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Industry Codes and Standards; Amended Requirements

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Information about this document as published in the Federal Register.

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Nuclear Regulatory Commission.


Final rule; correcting amendment.


This document corrects a final rule appearing in the Federal Register on September 22, 1999 (64 FR 51370), and reflected in the 2000 revision of the Code of Federal Start Printed Page 16391Regulations. This action corrects the final rule by specifying the use of a flaw length sizing criterion for reactor vessel qualification. This correction is necessary for clarity and consistency in the regulations.


Effective March 26, 2001.

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Donald G. Naujock [telephone (301) 415-2767, e-mail] of the Office of Nuclear Reactor Regulation, U.S. Nuclear Regulatory Commission, Washington, DC 20555-0001.

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On September 22, 1999 (64 FR 51370), a final rule “ Industry Codes and Standards; Amended Requirements” was published in the Federal Register. The purpose of the rule was to permit the use of improved methods in § 50.55a for construction, inservice inspection and inservice testing of nuclear power plant components. The rule, in part, permits licensees to modify implementation of Appendix VIII to Section XI of the American Society of Mechanical Engineers (ASME) Boiler and Pressure Vessel Code (the Code) provided that certain provisions specified in the regulations were followed. Paragraph (b)(2)(xv)(C) addressed the provisions regarding application of Supplement 4 to Appendix VIII. After the final rule was published, an error was discovered in paragraph (b)(2)(xv)(C)(1). Paragraph (b)(2)(xv)(C)(1) properly stipulated the use of a flaw depth sizing criterion, but failed to specify the use of an appropriate flaw length sizing criterion for reactor vessel qualification. It has always been the intent of the NRC to require the use of both depth and length criteria for flaw sizing qualification. This intent is evident in paragraph (b)(2)(xv)(F)(2) of § 50.55a which stipulates that length sizing qualifications must satisfy the acceptance criterion of Appendix VIII, Supplement 4.

With respect to a length sizing criterion, it was the intent of the NRC to specify in the final rule, the use of 0.75 inch root mean square (RMS) length sizing criterion in lieu of Appendix VIII, Supplement 4, Subparagraph 3.2(b). Since 1995, the NRC has supported the 0.75 inch RMS numeric value as an appropriate length sizing criterion for reactor vessels. This numeric value is the same as the length sizing criterion referenced in (b)(2)(xv)(E)(3).

Need for Correction

As published, the Federal Register and the Code of Federal Regulations contain an error which is misleading and needs to be corrected.

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List of Subjects in 10 CFR Part 50

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For the reasons set out in the preamble and under the authority of the Atomic Energy Act of 1954, as amended, the Energy Reorganization Act of 1974, as amended, and

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1. The authority citation for Part 50 continues to read as follows:

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Authority: Sections 102, 103, 104, 105, 161, 182, 183, 186, 189, 68 Stat. 936, 937, 938, 948, 953, 954, 955, 956, as amended, sec. 234, 83 Stat. 444, as amended (42 U.S.C. 2132, 2133, 2134, 2135, 2201, 2232, 2233, 2236, 2239, 2282); secs. 201, as amended, 202, 206, 88 Stat. 1242, as amended, 1244, 1246 (42 U.S.C. 5841, 5842, 5846).

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Section 50.7 also issued under Pub. L. 95-601, sec. 10, 92 Stat. 2951 (42 U.S.C. 5851). Section 50.10 also issued under secs. 101, 185, 68 Stat. 955 as amended (42 U.S.C. 2131, 2235), sec. 102, Pub. L. 91-190, 83 Stat. 853 (42 U.S.C. 4332). Sections 50.13, 50.54(dd), and 50.103 also issued under sec. 108, 68 Stat. 939, as amended (42 U.S.C. 2138). Sections 50.23, 50.35, 50.55, and 50.56 also issued under sec. 185, 68 Stat. 955 (42 U.S.C. 2235). Sections 50.33a, 50.55a and Appendix Q also issued under sec. 102, Pub. L. 91-190, 83 Stat. 853 (42 U.S.C. 4332). Sections 50.34 and 50.54 also issued under sec. 204, 88 Stat. 1245 (42 U.S.C. 5844). Sections 50.58, 50.91, and 50.92 also issued under Pub. L. 97-415, 96 Stat. 2073 (42 U.S.C. 2239). Section 50.78 also issued under sec. 122, 68 Stat. 939 (42 U.S.C. 2152). Sections 50.80-50.81 also issued under sec. 184, 68 Stat. 954, as amended (42 U.S.C. 2234). Appendix F also issued under sec. 187, 68 Stat. 955 (42 U.S.C. 2237).

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2. In § 50.55a, paragraph (b)(2)(xv)(C)(

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Codes and standards.
* * * * *

(b) * * *

(2) * * *

(xv) * * *

(C) * * *

(1) A depth sizing requirement of 0.15 inch RMS shall be used in lieu of the requirement in Subparagraph 3.2(a), and a length sizing requirement of 0.75 inch RMS shall be used in lieu of the requirement in Subparagraph 3.2(b).

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Dated at Rockville, Maryland, this 20th day of March, 2001.

For the Nuclear Regulatory Commission.

Michael T. Lesar,

Chief, Rules and Directives Branch, Division of Administrative Services, Office of Administration.

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[FR Doc. 01-7352 Filed 3-23-01; 8:45 am]