GB/T 16702.2-2025Design specification for mechanical components in nuclear island of pressurized water reactor nuclear power plants - Part 2: Class 1 components (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 2 of GB/T 16702 "Design Specification for Mechanical Equipment of Nuclear Island in Pressurized Water Reactor Nuclear Power Plant". The following parts are published.

2.Class 1 equipment;

3.Level 2 equipment;

4.Level 3 equipment;

5.Small equipment;

6.Reactor internals;

7.Equipment support;

8.Low-pressure or atmospheric pressure storage tanks. This document replaces Chapter

1 Scope

GB/T 16702.2-2025 is the Chinese national standard on design specification for mechanical components in nuclear island of pressurized water reactor nuclear power plants - part 2: class 1 components, in the field of energy and heat transfer engineering. The /T suffix marks it as a recommended standard: it is not compulsory by itself, but it becomes binding as soon as a contract, a tender or a customer specification calls it up - which in practice is how most foreign buyers meet it. It was issued on 28 February 2025 by the State Administration for Market Regulation; Standardization Administration of China, and has been in force since 28 February 2025. Classification: ICS 27.120.20, CCS F69.

This document specifies the materials, design, manufacturing, inspection and overpressure protection of Class 1 pressure equipment in the nuclear island mechanical equipment of a pressurized water reactor nuclear power plant. Requirements and corresponding tests are described. This document applies to the design of Class 1 pressure equipment and its components as specified in Chapter 5 of GB/T 16702.1-2025.

2 Normative references

The contents of the following documents constitute the 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 16702.1-2025 Specification for design of mechanical equipment for pressurized water reactor nuclear island Part

3 Level 2 equipment

GB/T 16702.6-2025 Specification for design of mechanical equipment for pressurized water reactor nuclear island Part

5 Level

1 Equipment of GB/T 16702-2019 "Design Specifications for Mechanical Equipment of Nuclear Island in Pressurized Water Reactor Nuclear Power Plants" and Compared with Chapter 5 in GB/T 16702-2019, in addition to structural adjustments and editorial changes, the main technical changes are as follows:

--- Added the boundaries of components and accessories of Level 1 equipment and pipelines (see 4.1);

--- Changed the material standard number; added 1 level of passive residual heat removal heat exchanger, core water tank, main pump external heat exchanger, etc. Equipment and material selection (see Table 1, Table 2 of the.2019 edition);

--- Changed the description of working condition classification (see 6.1.2,

5.3.1.2 of the.2019 edition);

--- Added B-level criteria and T-level criteria (see 6.1.4);

--- Added some typical stress classifications (see 6.2.3.1.7);

--- Changed the stress limits under some working conditions (see 6.2.3,

5.3.2.3 of the.2019 edition);

--- Added design principles for geometric and load discontinuity areas [see 6.3.4.2c)];

--- Increased maintainability (see 6.3.4.3);

--- Added the design of pressure relief valve (see 6.5.7);

--- Changed Table 7 and added the last two columns of materials and their corresponding data (see Table 7, Table 7 of the.2019 edition);

--- Changed the requirements for copper and phosphorus content in the weld metal of the high intensity irradiation zone in the welding procedure qualification of low alloy steel butt welds [see 7.2.3.1a), 5.4.2.3.1a) of the.2019 edition];

6 Reactor internals

GB/T 16702.7-2025 Specification for design of mechanical equipment for pressurized water reactor nuclear island Part

7.Equipment support parts NB/T.20001 Specification for the manufacture of mechanical equipment for nuclear island of pressurized water reactor nuclear power plant NB/T.20002.1 Specification for welding of mechanical equipment in nuclear island of pressurized water reactor nuclear power plant Part

1.General requirements NB/T.20002.2 Specification for welding of mechanical equipment in nuclear island of pressurized water reactor nuclear power plant Part

2.Acceptance of welding filler materials NB/T.20002.3 Specification for welding of mechanical equipment in nuclear island of pressurized water reactor nuclear power plant Part

3.Welding procedure qualification NB/T.20002.4 Specification for welding of mechanical equipment in nuclear island of pressurized water reactor nuclear power plant Part

4.Evaluation of welding filler materials NB/T.20002.5 Specification for welding of mechanical equipment in nuclear island of pressurized water reactor nuclear power plant Part

5.Assessment of manufacturing workshop NB/T.20002.6 Specification for welding of mechanical equipment in nuclear island of pressurized water reactor nuclear power plant Part

6.Product welding NB/T.20002.7 Specification for welding of mechanical equipment in nuclear island of pressurized water reactor nuclear power plant Part

7.Wear resistant cladding NB/T.20003.3 Nondestructive testing of mechanical equipment in nuclear island of nuclear power plant Part

3.Radiographic testing NB/T.20003.4 Nondestructive testing of mechanical equipment in nuclear island of nuclear power plant Part

4.Penetrant testing NB/T.20004 Physical and chemical testing methods for mechanical equipment materials in nuclear islands of nuclear power plants NB/T.20005.1 Carbon steel and low alloy steel for pressurized water reactor nuclear power plants Part

1.Forgings and rolled products for level 1, 2 and 3 equipment NB/T.20005.5 Carbon steel and low alloy steel for pressurized water reactor nuclear power plants Part

5.Grade 1, 2 and 3 pressure-bearing castings NB/T.20005.6 Carbon steel and low alloy steel for pressurized water reactor nuclear power plants Part

6.Reactor coolant pump motor frame castings NB/T.20005.7 Carbon steel and low alloy steel for pressurized water reactor nuclear power plants Part