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| issue date = 03/16/2015 | | issue date = 03/16/2015 | ||
| title = Letter, Exemption from Certain 10 CFR 50.61 and 10 CFR 50, Appendix G Requirements to Allow Use of Alternate Method to Determine Initial Nil Ductility Reference Temperature for Linde 80 Welds | | title = Letter, Exemption from Certain 10 CFR 50.61 and 10 CFR 50, Appendix G Requirements to Allow Use of Alternate Method to Determine Initial Nil Ductility Reference Temperature for Linde 80 Welds | ||
| author name = George A | | author name = George A | ||
| author affiliation = NRC/NRR/DORL/LPLIV-1 | | author affiliation = NRC/NRR/DORL/LPLIV-1 | ||
| addressee name = | | addressee name = | ||
Line 9: | Line 9: | ||
| docket = 05000313 | | docket = 05000313 | ||
| license number = DPR-051 | | license number = DPR-051 | ||
| contact person = George A | | contact person = George A | ||
| case reference number = TAC MF3700 | | case reference number = TAC MF3700 | ||
| document type = Exemption from NRC Requirements, Federal Register Notice, Letter | | document type = Exemption from NRC Requirements, Federal Register Notice, Letter | ||
Line 18: | Line 18: | ||
=Text= | =Text= | ||
{{#Wiki_filter:Vice President, Operations Arkansas Nuclear One Entergy Operations, Inc. 1448 S.R. 333 Russellville, AR 72802 | {{#Wiki_filter:UNITED STATES~:., | ||
NUCLEAR REGULATORY COMMISSION WASHINGTON, D.C. 20555~0001 March 16, 2015 Vice President, Operations Arkansas Nuclear One Entergy Operations, Inc. | |||
1448 S.R. 333 Russellville, AR 72802 | |||
==SUBJECT:== | ==SUBJECT:== | ||
ARKANSAS NUCLEAR ONE, UNIT NO. 1 -EXEMPTION FROM CERTAIN REQUIREMENTS OF 10 CFRPART 50, APPENDIX G AND 10 CFR 50.61, FOR INITIAL NIL DUCTILITY REFERENCE TEMPERATURE FOR LINDE 80 WELDS (TAC NO. MF3700) | ARKANSAS NUCLEAR ONE, UNIT NO. 1 - EXEMPTION FROM CERTAIN REQUIREMENTS OF 10 CFRPART 50, APPENDIX G AND 10 CFR 50.61, FOR INITIAL NIL DUCTILITY REFERENCE TEMPERATURE FOR LINDE 80 WELDS (TAC NO. MF3700) | ||
==Dear Sir or Madam:== | ==Dear Sir or Madam:== | ||
The U.S. Nuclear Regulatory Commission has approved the enclosed exemption from certain requirements of Title 10 of the Code of Federal Regulations (10 CFR), Part 50, Appendix G and 10 CFR 50.61, for Arkansas Nuclear One, Unit 1 (AN0-1 ). This action is in response to your application dated March 20, 2014, as supplemented by letter dated June 26, 2014, which requested an exemption from portions of the requirements of 10 CFR Part 50, Appendix G and 10 CFR 50.61, to allow the use of an alternate methodology to evaluate the integrity of the AN0-1 Linde 80 weld materials in the reactor pressure vessel beltline. | The U.S. Nuclear Regulatory Commission has approved the enclosed exemption from certain requirements of Title 10 of the Code of Federal Regulations (10 CFR), Part 50, Appendix G and 10 CFR 50.61, for Arkansas Nuclear One, Unit 1 (AN0-1 ). This action is in response to your application dated March 20, 2014, as supplemented by letter dated June 26, 2014, which requested an exemption from portions of the requirements of 10 CFR Part 50, Appendix G and 10 CFR 50.61, to allow the use of an alternate methodology to evaluate the integrity of the AN0-1 Linde 80 weld materials in the reactor pressure vessel beltline. | ||
The exemption has been forwarded to the Office of the Federal Register for publication. | The exemption has been forwarded to the Office of the Federal Register for publication. | ||
If you have any questions, please contact me at (301) 415-1081 or by e-mail. at Andrea.George@nrc.gov. | If you have any questions, please contact me at (301) 415-1081 or by e-mail. at Andrea.George@nrc.gov. | ||
Docket No. 50-313 | Sincerely, b~i~1"'-'~ ~ | ||
Andrea E. George, Project Manager Plant Licensing Branch IV-1 Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation Docket No. 50-313 | |||
==Enclosure:== | ==Enclosure:== | ||
Exemption cc w/encl: Distribution via Listserv | Exemption cc w/encl: Distribution via Listserv | ||
[Docket No. 50-313; Entergy Operations, Inc., Arkansas Nuclear One, Unit 1 AGENCY: Nuclear Regulatory Commission. | |||
ACTION: Exemption; issuance. | ENCLOSURE EXEMPTION ENTERGY OPERATIONS, INC. | ||
ARKANSAS NUCLEAR ONE, UNIT 1 DOCKET NO. 50-313 | |||
[7590-01-P] | |||
NUCLEAR REGULATORY COMMISSION | |||
[Docket No. 50-313; NRC-2015.:;;~~~] | |||
Entergy Operations, Inc., Arkansas Nuclear One, Unit 1 AGENCY: Nuclear Regulatory Commission. | |||
ACTION: Exemption; issuance. | |||
==SUMMARY== | ==SUMMARY== | ||
: The U.S. Nuclear Regulatory Commission (NRC) is issuing an exemption in response to a March 20, 2014, request from Entergy Operations, Inc. (Entergy or the licensee), from the requirements to use Charpy V-notch (Cv) and drop weight-based methodology to determine initial nil-ductility reference temperature (RT NoT) for use in evaluating the integrity of Linde 80 weld materials in the reactor pressure vessel (RPV) beltline at Arkansas Nuclear One * (ANO), Unit 1. This exemption would allow the licensee to use an alternate methodology to incorporate fracture toughness test data to determine RT NOT values for use in the evaluation of the RPV beltline weld material integrity in support of the development of updated pressure-temperature limit curves. DATES: [INSERT DATE OF PUBLICATION IN THE FEDERAL REGISTER]. | : The U.S. Nuclear Regulatory Commission (NRC) is issuing an exemption in response to a March 20, 2014, request from Entergy Operations, Inc. (Entergy or the licensee), | ||
ADDRESSES: | from the requirements to use Charpy V-notch (Cv) and drop weight-based methodology to determine initial nil-ductility reference temperature (RT NoT) for use in evaluating the integrity of Linde 80 weld materials in the reactor pressure vessel (RPV) beltline at Arkansas Nuclear One | ||
Please refer to Docket ID NRC-2015-xxxx when contacting the NRC about the availability of information regarding this document. | * (ANO), Unit 1. This exemption would allow the licensee to use an alternate methodology to incorporate fracture toughness test data to determine RT NOT values for use in the evaluation of the RPV beltline weld material integrity in support of the development of updated pressure-temperature limit curves. | ||
You may obtain publicly-available information related to this document using any of the following methods: | DATES: [INSERT DATE OF PUBLICATION IN THE FEDERAL REGISTER]. | ||
* Federal Rulemaking Web Site: Go to http://www.regulations.gov and search for Docket ID NRC-2015-xxxX. | ADDRESSES: Please refer to Docket ID NRC-2015-xxxx when contacting the NRC about the availability of information regarding this document. You may obtain publicly-available information related to this document using any of the following methods: | ||
Address questions about NRC dockets to Carol Gallagher; | * Federal Rulemaking Web Site: Go to http://www.regulations.gov and search for Docket ID NRC-2015-xxxX. Address questions about NRC dockets to Carol Gallagher; | ||
301-415-3463; e-mail: Carol.Gallagher@nrc.gov. | |||
For technical questions, contact the individual listed in the FOR FURTHER INFORMATION CONTACT section of this document. | telephone: 301-415-3463; e-mail: Carol.Gallagher@nrc.gov. For technical questions, contact the individual listed in the FOR FURTHER INFORMATION CONTACT section of this document. | ||
* NRC's Agencywide Documents and Management System (ADAMS): You may obtain publicly-available documents online in the ADAMS Public Documents collection at To begin the search, select "ADAMS Public Documents" and then select "Begin Web-based ADAMS Search." For problems with ADAMS, please contact the NRC's PublicDocument Room (PDR) reference staff at 1-800-397-4209, 301-415-4737, or by e-mail to pdr.resource@nrc.gov. | * NRC's Agencywide Documents A~cess and Management System (ADAMS): | ||
The ADAMS accession number for each document referenced in this document (if that document is available in ADAMS) is provided the first time that a document is referenced. | You may obtain publicly-available documents online in the ADAMS Public Documents collection at http://www.nrc.gov/reading~rm/adams.html. To begin the search, select "ADAMS Public Documents" and then select "Begin Web-based ADAMS Search." For problems with ADAMS, please contact the NRC's PublicDocument Room (PDR) reference staff at 1-800-397-4209, 301-415-4737, or by e-mail to pdr.resource@nrc.gov. The ADAMS accession number for each document referenced in this document (if that document is available in ADAMS) is provided the first time that a document is referenced. | ||
* NRC's PDR: You may examine and purchase copies of public documents at the NRC's PDR, Room 01-F21, One White Flint North, 11555 Rockville Pike, Rockville, Maryland 20852. FOR FURTHER INFORMATION CONTACT: Andrea George, Office of Nuclear Reactor Regulation, U.S. Nuclear Regulatory Commission, Washington DC 20555-0001; telephone: | * NRC's PDR: You may examine and purchase copies of public documents at the NRC's PDR, Room 01-F21, One White Flint North, 11555 Rockville Pike, Rockville, Maryland 20852. | ||
301-415-1081, e-mail: Andrea.George@nrc.gov . . SUPPLEMENTARY INFORMATION: | FOR FURTHER INFORMATION CONTACT: Andrea George, Office of Nuclear Reactor Regulation, U.S. Nuclear Regulatory Commission, Washington DC 20555-0001; telephone: | ||
301-415-1081, e-mail: Andrea.George@nrc.gov . | |||
. SUPPLEMENTARY INFORMATION: | |||
I.' Background. | I.' Background. | ||
Entergy is the holder of renewed Facility Operating License No. DPR-51, that authorizes operation of ANO, Unit 1. The license provides, among other things, that the facility is subject to , all rules, regulations, and orders of the NRG now or hereafter in effect. The ANO facility consists of two pressurized-water reactors, Units.1 and 2, located in Pope County, Arkansas. | Entergy is the holder of renewed Facility Operating License No. DPR-51, that authorizes operation of ANO, Unit 1. The license provides, among other things, that the facility is subject to | ||
, all rules, regulations, and orders of the NRG now or hereafter in effect. | |||
The ANO facility consists of two pressurized-water reactors, Units.1 and 2, located in Pope County, Arkansas. | |||
II. Request/Action. | II. Request/Action. | ||
Part 50 of title 10 of the Code of Federal Regulation (10 CFR), appendix G, "Fracture .Toughness Requirements," specifies fracture toughness requirements for ferritic materials of pressure-retaining components of the reactor coolant pressure boundary of light water reactors to provide adequate margins of safety during any condition of normal operation, including anticipated operational occurrences and system hydrostatic tests, to which the pressure boundary may be subjected to over'its service lifetime. | Part 50 of title 10 of the Code of Federal Regulation (10 CFR), appendix G, "Fracture | ||
Section 50.61, "Fracture toughness requirements for protection against pressurized thermal shock [PTS] events," provides fracture toughness requirements for protection against PTS events. A PTS event is an event or transient in pressurized waterreactors (PWRs) causing severe overcooling (thermal shock) concurrent with or followed by significant pressure in the reactor vessel. Pursuant to 10 CFR 50.12, "Specific exemptions," by letter dated March 20, 2014 (ADAMS Accession No. | .Toughness Requirements," specifies fracture toughness requirements for ferritic materials of pressure-retaining components of the reactor coolant pressure boundary of light water reactors to provide adequate margins of safety during any condition of normal operation, including anticipated operational occurrences and system hydrostatic tests, to which the pressure boundary may be subjected to over'its service lifetime. Section 50.61, "Fracture toughness requirements for protection against pressurized thermal shock [PTS] events," provides fracture toughness requirements for protection against PTS events. A PTS event is an event or transient in pressurized waterreactors (PWRs) causing severe overcooling (thermal shock) concurrent with or followed by significant pressure in the reactor vessel. Pursuant to 10 CFR 50.12, "Specific exemptions," by letter dated March 20, 2014 (ADAMS Accession No. ML14083A640), as supplemented by letter dated June 26, 2014 (ADAMS Accession No. ML 14*177A302), the licensee requested an exemption from certain requirements of 10 CFR part 50, appendix G, and 10 CFR 50.61, to revise certain ANO, Unit 1 RPV initial (unirradiated) properties using AREVA Topical Report (TR) BAW-2308, Revisions 1-A and 2-A, "Initial RTNDT | ||
of Linde 80 Weld Materials." Specifically, the licensee requested an exemption from 10 CFR part 50, appendix G.11.D(i), which requires that licensees evaluate the pre-service or unirradiated RT Nor according to the procedures in the American S.ociety of Mechanical Engineers (ASME) Code, Paragraph NB-2331, "Material for Vessels." The ASME Code Paragraph NB-2331 requires that | [nil-ductility reference temperature] of Linde 80 Weld Materials." | ||
The methodology in TR BAW-2308, Revisions 1-A and 2-A, is based on the use of the 1997 and 2002 editions of the American Society for Testing and Materials (ASTM) Standard Test Method E1921 (ASTM E1921), "Standard Test Method for Determination of Reference Temperature T 0 for Ferritic Steels in the Transition Range," and ASME Code Case N-629, "Use of Fracture Toughness Test Data to Establish Reference Temperature for Pressure Retaining Materials, Section Ill, Division 1, Class 1." Since.the licensee is proposing an alternate method to the Cv and drop weight-based test data required by procedures in the ASME Code, Paragraph NB-2331, an exemption from portions of 10 CFR part 50, appendix G, is required. | Specifically, the licensee requested an exemption from 10 CFR part 50, appendix G.11.D(i), which requires that licensees evaluate the pre-service or unirradiated RT Nor according to the procedures in the American S.ociety of Mechanical Engineers (ASME) Code, Paragraph NB-2331, "Material for Vessels." The ASME Code Paragraph NB-2331 requires that | ||
licensees use Charpy V-notch (Cv) and drop weight-based methodology to derive the initial RT NDT values. In lieu of the existing methodology described above, the licensee requested to use the alternate methodology in TR BAW-2308, Revisions 1-A and 2-A, to incorporate the use of fracture toughness test data for evaluating the integrity of the ANO, Unit 1, Linde 80 weld materials in the RPV beltline. The methodology in TR BAW-2308, Revisions 1-A and 2-A, is based on the use of the 1997 and 2002 editions of the American Society for Testing and Materials (ASTM) Standard Test Method E1921 (ASTM E1921), "Standard Test Method for Determination of Reference Temperature T 0 for Ferritic Steels in the Transition Range," and ASME Code Case N-629, "Use of Fracture Toughness Test Data to Establish Reference Temperature for Pressure Retaining Materials, Section Ill, Division 1, Class 1." Since.the licensee is proposing an alternate method to the Cv and drop weight-based test data required by procedures in the ASME Code, Paragraph NB-2331, an exemption from portions of 10 CFR part 50, appendix G, is required. | |||
The licensee also requested an exemption from 10 CFR 50.61 (a)(5), which defines the | The licensee also requested an exemption from 10 CFR 50.61 (a)(5), which defines the | ||
* method for evaluating initial (unirradiated) | * method for evaluating initial (unirradiated) RT NDT as one that uses the procedures in ASME Code, Paragraph NB-2331, which requires the use of Cv and drop weight-based test data. | ||
RT NDT as one that uses the procedures in ASME Code, Paragraph NB-2331, which requires the use of Cv and drop weight-based test data. 10 CFR 50.61 (a)(5) alternatively defines the method for evaluating RT NDT as a method other than that of ASME Code, Paragraph NB-2331 approved by the Director, Office of Nuclear Reactor Regulation (NRR). The licensee proposes to use the alternate methodology described above, in AREVA TR BAW-2308," Revisions 1-A and 2-A, to determine the initial RT Nor values for the Linde 80 weld materials present in the ANO, Unit 1, RPV beltline region, which is not the procedure in ASME Code, Paragraph NB-2331 or an alternative method approved by the Director of NRR. Therefore, an exemption from 10 CFR 50.61 (a)(5) is required. Ill. Discussion. | 10 CFR 50.61 (a)(5) alternatively defines the method for evaluating RT NDT as a method other than that of ASME Code, Paragraph NB-2331 approved by the Director, Office of Nuclear Reactor Regulation (NRR). The licensee proposes to use the alternate methodology described above, in AREVA TR BAW-2308," Revisions 1-A and 2-A, to determine the initial RT Nor values for the Linde 80 weld materials present in the ANO, Unit 1, RPV beltline region, which is not the procedure in ASME Code, Paragraph NB-2331 or an alternative method approved by the Director of NRR. Therefore, an exemption from 10 CFR 50.61 (a)(5) is required. | ||
Pursuant to 10 CFR 50.12, the Commission may, upon application by any interested person or upon its own initiative, grant exemptions from the requirements of 10 CFR part 50 when: (1) the exemptions are authorized by law, will not present an undue risk to public health or safety, and are consistent with the common defense and security; and (2) when special circumstances are present. Under 10 CFR 50.12(a)(2)(ii}, special circumstances include, among other things, When application ofthe specific regulation in the particular circumstance would not serve, or is not necessary to achieve, the underlying purpose of the rule. A. Authorized by Law. As stated above, | |||
Finally, this exemption would allow the licensee to make use of fracture toughness test data for evaluating the integrity of the ANO, Unit 1 RPV Linde 80 beltline weld materials, and would not result in changes to the operation of the plant. Therefore, the exemption is authorized by law. C. No Undue Risk to Public Health and Safety. The underlying purpose of appendix G to 10 CFR part 50 is to set forth fracture toughness requirements for ferritic materials of pressure-retaining components of the reactor coolant pressure boundary of light water nuclear power reactors to provide adequate margins of safety during any conditions of normal operation, including anticipated operational occurrences and system hydrostatic tests, to which the pressure boundary may be subjected over its service lifetime. | Ill. Discussion. | ||
The methodology underlying the requirements of appendix G to 10 CFR part 50 is based on the use of Cv and drop weight t_est data because of the reference to the ASME Code, Section Ill, Paragraph NB-2331. The licensee proposes to replace the use of existing Cv and | Pursuant to 10 CFR 50.12, the Commission may, upon application by any interested person or upon its own initiative, grant exemptions from the requirements of 10 CFR part 50 when: (1) the exemptions are authorized by law, will not present an undue risk to public health or safety, and are consistent with the common defense and security; and (2) when special circumstances are present. Under 10 CFR 50.12(a)(2)(ii}, special circumstances include, among other things, When application ofthe specific regulation in the particular circumstance would not serve, or is not necessary to achieve, the underlying purpose of the rule. | ||
The NRC staff has concluded that the requested exemption to Appendix G to 10 CFR part 50 is justified because the licensee will utilize the fracture toughness methodology specified in BAW-2308, Revisions 1-A and 2-A, within the conditions and limitations delineated in the NRC staffs safety evaluations (SEs) dated August 4, 2005, and March 24, 2008 (ADAMS Accession Nos. ML052070408 and ML080770349, respectively). | A. Authorized by Law. | ||
The use of the methodology specified in the NRC staff's SEs will ensure that pressure-temperature limits developed for the ANO, Unit 1 RPV will continue to be based on an adequately conservative estimate of RPV material properties and ensure that the pressure-retaining components of the reactor coolant pressure boundary retain adequate margins of safety during any condition of normal operation, including anticipated operational occurrences. | As stated above, 10 CFR 50.12(a) allows the NRC to grant exemptions from portions of the requirements of 10 CFR part 50, appendix G and 10 CFR 50.61. Moreover, Section 50.60(b) of 10 CFR part 50 specifically allows the use of alternative methods for determining the initial material properties to 10 CFR part 50, appendix G, or portions thereof, when an exemption is granted by the Commission under 10 CFR 50.12. Because the regulations contemplate exemptions, granting the licensee's proposed exemption will not result in a violation of the Atomic Energy Act of 1954, as amended, or the NRC's regulations. Finally, this exemption would allow the licensee to make use of fracture toughness test data for evaluating the integrity of the ANO, Unit 1 RPV Linde 80 beltline weld materials, and would not result in changes to the operation of the plant. Therefore, the exemption is authorized by law. | ||
This exemption only modifies the methodology to | |||
Also, based on the above information, the consequences of postulated accidents are not increased. | C. No Undue Risk to Public Health and Safety. | ||
Therefore, there is no undue risk to public health and safety associated with the proposed exemption to appendix G to 10 CFR part 50. The underlying purpose of 10 CFR 50.61 is to establish requirements for evaluating the fracture toughness of RPV materials to ensure that a licensee's RPV will be protected from failure during a PTS event. The licensee seeks an exemption from portions of 10 CFR 50.61 to use a methodology for the determination of adjusted/indexing PTS reference temperature (RT Prs) values. The licensee proposes to use the methodology of TR BAW-2308, Revisions 1-A and 2-A as an alternative to the Cv and drop weight-based methodology required by 10 CFR 50.61 for determining the initial, unirradiated properties when calculating RT PTS* The NRC has concluded that the exemption is justified because the licensee will utilize the methodology specified in the NRC staff's SEs regarding TR BAW-2308, Revisions 1-A and 2-A. In TR BAW-2308, Revision 1-A, the Babcock and Wilcox Owners Group proposed to perform fracture toughness testing based on the application of the Master Curve evaluation procedure, which permits data obtained from sample sets tested at different temperatures to be combined, as the basis for defining the initial material properties of Linde 80 welds based on To (initial temperature). | The underlying purpose of appendix G to 10 CFR part 50 is to set forth fracture toughness requirements for ferritic materials of pressure-retaining components of the reactor coolant pressure boundary of light water nuclear power reactors to provide adequate margins of safety during any conditions of normal operation, including anticipated operational occurrences and system hydrostatic tests, to which the pressure boundary may be subjected over its service lifetime. The methodology underlying the requirements of appendix G to 10 CFR part 50 is based on the use of Cv and drop weight t_est data because of the reference to the ASME Code, Section Ill, Paragraph NB-2331. The licensee proposes . to. replace the use of existing Cv and drop weight-based methodology with an alternate methodology that uses fracture toughness test data to demonstrate compliance with appendix G to 10 CFR part 50. The alternate method, described in AREVA TR BAW-2308, Revisions 1-A and 2-A, utilizes fracture toughness data to determine the initial RT NDT of the Linde 80 weld materials present in the ANO, Unit 1 RPV beltline. | ||
The NRC staff evaluated this methodology for determining Linde 80 weld initial material properties and uncertainty in those properties, as well as the overall method for combining initial material property measurements based on To values (i.e. initial unirradiated | The NRC staff has concluded that the requested exemption to Appendix G to 10 CFR part 50 is justified because the licensee will utilize the fracture toughness methodology specified in BAW-2308, Revisions 1-A and 2-A, within the conditions and limitations delineated in the NRC staffs safety evaluations (SEs) dated August 4, 2005, and March 24, 2008 (ADAMS Accession Nos. ML052070408 and ML080770349, respectively). The use of the methodology specified in the NRC staff's SEs will ensure that pressure-temperature limits developed for the ANO, Unit 1 RPV will continue to be based on an adequately conservative estimate of RPV material properties and ensure that the pressure-retaining components of the reactor coolant pressure boundary retain adequate margins of safety during any condition of normal operation, including anticipated operational occurrences. This exemption only modifies the methodology to | ||
(°F) (values greater than 167 °F were used for certain Linde 80 weld wire heat numbers if RG 1.99, Revision 2 indicated higher cher:nistry factors); | |||
(3) applied a value of 28°F for cr 6 (i.e., shift margin) in the margin term; and (4) submitted values for NDT and the margin term for each Linde 80 weld in the RPV though the end of the current operating license. Additionally, the NRC's SE for TR BAW-2308, Revision 2-A concludes that the revised | be used by the licensee under 10 CFR part 50, appendix G.11.D(i) and does not exempt the licensee from meeting any other requirement of appendix G to 10 CFR part 50. | ||
! | Based on the above information, no new accident precursors are created by allowing an exemption from the use of the existing Cv and drop weight-based methodology and the use of | ||
In the licensee's supplement dated June 26, 2014, the licensee provided the chemistry factors in Table 1, "10 CFR 50.61 Chemistry Factors for the AN0-1 RV [Reactor Vessel] Materials." The NRC staff confirmed that the chemistry factors used by the licensee in calculating the RT NOT values were determined using the methodology of RG 1. 99, Revision 2, and that 167°F is the minimum chemistry factor for Linde 80 materials. | ( | ||
The use of the methodology in TR BAW-2308, Revisions 1-A and 2-A, will ensure the PTS evaluation developed for the ANO, Unit 1 RPV will continue to be based on an adequately | an alternative fracture toughness-based methodology to demonstrate tompliance with appendix G to 10 CFR part 50; thus, the probability of postulated accidents is not increased. | ||
/ conservative estimate of RPV material properties and ensure that the RPV will be protected from failure during a PTS event. Based on the evaluations above, the NRC staff has concluded that all conditions and limitations outlined in the NRC staff's SEs for TR BAW-2308, Revisions 1-A and 2-A, have been met for ANO Unit 1. Based on the above information, no new accident precursors are created by allowing an exemption to the alternate methodology to comply with the requirements of | Also, based on the above information, the consequences of postulated accidents are not increased. Therefore, there is no undue risk to public health and safety associated with the proposed exemption to appendix G to 10 CFR part 50. | ||
Also, based on the above information, the consequences of postulated accidents are not increased. | The underlying purpose of 10 CFR 50.61 is to establish requirements for evaluating the fracture toughness of RPV materials to ensure that a licensee's RPV will be protected from failure during a PTS event. The licensee seeks an exemption from portions of 10 CFR 50.61 to use a methodology for the determination of adjusted/indexing PTS reference temperature (RT Prs) values. The licensee proposes to use the methodology of TR BAW-2308, Revisions 1-A and 2-A as an alternative to the Cv and drop weight-based methodology required by 10 CFR 50.61 for determining the initial, unirradiated properties when calculating RT PTS* The NRC has concluded that the exemption is justified because the licensee will utilize the methodology specified in the NRC staff's SEs regarding TR BAW-2308, Revisions 1-A and 2-A. | ||
Therefore there is no undue risk to public health and safety. D. Consistent with the Common Defense and Security. | In TR BAW-2308, Revision 1-A, the Babcock and Wilcox Owners Group proposed to perform fracture toughness testing based on the application of the Master Curve evaluation procedure, which permits data obtained from sample sets tested at different temperatures to be combined, as the basis for defining the initial material properties of Linde 80 welds based on To (initial temperature). The NRC staff evaluated this methodology for determining Linde 80 weld initial material properties and uncertainty in those properties, as well as the overall method for combining initial material property measurements based on To values (i.e. initial unirradiated | ||
The licensee requested an exemption in order to utilize an alternative methodology from that specified in portions of 10 CFR part 50, appendix G, and 10 CFR 50.61, to allow the use of fracture toughness test data for evaluating the integrity of the ANO, Unit 1 RPV beltline Linde 80 weld materials. | |||
This exemption request is not related to, and does not impact, any security issues at ANO, Unit 1. Therefore, the NRC has. determined that this exemption does not impact, and is consistent with, the common defense and security. | nil-ductility reference temperature (IRTT0) in the BAW-2308 terminology), with property shifts from models in Regulatory Guide (RG) 1:99, Revision 2, '.'Radiation Embrittlement of Reactor Vessel Materials," which are based on Cv testing and defined margin term to account for uncertainties in the NRC staff's SE for TR BAW-2308, Revision 1-A. In the same NRC staff SE, Table 3, "NRC Staff-Accepted IRTro and [Initial Margin] cri Values for Linde 80 Weld Wire Heats," contains the NRC staff's accepted IRTT0 and initial margin (denoted as cri) for specific Linde 80 weld wire heat numbers. | ||
In accordance with the limitations and conditions outlined in the NRC staff's SE for TR BAW-2308, Revision 1-A, for utilizing the values in Table 3: the licensee has (1) utilized the appropriate NRC staff-accepted IRTro and cri values for applicable Linde 80 weld wire heat numbers; (2) applied a minimum chemistry factor of 167 degrees Fahrenheit (°F) (values greater than 167 °F were used for certain Linde 80 weld wire heat numbers if RG 1.99, Revision 2 indicated higher cher:nistry factors); (3) applied a value of 28°F for cr 6 (i.e., shift margin) in the margin term; and (4) submitted values for ~RT NDT and the margin term for each Linde 80 weld in the RPV though the end of the current operating license. Additionally, the NRC's SE for TR BAW-2308, Revision 2-A concludes that the revised IRTro and cri values for Linde 80 weld materials are acceptable for referencing in plant-specific licensing applications as delineated in TR BAW-2308, Revision 2-A and to the extent specified under Section 4.0, "Limitations and Conditions," of the SE. Incidentally, although Section 4.0 of the NRC staff SE states "Future plant-specific applications for RPVs containing weld heat 72105, and weld heat 299L44, of Linde 80 must use the revised IRTro and cri values in TR BAW-2308, Revision 2," | |||
the NRC notes that neither of these weld heats is used at ANO, Unit 1. Therefore, this condition does not apply to ANO, Unit 1. | |||
During review of the licensee's exemption request, the NRC staff noted that additional information was required in order to complete its review regarding the chemistry factors used by the licensee for calculating !lRTNOT values. The NRC staff requested this additional information via letter dated June 4, 2014 (ADAMS Accession No. ML14148A382). In the licensee's supplement dated June 26, 2014, the licensee provided the chemistry factors in Table 1, "10 CFR 50.61 Chemistry Factors for the AN0-1 RV [Reactor Vessel] Materials." The NRC staff confirmed that the chemistry factors used by the licensee in calculating the RT NOT values were determined using the methodology of RG 1. 99, Revision 2, and that 167°F is the minimum chemistry factor for Linde 80 materials. | |||
The use of the methodology in TR BAW-2308, Revisions 1-A and 2-A, will ensure the PTS evaluation developed for the ANO, Unit 1 RPV will continue to be based on an adequately | |||
/ | |||
conservative estimate of RPV material properties and ensure that the RPV will be protected from failure during a PTS event. Based on the evaluations above, the NRC staff has concluded that all conditions and limitations outlined in the NRC staff's SEs for TR BAW-2308, Revisions 1-A and 2-A, have been met for ANO Unit 1. | |||
Based on the above information, no new accident precursors are created by allowing an exemption to the alternate methodology to comply with the requirements of 10 CFR 50.61 in determining adjusted/indexing reference temperatures; thus, the probability .of postulated accidents is not increased. Also, based on the above information, the consequences of postulated accidents are not increased. Therefore there is no undue risk to public health and safety. | |||
D. Consistent with the Common Defense and Security. | |||
The licensee requested an exemption in order to utilize an alternative methodology from that specified in portions of 10 CFR part 50, appendix G, and 10 CFR 50.61, to allow the use of fracture toughness test data for evaluating the integrity of the ANO, Unit 1 RPV beltline Linde 80 weld materials. This exemption request is not related to, and does not impact, any security issues at ANO, Unit 1. Therefore, the NRC has. determined that this exemption does not impact, and is consistent with, the common defense and security. | |||
E. Special Circumstances. | E. Special Circumstances. | ||
Special circumstances, in accordance with 10 CFR 50, 12(a)(2)(ii), are present whenever application of the regulation in the particular circumstances would not serve the underlying purpose of the rule or is not necessary to achieve the underlying purpose of the rule. The underlying purpose of 10 CFR 50.61(a)(5) and 10 CFR part 50, appendix G.11.D(i) is to set forth fracture toughness requirements (e.g., initial RT NDT values) for ferritic materials of pressure-retaining components of the reactor coolant pressure boundary of light water nuclear power reactors, in order to provide adequate margins of safety during any conditions of normal operation, including anticipated operational occurrences and system hydrostatic tests, to which the pressure boundary may be subjected over its service lifetime. | Special circumstances, in accordance with 10 CFR 50, 12(a)(2)(ii), are present whenever application of the regulation in the particular circumstances would not serve the underlying purpose of the rule or is not necessary to achieve the underlying purpose of the rule. The underlying purpose of 10 CFR 50.61(a)(5) and 10 CFR part 50, appendix G.11.D(i) is to set forth fracture toughness requirements (e.g., initial RT NDT values) for ferritic materials of pressure-retaining components of the reactor coolant pressure boundary of light water nuclear power reactors, in order to provide adequate margins of safety during any conditions of normal operation, including anticipated operational occurrences and system hydrostatic tests, to which the pressure boundary may be subjected over its service lifetime. The underlying purpose of 10 CFR 50.61 is to establish requirements for evaluating the fracture toughness of RPV materials to ensure that a licensee's RPV will be protected from failure during a PTS event. | ||
The underlying purpose of 10 CFR 50.61 is to establish requirements for evaluating the fracture toughness of RPV materials to ensure that a licensee's RPV will be protected from failure during a PTS event. Entergy's exemption request proposes an alternate methodology to evaluate the RT of Linde 80 weld materials in the RPV beltline region at ANO, Unit 1, based on fracture toughness test data found in AREVA TR BAW-2308, Revision 1-A and 2-A (in accordance with | Entergy's exemption request proposes an alternate methodology to evaluate the RT N~T of Linde 80 weld materials in the RPV beltline region at ANO, Unit 1, based on fracture toughness test data found in AREVA TR BAW-2308, Revision 1-A and 2-A (in accordance with | ||
The alternate methodology also achieves the underlying purpose of 10 CFR 50.61 (a)(5) because it will ensure that the PTS evaluation developed for the ANO, Unit 1 RPV will continue to be based on an adequately conservative estimate of RPV material properties and ensure that the RPV will be protected from failure during a PTS event. Accordingly, the NRC has concluded that using the procedures in the ASME Code, Paragraph NB-2331 is not necessary to achieve the underlying purpose of | |||
Therefore, in accordance with | ASTM Standard E1921 and ASME Code Case N-629). This proposed alternate methodology achieves the underlying purpose of 10 CFR Part 50 Appendix G.11.D(i) because it provides an adequate conservative estimate of RPV materials properties and ensures that the pressure-retaining components of the RPV retain adequate margins for safety during any condition of normal operation. The alternate methodology also achieves the underlying purpose of 10 CFR 50.61 (a)(5) because it will ensure that the PTS evaluation developed for the ANO, Unit 1 RPV will continue to be based on an adequately conservative estimate of RPV material properties and ensure that the RPV will be protected from failure during a PTS event. | ||
Accordingly, the NRC has concluded that using the procedures in the ASME Code, Paragraph NB-2331 is not necessary to achieve the underlying purpose of 10 CFR 50.61 (a)(5) and 10 CFR part 50 appendix G.11. D(i). Therefore, the special circumstances required by 10 CFR 50.12(a)(2)(ii) for the granting of an exemption exist. | |||
F. Environmental Considerations. | |||
, The NRC staff determined that the exemption discussed herein meets the eligibility criteria for the categorical exclusion set forth in 10 CFR 51. 22( c)(9) because it is related to a requirement concerning the installation or use of a facility component located within the restricted area, as defined in 10 CFR part 20, and issuance of this exemption involves: (i) No significant hazards consideration, (ii) no significant change in the types or a significant increase in the amounts of any effluents that may be released offsite, and (iii) no significant increase in individual or cumulative occupational radiation exposure. Therefore, in accordance with 10 CFR 51.22(b), no environmental impact statement or environmental assessment need be prepared in connection with the NRC's consideration of this exemption request. The basis for the NRC | |||
staffs determination is discussed as follows with an evaluation against each of the requirements in 10 CFR 51. 22(c)(9)(i)-(iii). | |||
Requirements in 10 CFR 51.22(c)(9)(i) | Requirements in 10 CFR 51.22(c)(9)(i) | ||
The NRC evaluated whether the exemption involves no significant hazards consideration using the standards described in 10 CFR 50.92(c), as presented below: 1. Does the proposed exemption involve a significant increase in the probability or consequences of an accident previously evaluated? | The NRC evaluated whether the exemption involves no significant hazards consideration using the standards described in 10 CFR 50.92(c), as presented below: | ||
Response: | : 1. Does the proposed exemption involve a significant increase in the probability or consequences of an accident previously evaluated? | ||
No. The exemption would allow the use of alternate methodologies from those specified in Appendix G to | Response: No. | ||
The change in reactor vessel material initial properties will continue to satisfy the intent of 10 CFR 50, Appendix G, and 10 CFR 50.61. The change does not | The exemption would allow the use of alternate methodologies from those specified in Appendix G to 10 CFR part 50, and 10 CFR 50.61, to allow the use of fracture toughness test data for evaluating the integrity of RPV beltline welds. Use of the alternate methodology for determining the initial, unirradiated material reference temperatures of the Linde 80 weld materials present in the RPV beltline region will not result in changes in operation of configuration of the facility. The change in reactor vessel material initial properties will continue to satisfy the intent of 10 CFR 50, Appendix G, and 10 CFR 50.61. The change does not adversely affect accident initiators or pre-cursors, nor alter the design assumptions, conditions, or the manner in which the plant is operated and maintained. The change does not alter or prevent the ability of structures, systems or components from performing their intended function to mitigate the consequences of an initiating event with the assumed acceptance limits. There will be no adverse change to normal plant operating parameters, engineered safety feature actuation setpoints, accident mitigation capabilities, or accident analysis assumptions or inputs. | ||
The change does not alter or prevent the ability of structures, systems or components from performing their intended function to mitigate the consequences of an initiating event with the assumed acceptance limits. There will be no adverse change to normal plant operating parameters, engineered safety feature actuation setpoints, accident mitigation capabilities, or accident analysis assumptions or inputs. The change does not affect the source term, containment isolation, or radiological release assumptions used in evaluating the radiological consequences of an accident previously evaluated. | The change does not affect the source term, containment isolation, or radiological release assumptions used in evaluating the radiological consequences of an accident previously evaluated. Further, the change does not increase the types of amounts of radioactive effluent | ||
Further, the change does not increase the types of amounts of radioactive effluent | |||
Therefore, the proposed exemption does not involve a significant increase in the probability or consequences of an accident previously evaluated. | that may be released offsite, nor significantly increase individual or cumulative occupational/public radiation exposures. | ||
Therefore, the proposed exemption does not involve a significant increase in the probability or consequences of an accident previously evaluated. | |||
: 2. Does the proposed exemption create the possibility of a new or different kin? of accident from any accident previously evaluated? | : 2. Does the proposed exemption create the possibility of a new or different kin? of accident from any accident previously evaluated? | ||
Response: | Response: No. | ||
No. The exemption would allow the use of alternate methodologies from those specified in Appendix G to 10 CFR part 50, and 10 CFR 50.61, to allow the use of fracture toughness test data for evaluating the integrity of RPV beltline welds. Use of the alternate methodology for determining the initial, unirradiated material reference temperatures of the Linde 80 weld materials present in the RPV beltline region will not result in changes in operation or configuration of the facility. | The exemption would allow the use of alternate methodologies from those specified in Appendix G to 10 CFR part 50, and 10 CFR 50.61, to allow the use of fracture toughness test data for evaluating the integrity of RPV beltline welds. Use of the alternate methodology for determining the initial, unirradiated material reference temperatures of the Linde 80 weld materials present in the RPV beltline region will not result in changes in operation or configuration of the facility. The change does not impose any new or different requirements or eliminate any existing requiremer:its. The change is consistent with the current safety analysis assumptions and current plant operating practice. No new accident scenarios, transient precursors, failure mechanisms, or limiting single failures are introduced as a result of the proposed change. Equipment important to safety will continue to operate as designed. The change does not result in any event previously deemed incredible being more credible. The change does not result in any adverse conditions or result in any increase in the challenges to safety_ systems. | ||
The change does not impose any new or different requirements or eliminate any existing requiremer:its. | Therefore, this change does not create the possibility of a new or different kind of acCident from an accident previously evaluated. | ||
The change is consistent with the current safety analysis assumptions and current plant operating practice. | : 3. Does the proposed exemption involve a significant reduction in a margin of safety? | ||
No new accident scenarios, transient precursors, failure mechanisms, or limiting single failures are introduced as a result of the proposed change. Equipment important to safety will continue to operate as designed. | Response: No. | ||
The change does not result in any event previously deemed incredible being more credible. | The proposed exemption does not alter safety limits, limiting safety system settings, or limiting conditions for operation. The setpoints at which protective actions are initiated are riot altered by the change. There are no new or significant changes to initial conditions contributing to accident severity or consequences. The exemption will not otherwise affect plant protective boundaries, will not cause a release of fission products to the public, nor will it degrade the performance of any other structures, systems or components important to safety. | ||
The change does not result in any adverse conditions or result in any increase in the challenges to safety_ systems. Therefore, this change does not create the possibility of a new or different kind of acCident from an accident previously evaluated. 3. Does the proposed exemption involve a significant reduction in a margin of safety? Response: | Therefore, the proposed exemption does not involve a. significant reduction in a margin of safety. | ||
No. The proposed exemption does not alter safety limits, limiting safety system settings, or limiting conditions for operation. | Based on the above evaluation of the standards set forth in 10 CFR 50.92(c), the NRC concludes that the proposed exemption involves no significant hazards consideration. | ||
The setpoints at which protective actions are initiated are riot altered by the change. There are no new or significant changes to initial conditions contributing to accident severity or consequences. | Accordingly, the requirements of 10 CFR 51.22(c)(9)(i) are met. | ||
The exemption will not otherwise affect plant protective boundaries, will not cause a release of fission products to the public, nor will it degrade the performance of any other structures, systems or components important to safety. Therefore, the proposed exemption does not involve a. significant reduction in a margin of safety. Based on the above evaluation of the standards set forth in 10 CFR 50.92(c), the NRC concludes that the proposed exemption involves no significant hazards consideration. | Requirements in 10 CFR 51.22(c)(9)(ii-iii) | ||
Accordingly, the requirements of | |||
The proposed exemption does not make any changes to the facility, equipment at the facility, or to fuel or core design. The proposed alternate methodology serves the same purpose as the requirements set forth in.10 CFR 50.61 and 10 CFR part 50, appendix G. Therefore, the NRC concludes that the exemption involves no significant change in the types or a significant increase in the amounts of any effluents that may be released offsite, and that there is no significant increase in individual or cumulative public or occupational radiation exposure. | The proposed exemption does not make any changes to the facility, equipment at the facility, or to fuel or core design. The proposed alternate methodology serves the same purpose as the requirements set forth in.10 CFR 50.61 and 10 CFR part 50, appendix G. Therefore, the NRC concludes that the exemption involves no significant change in the types or a significant increase in the amounts of any effluents that may be released offsite, and that there is no significant increase in individual or cumulative public or occupational radiation exposure. | ||
Therefore, the requirements of 10 CFR 51.22(c)(9)(ii-iii) are met. Conclusion Based on the above, the NRC concludes that the proposed exemption meets the | Therefore, the requirements of 10 CFR 51.22(c)(9)(ii-iii) are met. | ||
Therefore, in accordance with 10 CFR 51.22(b), no environmental impact statement or environmental assessment need be prepared in connection with the NRC's issuance of this exemption. | Conclusion Based on the above, the NRC concludes that the proposed exemption meets the | ||
eligibility criteria for the categorical exclusion set forth in 10 CFR 51.22(c)(9). Therefore, in accordance with 10 CFR 51.22(b), no environmental impact statement or environmental assessment need be prepared in connection with the NRC's issuance of this exemption. | |||
IV. Conclusions. | IV. Conclusions. | ||
Accordingly, the Commission has determined that, pursuant to | Accordingly, the Commission has determined that, pursuant to 10 CFR 50.12(a), the exemption is authorized by law, will not present an undue risk to the public health and safety, and is consistent with the common defense and security. Also, special circumstances are present. Therefore, the Commission hereby grants the licensee an exemption from 10 CFR part 50, appendix G.ll:D(i) and 10 CFR 50.61(a)(5) requirements, in order to use the alternate methodology specified in AREVA TR BAW-2308, Revisions 1-A and 2-A, in lieu of the existing requirement to use Cv and drop weight-b'ased methodologies to evaluate the initial (unirradiated) RT NOT of the Linde 80 weld materials in the RPV beltline region at ANO, Unit 1. | ||
Also, special circumstances are present. Therefore, the Commission hereby grants the licensee an exemption from 10 CFR part 50, appendix G.ll:D(i) and 10 CFR 50.61(a)(5) requirements, in order to use the alternate methodology specified in AREVA TR BAW-2308, Revisions 1-A and 2-A, in lieu of the existing requirement to use Cv and drop weight-b'ased methodologies to evaluate the initial (unirradiated) | This exemption is effective upon issuance. | ||
RT NOT of the Linde 80 weld materials in the RPV beltline region at ANO, Unit 1. This exemption is effective upon issuance. | th Dated at Rockville, Maryland, this /(() day of March 2015. | ||
th Dated at Rockville, Maryland, this /(() day of March 2015. For the Nuclear Regulatory Commission. | For the Nuclear Regulatory Commission. | ||
Michele G. Evans, Director, Division of Operating Reactor Licensing, Office of Nuclear Reactor Regulation. | Michele G. Evans, Director, Division of Operating Reactor Licensing, Office of Nuclear Reactor Regulation. | ||
Letter ML15056A367* Exemption ML15056A368 I *via email **via memo OFFICE NRRIDORL/LPL4-1 /PM NRR/DORL/LPL4-1 /PM NRR/DORL/LPL4-1 /PM NRR/DORL/LPL4-1 /LA NRR/DE/EVIB/BC NAME MWatford* JKlos* AGeorge JBurkhardt SRosenberg** | |||
DATE 3/12/15 3/12/15 3/2/15 2/25/15 8/13/14 OFFICE OGC-NLO NRR/DORL/LPL4-1 /BC NRR/DORL/D NRR/DORL/LPL4-1 /PM NAME Jlindell MMarkley MEvans* AGeorge (BASingal for) | |||
Exemption | DATE 3/10/15 3/12/15 3/16/15 3/16/15}} | ||
*via email **via memo | |||
/PM NRR/DORL/LPL4-1 | |||
/PM NRR/DORL/LPL4-1 | |||
/PM NRR/DORL/LPL4-1 | |||
/LA NRR/DE/EVIB/BC NAME MWatford* | |||
JKlos* AGeorge JBurkhardt SRosenberg** | |||
DATE 3/12/15 3/12/15 3/2/15 2/25/15 8/13/14 OFFICE OGC-NLO NRR/DORL/LPL4-1 | |||
/BC NRR/DORL/D NRR/DORL/LPL4-1 | |||
/PM NAME Jlindell MMarkley MEvans* AGeorge (BASingal for) DATE 3/10/15 3/12/15 3/16/15 3/16/15 |
Latest revision as of 14:05, 5 February 2020
ML15056A367 | |
Person / Time | |
---|---|
Site: | Arkansas Nuclear |
Issue date: | 03/16/2015 |
From: | Andrea George Plant Licensing Branch IV |
To: | Entergy Operations |
George A | |
References | |
TAC MF3700 | |
Download: ML15056A367 (18) | |
Text
UNITED STATES~:.,
NUCLEAR REGULATORY COMMISSION WASHINGTON, D.C. 20555~0001 March 16, 2015 Vice President, Operations Arkansas Nuclear One Entergy Operations, Inc.
1448 S.R. 333 Russellville, AR 72802
SUBJECT:
ARKANSAS NUCLEAR ONE, UNIT NO. 1 - EXEMPTION FROM CERTAIN REQUIREMENTS OF 10 CFRPART 50, APPENDIX G AND 10 CFR 50.61, FOR INITIAL NIL DUCTILITY REFERENCE TEMPERATURE FOR LINDE 80 WELDS (TAC NO. MF3700)
Dear Sir or Madam:
The U.S. Nuclear Regulatory Commission has approved the enclosed exemption from certain requirements of Title 10 of the Code of Federal Regulations (10 CFR), Part 50, Appendix G and 10 CFR 50.61, for Arkansas Nuclear One, Unit 1 (AN0-1 ). This action is in response to your application dated March 20, 2014, as supplemented by letter dated June 26, 2014, which requested an exemption from portions of the requirements of 10 CFR Part 50, Appendix G and 10 CFR 50.61, to allow the use of an alternate methodology to evaluate the integrity of the AN0-1 Linde 80 weld materials in the reactor pressure vessel beltline.
The exemption has been forwarded to the Office of the Federal Register for publication.
If you have any questions, please contact me at (301) 415-1081 or by e-mail. at Andrea.George@nrc.gov.
Sincerely, b~i~1"'-'~ ~
Andrea E. George, Project Manager Plant Licensing Branch IV-1 Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation Docket No. 50-313
Enclosure:
Exemption cc w/encl: Distribution via Listserv
ENCLOSURE EXEMPTION ENTERGY OPERATIONS, INC.
ARKANSAS NUCLEAR ONE, UNIT 1 DOCKET NO. 50-313
[7590-01-P]
NUCLEAR REGULATORY COMMISSION
[Docket No. 50-313; NRC-2015.:;;~~~]
Entergy Operations, Inc., Arkansas Nuclear One, Unit 1 AGENCY: Nuclear Regulatory Commission.
ACTION: Exemption; issuance.
SUMMARY
- The U.S. Nuclear Regulatory Commission (NRC) is issuing an exemption in response to a March 20, 2014, request from Entergy Operations, Inc. (Entergy or the licensee),
from the requirements to use Charpy V-notch (Cv) and drop weight-based methodology to determine initial nil-ductility reference temperature (RT NoT) for use in evaluating the integrity of Linde 80 weld materials in the reactor pressure vessel (RPV) beltline at Arkansas Nuclear One
- (ANO), Unit 1. This exemption would allow the licensee to use an alternate methodology to incorporate fracture toughness test data to determine RT NOT values for use in the evaluation of the RPV beltline weld material integrity in support of the development of updated pressure-temperature limit curves.
DATES: [INSERT DATE OF PUBLICATION IN THE FEDERAL REGISTER].
ADDRESSES: Please refer to Docket ID NRC-2015-xxxx when contacting the NRC about the availability of information regarding this document. You may obtain publicly-available information related to this document using any of the following methods:
- Federal Rulemaking Web Site: Go to http://www.regulations.gov and search for Docket ID NRC-2015-xxxX. Address questions about NRC dockets to Carol Gallagher;
telephone: 301-415-3463; e-mail: Carol.Gallagher@nrc.gov. For technical questions, contact the individual listed in the FOR FURTHER INFORMATION CONTACT section of this document.
- NRC's Agencywide Documents A~cess and Management System (ADAMS):
You may obtain publicly-available documents online in the ADAMS Public Documents collection at http://www.nrc.gov/reading~rm/adams.html. To begin the search, select "ADAMS Public Documents" and then select "Begin Web-based ADAMS Search." For problems with ADAMS, please contact the NRC's PublicDocument Room (PDR) reference staff at 1-800-397-4209, 301-415-4737, or by e-mail to pdr.resource@nrc.gov. The ADAMS accession number for each document referenced in this document (if that document is available in ADAMS) is provided the first time that a document is referenced.
- NRC's PDR: You may examine and purchase copies of public documents at the NRC's PDR, Room 01-F21, One White Flint North, 11555 Rockville Pike, Rockville, Maryland 20852.
FOR FURTHER INFORMATION CONTACT: Andrea George, Office of Nuclear Reactor Regulation, U.S. Nuclear Regulatory Commission, Washington DC 20555-0001; telephone:
301-415-1081, e-mail: Andrea.George@nrc.gov .
. SUPPLEMENTARY INFORMATION:
I.' Background.
Entergy is the holder of renewed Facility Operating License No. DPR-51, that authorizes operation of ANO, Unit 1. The license provides, among other things, that the facility is subject to
, all rules, regulations, and orders of the NRG now or hereafter in effect.
The ANO facility consists of two pressurized-water reactors, Units.1 and 2, located in Pope County, Arkansas.
II. Request/Action.
Part 50 of title 10 of the Code of Federal Regulation (10 CFR), appendix G, "Fracture
.Toughness Requirements," specifies fracture toughness requirements for ferritic materials of pressure-retaining components of the reactor coolant pressure boundary of light water reactors to provide adequate margins of safety during any condition of normal operation, including anticipated operational occurrences and system hydrostatic tests, to which the pressure boundary may be subjected to over'its service lifetime. Section 50.61, "Fracture toughness requirements for protection against pressurized thermal shock [PTS] events," provides fracture toughness requirements for protection against PTS events. A PTS event is an event or transient in pressurized waterreactors (PWRs) causing severe overcooling (thermal shock) concurrent with or followed by significant pressure in the reactor vessel. Pursuant to 10 CFR 50.12, "Specific exemptions," by letter dated March 20, 2014 (ADAMS Accession No. ML14083A640), as supplemented by letter dated June 26, 2014 (ADAMS Accession No. ML 14*177A302), the licensee requested an exemption from certain requirements of 10 CFR part 50, appendix G, and 10 CFR 50.61, to revise certain ANO, Unit 1 RPV initial (unirradiated) properties using AREVA Topical Report (TR) BAW-2308, Revisions 1-A and 2-A, "Initial RTNDT
[nil-ductility reference temperature] of Linde 80 Weld Materials."
Specifically, the licensee requested an exemption from 10 CFR part 50, appendix G.11.D(i), which requires that licensees evaluate the pre-service or unirradiated RT Nor according to the procedures in the American S.ociety of Mechanical Engineers (ASME) Code, Paragraph NB-2331, "Material for Vessels." The ASME Code Paragraph NB-2331 requires that
licensees use Charpy V-notch (Cv) and drop weight-based methodology to derive the initial RT NDT values. In lieu of the existing methodology described above, the licensee requested to use the alternate methodology in TR BAW-2308, Revisions 1-A and 2-A, to incorporate the use of fracture toughness test data for evaluating the integrity of the ANO, Unit 1, Linde 80 weld materials in the RPV beltline. The methodology in TR BAW-2308, Revisions 1-A and 2-A, is based on the use of the 1997 and 2002 editions of the American Society for Testing and Materials (ASTM) Standard Test Method E1921 (ASTM E1921), "Standard Test Method for Determination of Reference Temperature T 0 for Ferritic Steels in the Transition Range," and ASME Code Case N-629, "Use of Fracture Toughness Test Data to Establish Reference Temperature for Pressure Retaining Materials, Section Ill, Division 1, Class 1." Since.the licensee is proposing an alternate method to the Cv and drop weight-based test data required by procedures in the ASME Code, Paragraph NB-2331, an exemption from portions of 10 CFR part 50, appendix G, is required.
The licensee also requested an exemption from 10 CFR 50.61 (a)(5), which defines the
- method for evaluating initial (unirradiated) RT NDT as one that uses the procedures in ASME Code, Paragraph NB-2331, which requires the use of Cv and drop weight-based test data.
10 CFR 50.61 (a)(5) alternatively defines the method for evaluating RT NDT as a method other than that of ASME Code, Paragraph NB-2331 approved by the Director, Office of Nuclear Reactor Regulation (NRR). The licensee proposes to use the alternate methodology described above, in AREVA TR BAW-2308," Revisions 1-A and 2-A, to determine the initial RT Nor values for the Linde 80 weld materials present in the ANO, Unit 1, RPV beltline region, which is not the procedure in ASME Code, Paragraph NB-2331 or an alternative method approved by the Director of NRR. Therefore, an exemption from 10 CFR 50.61 (a)(5) is required.
Ill. Discussion.
Pursuant to 10 CFR 50.12, the Commission may, upon application by any interested person or upon its own initiative, grant exemptions from the requirements of 10 CFR part 50 when: (1) the exemptions are authorized by law, will not present an undue risk to public health or safety, and are consistent with the common defense and security; and (2) when special circumstances are present. Under 10 CFR 50.12(a)(2)(ii}, special circumstances include, among other things, When application ofthe specific regulation in the particular circumstance would not serve, or is not necessary to achieve, the underlying purpose of the rule.
A. Authorized by Law.
As stated above, 10 CFR 50.12(a) allows the NRC to grant exemptions from portions of the requirements of 10 CFR part 50, appendix G and 10 CFR 50.61. Moreover, Section 50.60(b) of 10 CFR part 50 specifically allows the use of alternative methods for determining the initial material properties to 10 CFR part 50, appendix G, or portions thereof, when an exemption is granted by the Commission under 10 CFR 50.12. Because the regulations contemplate exemptions, granting the licensee's proposed exemption will not result in a violation of the Atomic Energy Act of 1954, as amended, or the NRC's regulations. Finally, this exemption would allow the licensee to make use of fracture toughness test data for evaluating the integrity of the ANO, Unit 1 RPV Linde 80 beltline weld materials, and would not result in changes to the operation of the plant. Therefore, the exemption is authorized by law.
C. No Undue Risk to Public Health and Safety.
The underlying purpose of appendix G to 10 CFR part 50 is to set forth fracture toughness requirements for ferritic materials of pressure-retaining components of the reactor coolant pressure boundary of light water nuclear power reactors to provide adequate margins of safety during any conditions of normal operation, including anticipated operational occurrences and system hydrostatic tests, to which the pressure boundary may be subjected over its service lifetime. The methodology underlying the requirements of appendix G to 10 CFR part 50 is based on the use of Cv and drop weight t_est data because of the reference to the ASME Code, Section Ill, Paragraph NB-2331. The licensee proposes . to. replace the use of existing Cv and drop weight-based methodology with an alternate methodology that uses fracture toughness test data to demonstrate compliance with appendix G to 10 CFR part 50. The alternate method, described in AREVA TR BAW-2308, Revisions 1-A and 2-A, utilizes fracture toughness data to determine the initial RT NDT of the Linde 80 weld materials present in the ANO, Unit 1 RPV beltline.
The NRC staff has concluded that the requested exemption to Appendix G to 10 CFR part 50 is justified because the licensee will utilize the fracture toughness methodology specified in BAW-2308, Revisions 1-A and 2-A, within the conditions and limitations delineated in the NRC staffs safety evaluations (SEs) dated August 4, 2005, and March 24, 2008 (ADAMS Accession Nos. ML052070408 and ML080770349, respectively). The use of the methodology specified in the NRC staff's SEs will ensure that pressure-temperature limits developed for the ANO, Unit 1 RPV will continue to be based on an adequately conservative estimate of RPV material properties and ensure that the pressure-retaining components of the reactor coolant pressure boundary retain adequate margins of safety during any condition of normal operation, including anticipated operational occurrences. This exemption only modifies the methodology to
be used by the licensee under 10 CFR part 50, appendix G.11.D(i) and does not exempt the licensee from meeting any other requirement of appendix G to 10 CFR part 50.
Based on the above information, no new accident precursors are created by allowing an exemption from the use of the existing Cv and drop weight-based methodology and the use of
(
an alternative fracture toughness-based methodology to demonstrate tompliance with appendix G to 10 CFR part 50; thus, the probability of postulated accidents is not increased.
Also, based on the above information, the consequences of postulated accidents are not increased. Therefore, there is no undue risk to public health and safety associated with the proposed exemption to appendix G to 10 CFR part 50.
The underlying purpose of 10 CFR 50.61 is to establish requirements for evaluating the fracture toughness of RPV materials to ensure that a licensee's RPV will be protected from failure during a PTS event. The licensee seeks an exemption from portions of 10 CFR 50.61 to use a methodology for the determination of adjusted/indexing PTS reference temperature (RT Prs) values. The licensee proposes to use the methodology of TR BAW-2308, Revisions 1-A and 2-A as an alternative to the Cv and drop weight-based methodology required by 10 CFR 50.61 for determining the initial, unirradiated properties when calculating RT PTS* The NRC has concluded that the exemption is justified because the licensee will utilize the methodology specified in the NRC staff's SEs regarding TR BAW-2308, Revisions 1-A and 2-A.
In TR BAW-2308, Revision 1-A, the Babcock and Wilcox Owners Group proposed to perform fracture toughness testing based on the application of the Master Curve evaluation procedure, which permits data obtained from sample sets tested at different temperatures to be combined, as the basis for defining the initial material properties of Linde 80 welds based on To (initial temperature). The NRC staff evaluated this methodology for determining Linde 80 weld initial material properties and uncertainty in those properties, as well as the overall method for combining initial material property measurements based on To values (i.e. initial unirradiated
nil-ductility reference temperature (IRTT0) in the BAW-2308 terminology), with property shifts from models in Regulatory Guide (RG) 1:99, Revision 2, '.'Radiation Embrittlement of Reactor Vessel Materials," which are based on Cv testing and defined margin term to account for uncertainties in the NRC staff's SE for TR BAW-2308, Revision 1-A. In the same NRC staff SE, Table 3, "NRC Staff-Accepted IRTro and [Initial Margin] cri Values for Linde 80 Weld Wire Heats," contains the NRC staff's accepted IRTT0 and initial margin (denoted as cri) for specific Linde 80 weld wire heat numbers.
In accordance with the limitations and conditions outlined in the NRC staff's SE for TR BAW-2308, Revision 1-A, for utilizing the values in Table 3: the licensee has (1) utilized the appropriate NRC staff-accepted IRTro and cri values for applicable Linde 80 weld wire heat numbers; (2) applied a minimum chemistry factor of 167 degrees Fahrenheit (°F) (values greater than 167 °F were used for certain Linde 80 weld wire heat numbers if RG 1.99, Revision 2 indicated higher cher:nistry factors); (3) applied a value of 28°F for cr 6 (i.e., shift margin) in the margin term; and (4) submitted values for ~RT NDT and the margin term for each Linde 80 weld in the RPV though the end of the current operating license. Additionally, the NRC's SE for TR BAW-2308, Revision 2-A concludes that the revised IRTro and cri values for Linde 80 weld materials are acceptable for referencing in plant-specific licensing applications as delineated in TR BAW-2308, Revision 2-A and to the extent specified under Section 4.0, "Limitations and Conditions," of the SE. Incidentally, although Section 4.0 of the NRC staff SE states "Future plant-specific applications for RPVs containing weld heat 72105, and weld heat 299L44, of Linde 80 must use the revised IRTro and cri values in TR BAW-2308, Revision 2,"
the NRC notes that neither of these weld heats is used at ANO, Unit 1. Therefore, this condition does not apply to ANO, Unit 1.
During review of the licensee's exemption request, the NRC staff noted that additional information was required in order to complete its review regarding the chemistry factors used by the licensee for calculating !lRTNOT values. The NRC staff requested this additional information via letter dated June 4, 2014 (ADAMS Accession No. ML14148A382). In the licensee's supplement dated June 26, 2014, the licensee provided the chemistry factors in Table 1, "10 CFR 50.61 Chemistry Factors for the AN0-1 RV [Reactor Vessel] Materials." The NRC staff confirmed that the chemistry factors used by the licensee in calculating the RT NOT values were determined using the methodology of RG 1. 99, Revision 2, and that 167°F is the minimum chemistry factor for Linde 80 materials.
The use of the methodology in TR BAW-2308, Revisions 1-A and 2-A, will ensure the PTS evaluation developed for the ANO, Unit 1 RPV will continue to be based on an adequately
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conservative estimate of RPV material properties and ensure that the RPV will be protected from failure during a PTS event. Based on the evaluations above, the NRC staff has concluded that all conditions and limitations outlined in the NRC staff's SEs for TR BAW-2308, Revisions 1-A and 2-A, have been met for ANO Unit 1.
Based on the above information, no new accident precursors are created by allowing an exemption to the alternate methodology to comply with the requirements of 10 CFR 50.61 in determining adjusted/indexing reference temperatures; thus, the probability .of postulated accidents is not increased. Also, based on the above information, the consequences of postulated accidents are not increased. Therefore there is no undue risk to public health and safety.
D. Consistent with the Common Defense and Security.
The licensee requested an exemption in order to utilize an alternative methodology from that specified in portions of 10 CFR part 50, appendix G, and 10 CFR 50.61, to allow the use of fracture toughness test data for evaluating the integrity of the ANO, Unit 1 RPV beltline Linde 80 weld materials. This exemption request is not related to, and does not impact, any security issues at ANO, Unit 1. Therefore, the NRC has. determined that this exemption does not impact, and is consistent with, the common defense and security.
E. Special Circumstances.
Special circumstances, in accordance with 10 CFR 50, 12(a)(2)(ii), are present whenever application of the regulation in the particular circumstances would not serve the underlying purpose of the rule or is not necessary to achieve the underlying purpose of the rule. The underlying purpose of 10 CFR 50.61(a)(5) and 10 CFR part 50, appendix G.11.D(i) is to set forth fracture toughness requirements (e.g., initial RT NDT values) for ferritic materials of pressure-retaining components of the reactor coolant pressure boundary of light water nuclear power reactors, in order to provide adequate margins of safety during any conditions of normal operation, including anticipated operational occurrences and system hydrostatic tests, to which the pressure boundary may be subjected over its service lifetime. The underlying purpose of 10 CFR 50.61 is to establish requirements for evaluating the fracture toughness of RPV materials to ensure that a licensee's RPV will be protected from failure during a PTS event.
Entergy's exemption request proposes an alternate methodology to evaluate the RT N~T of Linde 80 weld materials in the RPV beltline region at ANO, Unit 1, based on fracture toughness test data found in AREVA TR BAW-2308, Revision 1-A and 2-A (in accordance with
ASTM Standard E1921 and ASME Code Case N-629). This proposed alternate methodology achieves the underlying purpose of 10 CFR Part 50 Appendix G.11.D(i) because it provides an adequate conservative estimate of RPV materials properties and ensures that the pressure-retaining components of the RPV retain adequate margins for safety during any condition of normal operation. The alternate methodology also achieves the underlying purpose of 10 CFR 50.61 (a)(5) because it will ensure that the PTS evaluation developed for the ANO, Unit 1 RPV will continue to be based on an adequately conservative estimate of RPV material properties and ensure that the RPV will be protected from failure during a PTS event.
Accordingly, the NRC has concluded that using the procedures in the ASME Code, Paragraph NB-2331 is not necessary to achieve the underlying purpose of 10 CFR 50.61 (a)(5) and 10 CFR part 50 appendix G.11. D(i). Therefore, the special circumstances required by 10 CFR 50.12(a)(2)(ii) for the granting of an exemption exist.
F. Environmental Considerations.
, The NRC staff determined that the exemption discussed herein meets the eligibility criteria for the categorical exclusion set forth in 10 CFR 51. 22( c)(9) because it is related to a requirement concerning the installation or use of a facility component located within the restricted area, as defined in 10 CFR part 20, and issuance of this exemption involves: (i) No significant hazards consideration, (ii) no significant change in the types or a significant increase in the amounts of any effluents that may be released offsite, and (iii) no significant increase in individual or cumulative occupational radiation exposure. Therefore, in accordance with 10 CFR 51.22(b), no environmental impact statement or environmental assessment need be prepared in connection with the NRC's consideration of this exemption request. The basis for the NRC
staffs determination is discussed as follows with an evaluation against each of the requirements in 10 CFR 51. 22(c)(9)(i)-(iii).
Requirements in 10 CFR 51.22(c)(9)(i)
The NRC evaluated whether the exemption involves no significant hazards consideration using the standards described in 10 CFR 50.92(c), as presented below:
- 1. Does the proposed exemption involve a significant increase in the probability or consequences of an accident previously evaluated?
Response: No.
The exemption would allow the use of alternate methodologies from those specified in Appendix G to 10 CFR part 50, and 10 CFR 50.61, to allow the use of fracture toughness test data for evaluating the integrity of RPV beltline welds. Use of the alternate methodology for determining the initial, unirradiated material reference temperatures of the Linde 80 weld materials present in the RPV beltline region will not result in changes in operation of configuration of the facility. The change in reactor vessel material initial properties will continue to satisfy the intent of 10 CFR 50, Appendix G, and 10 CFR 50.61. The change does not adversely affect accident initiators or pre-cursors, nor alter the design assumptions, conditions, or the manner in which the plant is operated and maintained. The change does not alter or prevent the ability of structures, systems or components from performing their intended function to mitigate the consequences of an initiating event with the assumed acceptance limits. There will be no adverse change to normal plant operating parameters, engineered safety feature actuation setpoints, accident mitigation capabilities, or accident analysis assumptions or inputs.
The change does not affect the source term, containment isolation, or radiological release assumptions used in evaluating the radiological consequences of an accident previously evaluated. Further, the change does not increase the types of amounts of radioactive effluent
that may be released offsite, nor significantly increase individual or cumulative occupational/public radiation exposures.
Therefore, the proposed exemption does not involve a significant increase in the probability or consequences of an accident previously evaluated.
- 2. Does the proposed exemption create the possibility of a new or different kin? of accident from any accident previously evaluated?
Response: No.
The exemption would allow the use of alternate methodologies from those specified in Appendix G to 10 CFR part 50, and 10 CFR 50.61, to allow the use of fracture toughness test data for evaluating the integrity of RPV beltline welds. Use of the alternate methodology for determining the initial, unirradiated material reference temperatures of the Linde 80 weld materials present in the RPV beltline region will not result in changes in operation or configuration of the facility. The change does not impose any new or different requirements or eliminate any existing requiremer:its. The change is consistent with the current safety analysis assumptions and current plant operating practice. No new accident scenarios, transient precursors, failure mechanisms, or limiting single failures are introduced as a result of the proposed change. Equipment important to safety will continue to operate as designed. The change does not result in any event previously deemed incredible being more credible. The change does not result in any adverse conditions or result in any increase in the challenges to safety_ systems.
Therefore, this change does not create the possibility of a new or different kind of acCident from an accident previously evaluated.
- 3. Does the proposed exemption involve a significant reduction in a margin of safety?
Response: No.
The proposed exemption does not alter safety limits, limiting safety system settings, or limiting conditions for operation. The setpoints at which protective actions are initiated are riot altered by the change. There are no new or significant changes to initial conditions contributing to accident severity or consequences. The exemption will not otherwise affect plant protective boundaries, will not cause a release of fission products to the public, nor will it degrade the performance of any other structures, systems or components important to safety.
Therefore, the proposed exemption does not involve a. significant reduction in a margin of safety.
Based on the above evaluation of the standards set forth in 10 CFR 50.92(c), the NRC concludes that the proposed exemption involves no significant hazards consideration.
Accordingly, the requirements of 10 CFR 51.22(c)(9)(i) are met.
Requirements in 10 CFR 51.22(c)(9)(ii-iii)
The proposed exemption does not make any changes to the facility, equipment at the facility, or to fuel or core design. The proposed alternate methodology serves the same purpose as the requirements set forth in.10 CFR 50.61 and 10 CFR part 50, appendix G. Therefore, the NRC concludes that the exemption involves no significant change in the types or a significant increase in the amounts of any effluents that may be released offsite, and that there is no significant increase in individual or cumulative public or occupational radiation exposure.
Therefore, the requirements of 10 CFR 51.22(c)(9)(ii-iii) are met.
Conclusion Based on the above, the NRC concludes that the proposed exemption meets the
eligibility criteria for the categorical exclusion set forth in 10 CFR 51.22(c)(9). Therefore, in accordance with 10 CFR 51.22(b), no environmental impact statement or environmental assessment need be prepared in connection with the NRC's issuance of this exemption.
IV. Conclusions.
Accordingly, the Commission has determined that, pursuant to 10 CFR 50.12(a), the exemption is authorized by law, will not present an undue risk to the public health and safety, and is consistent with the common defense and security. Also, special circumstances are present. Therefore, the Commission hereby grants the licensee an exemption from 10 CFR part 50, appendix G.ll:D(i) and 10 CFR 50.61(a)(5) requirements, in order to use the alternate methodology specified in AREVA TR BAW-2308, Revisions 1-A and 2-A, in lieu of the existing requirement to use Cv and drop weight-b'ased methodologies to evaluate the initial (unirradiated) RT NOT of the Linde 80 weld materials in the RPV beltline region at ANO, Unit 1.
This exemption is effective upon issuance.
th Dated at Rockville, Maryland, this /(() day of March 2015.
For the Nuclear Regulatory Commission.
Michele G. Evans, Director, Division of Operating Reactor Licensing, Office of Nuclear Reactor Regulation.
Letter ML15056A367* Exemption ML15056A368 I *via email **via memo OFFICE NRRIDORL/LPL4-1 /PM NRR/DORL/LPL4-1 /PM NRR/DORL/LPL4-1 /PM NRR/DORL/LPL4-1 /LA NRR/DE/EVIB/BC NAME MWatford* JKlos* AGeorge JBurkhardt SRosenberg**
DATE 3/12/15 3/12/15 3/2/15 2/25/15 8/13/14 OFFICE OGC-NLO NRR/DORL/LPL4-1 /BC NRR/DORL/D NRR/DORL/LPL4-1 /PM NAME Jlindell MMarkley MEvans* AGeorge (BASingal for)
DATE 3/10/15 3/12/15 3/16/15 3/16/15