NB/T 20002 Welding rules for mechanical components of PWR nuclear islands consists of the following seven parts:
——Part 1: General requirements;
——Part 2: Acceptance for welding filler materials;
——Part 3: Welding procedure qualification;
——Part 4: Qualification of filler materials;
——Part 5: Technical qualification for production workshops;
——Part 6: Production welds;
——Part 7: Hardfacing.
This part is the sixth part of NB/T 20002.
Welding rules for mechanical components of PWR nuclear islands - Part 6: Production welds
1 Scope
This part specifies the preparation of surface to be welded, usage of welding filler materials, the welding methods used in product welding and repair welding, final processing of product welding seam and repair welding seam, relevant heat treatment (preheating, post-heating, stress relief heat treatment) and nondestructive testing, implementation of product weld test coupon and other welding operations in the manufacturing and installation of mechanical components of pressurized water reactor nuclear islands.
This part is applicable to product welding and inspection on mechanical components of pressurized water reactor nuclear power nuclear island (PWR nuclear island).
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.
GB/T 3375 Welding terminology
GB/T 5185 Welding and allied processes - Nomenclature of processes and reference numbers (GB/T5185-2005, ISO 4063:1998, IDT)
GB/T 16702-1996 Design rules for mechanical components of PWR nuclear islands
GB/T 19866 Specification and qualification of welding procedures for metallic materials - General rules (GB/T 19866-2005, ISO 15607:2003, IDT)
NB/T 20001 Fabrication rules for mechanical components of nuclear power plant nuclear island
NB/T 20002.1 Welding code for mechanical components of PWR nuclear islands - Part 1: General requirements
NB/T 20002.2 Welding code for mechanical components of PWR nuclear islands - Part 2: Acceptance for welding filler materials;
NB/T 20002.3 Welding code for mechanical components of PWR nuclear islands - Part 3: Welding procedure qualification
NB/T 20002.4 Welding code for mechanical components of PWR nuclear islands - Part 4: Qualification of filler materials
NB/T 20002.5 Welding code for mechanical components of PWR nuclear islands - Part 5: Technical qualification for production workshops
NB/T 20003 Non-destructive testing for mechanical components in nuclear island of nuclear power plants
NB/T 20004 Physical and chemical test methods for material used in nuclear island mechanical components of nuclear power plants
For the purpose of this part, the terms and definitions given in GB/T 3375, GB/T 5185, and GB/T 19866 apply.
4 Documentation requirements
All welding and related operations shall be carried out in accordance with the technical requirements specified in the official documents. These documents shall at least include the following contents:
a) Welding procedure specification (WPS);
b) Operating instructions for welders, welding operators and others in workshops;
c) Record sheet of product welding process.
5 Storage and use of welding materials
5.1 Storage conditions
The welding materials shall be stored in an enclosed dry place, heated if necessary.
The Manufacturer is responsible for fixing the minimum temperature and the maximum relative humidity required (Referring to the specific requirements of the welding material supplier on welding materials storage).
5.1.1 Entry into storage
Each package of acceptance-tested materials shall be adequately identified (e.g. with a stamp) on entry in storage. By "Package" is meant: the package of electrodes (or a larger package containing several individually packaged units) a coil or spool or bundle of wire, sack or container of flux.
Materials acceptance-tested after entry into store shall be identified following each acceptance-testing.
5.1.2 Storage period
If the same place is used for the storage of acceptance-tested products and those awaiting acceptance-testing or other materials, a physical separation shall be made between these products.
During storage, products shall remain in their original intact package. Welding electrodes shall be kept from coating damage during handling.
Any product which has deteriorated or whose identity has been lost shall be discarded.
5.1.3 Storage control
The department in charge of stock control of acceptance-tested products shall check the following details of the products of each lot / batch or with same heat number:
——Designation;
——Dimensions;
——Acceptance-tested quantity taken into store;
——Date of acceptance test;
——Where applicable, the expiry date;
——Lot number of the associated product (e.g. wire flux couple);
——Date of removal from store;
——Quantity removed; and
——Reference of the stored release document or note of materials discarded.
5.1.4 Release from store
Products shall only be released from store upon presentation to the storeman of a document which shall contain at least the following information:
——Designation;
Foreword i 1 Scope 2 Normative references 3 Terms and definitions 4 Documentation requirements 5 Storage and use of welding materials 6 Preparation and testing of bevels and surfaces for welding 7 Execution on production welds 8 Weld Related Heat Treatments 9 Repair by welding 10 Non-destructive testing on production welds 11 Production weld test coupons
