IEC 62117:1999 pdf download – Nuclear reactor instrumentation – Pressurized light water reactors (PWR)-Monitoring adequate cooling within the coreduring cold shutdown

IEC 62117:1999 pdf download – Nuclear reactor instrumentation – Pressurized light water reactors (PWR)-Monitoring adequate cooling within the coreduring cold shutdown.
IEC 62117 applies to pressurized water reactors (PWRs) with configurations similar to those shown in figures 1 and 2 and presents requirements for the monitoring of adequate cooling within the core during cold shutdown operations.
Adequate core cooling can be achieved oniy by providing sufficient coolant flow to the core to remove the heat. During cold shutdown operations, core cooling is provided by forced circulation with the residual heat removal system (RHRS), However, in certain shutdown operations when water level in the reactor pressure vessel (RPV) is reduced for maintenance operations, forced circulation may be interrupted, and the core may become overheated.
It is important that plant operators have reliable information to confirm that the temperature and flow of coolant circulated through the RPV is adequate to remove heat from the core. This information Includes a reliable measurement of water level In the RPV outlet plp4ng used for circulating the flow from the core to the RHRS. as well as measurements of temperature and 110w of the coolant. An unreliable measurement of water level can result in interruption of coolant flow and overheating of the core, an event that has occurred at several PWRs. Annex A. which describes some of these events, identifies conditions which should be considered In the design of core cooling monitoring Instrumentation.
Good international practices to be used when designing now or upgrading existing PWR core cooling monitors are summarized in this standard.
Requirements are given in this standard for instrumentation to monitor core cooling for sale operation of PWRs during cold shutdown operations when the coolant temperature is below 100 C (212 9. Requirements for core cooling monitoring during conditions beyond a design basis accident (DBA), which could be a specific national requirement or consideration, are not covered in this standard.
The core cooling monitoring instrumentation for cold shutdown functions when the reactor coolant system (RCS) is configured for cold shutdown maintenance or refuelling. The circumstances under which these measurement systems need to function are described in this standard. Descriptions of diverse measuring principles and suitable devces are given together with requirements for the following:
— operational conditions;
— inslallation:
— operator displays:
— testing, calibration and maintenance:
— equipment qualification:
— documentation.
Typical applications in operating power plants are also presented.
2 Normative references
The following normative documents contain provisions which, through reference in this text, constitute provisions of this International Standard. For dated references, subsequent amendments to, or revisions of, any of these publications do not apply. However, parties to agreements based on this International Standard are encouraged to investigate the possibility of applying the most recent editions of the normative documents indicated below. For undated references, the latest edition of the normative document referred to applies. Members of lC and ISO maintain regIsters of currently valid International Standards.
IEC 60050(393)1996. Inreinational Electrolechnical Vocabulary (1EV) — Chaptei 393: Nuclear instrumentation: Physical phenomena and basic concepts
lEG 60737:1982, In-core temperature or primary envelope temperature measurements in nuclear power reactors — Characteristics and test methods
lEG 60770-1:1999, Transmitters for use in industrial-process control systems — Part 1: Methods for performance evaluation
lEG 60780:1998. Nuclear power plants – Electrical equipment 01 the safety system — Qualification
IEC 60880:1986, Software for computers in the safety systems of nuclear power stations
lEG 60911:1987, Measurements for monitoring adequate cooling within the core of pressurized light water reactors
lEG 60964:1989, Design for control rooms 01 nuclear power plants
lEG 60980:1989. Recommended practices for seismic qualification ol electrical equipment of the safety system for nuclear generating si ations
IEC 60987:1989, Programmed digital computers important to safety for nuclear power stations
IEC 61225:1993, Nuclear power plants — Instrumentation and control systems important for safety — Requirements for electrical supplies
IEC 61226:1993, Nuclear power plants — Instrumentation and control systems important for safety — Classification
IEC 61227:1993, Nuclear power plants — Control rooms — Operator controls
IEC 61343:1996. Nuclear reactor instrumentation — Boiling light water reactors (BWR) — Measurements in the reactor vessel for monitoring adequate cooling within the core
IAEA Safety Guide 50•SG•D8:1984. Safety related instrumentation and control systems for nuclear power plants.