accidents can neither (1) result in damage to the reactor coolant pressure boundary greater than limited local 5uelding nor (2) sufficiently disturb the core, its support structures or other reactor pressure vessel internals to impair significantly the capability to cool the core. These postulated reactivity accidents shall include consideration of rod ejection (imless prevented by positive means), rod dropout, steam line rupture, changes in reactor coolant temperatme and pressure, and cold water addition. [Pg.349]

Criterion 29 - Protection against anticipated operational occurrences. The protection and reactivity control systems shall be designed to assure an extremely high probability of accomplishing their safety functions in the event of anticipated operational occurrences. [Pg.349]

On the upper unit of V-392 reactor 121 nozzles are provided for the members of reactivity control system and reactor emergency protection (CPS) in comparison with 61 nozzles in V-320 reactor. This gives a possibility to vary the number and arrangement of CPS members and to optimise each fuel cycle for reaching the best characteristics of the core safety and efficiency. [Pg.146]

In the event that all normal reactivity control systems fail, the negative temperature coefficients of the graphite moderator and fuel (Figures 8 and 9) shut the reactor down well before the integrity of the fuel is threatened. [Pg.98]

The safety analysis should establish the design capabilities and protection system set points to ensure that the fundamental safety functions are always maintained. The design basis events are the basis for the design of the reactivity control systems, the reactor coolant system, the engineered safety features (for example, the emergency core cooling system, the containment system and containment protection... [Pg.44]

Reactivity control system X Reactor scram function RPS, scram valves, hydraulic insertion of control rods (non-safety scram backup via el mech drives), boron mjection system... [Pg.52]

Diverse Reactivity Control System X boron injection, via passive safety injection system... [Pg.74]

The neutron-physical characteristics and the efficiency of the reactivity control system are such that at any moment in the reactor life cycle, cold subcriticality, with no dissolved boron is assured, even in the case of the most effective rod being stuck in its upper position. The liquid absorber injection system is used only in beyond design accidents. [Pg.145]

Reactivity control system X Highly borated reactor pool (m PCRV cavity) scram valve system (4x2 valves)... [Pg.245]

The moderate power density of the core allowed the designers to reduce the content of boric acid in the coolant compared to WER, to dispense with operational control of boric acid concentration at start up and shut down and for power manoeuvres. Slow compensation of reactivity for fuel bumup is provided by ion-exchange filters operating in the leak-tight closed purification and reactivity control system. [Pg.375]

The primary circuit (Fig7.2.2.) includes the reactor coolant flow path and pressurizing system enclosed in the reactor pressure vessel, as well as the purification and boron reactivity control system connected to the reactor when the plant is in operation. [Pg.376]

The purification and boron reactivity control system serves to maintain the required primary coolant quality during operation and for periodic removal of excessive boron (15-20 times for core life) thus compensating the fuel bumup. The system includes a recuperator, cooler, pumps and ion-exchangers. [Pg.376]

Divers Reactivity Control System X Borated water injection by PBIS... [Pg.411]

Diverse Reactivity Control System Yes No negative temperature coefficient Manual emergency boration... [Pg.428]

The core has self-regulating and self-stabilizing features due to the negative temperature, power and void reactivity coefficients. Also, the use of burnable poison reduces the excess reactivity margin to be compensated by the mechanical reactivity control system. [Pg.456]

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