Hivatkozási szám

MSZ IEC 60231D:2010

Dokumentumazonosító

150963

Cím

Az IEC 60231 (1967) negyedik kiegészítése: Atomreaktorok műszerezettségi alapelvei. Nyomott vizesreaktorok műszerezettségi alapelvei

Angol cím

Fourth supplement: to publication 60231 (1967). General principles of nuclear reactor instrumentation. Principles of instrumentation for pressurized water reactors

Alkalmazási terület

This supplement relates to general principles of instrumentation applied to pressurized water reactors (PWR’s) having the following characteristics: a) the pressurized light water coolant serves as moderator and appreciable boiling does not occur in the reactor pressure vessel. Steam to drive the turbine is generated in a heat exchanger; b) fuel and primary coolant enclosed in an envelope (primary envelope) of high integrity which is usually enclosed in a containment structure of high integrity; c) solid ceramic fuel enclosed in metallic cladding; d) fixed fuel/moderator/reflector geometry; e) operational control of reactivity by remotely-actuated mechanisms which move core control components; f) supplementary operational control of reactivity sometimes accomplished by use of fixed-position neutron-absorbing materials and/or by slowly varying concentration of neutron absorbing material dissolved in the moderator. 1.3 General requirements 1.3.4 The parameter of greatest concern is considered to be the fuel cladding temperature. This is not measured directly but inferred from measurements of temperature, pressure and flow of the primary coolant system as well as the magnitude and spatial distribution of the power generation. Confirmation that the power generation and the spatial distribution of power density are within allowable limits is obtained from nuclear and thermal measurements and measurements to verity that the proper control rod pattern, consistent with power level and other reactor conditions, is maintained. Measurements which indicate the presence of a significant unbalance between power generation and power demand may be used to provide secondary protective functions. These measurements include high- and low-primary system coolant volume, usually inferred from the measurement of pressurizer level. In addition, conditions which lead to an unbalance between reactor power generation and power demand may be measured and employed as secondary protective functions. Such conditions may include turbine trip and loss of heat sink (which may be indicated by low-steam generator level or low-feedwater flow). Overpressure of the primary envelope is prevented by actuation of safety valves and/or by reduction of reactor power. A breach in the primary envelope beyond the capability of the water charging system leads to low-primary coolant system pressure, low-pressurizer water level and high-containment pressure. The containment barrier, designed to withstand the pressure, temperature, etc., resulting from a breach in the primary envelope, shall be provided with instrumentation to initiate the protection system to ensure the short- and long-term integrity of the containment following an accident. Although direct measurement of barrier integrity cannot always be achieved, process parameters shall be measured which indicate a condition (a) which by itself would overstress one of the three barriers (fuel cladding, primary envelope and containment) or (b) which if left unbated would result in a condition which would overstress one of the three barriers. By proper selection of measurements related to these two types of conditions, it should be possible, in most abnormal situations, to provide first and second line protective functions for the physical barriers which guard against uncontrolled release of radioactivity. *1.3.5 Most of the functions perfomed by the control system require measurements of the same process parameters as are used for the protection system, in many cases with similar accuracy, speed of response, etc. By minimizing the number of measurements of a particular parameter, the problems associated with physical mounting of the measuring devices (such as obtaining the optimum location, the provision of support structures and ensuring protection against adverse environmental factors) may be reduced. This suggests the use of the same redundant process measurement for both control and safety functions, where this is permissible without violating protection-system requirements. When this is done, the technical and safety reasons should be stated and the design should incorporate the provisions of Sub-clause 5.5 of this standard. *1.3.6 Suitable provisions shall be made to permit demonstration, during initial plant operation, that system performance objectives for safe operation are being met. It may be necessary to install, temporarily or permanently, additional equipment for this purpose. *1.3.7 Detectors which are vital for control and protection and for which no installed spares are provided ahould be installed in a manner that permits replacement without the necessity for removing the core.

ICS

27.120.20 Atomerőművek. Biztonság

Műszaki Bizottság

A szabvány nyelve

angol

Az érvényesség kezdete

2011-01-01

Forrás

idt IEC 60231D:1975

Előd

Utód

Módosítás

Kiegészítő információk

SZK-közlemények

Kapcsolódó európai jogszabály

A szabvány

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