ML19221B068
| ML19221B068 | |
| Person / Time | |
|---|---|
| Issue date: | 03/31/1979 |
| 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 7907120347 | |
| Download: ML19221B068 (5) | |
Text
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o4 U.S. NUCLEAR REGULATORY COMMISSION h.:' Nh)STANDARD REVIEW PLAN
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OFFICE OF NUCLEAR REACTOR REGULATION SECTION 4.5.2 REACTOR INT [RNALS MATERIALS 9fVI[W RESPONSI8Ill! }
Primary - Materials Engineering Branch (MTEB)
Secondary - None I.
AREAS OF RIVIEW General Design Criteria 1 and 14 require that structures, systems, and component, impor-tant to safety shall be designed, f abricated, and tested to quali ty '. tar.dai us comm' nsurate 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 specifications for the materials, including weld materials, to be used for major components of the reactor internals which consist of the core support structures and the iv*ernal structures. For boiling water reactors (BWR's),
these specifications should include materials for shrouds, shroud supports, top guides, fuel support pieces, control rod crive tubes, jet pump assemblies, shroud head and steam separator assembly, and steam dryers. For pressurized water reactors (PWR's), the specifications should include materials for the lower core support
- t. _ Lures, including the core barrel, neutren shield pad assembly, core baffle, lower core plate, and core supports, and materials f or the upper core support struc-tures including the top support 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 thc above applications are reviewed in terms of their mechanical properties, stress corrosion resistance, and fabricability.
2.
Controls nn Welding The review includes the controls on welding of materials used e reactor internals.
3.
Nondestructive Examination of Wrought Seamless Tubular Products and (itting The review includes the information submitted by the applicant on the pondestructive examinations used for inspection of the subject product forms.
USNRC STANDARD REVIEW PLAN
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4.
Austenitic Stainless Steel Austenitic stainless steels, in a variety of product forms, are used 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 sensiti-zation of the material, and to minimize exposure of the stainless steel to contami-nants that could lead to stress-corrosion cracking. The review includes information submitted by the applicant in these areas, as described in SRP 5ection 5.2.3, " Reactor Coolant Pressure Boundary Materials."
Other Materials Materials other than austenitic stainless steels are revieweo in terms of their properties, stress corrosion resistance and fabricability.
II.
ACCEPTANCE CRITERIA The acceptance criteria for the areas of review described in Subsection I of this plen are as follows:
1.
Material Specifications For core support structures and reactor internal structures, the permitted material specifications are those given in tne ASME Boiler and Pressure Vessel Code (hereafter "the Code"),Section III, NG-2121, and Tables 1-1.1 and 1-1.2 of Appendix 1.
These materials are described in detail in the Code,Section II, Parts A, B, and C.
Additional permitted materials are those shown in ASME Code Cases approved for use by Regulatory Guide 1.85, " Code Case Acceptability, ASME Section III Materials."
2.
Controls on Welding The welds of components for core support structures and reactor internals are fabricated in accordance with the Code,Section III, NG-4400, and must meet t..e examination and acceptance criteria shown in NG-5000.
3.
Nordestructive Examination of Wrought Seamless Tubular Products and Fittings Examination shall be in accoedance with the requircments of ASME Code Section III, NG-2550.
The acceptance criteria shall be in accordance with the requirements of ASME Code Section III, NG-5300.
9 1/7 036 Revision 1 4.5.2-2
4.
Austenitic Stainless Steels The acceptance criteria for this area of review are given in Section II.4 of SRP Section 5.2.3, " Reactor Coolant Pressure Boundary Materials."
5.
Other Materials All materials used for reactor internals must be selected for their com W ibility with the reactor coolant, as described in Subarticles NG-2160 and NG-3120 of the Code.
The tempering temperature of martensitic stainless steels and the aging tempera-tur* of precipitation-hardened stainless steels should be specified to provide assu-ance that these materials will not deteriorate in service. Acceptable heat treatment temprratures are aging at 1050 F - 1100 F for Type 17-4 PH and tempering at 1050 F l
fo Type 410 stainless steel.
Other materials shall have similar appropriate heat treat and fabrication controls in accordance with strength and corapatibility requirements.
III. REVIEW PROCEDURES The reviewer will select and emphasize material from the procedures described below, as may be appropriate for a particular case.
For the areas of review described in Subsection I of this plan, the review procedure is as follows:
1.
Material Specifications The list of the materials of construrLion of a components of the reactor internals that are exposed to the reector coolant is reviewed.
The material specifications for each component or part used in the reactor internals are compared with the acceptable specifications listed in the Code, Sections II 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 such materials.
2.
Controls on Welding The information submitted by the applicant i' 'eviewed to provide assurance that
-elding of materials used for components of tne reactor internals is in accordance with the procedures of the Code,Section III, f4G-4400.
The controls on welding, l
discussed in SRP Section 5.2.3, are considered applicable to welding of reactor internals, and information in this area is verified. The reviewer assures that any special welding process or wciding control conforms to the qualification requirements of the Code,Section IX, or that justification is made for any deviation.
3.
Nondestructive Examination of Wrought Seamless Tubular Products The information submitted by the applicant is reviewed to determine methods used for nondestructive examination. The Code,Section III, NG-2550(d) specifies that examina-tion by either radiog-aplic or ultrasonic examination is acceptable.
4.5.?-3 Revision 1
4.
Austenitic Stainless Str?ll The materials and fabrication procedures used for reactor internals are reviewed.
Th areas of review and review procedures follow closely those spellt.1 out in SRP Sec t i c.
5.2.3, " React in* Pressure Boundary Materials." Environment:1 condi-tions must be c_. trol.
a *d s--fing procedures must be such that the probability of s
sensitizatio. and microfis,aring is reduced. In addition, the reviewer verifies that the materia and raactor coolant compositions have been selected to assure compati-bili t; and '
.he fabrication and cleaning controls imposed on stainless steel c.n..ponents are designed to prevent contamination with chloride and fluoride ions.
3.
Other Materials The material specifications and fabrication procedures are reviewed to verify that the heat treatment and welding controls are appropriate for the material. The reviewer verifies that the fabrication and cleaning controls will preclude contami-nation of nickel base alloys by chloride ions, fluoride ions or lead.
6.
Additional Information Request If the information contained in the SAR does not comply with the appropriate accep-tance criteria, or if the information provided is inadequate to establish such compli-ance, the reviewer prepares a request for additional information for transmittal to l
Project Management. 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 information has been provided to satisfy the requirements of the SRP section, and that his evaluation supports conclusions of the following type, to be included in the staf.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 conformance with the requirements of Section III of the ASME Code.
"The materials for reactor internals exposed to the reactor coolant have been identi-fied ano all of the materials are compatible with the expected environment, as proven by extensive testing and satisfactory performance. General corro<. ion 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
.ich could I ud to stress ccrrosion of the materials and loss of component struc-tural integrity.
O Revision 1 4.5.2-4
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"The controls imposed upon components constructed of austenitic stainless steel, as used in the reactor internals, satisfy the recommendations of Regulatory Guide 1.31,
" Control of Ferrite Content in Stainless Steel Weld Metal, and Regulatory Guide 1.44, j
" Control of the Use of Sensitized Stainless Steel."
Material selection, fabrication practices, examination procedures, and protection procedures performed in accordance with these recommendations provide reasonable assurance that the materials 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 requiremerts of General Design Criteria 1 and 14."
V.
REFERENCES 1,
10 CFR Part 50, Appendix A " General Design Criteria for Nuclear Plants."
2.
ASME Boiler and Pressure Vessel Code,Section II, Parts A, B, and C,Section III, and Section IX, American Society of Mechanical Engineers.
3.
Regulatory Guide 1.31, " Control of Ferrite Content in Stainless Steel Weld Metal."
4.
Regulatory Guide 1.44, " Control of the Use of Sensitized Stainless Steel."
5.
SRP Section 5.2.3, " Reactor Coolant Pressure Boundary Materials."
147 039 4.5.2-5 Revision 1