1 Scope
NB/T 20003 specifies the non-destructive testing method, quality classification of testing results and recommendatory acceptance criteria of mechanical components in nuclear island of nuclear power plants.
This part of NB/T 20003 specifies technical requirements and acceptance criteria with mechanical components in nuclear island of nuclear power plants tested by X-ray and γ-ray.
This part is applicable to radiographic testing of castings and welded joints in mechanical components in nuclear island of nuclear power plants when in manufacture and assembly processes.
2 Normative References
The following referenced documents are indispensable for the application 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.
GBZ 117 Radiological Protection Standards for Industrial X-ray Detection
GBZ 132 Radiological Protection Standards for Industrial Ganna-radiography
GB 11533 Standard for Logarithmic Visual Acuity Charts
GB/T 12604.2 Terminology for Nondestructive Testing Radiographic Testing
GB 18871 Basic Standards for Protection against Lonizing Radiation and for the Safety of Radiation Sources
JB/T 7902 Non-destructive Testing-Image Quality Indicators (Wire Type) for Radiographic Testing
JB/T 7903 Industrial Radiographic Illuminators
NB/T 20003.1 Non-destructive Testing for Mechanical Components in Nuclear Island of Nuclear Power Plants - Part 1: General Requirements
ASTM E186 Standard Reference Radiographs for Heavy-walled (2 to 41/2-in.[51 to 114-m m]) Steel Castings
ASTM E192 Standard Reference Radiographs for Investment Steel Castings for Aerospace Applications
ASTM E280 Standard Reference Radiographs for Heavy-walled (41/2 to 12-in.[114 to 305-mm]) Steel Castings
ASTM E446 Standard Reference Radiographs for Steel Casting up to 2 in.[51mm] in Thickness
3 Terms and Definitions
For the purposes of this document, the terms and definitions given in GB/T 12604.2 and NB/T 20003.1 and the following apply.
3.1
penetrated thickness
T
the nominal thickness of material in the direction of radiography, or the sum of nominal thicknesses of each layer of materials in case of multiple-wall radiography
3.2
object-to-film distance
b
the distance between the surface of tested workpiece at the radiographic source side and the film measured along the central axis of the radiation beam
3.3
source-to-object distance
f
the distance between the radiographic source and the surface of tested workpiece at the radiographic source side measured along the central axis of the radiation beam
3.4
source-to-film distance
F
the distance between the radiographic source and the film measured along the central axis of the radiation beam
3.5
source size
d
the effective focal spot size of radioactive isotope source or X-ray tube
3.6
rounded defect
Foreword i
1 Scope
2 Normative References
3 Terms and Definitions
4 General Requirements
4.1 Testing Personnel
4.2 Testing Documentation
4.3 Reference Negative Film
4.4 Testing Range
4.5 Radiation Protection
5 Equipment and Apparatus
5.1 Radiographic Source
5.2 Film System
5.3 Densitometer and Standard Density Strip
5.4 Film Viewing Illuminator
6 Testing Conditions
6.1 Surface Preparation
6.2 Selection of Ray Energy
6.3 Geometric Unsharpness
6.4 Ratio of Max. and Min. Penetrated Thickness
7 Testing Technology
7.1 Radiography Arrangement
7.2 Image Quality Indicator(IQI)
7.3 Cassette Composition
7.4 Filter
7.5 Masking Board and Protection against Scattered Rays
7.6 Mark
8 Darkroom Processing of Film
9 Film Evaluation Requirements
10 Quality of Negative Film
10.1 Negative Film Mark
10.2 Pseudo-flaw of Negative Film
10.3 Density of Negative Film
10.4 Image Quality of Negative Film
11 Radiographic Testing of Castings
11.1 General Requirements
11.2 Timing of Testing
11.3 Testing Range
11.4 Surface Cleaning
11.5 Type of Film
11.6 Filter
11.7 Radiography Mode and Negative Film Evaluation
11.8 Image Quality Indicator (IQI)
11.9 Radiographing of Rough Castings
11.10 Protection against Occultation and Limb Scattering
11.11 Small-diameter Pumps and Valves
11.12 Radiographing Area
11.13 Testing of Repair Welded Areas
11.14 Acceptance Criteria
12 Radiographic Testing of Welded Joints
12.1 General Requirements
12.2 Timing of Testing
12.3 Testing Area
12.4 Surface Preparation
12.5 Type of Film
12.6 Radiography Mode
12.7 Image Quality Indicator
12.8 Special Conditions
12.9 Marking of Tested Area
12.10 Testing of Repair Area
12.11 Acceptance Criteria
13 Test Report
Annex A (Normative) Characteristic Indexes of Industrial Radiographic Film System
Annex B (Normative) Calculation of Effective Focus Size of Radiographic Source
Annex C (Informative) Schematic Diagrams for Typical Radiography Modes of Welded Joints
Annex D (Informative) Method for Determining the Minimum Radiography Times of Circumferential Butt Welded Joints
Annex E (Normative) Placement Position of Overlapping Marks
Annex F (Informative) Manual Processing of the Film
Annex G (Informative) Radiographing Area Denotation of Casting
Annex H (Normative) Radiography Mode for Full Penetration Corner Joints
Annex I (Normative) Special Image Quality Indicator
