NB/T 20001-2023 Manufacturing specifications for nuclear island machinery and equipment in pressurized water reactor nuclear power plants
1 Scope
This document specifies the technical requirements, such as identification and marking, cutting and trimming without repair welding, forming and tolerance, assembly alignment of weldments, expansion joint of heat exchanger tube and tube plate, surface treatment, cleaning, flange bolt connection, heat treatment, test and inspection, preparation, packaging and transportation of welding witness parts and base material witness parts in the fabrication process of mechanical components of PWR nuclear island within the scope specified in GB/T 16702.
This document is applicable to the fabrication and inspection of mechanical components of PWR nuclear island.
2 Normative references
The following documents contain requirements which, through reference in this text, constitute provisions of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies.
GB/T 1031 Geometrical product specifications (GPS) - Surface texture: Profile method - Surface roughness parameters and their values
GB/T 1184 Geometrical tolerancing - Geometrical tolerance for features without individual tolerance indications
GB/T 1239.2-2009 Cold coiled helical springs technical specifications - Part 2: Compressions spring
GB/T 1804 General tolerances - Tolerances for linear and angular dimensions without individual tolerance indications
GB/T 4334 Corrosion of metals and alloys - Test methods for intergranular corrosion of austenitic and ferritic-austenitic (duplex) stainless steels
GB/T 4340.1 Metallic materials - Vickers hardness test - Part 1: Test method
GB/T 4955 Metallic coatings - Measurement of coating thickness - Coulometric method by anodic dissolution
GB/T 4956 Non-magnetic coatings on magnetic substrates - Measurement of coating thickness - Magnetic method (GB/T 4956-2003, ISO 2178:1982, MOD)
GB/T 5270 Metallic coatings on metallic substrates - Electrodeposited and chemically deposited coatings - Review of methods available for testing adhesion (GB/T 5270-2005, ISO 2819:1980, IDT)
GB/T 6462 Metallic and oxide coatings - Measurement of coating thickness - Microscopical method
GB/T 6463 Metallic and other inorganic coatings - Review of methods of measurement of thickness
GB/T 7232 Terminology of metal heat treatment
GB/T 9239.1-2006 Mechanical vibration - Balance quality requirements for rotors in a constant (rigid) state - Part 1: Specification and verification of balance tolerances (ISO 1940-1: 2003, IDT)
GB/T 9239.12 Mechanical vibration - Rotor balancing - Part 12:Procedures and tolerances for rotors with flexible behaviour (ISO 21940-12: 2016, IDT)
GB/T 10125 Corrosion tests in artificial atmospheres - Salt spray tests
GB/T 11354 Determination of nitrided case depth and metallographic microstructure examination for steel and iron parts
GB/T 11376-1997 Phosphate conversion coatings for metals (ISO 9717:1990, EQV)
GB/T 19349 Metallic and other inorganic coatings - Pretreatment of iron or steel to reduce the risk of hydrogen embrittlement
GB/T 29531 Methods of measuring and evaluating vibration of pumps
GB/T 29529 Methods of measuring and evaluating noise of pumps
JB/T 6050 Generalization of hardness test for heat treated iron and steel parts
NB/T 20002
(All parts) Welding code for mechanical components of PWR nuclear islands - Part 1: General requirements
NB/T 20003
(All parts) Non-destructive testing for mechanical components in nuclear island of nuclear power plants
NB/T 20004 Physical and chemical test methods for materials used in nuclear island components of nuclear power plants
NB/T 20008.23 Other material for pressurized water reactor nuclear power plants - Part 23: Ni-base-alloy wires used for CRDM
NB/T 20008.25 Other material for pressurized water reactor nuclear power plants - Part 25: GH4169 alloy wires for reactor vessel internals
NB/T 20133
(All parts) Specifications for protective coatings used in pressurized water reactor nuclear power plants
NB/T 20408 Requirements for packaging, shipping, handling, receiving, storage and maintaining of item for nuclear power plants
3 Terms and definitions
For the purposes of this document, the terms and definitions given in GB/T 16702 and the following apply.
3.1
process fluid
liquid or gas in various systems or equipment of a nuclear power plant
3.2
thermal contraction
contraction deformation process in which pipe fittings or pipe sections are partially heated, and no mechanical means are used during the cooling
3.3
corrosion resistant surface
equipment surface made of corrosion resistant materials such as austenitic stainless steel or nickel-based alloy that are in (no) contact with process fluid
3.4
critical surface
surface subjected to friction (e.g. bearings, pivots, bearing surfaces and sealing contact surfaces) and heat transfer tube surface of heat exchanger
3.5
invisible surface
surface not visible to naked eyes or with the aid of an endoscope, and inner surface of a tube having a nominal diameter of not greater than 150mm during cleanliness inspection
3.6
lixiviation
physical process of dissolving an extracted compound with water, saturated steam or other solvent
3.7
identification
number corresponding to an item or a batch of items, which is used to establish a clear connection between equipment parts and their related documents
3.8
marking
mark indicating the assembly position, welding position and other state information of an item
4 General provisions
This document specifies the basic requirements for the fabrication of mechanical components of PWR nuclear island. The fabrication of mechanical components of PWR nuclear island shall also meet the supplementary requirements of GB/T 16702 and the equipment specifications.
5 Identification and marking
5.1 General requirements
The identification and marking shall meet the following general requirements:
a) the characters of identification and marking shall be legible;
b) the identification and marking shall be made by a method that neither contaminate materials nor cause obvious work hardening or stress concentration;
c) the identification and marking shall be located in areas where the member is least stressed, avoiding stress concentration areas (especially areas of sudden shape change) and heat-affected zones of welded joints;
d) the identification and marking shall not hinder the judgment of nondestructive testing results;
e) the identification and marking removed or erased during processing shall be transplanted or remade;
f) the identification and marking procedures shall be prepared, which shall include the requirements for permanent identification and marking methods, temporary identification and marking methods, restrictions on identification and marking methods, identification and marking content, identification and marking locations as well as identification and marking records.
Foreword i Introduction iv 1 Scope 2 Normative references 3 Terms and definitions 4 General provisions 5 Identification and marking 5.1 General requirements 5.2 Methods 5.3 Position marking 5.4 State marking 5.5 Identification list 6 Cutting and trimming without repair welding 6.1 Cutting 6.2 Trimming without repair welding 7 Forming and tolerance 7.1 Forming 7.2 Tolerance 7.3 Springs 8 Machining 8.1 General requirements 8.2 Process test or evaluation 8.3 Preparation before machining 8.4 Clamping requirements for tools and workpiece 8.5 Machining requirements 8.6 Machining cleanliness control 8.7 Inspection 9 Assembly alignment of weldments 9.1 General requirements 9.2 Assembly alignment tolerances of double-welding joint or single-welded joint accessible from the other side 9.3 Assembly alignment tolerance of welded joints for external welding when inner surfaces are inaccessible 9.4 Assembly alignment tolerance of welded joints of welded heads 9.5 Assembly alignment tolerance of tubes and pipes 9.6 Trimming in case of out of tolerance 10 Welding requirements 11 Expansion joint of heat exchanger tube and tube plate 11.1 General requirements 11.2 Expansion joint 11.3 Inspection 11.4 Rework 12 Surface treatment 12.1 Chrome plating 12.2 Galvanizing 12.3 Nickel plating 12.4 Electrolytic tin plating 12.5 Cadmium plating treatment 12.6 Phosphating treatment 12.7 Electropolishing 12.8 Zinc spraying 12.9 Painting 12.10 Nitriding treatment 12.11 Other metallic coatings or surface treatments 13 Cleaning 13.1 General requirements 13.2 Cleanliness classes, work areas and work zones in nuclear power plant site 13.3 Cleanliness inspection 13.4 Contamination prevention 13.5 Cleaning methods 13.6 Cleanliness maintenance 14 Bolt 14.1 General 14.2 Procedure or process 14.3 Assembly requirements 14.4 Requirements for lubricants 14.5 Requirements for threads 14.6 Requirements for sealing surfaces 14.7 Requirements for assembly tools 14.8 Surface pretreatment of fasteners 15 Heat treatment 15.1 General requirements 15.2 Heat treatment after forming 15.3 Post-weld heat treatment 15.4 Dimensional stabilization treatment 15.5 Bright annealing of austenitic stainless steel parts 15.6 Anti-dent control requirements for heat transfer tube of steam generator 16 Test and inspection 16.1 Application scope 16.2 Hydrostatic test of vessel (cavity) 16.3 Air pressure test of vessel (cavity) 16.4 Special circumstances of vessel (cavity) pressure test 16.5 Valve test 16.6 Pump tests 16.7 Steam generator wanding testing and rodding testing 16.8 Nondestructive testing 16.9 Dimension and geometric tolerance testing 17 Packaging, storage and transportation 18 Product welding witness parts and archived materials 18.1 Product welding witness parts 18.2 Archived materials Annex A (Normative) Evaluation of forming process A.1 Evaluation of bending process for heat transfer tubes of Stage 2 and 3 heat exchangers A.2 Evaluation of forming processes other than bending process for heat transfer tubes of heat exchangers Annex B (Normative) Process evaluation for expansion joint of heat exchanger tube and tube plate B.1 Preliminary test B.2 Process evaluation Annex C (Normative) Cleanliness inspection C.1 Description C.2 Visible surface C.3 Invisible surface Annex D (Normative) Water quality
