ML20094B693
| ML20094B693 | |
| Person / Time | |
|---|---|
| Issue date: | 11/24/1975 |
| From: | Office of Nuclear Reactor Regulation |
| To: | |
| References | |
| NUREG-75-087, NUREG-75-087-04.5.2, NUREG-75-87, NUREG-75-87-4.5.2, SRP-04.05.02, SRP-4.05.02, NUDOCS 9511010201 | |
| Download: ML20094B693 (6) | |
Text
I NUREG 75/087 p aa
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e,g. U.S. NUCLEAR REGULATORY COMMISSION 1
STANDARD REVIEW PLAN OFFICE OF NUCLEAR REACTOR REGULATION V
SECTION 4.5.2 REACTOR INTERNALS MATERIALS REVIEW RESPONSIBILITIES Primary - Materials Engineering Branch (MTEB)
Secondary - None I.
AREAS OF REVIEW General Design Criteria 1 and 14 require that structures, systems, and components important to safety shall be designed, fabricated, and tested to quality standards coninensurate with the importance of the safety functions to be performed.
The following areas in the applicant's safety analysis report (SAR) relating to reactor internals materials are reviewed:
1.
Material Specifications The review includes the material specifications for austenitic stainless steels, including weld materials, to be used for major components of the reactor internals and core support structures. These specifications should include, for boiling water reactors (BWR's), materials for shrouds, shroud supports, top guides, fuel support pieces, control rod drive tubes, jet pump assemblies. shroud head and steam separator assembly, and steam dryers; or for pressurized water reactors (PWR's), materials for the lower core support structures, including the core barrel, neutron shield pad assembly, core baffle, lower core plate, and core supports, the upper core support structures including the top supoort plate, beam sections, upper core plate, support columns, and guide tube assemblies, and the in-core instrumentation support structure.
The adequacy and suitability of the materials specified for the above applications are reviewed in terms of their mechanical properties, stress-corrosion resistance, and fabricability.
2.
Controls on Welding The review includes the controls on welding of materials used for reactor internals.
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3.
Nondestructive Enamination of Mrought, Seamless Tubular Products and Fittings The review includes tho information submitted by the applicant on the nondestructive examinations used for inspection of the subject product forms.
4.
Austenitic Stainless Steel Quantities of austenitic stainless steels, in a variety of product forms, are used
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for construction of components in the reactor internals. Unstabilized austenitic type stainless steels, which include American Iron and Steel Institute (AISI) Types 304 and 316 are normally used.
Since these compositions are susceptible to stress-corrosion cracking when exposed to certain environmental conditions, process controls must be exercised during all stages of component manufacturing and reactor construction to avoid severe sensitization of the material, and to minimize exposure of the stainless steel to contaminants that could lead to stress-corrosion cracking. The review includes information submitted by the applicant in these areas, as described in Standard Review Plan 5.2.3, " Reactor Coolant Pressure Boundary Materials."
II. ACCEPTANCE CRITERIA The acceptance criteria for the areas of review described in Section I of this plan are as follows:
1.
Material Specifications Permitted material specifications are those shown in the ASME Boiler and Pressure s
Vessel Code (hereafter "the Code")Section III NG-2121, and Tables 1-1.1 and 1-1.2 of Appendix 1.
These meterials are described in detail in the Code,Section II, Parts A, B, and C.
2.
Controls on Welding The welds of components for reactor internals, fabricated in accordance with the Code,Section III, NG-4400,must meet the acceptance criteria shown in NG-5000.
3.
Nondestructive Examination of Wrought Seamless Tubular Products and Fittings The acceptance criteria for eddy-current and ultrasonic examination of wrought seamless tubular products and fittings are given in Regulatory Guide No.1.66, " Nondestructive Examination of Tubular Products."
The acceptance criteria for radiographic examination of such products are given in the Code Section III, NG-5320.
4.
Austenitic Stainless Steels The acceptance criteria for this area of review are given in item II.4 of Standard Review Plan 5.2.3, " Reactor Coolant Pressure Boundary Materials."
III. REVIEW PROCEDURES The reviewer will select and emphasize material from the procedures described below, as may be appropriate for a particular case.
4.5.2-2 11/24/75 T-
For the areas of review described in Section I of this plan, the reviGW procedure is as i
follows:
1.
Material Specifications The list of the materials of construction,of the components of the reactor internals that are exposed to the reactor coolant is reviewed.
The material specifications for each major pressure-retaining component or part used in the reactor coolant boundary are compared with the acceptable specifications listed in the Code, Sections 11 and III, as shown in the acceptance criteria. Any exceptions to the Code materials specifications are clearly identified. The reviewer evaluates the basis for the exceptions, taking into account precedents set in earlier cases, and determines the acceptability of the proposed exceptions, j
2.
Centrols on Welding The infonnation submitted by the applicant is reviewed to provide assurance that welding of materials used for components of the reactor internals is in accordance with the procedures of the Code, Section Ill, NG-4400. The controls on welding of austenttic stainless steels, discussed in Standard Review Plan 5.2.3, are considered applicable to welding of reactor internals, and infonnation in this area is verified.
The reviewer assures that any special welding process or welding control conforms to the qualification requirements of the Code,Section IX, or that justification is made for any deviation.
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3.
Nondestructive Examination of Wrought Seamless Tubular Products The information submitted by the applicant is reviewed to detennine methods used for j
nondestructive examination. The Code Section III, NG-2551(d) specifies that j
exanination by either radiographic or ultrasonic examination is acceptable.
However, Regulatory Guide 1.66, " Nondestructive Examination of Tubular Products" provides new calibration standards and procedures for ultrasonic examination which are considered more sensitive, and more consistently able to detect defects regard-less of shapes or orientation. The reviewer verifies that ultrasonic examinations of the subject product form are specified to be in accordance with this Regulatory Guide.
4.
Austenitic Stainless Steel The materials and fabrication procedures used for reactor internals are reviewed.
The specific area of review and review procedures follow closely those spelled out in Standard Review Plan 5.2.3, " Reactor Coolant Pressure Boundary Materials." Envi ron-mental conditions must be controlled and welding procedures must be such that the probability of sensitization and microfissuring is reduced. In addition, the reviewer verifies that the material and reactor coolant compositions have been selected to assum compatibility, and that the fabrication and cleaning controls imposed on stain-less steel components will minimize contamination with chloride and fluoride ions.
4.5.2-3 11/24/75
5.
Additional Information Request If the infomation containQd in the SAR does not comply with the appropriate acceptance criteria, or if the infomation provided is inadequate to establish such compliance, the reviewer prepares a request for additional infomation for transmittal to Reactor Projects. Such requests not only identify the additional information required, but also specify the changes needed in the SAR or the plant Technical Specifications to meet acceptance criteria. Subsequent amendments received in response to these requests are reviewed for compliance with the acceptance criteria.
IV. EVALUATION FINDINGS The reviewer verifies that sufficient and adequate infomation has been provided to satisfy the requirements of the review plan, and that his ' evaluation supports conclusions of the following type, to be included in the staff's safety evaluation report:
"The materials used for construction of components of the reactor internals have been identified by specification and found to be in confonnance with the require-ments of Section I!! of the ASME Code.
"The materials for reactor internals exposed to the reactor coolant have been identified and all of the materials are compatible with the expected environment, as proven by extensive testing and satisfactory performance. General corrosion on all materials is expected to be negligible.
"The controls imposed on reactor coolant chemistry provide reasonable assurance that the reactor internals will be adequately protected during operation from conditions which could lead to stress corrosion of the materials and loss of component struc-tural integrity.
"The controls imposed upon components constructed of austenitic stainless steel, as used in the reactor internals, satisfy the recommendations of Regulatory Guide No.
1.31 " Control of Sainless Steel Welding," Regulatory Guide No. l.34, " Control of a
Electroslag Weld Properties," Regulatory Guide No.1.44, " Control of ine use of Sensitized Stainless Steel," and Regulatory Guide No.1.66, " Nondestructive Examina-tion of Tubular Products." Material selection, fabrication practices, examination procedures, and protection procedures perfomed in accordance with these reconinenda-tion provide reasonable assurance that the austenitic stainless steel used for reactor internals will be in a metallurgical condition which precludes susceptibility to stress-corrosion cracking during service. Conformance with these Regulatory Guides constitutes an acceptable basis for meeting in part the requirements of General Design Criteria 1 and 14."
V.
REFERENCES 1.
10 CFR Part 50, Appendix A. "Gt9eral Design Criteria for Nuclear Plants."
2.
ASME Boiler and Pressure Vessel C;de Section II, Parts A, B, and C, and Section III, American Society of Mechanical Engineers.
4.5.2-4
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3.
ASTM A-262-70 Practice E. " Copper-Copper Sulfote-Sulfuric Acid Test for Detecting Susceptibility to Intergranular Attack in Stainless Steels " Annual Book of ASTM Standards, Part 3. American Society for Testing and Materials.
I 4
Regulatory Guide 1.37, " Quality Assurance Requirements for Cleaning of Fluid Systems and Associated Components of Water Cooled Nuclear Power Plants."
5.
Regulatory Guide 1.44, " Control of the Use of Sensitized Stainless Steel."
6.
Regulatory Guide 1.66, " Nondestructive Examination of Tubular Products."'
7.
Regulatory Guide 1.71, " Welder Qualification for Limited Accessibility Areas."
8.
Standard Review Plan 5.2.3 and Branch Technical Position - MTEB No. 5-1, " Interim Position on Regulatory Guide 1.31, ' Control of Stainless Steel Welding'," appended to Standard Review Plan 5.2.3.
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