[Federal Register Volume 70, Number 30 (Tuesday, February 15, 2005)]
[Pages 7777-7778]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 05-2853]



Draft Regulatory Guide; Issuance, Availability

    The U.S. Nuclear Regulatory Commission (NRC) has issued for public 
comment a draft revision to an existing guide in the agency's 
Regulatory Guide Series. This series has been developed to describe and 
make available to the public such information as methods that are 
acceptable to the NRC staff for implementing specific parts of the 
NRC's regulations, techniques that the staff uses in evaluating 
specific problems or postulated accidents, and data that the staff 
needs in its review of applications for permits and licenses.
    The draft Revision 2 of Regulatory Guide 1.92, entitled ``Combining 
Modal Responses and Spatial Components in Seismic Response Analysis,'' 
is temporarily identified by its task number, DG-1127, which should be 
mentioned in all related correspondence. Like its predecessors, the 
proposed revision describes methods that the NRC staff finds acceptable 
for complying with the NRC's regulatory requirements in Criterion 2, 
``Design Bases for Protection Against Natural Phenomena,'' as it 
appears in Appendix A, ``General Design Criteria for Nuclear Power 
Plants,'' to Title 10, Part 50, of the Code of Federal Regulations (10 
CFR Part 50). Specifically, Criterion 2 requires, in part, that nuclear 
power plant (NPP) structures, systems, and components (SSCs) that are 
important to safety must be designed to withstand the effects of 
natural phenomena (such as earthquakes) without losing their capability 
to perform their respective safety functions.
    For several decades, the nuclear industry fulfilled Criterion 2 
using the response spectrum method and the time history method for 
seismic analysis and design of NPP SSCs. Then, in 1976, the NRC issued 
Revision 1 of Regulatory Guide 1.92, which described then-up-to-date 
guidance for using the response spectrum and time history methods. 
Since that time, research in the United States has resulted in improved 
methods that yield more accurate estimates of SSC seismic response, 
while reducing unnecessary conservatism. In view of those improvements, 
DG-1127 describes methods that the NRC staff finds acceptable for 
combining modal responses and spatial components in seismic response 
analysis. The NRC staff initially published Revision 2 of Regulatory 
Guide 1.92 as DG-1108, dated August 2001. The staff subsequently 
considered stakeholders' feedback on DG-1108, and incorporated the 
necessary changes in DG-1127.
    The NRC staff is soliciting comments on Draft Regulatory Guide DG-
1127, and specifically on the new regulatory position regarding 
residual rigid response of the missing mass modes, as described in 
Sections 1.4 and 1.5 of DG-1127. Comments may be accompanied by 
relevant information or supporting data. Please mention DG-1127 in the 
subject line of your comments. Comments on this draft regulatory guide 
submitted in writing or in electronic form will be made available to 
the public in their entirety in the NRC's Agencywide Documents Access 
and Management System (ADAMS). Personal information will not be removed 
from your comments. You may submit comments by any of the following 
    Mail comments to: Rules and Directives Branch, Office of 
Administration, U.S. Nuclear Regulatory Commission, Washington, DC 
    E-mail comments to: [email protected]. You may also submit comments 
via the NRC's rulemaking Web site at http://ruleforum.llnl.gov. Address 
questions about our rulemaking Web site to Carol A. Gallagher (301) 
415-5905; e-mail [email protected].
    Hand-deliver comments to: Rules and Directives Branch, Office of 
Administration, U.S. Nuclear Regulatory Commission, 11555 Rockville 
Pike, Rockville, Maryland 20852, between 7:30 a.m. and 4:15 p.m. on 
Federal workdays.
    Fax comments to: Rules and Directives Branch, Office of 
Administration, U.S. Nuclear Regulatory Commission at (301) 415-5144.
    Requests for technical information about draft regulatory guide DG-
1127 may be directed to Dr. T.Y. Chang, at (301) 415-6450 or via e-mail 
to [email protected].
    Comments would be most helpful if received by April 15, 2005. 
Comments received after this date will be considered if it is practical 
to do so, but the NRC is able to ensure consideration only for comments 
received on or before

[[Page 7778]]

this date. Although a time limit is given, comments and suggestions in 
connection with items for inclusion in guides currently being developed 
or improvements in all published guides are encouraged at any time.
    Electronic copies of the draft regulatory guide are available 
through the NRC's public Web site under Draft Regulatory Guides in the 
Regulatory Guides document collection of the NRC's Electronic Reading 
Room at http://www.nrc.gov/reading-rm/doc-collections/. Electronic 
copies are also available in the NRC's Agencywide Documents Access and 
Management System (ADAMS) at http://www.nrc.gov/reading-rm/adams.html, 
under Accession ML050230006. Note, however, that the NRC has 
temporarily suspended public access to ADAMS so that the agency can 
complete security reviews of publicly available documents and remove 
potentially sensitive information. Please check the NRC's Web site for 
updates concerning the resumption of public access to ADAMS.
    In addition, regulatory guides are available for inspection at the 
NRC's Public Document Room (PDR), which is located at 11555 Rockville 
Pike, Rockville, Maryland; the PDR's mailing address is USNRC PDR, 
Washington, DC 20555-0001. The PDR can also be reached by telephone at 
(301) 415-4737 or (800) 397-4205, by fax at (301) 415-3548; and by e-
mail to [email protected]. Requests for single copies of draft or final 
guides (which may be reproduced) or for placement on an automatic 
distribution list for single copies of future draft guides in specific 
divisions should be made in writing to the U.S. Nuclear Regulatory 
Commission, Washington, DC 20555-0001, Attention: Reproduction and 
Distribution Services Section; by e-mail to [email protected]; or by 
fax to (301) 415-2289. Telephone requests cannot be accommodated.
    Regulatory guides are not copyrighted, and Commission approval is 
not required to reproduce them.
(5 U.S.C. 552(a)).

    Dated at Rockville, Maryland, this 3rd day of February, 2005.

    For the U.S. Nuclear Regulatory Commission.
Michael E. Mayfield,
Director, Division of Engineering Technology, Office of Nuclear 
Regulatory Research.
[FR Doc. 05-2853 Filed 2-14-05; 8:45 am]