[Federal Register Volume 83, Number 108 (Tuesday, June 5, 2018)]
[Notices]
[Pages 26111-26112]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2018-11996]


-----------------------------------------------------------------------

NUCLEAR REGULATORY COMMISSION

[NRC-2014-0023]


Effect of LWR Water Environments on the Fatigue Life of Reactor 
Materials

AGENCY: Nuclear Regulatory Commission.

ACTION: NUREG; issuance.

-----------------------------------------------------------------------

SUMMARY: The U.S. Nuclear Regulatory Commission (NRC) is issuing NUREG/
CR-6909, Revision 1, ``Effect of LWR Water Environments on the Fatigue 
Life of Reactor Materials.'' This report summarizes the results of NRC 
research efforts and work performed at Argonne National Laboratory on 
the fatigue of piping and pressure vessel steels in light-water reactor 
(LWR) environments. Revision 1 of this report provides updates and 
improvements to the environmental fatigue correction factor approach 
based on an extensive update to available laboratory fatigue data from 
testing and results available since this report was first published in 
2007. This final document also incorporates changes to address public 
comments provided on the draft of Revision 1 of NUREG/CR-6909.

ADDRESSES: Please refer to Docket ID NRC-2014-0023 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 Website: Go to http://www.regulations.gov and search for Docket ID NRC-2014-0023. Address 
questions about NRC dockets to Jennifer Borges; telephone: 301-287-
9127; email: [email protected]. For technical questions, contact 
the individuals 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 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 Public Document Room (PDR) reference staff at 
1-800-397-4209, 301-415-4737, or by email to [email protected]. The 
ADAMS accession number for each document referenced (if it is available 
in ADAMS) is provided the first time that it is mentioned in this 
document. Revision 1 of NUREG/CR-6909 is available in ADAMS under 
Accession No. ML16319A004.
     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.

FOR FURTHER INFORMATION CONTACT: Robert Tregoning, Office of Nuclear 
Regulatory Research, telephone: 301-415-2324, email: 
[email protected]; or Appajosula Rao, Office of Nuclear 
Regulatory Research, telephone: 301-415-2381, email: 
[email protected], U.S. Nuclear Regulatory Commission, Washington 
DC 20555-0001.

SUPPLEMENTARY INFORMATION: 
    The American Society of Mechanical Engineers Boiler and Pressure 
Vessel Code (Code) provides rules for the design of Class 1 components 
of nuclear power plants. Appendix I to Section III of the Code contains 
fatigue design curves for applicable structural materials. However, the 
effects of LWR water environments are not explicitly addressed by the 
Code design curves. The existing fatigue strain-vs.-life ([epsi]-N) 
data illustrate potentially significant effects of LWR water 
environments on the fatigue resistance of pressure vessel and piping 
steels. Under certain environmental and loading conditions, fatigue 
lives in water relative to those in air can be significantly lower for 
austenitic stainless steels, nickel alloy materials, carbon steels, and 
low-alloy steels. In March 2007, Revision 0 of NUREG/CR-6909 (ADAMS 
Accession No. ML070660620) was issued. That report was the technical 
basis document for NRC Regulatory Guide (RG) 1.207, Revision 0, 
``Guidelines for Evaluating Fatigue Analyses Incorporating the Life 
Reduction of Metal Components Due to the Effects of the Light-Water 
Reactor Environment for New Reactors'' (ADAMS Accession No. 
ML070380586). Revision 0 of NUREG/CR-6909 summarized the work performed 
at Argonne National Laboratory on the fatigue of piping and pressure 
vessel steels in LWR coolant environments. That report evaluated the 
existing laboratory fatigue data to identify the various materials, 
environmental, and loading parameters that influence fatigue crack 
initiation and summarized the effects of key parameters on the fatigue 
lives of pressure vessel and piping steels. The report presented models 
for estimating fatigue lives as a function of material, loading, and 
environmental conditions, and described the environmental fatigue 
correction factor for incorporating the effects of LWR coolant 
environments into Code fatigue evaluations.
    Revision 1 of NUREG/CR-6909 provides updates and improvements to 
the environmental fatigue correction factor approach based on 
additional laboratory fatigue data and other results available since 
2007. On April 17, 2014 (79 FR 21811), a draft of Revision 1 was 
noticed in the Federal Register for public comment under Docket ID NRC-
2014-0023. The public comment period ended on June 2, 2014. The final 
version of Revision 1 of NUREG/CR-6909 reflects changes made to address 
the public comments. Appendix F of the document provides responses to 
the public comments received.
    Revision 1 of NUREG/CR-6909 is the technical basis document for 
Revision 1 of RG 1.207, ``Guidelines for Evaluating the Effects of 
Light-Water Reactor Water Environments in Fatigue Analyses of Metal 
Components'' (ADAMS Accession No. ML16315A130). This RG describes 
methods and procedures that the NRC staff considers acceptable for use 
in determining the acceptable fatigue lives

[[Page 26112]]

of components evaluated by a cumulative usage factor calculation in 
accordance with the fatigue design provisions in Section III, ``Rules 
for Construction of Nuclear Power Plant Components,'' of the American 
Society of Mechanical Engineers Boiler and Pressure Vessel Code to 
account for the effects of LWR water environments. The NRC is issuing 
Revision 1 of RG 1.207 concurrently with Revision 1 of NUREG/CR-6909 
under a separate notice associated with Docket ID NRC-2014-0244.
    The NRC notes that Revision 1 of RG 1.207 was issued in draft form 
as a draft RG (DG-1309). The NRC published a notice of the availability 
of DG-1309 in the Federal Register on November 24, 2014 (79 FR 69884), 
under Docket ID NRC-2014-0244, with a public comment period that closed 
on January 24, 2015. Public comments on DG-1309 and the NRC staff's 
responses are available in ADAMS under Accession No. ML16315A127.

    Dated at Rockville, Maryland, this 30th day of May 2018.

    For the Nuclear Regulatory Commission.
Thomas Boyce,
Chief, Regulatory Guidance and Generic Issues Branch, Division of 
Engineering, Office of Nuclear Regulatory Research.
[FR Doc. 2018-11996 Filed 6-4-18; 8:45 am]
 BILLING CODE 7590-01-P