GB/T 12789.1-2025Criteria for nuclear reactor instrumentation - Part 1: General principles (English PDF)

Foreword

This document is in accordance with the provisions of GB/T 1.1-2020 "Guidelines for standardization work Part 1: Structure and drafting rules for standardization documents" Drafting.

This document is part 1 of GB/T 12789 "Criteria for nuclear reactor instrumentation". GB/T 12789 has been published in the following parts.

--- Part 1: General principles;

--- Part 2: Pressurized water reactor;

--- Part 3: High temperature gas-cooled reactor;

--- Part 4: Liquid metal cooled fast reactor.

This document replaces GB/T 12789.1-1991 "Nuclear reactor instrumentation standards Part 1: General principles" and is compatible with GB/T 12789.1-Compared with 1991, in addition to structural adjustments and editorial changes, the main technical changes are as follows.

--- Added terms and definitions (see Chapter 3);

--- Changed the content of pulse counting instrument (see 5.3.4, 4.4.4 of the 1991 edition);

--- Changed the content of fuel assembly temperature measurement (see 6.2, 5.3 of the 1991 edition);

--- Changed the content of instrument power source (see Chapter 9, Chapter 8 of the 1991 edition);

--- Changed the content of control facilities (see Chapter 10, Chapter 9 of the 1991 edition);

--- Changed the content of alarm devices (see Chapter 11, Chapter 10 of the 1991 edition).

Introduction

GB/T 12789 "Guidelines for Nuclear Reactor Instrumentation" is intended to consist of four parts.

--- Part 1: General principles. The purpose is to specify the principles necessary for the safe operation of pressurized water reactors, high temperature gas-cooled reactors, and liquid metal-cooled fast reactors.

The required special instruments and general principles of their application.

--- Part 2: Pressurized water reactor. The purpose is to supplement Part 1 and specify the general requirements for pressurized water reactor type instrumentation and its application.

in principle.

--- Part 3: High temperature gas-cooled reactor. The purpose is to supplement Part 1 and specify the instrumentation and General principles for its application.

--- Part 4: Liquid metal cooled fast reactor. The purpose is to supplement Part 1 and specify the fast reactor instrumentation and its application.

General principles.

Nuclear Reactor Instrumentation Guidelines Part 1: General principles

1 Scope

This document specifies the general specifications of the special instruments and their applications necessary for the safe operation of pressurized water reactors, high temperature gas-cooled reactors, and liquid metal-cooled fast reactors.

Requirements, including general requirements, neutron flux rate measurement, temperature measurement, coolant measurement, protection system, instrument power source, control facilities, alarm Requirements for devices, etc.

This document is applicable to the design and implementation of instruments directly related to reactor safety and control, and is used as a reference for other reactor types.

2 Normative references

The contents of the following documents constitute essential clauses of this document through normative references in this document.

For referenced documents without a date, only the version corresponding to that date applies to this document; for referenced documents without a date, the latest version (including all amendments) applies to this document.

GB/T 4960.2 Nuclear Science and Technology Terminology Part 2: Fission Reactor GB/T 4960.6 Nuclear Science and Technology Terminology Part 6: Nuclear Instrumentation GB/T 13284 Nuclear power plant safety system design criteria GB/T 13630-2015 Nuclear power plant control room design

3 Terms and definitions

The terms and definitions defined in GB/T 4960.2 and GB/T 4960.6 apply to this document.

4 General requirements

4.1 The nuclear reactor operator shall be responsible for the safe operation of the reactor, but the reactor instrumentation should be designed to be easy to use throughout the reactor life.

Safe operation under various credible working conditions.

4.2 The instrument design should enable operators to respond promptly to and fully evaluate the physical state and dynamic characteristics of the reactor and provide appropriate alarm to indicate abnormal conditions.

4.3 The safety classification of the instrument is determined by the following factors.

a) the safety functions that the instrument is to perform;

b) the consequences of failure to perform its safety functions;

c) the possibility that the instrument is required to perform a safety function;

d) The time or duration for which the instrument is required to perform a certain safety function after the occurrence of the assumed initiating event.

4.4 Considering the various natures of accidents, the complexity of core performance caused by over-irradiation of the core and the numerical methods used to estimate the impact of accidental events, the mathematical model may introduce unknown errors, and the use of a single parameter measurement generally does not provide adequate protection. Therefore, at least two independent parameters should be measured.

To monitor some kind of accidental event and perform protection, one of the parameters should be measured directly.

4.5 The reactor control system and the reactor safety system should remain independent, and the failure of one system will not cause the malfunction of the other system.