IEC 61505:1998 pdf download – Nuclear reactor instrumentation -Boiling water reactors (BWR)-Stability monitoring

IEC 61505:1998 pdf download – Nuclear reactor instrumentation -Boiling water reactors (BWR)-Stability monitoring.
IEC 61505 applies to boiling water reactors (BWR) designed to ensure that thermal-hydraulic oscillations are either not possible, or can be reliably and readily detected and suppressed. Compliance with the criteria can be demonstrated by:
a) preventing power oscillations;
b) detecting and automatically suppressing power oscillations.
Monitoring of the reactor stability state, which is the object of this standard, can support a) and b) by providing information on plant stability characteristics. Monitoring will detect the approach to, and occurrence of, oscillations.
The purpose of this standard is to
— describe appropriate plant parameters br use in stability monitoring:
— define analysis methods for relating time-varying plant information to reactor stability figures of merit, such as the decay ratio;
— provide technical guidelines regarding stability monitoring functional and performance requirements,
The following items are not covered by this standard:
a) control system instability:
b) recommendations for implementing a particular solution or a combination of solutions:
C) requirements for analytical methods associated with each method;
d) requirements for manual operator and automatic actions necessary to suppress power oscillations or reduce decay ratios:
e) general safety significance of reactor instability.
This standard also does not cover predictor type stability monitors (e.g. frequency domain models which may be used on line to calculate decay ratio tor current reactor conditions).
2 Normative references
The following normative documents contain provisions which, through reference in this text, constitute provisions ol this International Standard. Al the time of publication, the editions indicated were valid. All normative documents are subject to revision, and parties to agreements based on this International Standard are encouraged to investigate the possibility ol applying the most recent editions of the normative documents indicated below. Members of lEG and ISO maintain registers of currently valid International Standards.
IEC 60050(393):1 996, International Electrotechntcal Vocabulary (1EV) — Chapter 393: Nuclear instrumentation: Physical phenomena and basic concepts
IEC 60557:1982, IEC terminology in the nuclear reactor field
lEG 60780:1998, Nuclear power plants — Electrical equ4oment of lIve safely system — Qualification
IEC 60880:1986, Software for computers in the safety systems of nuclear power stations
IEC 60964:1989, Design for control rooms of nuclear power plants
IEC 60980:1989, Recommended practices for seismic qualification of electrical equipment of the safety system for nuclear generating stations
lEG 60987:1989, Programmed digital computers important to safety for nuclear power stations lEG 61000-4,— Electromagnetic compatibility (EUC) — Part 4: Testing and measurement techniques
EC 61226:1993, Nuclear power plants — Instrumentation and control systems important for safety — Classification
IEC 61343:1996, Nuclear reactor instrumentation — Boiling light water reactors (BWR) — Measurements in the reactor vessel for monitoring adequate cooling within the core IAEA Sifety Guide 50-SG-D8:1984. Safety-related instrumentation and control systems fur nuclear power plants
3 Terms and definitions
For the purposes of this International Standard, the following definitions are applicable. For
terms delined elsewhere, the source is given in parentheses
alarms
signals given by annunciators or other display systems to alert the operator to plant and equipment faults and out-of tolerance changes in plant conditions requiring action by the operator (IEC 609641
3.2
boiling water reactor (BWR)
a nuclear steam supply system in which process steam is generated in the reactor vessel
[lEG 613431
3.3
coolant
water andor steam for heat removal from the core IIEC 61343]
3.4
decay ratio
decay ratio (DR) of an oscillating system is defined as the ratio between two consecutive maximal of the system impulse response and gives information about the system stability. An oscillation which decreases In size has a DR ‘ci ,0, while a growing oscillation has a OR >1.0. Decay ratios greater than 1,0 are olten referred to as growth rates.
3.5
manmachlne interlace
interface between operating stall and I&C systems and computer systems linked with plant. The interface includes displays, controls, and the Operator Support System Interlace.