Regulatory Guide 3.27
| ML003739364 | |
| Person / Time | |
|---|---|
| Issue date: | 05/31/1977 |
| From: | Office of Nuclear Regulatory Research |
| To: | |
| References | |
| RG-3.27 Rev 1 | |
| Download: ML003739364 (5) | |
Revision I
May 1977 U.S. NUCLEAR REGULATORY COMMISSION
REGULATORY GUIDE
OFFICE OF STANDARDS DEVELOPMENT
REGULATORY GUIDE 3.27 LINERS
NONDESTRUCTIVE EXAMINATION OF WELDS IN THEPLANTS
OF CONCRETE BARRIERS IN FUEL REPROCESSING
evaluation of fuel reprocessing plants, through
A. INTRODUCTION
thickness cracks in these liners are unacceptable. Sur face cracks and other weld defects that can hold up Section 50.34, "Contents of Applications; radioactive solutions or particulates may complicate Technical Information," of 10 CFR Part 50, "Licens decontamination of the liners for decommissioning ing of Production and Utilization Facilities," re or when direct repair, maintenance, or inspection of quires, among other things, that each application for the liner or of other components within the liner must a construction permit or operating license for a fuel be made. They can also cause leakage of the liner by reprocessing plant include a discussion of how the ap initiating accelerated crevice corrosion by either the plicable requirements of Appendix B, "Quality As operation or decontamination environment. These surance Criteria for Nuclear Power Plants and Fuel surface cracks and weld defects, therefore, should be Reprocessing Plants," to 10 CFR Part 50 will be avoided.
satisfied. As used in Appendix B, "quality assurance"
comprises all those planned and systematic actions The leaktight integrity. of confinement barrier necessary to provide adequate confidence that safety liners should be confirmed by examination. Many ac related structures, systems, and components will per ceptable nondestructive testing methods and form satisfactorily in service. Appendix B requires, in procedures are available and have been used for the part, that measures be established to ensure that nondestructive examination of liner welds. These special processes, including welding, heat treating, practices have differed significantly because there has and nondestructive testing, be controlled and ac not been sufficient guidance toward standardization.
complished by qualified personnel using qualified This guide standardizes procedures acceptable to the procedures. NRC staff for the nondestructive examination of liner welds. These procedures, which draw on those The leaktight integrity of metal liners of concrete used for nuclear power plants, will provide a uniform confinement barriers is an important consideration in quality level consistent with the safety function of safety evaluations. The methods described in this confinement barrier liners in fuel reprocessing plants.
guide are the most recent general approaches accep
C. REGULATORY POSITION
table to the NRC staff for handling the problem and reflect the results of staff review and action on The following criteria delineate the latest general specific cases. If new information that may be approaches acceptable to the NRC staff. An appli developed in the future results in alternative methods, cant who desires to use an alternative method based such methods will be reviewed by the staff to deter upon newly developed information may do so after mine their acceptabilitv. the NRC staff reviews the proposal and if it approves the method as acceptable for use.
B. DISCUSSION
Welds in the metal liners of concrete confinement Metal liners of confinement systems in fuel barriers in fuel reprocessing plants should be non reprocessing plants keep radiochemicals from con destructively examined using the following methods:
taminating the environs. Because their Icaktight in tegrity is an important consideration in the safety 1. Nondestructive Examination Methods for Liner Seam Welds
- Lines indicate substantive changes from previous issue.
Regu of the Commission. US. NuclearService Comments should be sent to the Secretary USNRC REGULATORY GUIDES latory Commission, Washington, D.C. 20555, Attention:
DOcketing and to the public methods Branch.
Regulatory Guides are issued to describe and make available parts of the Commission's acceptable to the NRC staff of implementing specific The guides ure Issued In the following ten broad divisions:
in evaluating specific problems regulations, to delineate techniques used by the staff .. r Regulatory Guides or postulated accidents, or to provide guidance to applicants. . Power Reactors G. Products with them Is not required.
are not substitutes for regulations, and compnance 2. Researchand Test Reactors 7. o rtation guides will be accept- Methods and solutions different from those set out in the 34 Fuel ae and i ties 8. AtionalRealth or continuance able If they provide a basis for the findings requisite to the Issuance
5. Materials and Plant Protection 10. General of a permit or license by the Commission.
Requests for single copies of Issued guides (which may be reproduced) or for place Comments end suggestions for Iprovements in these guides ae encouraged at all manson en automatic distribution lis for single copies of future guides In specific comments and times, and gulideswill be revised, as appropriate, to accommodate divisions should be made in writing to the US. Nuclear Regulatory Commission.
as a result of to reflect now information or experience. This guide was revised staff review. Washington, D.C. 20655. Attention: Director. Division of Document Control.
the public and additional substantive comments received from i I
a. For each welder and welding (flat, vertical, horizontal, and overhead), theposition first 10
liners and frames for airlocks and access openings, feet of weld and a minimum of one spot (not less than should be fully examined (1) in accordance with
12 inches in length) in each additional 50-foot incre regulatory position 2.a above or (2) by the magnetic ment of weld (weld test unit) or fraction thereof particle method for magnetic welds or the liquid should be examined radiographically. penetrant method for nonmagnetic welds.
b. Where radiographic examination of liner c. All welds in bellows-type expansion joints provided seam welds is not feasible or where the weld is located in penetration assemblies should be in an area that will not be accessible after the con tested by the magnetic-particle method for magnetic struction of the confinement barrier, the entire length welds or by the liquid-penetrant method for non-.
of weld should be examined by the ultrasonic method magnetic welds.
or the magnetic-particle method for magnetic welds or by the ultrasonic method or the liquid-penetrant 3. Nondestructive Examination. Procedures and method for nonmagnetic welds. Techniques c. All liner seam welds should be tested for a. Radiographic examination should be leaktightness by the vacuum box method, by the performed in accordance with the techniques and re halogen diode method, or by the helium mass quirements of Articles 1 and 2 of Section V,
spectrometer method (or by other methods of "Nondestructive Examination," of the ASME Code.
equivalent sensitivity).
b. Magnetic-particle examination should itld. Where leak-chase-system channels are be performed in accordance with Articles 1 and 7 of installed over liner welds, channel-to-liner-plate Section V of the ASME Code.
welds should be tested for leaktightness by pressuriz ing the channels to a minimum pressure of 25-psi c. Ultrasonic examination should be per gauge. If any indicated loss of channel test pressure formed in accordance with Articles I and 5 of Section occurs within 2 hours2.314815e-5 days <br />5.555556e-4 hours <br />3.306878e-6 weeks <br />7.61e-7 months <br />, as evidenced by a test gauge V of the ASME Code.
that meets the requirements of NB-6400 of Section III of the American Society of Mechanical Engineers d. Liquid-penetrant examination should be Boiler and Pressure Vessel Code* (ASME Code), the performed in accordance with Articles I and 6 of Sec channel-to-liner welds should be leak tested by one of tion V of the ASME Code.
the methods specified in regulatory position L.c above. e. Leak testing by the vacuum box method should be performed in accordance with Article 1 of
2. Nondestructive Examination Methods for. Section V of the ASME Code and Appendix A to this Penetration, Airlock, and Access Opening Welds guide. Leak testing by the halogen diode method should be performed in accordance with Articles 1 a. All welds in penetrations, airlocks, and and 10 of Section V of the ASME Code. Leak testing access openings that are not backed by concrete, such by the helium mass spectrometer method should be as welds between penetrations and flued fittings and performed in accordance with Articles I and 10 of the between flued fittings and pipelines, should be fully Section V of the ASME Code.
examined in accordance with the examination methods of NE-5200 of Section III of the ASME 4. Qualifications of Nondestructive Examina Code. Procedures and techniques that should be used tion Personnel for these examination methods are given in regulatory position 3 of this guide. Nondestructive examination should be per formed by personnel designated by the licensee or his b. All welds in the vicinity of penetrations, agent and qualified in accordance with the provisions airlocks, and access openings that are backed by con of Article 1, and other applicable articles for the par crete, such as welds between penetration and rein ticular test method used, of Section V of the ASME
forcing plate," penetration and liner, reinforcing Code.
plate and liner, liner insert and liner, reinforcing plate and frames for airlocks and access openings, and
5. Selection of Spots for Radiographic Ex
- American Society of Mechanical Engineers Boiler and Pressure amination Vessel Code, 1974 Edition including the 1975 Winter Addenda.All references to the ASME Code are to the 1974 Edition including
1975 Winter Addenda. Copies may be obtairlSd from the American the The spots of liner seam welds to be Society of Mechanical Engineers, United Engineering radiographically examined should be randomly Center, 345 East 47th Street, New York, N.Y. 10017. selected, but no two spots in adjacent weld test units
"* Thickened liner insert that provides local reinforcement.
should be closer together than 10 feet. Locations of examined spots should be recorded.
3.27-2
6. Time of Examination The requirements of Section III, Division 2 CC-5000 of the ASME Code should be followed.
,) All examinations should be performed aLS
soon as practicable after completion of the lineal inI 9. Repair and Reexamination crement of weld to be examined. If postweld he4It treatment is required, examinations should be per formed as soon as practicable after the heat treat The requirements of Section III, Division CC-5000 of the ASME Code should be followed.
21 ment.
7. Postexamination Cleaning 10. Records Following each procedure in which examina Records of radiographs and other non tion materials, remain on the surface, the surfac destructive examinations, including those for should be cleaned in accordance with the require repaired defective welds, should be retained by the ments for the finished liner. licensee in compliance with the provisions of Criterion XVII, "Quality Assurance Records," of
8. Acceptance Standards Appendix B to 10 CFR Part 50.
3.27-3
APPENDIX A
VACUUM BOX EXAMINATION OF LINER SEAM WELDS
I. Scope: This appendix gives the procedure and re prior to application of the bubble-forming solu quirements for examination of welds by the tion.
vacuum box method. Much of the information presented is adapted for this test method from b. Bubble Solution. The bubble-forming solu different parts of Section V of the ASME Code. tion should produce a film that does not break away from the area to be tested, and the bubble
2. Applications; The vacuum box examination formed should not break rapidly due to air dry method allows through-thickness indications ing or low surface tension. The number of bub such as leaks, pores, and the lack of fusion in bles contained in the solution should be welds to be detected. The method does not allow minimized to reduce the problem of dis for quantitative determinations, but the presence criminating between existing bubbles and those of leaks and their positions can be determined. A caused by the test. Ordinary household soap or bubble-forming solution is applied to the weld, detergent should not be permitted as substitutes and a vacuum box with a viewing window is for bubble-testing solutions in which, in princi placed over the area to be tested. The box is ple, a bubble will form when there is leakage pre evacuated, and through-thickness leaks are sent. (The above description is taken from Arti detected by the formation of bubbles on the sur cle 6,Section V, ASME Code.) The test solution face. should be checked every hour with a suitable test leak to verify the bubble formation property of
3. Written Procedure: The vacuum box test ex the solution used.
amination should be performed to detailed writ ten procedures in accordance with Article I of c. Application of Solution: The bubble Section V of the ASME Code and with the ap forming solution is applied to the low-pressure side of the surface to be examined. The entire plicable requirements of this appendix.
test area should be evenly coated by flowing the solution over it. The temperature of the surface
4. Personnel Qualification: Personnel performing to be examined should be in the range of 40' to leak testing by the vacuum box method should be qualified in accordance with the requirements of
100"F. The solution should be applied im mediately before the test, not more than I
K
Article I of Section V of the ASME Code. minute before testing.
5. Procedure: The following procedure should be d. Vacuum Test. A vacuum box containing a used for weld examination by the vacuum box viewing window is placed over the area to be method: tested and evacuated to produce at least 5-psi differential with the atmospheric pressure. The 5 a. Surface Preparation (Adapted from Article psi differential in pressure should be verified by
6,Section V, ASME Code). Satisfactory results the use of a calibrated gauge and maintained for.
are obtained when the surface is in the as-welded a minimum of 20 seconds. Leaks in welds, if pre condition. The surface to be examined should be sent, are detected by formation of bubbles. An free of any dirt, grease, paint, scale, welding flux, overlap of 2 inches should be used for each ad weld spatter, slag, or other material that could ditional examination along the seam weld.
otherwise interfere with the examination or the interpretation of the test results. Cleaning may e. Visual Examination. (T-1032-3 of Article 10,
be accomplished by wire brushing with a Section V, ASME Code). When performing the stainless steel brush or by the use of cleaning visual examination, access to the area to be agents such as detergents, organic solvents, viewed should permit placing the eye within at descaling solutions, and paint removers. Clean least 24 inches of the surface to be examined, at ing solvents should meet the requirements of T an angle of no less than 30 degrees with the sur
630(b) of Article 6 of Section V of the ASME face to be examined. Mirrors may be used to Code. Drying, after cleaning, of the surfaces to improve the angle of vision, and aids such as be examined should be accomplished by normal magnifying lenses may be used to assist examina evaporation or with forced hot air, as ap tions. Natural or artificial lighting may be used propriate. A minimum period of time should be to illuminate the area to be examined. The established and included in the procedure to en lighting in the area to be examined should be a sure that the cleaning solution has evaporated minimum of 350 lux (32.5 footcandles).
K
3.27-4
UNITED STATES
NUCLEAR REGULATORY COMMISSION
WASHINGTON. D. C. 20555 POSTAGE AND FEES PAID
OFFICIAL BUSINESS UNITED STATES NUCLEAR
REGULATORY COMMISSION
PENALTY FOR PRIVATE USE. $300
K
1".