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
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
