Regulatory Guide 1.71
| ML003740244 | |
| Person / Time | |
|---|---|
| Issue date: | 12/31/1973 |
| From: | Office of Nuclear Regulatory Research |
| To: | |
| References | |
| RG-1.71 | |
| Download: ML003740244 (2) | |
December 1973 U.S. ATOMIC ENERGY COMMISSION
REGULATORY GUIDE
DIRECTORATE OF REGULATORY STANDARDS
REGULATORY GUIDE 1.71 WELDER QUALIFICATION FOR AREAS OF LIMITED ACCESSIBILITY
A. INTRODUCTION
Performance Qualification Section III and Section VIII require adherence to General Design Criterion 1, "Quality Standards and ASME Boiler and Pressure Vessel Code,Section IX,
Records," of Appendix A, "General Design Criteria for "Welding Qualifications." I One of the requirements is Nuclear Power Plants" to 10 CFR Part 50, "Licensing welder qualification for production welds. Review of the of Production and Utilization Facilities," requires that requirements of Section IX for performance structures, systems, and components important to safety qualifications indicates the desirability of supplementary be designed, fabricated, erected, and tested to quality requirements to provide better control of welder standards commensurate with the importance of the technique in the production welding of low-alloy and safety function to be performed. Appendix B, "Quality high-alloy steels. Specifically, the assurance of Assurance Criteria for Nuclear Power Plants and .Fuel satisfactory welds in locations of restricted direct Reprocessing Plants," to 10 CFR Part 50 requires that physical and visual accessibility can be increased measures be established to assure control of materials significantly by qualifying the welder under conditions and of special processes such as welding, and that proper simulating the space limitations under which the actual welder qualifications be performed. Section 50.55a, welds must be made.
"Codes and Standards," of 10 CFR Part 50 requires, in part, that components of the reactor coolant pressure boundary be designed. fabricated, erected, and tested in Experience has shown that a welder qualified to accordance with the requirements of Section III, weld components under normal fabricating conditions
"Nuclear Power Plant Components," of the American may not produce acceptable welds if the accessibility to Society of Mechanical Engineers (ASME) Code or the weld area is restricted. Limited accessibility can equivalent quality standards. This guide describes a occur when component parts are joined or repaired in method acceptable to the Regulatory staff for the final assembly or at the plant site where other implementing these requirements with regard to the adjacent components or structures prevent the welder control of welding for nuclear components. This guide from assuming an advantageous position during the welding operation. This disadvantage is particularly applies to light-water-cooled and gas-cooled reactors.
important in the welding of high-alloy steels and nickel The Advisory Committee on Reactor Safeguards has base alloys because welder technique such as electrode been consulted concerning this guide and has concurred manipulation is an important variable in the welding in the regulatory position. procedure.
B. DISCUSSION
Section IX, paragraph Q-22, specifies conditions for which a welder must requalify, but it lacks specific The American Society of Mechanical Engineers (ASME) Boiler and Pressure Vessel Code, Section 11,
"Nuclear Power Plant Components," and Section VIII, I Copies may be obtained from American Society of Vessels" I specify requirements for Mechanical Engineers, United Engineering Center, 345 East 47th
"Pressure Street, New York, N.Y. 10017.
fabricating Class 1,2, and 3 components.
copies of published guides may be obtained by equest Wcd.ting D. the divisions USAEC REGULATORY GUIDES 2064S.
desired to the US. Atomic Energy Commission, Was.hington.
Attention: Director of Regulatory Standards. Comments aid auggestionl for Gudes eam lagulatorv *
kesd o daslrbe and make avloble to the pulic werencouraged end should be sent to the SacrterseY
staff of Implementing specif icpeats of IIVueUWinte guides c.Atomic Energy Commision. Washington. DC. 20545 amtod acceptable Vothe AEC Regulatory used by h t@f In n l the commission's regulations, to delineate chniques or to provide guidanci to Atention: Chief. Public Proeedings Staff.
oveluting spdcific Problems or postulated accidents.
applisents. Regulatory Guides amenot substitutes for regulations from and compliarcer those et out in The guides e issued In the following ten broad divisions:
with them It notaquired. Methods and solutions different ~
the guieswil be eccnptabla if they proWd a basis the for the findingt requisite to ReactorsS.Pout Commission. 1. Power V.cIsuaowor etlnuenta of apermit or Ilanse by 2. Resarch and Test Reactors
7. Transportation
2. Fuels end Materials Facilities a Occupetlonsl Health
4. Environmental end Siting S. Antitrust Review Published guides will be revised periodially. asappropriate, to accommodate L Materials end Plant Protection 10. General comnwms to rlflect a new Information or experience.
-ference to conditions with visibility. It is general practice inlimited accessibility nuclear ship buildingandto production welds will be made within the specified include requirements for welder accessibility requirements. To assure that the welds will be production welds. This practice requires that to acceptable, the welding process should be audited for of restricted welder accessibility to a production simulated when the clearance is less than conditions weld be correct application of procedure parameters and welder technique.
K1
30 cm (12 inches) in any direction from the joint.
However,
C. REGULATORY POSITION
requalification would not be required for different restricted accessibility conditions unless other essential Weld fabrication and repair for wrought low-alloy elements listed in Section IX are changed.
and high.alloy steels, including nickel base alloys, or Section IX, paragraph Q-3, specifies test positions other materials such as static and centrifugal castings and for groove welds. Positions 2G and SG with bimetallic joints should comply with the fabrication a corner requirements specified in Section II1 2 and Section IX 3 structural enclosure which limits access to within
30 to supplemented by the following:
35 cm (12 to 14 inches) on two sides and overheaa would provide acceptable simulation of welder I. The performance qualification should require accessibility. Evaluation of tests should be in accordance testing of the welder under simulated access conditions with Section IX with at least one test specimen when physical conditions restrict the welder's access representing the least favorable position imposed to a on the production weld to less than 30 to 35 cm (12 welder. to 14 inches) in any direction from the joint.
As an alternative, the structure to be welded, including its actual access limits, may be 2. Requalification is required:
simulated.
From this mockup, one test specimen should be taken a. when significantly different restricted from the weld location representing the least favorable accessibility conditions occur, or position imposed on the welder. The test specimen b. when any of the essential welding variables should be evaluated in accordance with the radiographic requirements of Section IX, paragraphs Q-24(d) listed in Section IX are changed.
and Q-25(3). In addition, the test section should sectioned be 3. Production welding should be monitored for macro examination and hardness and adherence to welding qualification requirements evaluation of the composite weldment with should particular be certified.
attention to the root fusion and weld toe conditions.
Production Welds K
The welding qualification (procedure performance) by itself does not assure and ASME B&PV Code,Section III
that the
- ASME B&PV Code,Section IX
1.71-2