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Instrument Sensing Lines

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Nuclear Regulatory Commission.


Regulatory guide, issuance.


The U.S. Nuclear Regulatory Commission (NRC) is issuing Revision 2 to Regulatory Guide (RG) 1.151, “Instrument Sensing Lines.” RG 1.151 describes an approach that is acceptable to the staff of the NRC to meet regulatory requirements for instrument sensing lines in nuclear power plants. The RG would endorse, with certain exceptions, standards that were updated and corrected subsequent to the last time the NRC endorsed them in RG 1.151. More information on updates can be found in the Supplementary Information section below.


Revision 2 to RG 1.151 is available on February 13, 2020.


Please refer to Docket ID NRC-2019-0041 when contacting the NRC about the availability of information regarding this document. You may obtain publicly-available information related to this document using one of the following methods:

  • Federal Rulemaking Website: Go to and search for Docket ID NRC-2019-0041. Address questions about NRC docket IDs in to Jennifer Borges; telephone: 301-287-9127; email: For technical questions, contact the individual(s) listed in the FOR FURTHER INFORMATION CONTACT section of this document.
  • NRC's Agencywide Documents Access and Management System (ADAMS): You may obtain publicly-available documents online in the ADAMS Public Documents collection at​reading-rm/​adams.html. To begin the search, select “Begin Web-based ADAMS Search.” For problems with ADAMS, please contact the NRC's Public Document Room (PDR) reference staff at 1-800-397-4209, 301-415-4737, or by email to Revision 2 to RG 1.151 and the regulatory analysis may be found in ADAMS under Accession Nos. ML19156A129 and ML18158A301, respectively.
  • NRC's PDR: You may examine and purchase copies of public documents at the NRC's PDR, Room O1-F21, One White Flint North, 11555 Rockville Pike, Rockville, Maryland 20852.

Regulatory guides are not copyrighted, and NRC approval is not required to reproduce them.

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David Dawood, telephone: 301-415-2389, email:; Yaguang Yang, telephone: 301-415-0655, email:; and Michael Eudy, telephone: 301-415-3104, email: All are staff members of the Office of Nuclear Regulatory Research, U.S. Nuclear Regulatory Commission, Washington, DC 20555-0001.

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I. Discussion

The NRC is issuing a revision to an existing guide in the NRC's “Regulatory Guide” series. This series was developed to describe and make available to the public information regarding methods that are acceptable to the NRC staff for implementing specific parts of the agency's regulations, techniques that the NRC staff uses in evaluating specific issues or postulated events, and data that the NRC staff needs in its review of applications for permits and licenses.

Revision 2 of RG 1.151 was issued with a temporary identification of Draft Regulatory Guide, DG-1352. Revision 2 of RG 1.151 describes an approach that is acceptable to the staff of the NRC to meet regulatory requirements for instrument sensing lines in nuclear power plants. It endorses, with certain exceptions, American National Standards Institute/International Society of Automation (ANSI/ISA)-67.02.01-2014, “Nuclear Safety-Related Instrument Sensing Line Piping and Tubing Standard for Use in Nuclear Start Printed Page 8327Power Plants” and it determines that the Institute of Electrical and Electronic Engineers (IEEE) Standard (Std.) 622-1987, “IEEE Recommended Practice for the Design and Installation of Electric Heat Tracing Systems for Nuclear Power Generating Systems,” reaffirmed in 1994, is acceptable for use. The revision of ANSI/ISA-67.02.01 previously endorsed by the NRC in RG 1.151 was revised and corrected by ANSI/ISA in 2014. In addition, this RG revision discusses recent operating experience, as described in NRC Information Notice (IN) 2013-12, “Improperly Sloped Instrument Sensing Lines,” dated July 3, 2013.

II. Additional Information

The NRC published a notice of the availability of DG-1352 in the Federal Register on February 8, 2019 (84 FR 2934) for a 60-day public comment period. The public comment period closed on April 9, 2019 and the NRC received three comment documents. Public comments on DG-1352 and the staff responses to the public comments are available under ADAMS under Accession No. ML19156A128.

III. Congressional Review Act

This RG is a rule as defined in the Congressional Review Act (5 U.S.C. 801-808). However, the Office of Management and Budget has not found it to be a major rule as defined in the Congressional Review Act.

IV. Backfitting and Issue Finality

Revision 2 of RG 1.151 describes an approach that is acceptable to the NRC staff for applicants and licensees under 10 CFR parts 50 and 52 to meet regulatory requirements for instrument sensing lines in nuclear power plants. The issuance of this regulatory guide does not constitute backfitting as defined in 10 CFR 50.109, “Backfitting,” and as described in NRC Management Directive 8.4, “Management of Backfitting, Forward Fitting, Issue Finality, and Information Requests,” or affect issue finality of any approval issued under 10 CFR part 52, “Licenses, Certificates, and Approvals for Nuclear Power Plants,” because, as explained in this regulatory guide, applicants and licensees are not required to comply with the positions set forth in this regulatory guide.

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Dated at Rockville, Maryland, this 7th day of February, 2020.

For the Nuclear Regulatory Commission.

Robert Roche-Rivera,

Acting Chief, Regulatory Guidance and Generic Issues Branch, Division of Engineering, Office of Nuclear Regulatory Research.

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[FR Doc. 2020-02874 Filed 2-12-20; 8:45 am]